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Literature involving Thellungiella
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v 2 Modified: August 01 2017. |
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This page is a collection of all papers with "Thellungiella" or "Eutrema" (except E. japonica - wasabi) or "Schrenkiella" in the title (or keywords or abstract in some cases) that show up in a Web of Science searches. It is probably not complete; please email thellungiella.org (from the link in the header) with additions. In addition to this on-line version, a text file is downloadable from the Literature link in the Menu to the left. A zipped Endnote-generated xml file - also downloadable - can be imported into Endnote, Papers, Mendeley and other reference managers.[N.B. - In the interests of (my) time, no editing or formatting of this list has been done.]
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Puccinellia tenuiflora is a typical salt-excluding halophytic grass with excellent salt tolerance. Plasma membrane Na+/H+ transporter SOS1, HKT-type protein and tonoplast Na+/H+ antiporter NHX1 are key Na+ transporters involved in plant salt tolerance. Based on our previous research, we had proposed a function model for these transporters in Na+ homeostasis according to the expression of PtSOS1 and Na+, K+ levels in P. tenuiflora responding to salt stress. Here, we analyzed the expression patterns of PtSOS1, PtHKT1; 5, and PtNHX1 in P. tenuiflora under 25 and 150 mM NaCl to further validate this model by combining previous physiological characteristics. Results showed that the expressions of PtSOS1 and PtHKT1; 5 in roots were significantly induced and peaked at 6 h under both 25 and 150 mM NaCl. Compared to the control, the expression of PtSOS1 significantly increased by 5.8-folds, while that of PtHKT1; 5 increased only by 1.2-folds in roots under 25 mM NaCl; on the contrary, the expression of PtSOS1 increased by 1.4-folds, whereas that of PtHKT1; 5 increased by 2.2-folds in roots under 150 mM NaCl. In addition, PtNHX1 was induced instantaneously under 25 mM NaCl, while its expression was much higher and more persistent in shoots under 150 mM NaCl. These results provide stronger evidences for the previous hypothesis and extend the model which highlights that SOS1, HKT1; 5, and NHX1 synergistically regulate Na+ homeostasis by controlling Na+ transport systems at the whole-plant level under both lower and higher salt conditions. Under mild salinity, PtNHX1 in shoots compartmentalized Na+ into vacuole slowly, and vacuole potential capacity for sequestering Na+ would enhance Na+ loading into the xylem of roots by PtSOS1 through feedback regulation; and consequently, Na+ could be transported from roots to shoots by transpiration stream for osmotic adjustment. While under severe salinity, Na+ was rapidly sequestrated into vacuoles of mesophyll cells by PtNHX1 and the vacuole capacity became saturated for sequestering more Na+, which in turn regulated long-distance Na+ transport from roots to shoots. As a result, the expression of PtHKT1; 5 was strongly induced so that the excessive Na+ was unloaded from xylem into xylem parenchyma cells by PtHKT1; 5.
Wang, J., Q. Zhang, et al. (2017) Genome-Wide Analysis of Gene Expression Provides New Insights into Cold Responses in Thellungiella salsuginea Frontiers in Plant Science 8: 713 10.3389/fpls.2017.00713Low temperature is one of the major environmental stresses that affects plant growth and development, and leads to decrease in crop yield and quality. Thellungiella salsuginea (salt cress) exhibits high tolerance to chilling, is an appropriate model to investigate the molecular mechanisms of cold tolerance. Here, we compared transcription changes in the roots and leaves of T. salsuginea under cold stress using RNA-seq. We identified 2,782 and 1,430 differentially expressed genes (DEGs) in leaves and roots upon cold treatment, respectively. The expression levels of some genes were validated by quantitative real-time-PCR (qRT-PCR). Among these DEGs, 159 (11.1%) genes in roots and 232 (8.3%) genes in leaves were annotated as various types of transcription factors. We found that five aquaporin genes (three TIPs, one PIPs, and one NIPs) responded to cold treatment. In addition, the expression of COR47, ICE1, and CBF1 genes of DREB1/CBF-dependent cold signaling pathway genes altered in response to low temperature. KEGG pathway analysis indicated that these cold regulated genes were enriched in metabolism, photosynthesis, circadian rhythm, and transcriptional regulation. Our findings provided a complete picture of the regulatory network of cold stress response in T. salsuginea. These cold-responsive genes could be targeted for detail functional study and utilization in crop cold tolerance improvement.
Wang, D., S. Lv, et al. (2017) Roles, Regulation, and Agricultural Application of Plant Phosphate Transporters Frontiers in Plant Science 8: 817 10.3389/fpls.2017.00817Phosphorus (P) is an essential mineral nutrient for plant growth and development. Low availability of inorganic phosphate (orthophosphate; Pi) in soil seriously restricts the crop production, while excessive fertilization has caused environmental pollution. Pi acquisition and homeostasis depend on transport processes controlled Pi transporters, which are grouped into five families so far: PHT1, PHT2, PHT3, PHT4, and PHT5. This review summarizes the current understanding on plant PHT families, including phylogenetic analysis, function, and regulation. The potential application of Pi transporters and the related regulatory factors for developing genetically modified crops with high phosphorus use efficiency (PUE) are also discussed in this review. At last, we provide some potential strategies for developing high PUE crops under salt or drought stress conditions, which can be valuable for improving crop yields challenged by global scarcity of water resources and increasing soil salinization.
Sonah, H., R. K. Deshmukh, et al. (2017) Analysis of aquaporins in Brassicaceae species reveals high level of conservation and dynamic role against biotic and abiotic stress in canola Scientific Reports 7: 2771 10.1038/s41598-017-02877-9Aquaporins (AQPs) are of vital importance in the cellular transport system of all living organisms. In this study, genome-wide identification, distribution, and characterization of AQPs were determined in Arabidopsis lyrata, Capsella grandiflora, C. rubella, Eutrema salsugineum, Brassica rapa, B. oleracea, and B. napus (canola). Classification and phylogeny of AQPs revealed the loss of XIPs and NIP-IIIs in all species. Characterization of distinctive AQP features showed a high level of conservation in spacing between NPA-domains, and selectivity filters. Interestingly, TIP3s were found to be highly expressed in developing seeds, suggesting their role in seed desiccation. Analysis of available RNA-seq data obtained under biotic and abiotic stresses led to the identification of AQPs involved in stress tolerance mechanisms in canola. In addition, analysis of the effect of ploidy level, and resulting gene dose effect performed with the different combinations of Brassica A and C genomes revealed that more than 70% of AQPs expression were dose-independent, thereby supporting their role in stress alleviation. This first indepth characterization of Brassicaceae AQPs highlights transport mechanisms and related physiological processes that could be exploited in breeding programs of stress-tolerant cultivars.
Shang, H., Y. Li, et al. (2017) Characterization of the complete chloroplast genome of two sister species of salt cress (Brassicaceae) Conservation Genetics Resources 9: 237-239. 10.1007/s12686-016-0661-5The complete chloroplast genomes from two salt cresses (Eutrema halophilum and Eutrema botschantzevii), plants known to tolerate high levels of salt, are determined in this study. The genome sizes were 153,312 and 153,280 bp. Both genomes containing a large single copy region (LSC) of 84k bp and a small single copy region (SSC) of 18k bp, which were separated by a pair of 25,928 bp inverted repeat regions (IRs). The cpDNA contained 125 genes, including 87 protein-coding genes (79 PCG species), 30 tRNA genes (25 tRNA species) and eight ribosomal RNA genes (4 rRNA species). The most of gene species occur as a single copy, while 17 gene species occur in double copies. These complete chloroplast genomes can be subsequently used for population studies of Eutrema, and provide valuable insight into conservation and restoration efforts for this endangered species.
Shamustakimova, A. O., T. G. Leonova, et al. (2017) Cold stress increases salt tolerance of the extremophytes Eutrema salsugineum (Thellungiella salsuginea) and Eutrema (Thellungiella) botschantzevii Journal of Plant Physiology 208: 128-138. 10.1016/j.jptph.2016.10.0009A comparative study was performed to analyze the effect of cold acclimation on improving the resistance of Arabidopsis thaliana, Eutrema salsugineum and Eutrema botschantzevii plants to salt stress. Shoot FW, sodium and potassium accumulation, metabolite content, expression of proton pump genes VABI, VAB2,VAB3, VP2, HA3 and genes encoding ion transporters SOS1, HICTI, NHXI, NHX2, NHX5 located in the plasma membrane or tonoplast were determined just after the cold treatment and the onset of the salt stress. In the same cold -acclimated E. botschantzevii plants, the Na+ concentration after salt treatment was around 80% lower than in non -acclimated plants, whereas the k(+) concentration was higher. As a result of cold acclimation, the expression of, VAB3, NHX2, NHX5 genes and of 5051, VP2, HA3 genes was strongly enhanced in E. botschantzevii and in E. salsugineum plants correspondently. None of the 10 genes analyzed showed any expression change in A. thaliana plants after cold acclimation. Altogether, the results indicate that cold -induced adaptation to subsequent salt stress exists in the extremophytes E. botschantzevii and to a lesser extend in E. salsugineum and is absent in Arabidopsis. This phenomenon may be attributed to the increased expression of ion transporter genes during cold acclimation in the Eutrema species. (C) 2016 Elsevier GmbH. All rights reserved.
Nawaz, I., M. Iqbal, et al. (2017) Salt and heavy metal tolerance and expression levels of candidate tolerance genes among four extremophile Cochlearia species with contrasting habitat preferences Science of the Total Environment 584: 731-741. 10.1016/j.scitonv.2017.01.111To test the concept of a general "mineral stress tolerance", we compared four extremophile Cochlearia species for salt (NaCI), zinc (Zn) and cadmium (Cd) tolerance and accumulation, and for expression of candidate tolerance genes for salt and Zn tolerance. Salt tolerance decreased in the order C. anglica > C. x hollandica > C. danica > C. pyrenaica, corresponding with the average salinity levels in the species' natural environments. The glycophytic metallophyte, C pyrenaica, showed a relatively high level of salt tolerance, compared to other glycophytic Brassicaceae. Salt tolerance was positively correlated with HKT1 expression and the K+ concentration in roots under salt exposure, but uncorrelated with the Na+ concentrations in roots and shoots. All the species accumulated Na+ primarily in their leaves, and exhibited a high NHX1 expression in leaves, in comparison with other glycophytic Brassicaceae, suggesting that salt tolerance in Cochlearia is based on an efficient vacuolar sequestration of Na+ in leaves. The metallicolous C pyrenaica population was hypertolerant to Zn, but not to Cd, in comparison With the other Cochlearia species. All the Cochlearia species accumulated Zn and Cd primarily in roots, and showed high levels of Cd and Zn tolerance, with unusually low rates of metal accumulation, in comparison with non-metallophytes, or non-metallicolous metallophyte populations, of species belonging to other genera or families. Although Cochlearia, as a genus, shows relatively high levels of tolerance to both salt and heavy metals, this is most probably not due to a common 'mineral stress tolerance' mechanism. (C) 2017 Elsevier B.V. All rights reserved.
Mishra, A. and B. Tanna. (2017) Halophytes: Potential Resources for Salt Stress Tolerance Genes and Promoters Frontiers in Plant Science 8: 829 10.3389/fpls.2017.00829Halophytes have demonstrated their capability to thrive under extremely saline conditions and thus considered as one of the best germplasm for saline agriculture. Salinity is a worldwide problem, and the salt affected areas are increasing day-by-day because of scanty rainfall, poor irrigation system, salt ingression, water contamination, and other environmental factors. The salinity stress tolerance mechanism is a very complex phenomenon, and some pathways are coordinately linked for imparting salinity tolerance. Though a number of salt responsive genes have been reported from the halophytes, there is always a quest for promising stress-responsive genes that can modulate plant physiology according to the salt stress. Halophytes such as Aeluropus, Mesembryanthemum, Suaeda, Atriplex, Thellungiella, Cakile, and Salicornia serve as a potential candidate for the salt-responsive genes and promoters. Several known genes like antiporters (NHX, SOS, HKT, VTPase), ion channels (Cl-,Ca2+, aquaporins), antioxidant encoding genes (APX, CAT, GST, BADH, SOD) and some novel genes such as USP, SDR1, SRP etc. were isolated from halophytes and explored for developing stress tolerance in the crop plants (glycophytes). It is evidenced that stress triggers salt sensors that lead to the activation of stress tolerance mechanisms which involve multiple signaling proteins, up- or down regulation of several genes, and finally the distinctive or collective effects of stress-responsive genes. In this review, halophytes are discussed as an excellent platform for salt responsive genes which can be utilized for developing salinity tolerance in crop plants through genetic engineering.
Iwase, A., H. Harashima, et al. (2017) WIND1 Promotes Shoot Regeneration through Transcriptional Activation of ENHANCER OF SHOOT REGENERATION1 in Arabidopsis Plant Cell 29: 54-69. 10.1105/tpc.16.00623Many plant species display remarkable developmental plasticity and regenerate new organs after injury. Local signals produced by wounding are thought to trigger organ regeneration but molecular mechanisms underlying this control remain largely unknown. We previously identified an AP2/ERF transcription factor WOUND INDUCED DEDIFFERENTIATION1 (WIND1) as a central regulator of wound-induced cellular reprogramming in plants. In this study, we demonstrate that WIND1 promotes callus formation and shoot regeneration by upregulating the expression of the ENHANCER OF SHOOT REGENERATION1 (ESR1) gene, which encodes another AP2/ERF transcription factor in Arabidopsis thaliana. The esr1 mutants are defective in callus formation and shoot regeneration; conversely, its overexpression promotes both of these processes, indicating that ESR1 functions as a critical driver of cellular reprogramming. Our data show that WIND1 directly binds the vascular system-specific and wound-responsive cis-element-like motifs within the ESR1 promoter and activates its expression. The expression of ESR1 is strongly reduced in WIND1-SRDX dominant repressors, and ectopic overexpression of ESR1 bypasses defects in callus formation and shoot regeneration in WIND1-SRDX plants, supporting the notion that ESR1 acts downstream of WIND1. Together, our findings uncover a key molecular pathway that links wound signaling to shoot regeneration in plants.
Huang, Y., D.-H. Chen, et al. (2017) Conservation and diversification of polycomb repressive complex 2 (PRC2) proteins in the green lineage Briefings in Functional Genomics 16: 106-119. 10.1093/bfgp/elw007The polycomb group (PcG) proteins are key epigenetic regulators of gene expression in animals and plants. They act in multiprotein complexes, of which the best characterized is the polycomb repressive complex 2 (PRC2), which catalyses the tri-methylation of histone H3 at lysine 27 (H3K27me3) at chromatin targets. In Arabidopsis thaliana, PRC2 proteins are involved in the regulation of diverse developmental processes, including cell fate determination, vegetative growth and development, flowering time control and embryogenesis. Here, we systematically analysed the evolutionary conservation and diversification of PRC2 components in lower and higher plants. We searched for and identified PRC2 homologues from the sequenced genomes of several green lineage species, from the unicellular green alga Ostreococcus lucimarinus to more complicated angiosperms. We found that some PRC2 core components, e.g. E(z), ESC/FIE and MSI/p55, are ancient and have multiplied coincidently with multicellular evolution. For one component, some members are newly formed, especially in the Cruciferae. During evolution, higher plants underwent copy number multiplication of various PRC2 components, which occurred independently for each component, without any obvious co-amplification of PRC2 members. Among the amplified members, usually one was well-conserved and the others were more diversified. Gene amplification occurred at different times for different PcG members during green lineage evolution. Certain PRC2 core components or members of them were highly conserved. Our study provides an insight into the evolutionary conservation and diversification of PcG proteins and may guide future functional characterization of these important epigenetic regulators in plants other than Arabidopsis.
Hara, M., T. Endo, et al. (2017) The role of hydrophobic amino acids of K-segments in the cryoprotection of lactate dehydrogenase by dehydrins Journal of Plant Physiology 210: 18-23. 10.1016/j.jplph.2016.12.003Dehydrins, which are group 2 late embryogenesis abundant (LEA) proteins, accumulate in plants during the development of the embryo and exposure to abiotic stresses including low temperature. Dehydrins exhibit cryoprotection of freezing-sensitive enzymes, e.g. lactate dehydrogenase (LDH). Although it has been reported that K-segments conserved in dehydrins are related to their cryoprotection activity, it has not been determined which sequence features of the K-segments contribute to the cryoprotection. A cryoprotection assay using LDH indicated that 13 K-segments including 12 K-segments found in Arabidopsis dehydrins and a typical K-segment (TypK, EKKGIMEKIKEKLPG) derived from the K-segments of many plants showed similar cryoprotective activities. Mutation of the TypK sequence demonstrated that hydrophobic amino acids were clearly involved in preventing the cryoinactivation, cryoaggregation, and cryodenaturation of LDH. We propose that the cryoprotective activities of dehydrins may be made possible by the hydrophobic residues of the K-segments. (C) 2016 Elsevier GmbH. All rights reserved.
Hao, G., C. Zhang, et al. (2017) Eutrema giganteum (Brassicaceae), a new species from Sichuan, southwest China Phytokeys 15-26. 10.3897/phytokeys.82.12329Eutrema giganteum (Brassicaceae), a new species from Hengduan Mountains in Sichuan Province, southwest China, is described, and its relationships to the closely related E. yunnanense is discussed based on morphological, cytological, and molecular data. It is similar morphologically to E. yunnanense but is readily distinguished by having robust (vs. slender), erect (vs. decumbent), and branched (vs. mostly simple), and rather tall stems (60-110 cm vs. 20-60 cm); curved (vs. straight), smooth (vs. torulose), and shorter fruit (5-8 mm vs. 8-15 mm); and fewer ovules per ovary (1-4 vs. 6-10). All examined individuals from different populations of E. giganteum clustered into a single clade sister to E. yunnanense in phylogenetic analyses using the combined nuclear ITS and plastid DNA datasets. Our cytological studies revealed that the chromosome number of E. giganteum is 2n = 44, with a genome size of 1160 (+/- 8) Mb, while that of E. yunnanense is 2n = 28, with a genome size of 718 (+/- 15) Mb. Multiple lines of evidence support the recognition of E. giganteum as a distinct species well differentiated from E. yunnanense.
Hao, G., I. A. Al-Shehbaz, et al. (2017) An integrative study of evolutionary diversification of Eutrema (Eutremeae, Brassicaceae) Botanical Journal of the Linnean Society 184: 204-223.In this comprehensive study of Eutrema (Brassicaceae), five DNA markers [nuclear internal transcribed spacer (ITS) and plastid matK, rbcL, trnH-psbA and trnL-F] were sequenced for 183 individuals of 32 species of Eutrema s. l. and the closely related members of tribe Eutremeae, Chalcanthus and Pegaeophyton. The genetic-gap analyses showed that five previously described taxa are polyphyletic, and we identified 37 potential species units or independently evolving lineages. Further phylogenetic analyses were based on sequence variations of these five-marker barcodes for the typical representatives of all species units and they showed that the monospecific Chalcanthus, Pegaeophyton nepalense and P. scapiflorum are nested in and should be transferred to Eutrema, whereas P. watsonii was sister to Pycnoplinthopsis of tribe Euclidieae. Three clades were recovered in the expanded Eutrema based on the plastid DNA phylogenetic trees. However, phylogenetic relationships of some species in two later diverging clades are incongruent between ITS and plastid DNA trees and within them. These incongruences suggest possible hybridizations, incomplete lineage sorting or parallel evolution during recent species diversification in the genus. Furthermore, molecular dating and biogeographical analyses suggested that the recircumscribed Eutrema s. l. probably originated in eastern Asia, probably in central China. The origin and early divergence between three major clades of Eutrema, which are distributed mainly in central China, central Asia and the Qinghai-Tibetan Plateau (QTP), occurred in the Late Oligocene and Early Miocene, probably reflecting the extensive plateau uplifts and Asian aridification during that period. However, further diversification events from the Late Miocene to the Pleistocene, especially in response to the later QTP uplifts and climatic oscillations, might have promoted speciation of more current species through allopatric divergence and hybridization in that region. Several important taxonomic traits seem to have arisen multiple times with obvious parallel evolution. The new name E. baimashanicum and the new combinations E. nepalense, E. purii, E. renifolium, E. robustum, E. scapiflorum, E. xingshanensis and Aphragmus minutus are proposed. This case study highlights the importance of using DNA barcode sequences from multiple individuals or populations to solve evolutionary questions in a given genus.
German, D. A. and M. A. Koch. (2017) Eutrema salsugineum (Cruciferae) new to Mexico: a surprising generic record for the flora of Middle America PhytoKeys 13-21. 10.3897/phytokeys.76.9731The paper reports Eutrema salsugineum as a novelty to the flora of Mexico and Middle America in general. The finding stands ca. 1600 km apart from the closest known locality in the Rocky Mountains of Colorado, USA. The species is considered native to NW Mexico and its late discovery in the region is presumably explained by its tiny habit, early flowering time, and subephemeral life cycle. The phylogenetic position of this Mexican population in a haplotype network based on the chloroplast DNA fragment psbA-trnH confirms this hypothesis and also suggests, in contrast to the previously held viewpoint, multiple colonizations of North American continent from Asia.
Gamburg, K. Z., G. B. Borovskii, et al. (2017) The study of the participation of heat shock proteins in the resistance to high and low temperatures with the use of Thellungiella (Thellungiella salsuguinea) and transgenic lines of Arabidopsis (Arabidopsis thaliana) Journal of Stress Physiology & Biochemistry 13: 23-34.Transgenic lines of Arabidopsis with HSP101 gene in sense and anti sense orientations acquired resistance to hard heat shock (50°C 10 min or 45-47°C 1 hour) and to freezing (-4°C 2 hours) due to the preliminary 2 hour's heating at 37°C. Thus, it was shown at the first time that the induction of the resistance to hard heat shock and freezing with mild heat shock is possible in the absence of HSP101 synthesis. Thellungiella with the genome to 95-97% identical to the genome of Arabidopsis did not have higher resistance to high temperature, but was significantly more resistant to freezing. It differed from Arabidopsis by several times higher contents of HSP101, HSP60 and HSC70. Contents of these HSPs in Arabidopsis increased as a result of hardening at 4°C what was accompanied by the increase of the resistance to freezing. It is supposed that the resistances to heat and cold shocks are dependent not only from HSP101, but also from other HSPs.
Eshel, G., R. Shaked, et al. (2017) Anastatica hierochuntica, an Arabidopsis Desert Relative, Is Tolerant to Multiple Abiotic Stresses and Exhibits Species-Specific and Common Stress Tolerance Strategies with Its Halophytic Relative, Eutrema (Thellungiella) salsugineum Frontiers in Plant Science 7: 1992 10.3389/fpls.2016.01992The search for novel stress tolerance determinants has led to increasing interest in plants native to extreme environments -so called "extremophytes." One successful strategy has been comparative studies between Arabidopsis thaliana and extremophyte Brassicaceae relatives such as the halophyte Eutrema salsugineum located in areas including cold, salty coastal regions of China. Here, we investigate stress tolerance in the desert species, Anastatica hierochuntica (True Rose of Jericho), a member of the poorly investigated lineage Ill Brassicaceae. We show that A. hierochuntica has a genome approximately 4.5-fold larger than Arabidopsis, divided into 22 diploid chromosomes, and demonstrate that A. hierochuntica exhibits tolerance to heat, low N and salt stresses that are characteristic of its habitat. Taking salt tolerance as a case study, we show that A. hierochuntica shares common salt tolerance mechanisms with E. salsugineum such as tight control of shoot Na+ accumulation and resilient photochemistry features. Furthermore, metabolic profiling of E. salsugineum and A. hierochuntica shoots demonstrates that the extremophytes exhibit both species-specific and common metabolic strategies to cope with salt stress including constitutive up-regulation (under control and salt stress conditions) of ascorbate and dehydroascorbate, two metabolites involved in ROS scavenging. Accordingly, A. hierochuntica displays tolerance to methyl viologen-induced oxidative stress suggesting that a highly active antioxidant system is essential to cope with multiple abiotic stresses. We suggest that A. hierochuntica presents an excellent extremophyte Arabidopsis relative model system for understanding plant survival in harsh desert conditions.
Ellouzi, H., S. Sghayar, et al. (2017) H2O2 seed priming improves tolerance to salinity; drought and their combined effect more than mannitol in Cakile maritima when compared to Eutrema salsugineum Journal of Plant Physiology 210: 38-50. 10.1016/j.jplph.2016.11.014The effect of H2O2 and mannitol seed priming was investigated on plant growth, oxidative stress biomarkers and activities of antioxidant enzymes in leaves of Cakile maritima and Eutrema salsugineum, when exposed to drought and salt stress, either separately applied or combined. Under unprimed conditions, drought severely restricted growth (40% as compared to the control) and redox balance of C. maritima seedlings, whereas E. salsugineum showed these drastic effects under individual salinity (33% as compared to the control). Combined salinity and drought maintained and even stimulated the antioxidant defense of both plants from unprimed seeds. Both priming agents (mannitol and H2O2) significantly ameliorated growth and antioxidant defense of both species grown under salinity, drought and their combined effect. However, H2O2 priming appeared to be more beneficial in C. maritima seedlings. Indeed, oxidative injuries were significantly reduced, together with significantly higher concentrations of ascorbic acid (36%), glutathione (2-fold) and proline production (2-fold), leading to a greater redox balance that was closely associated with enhanced antioxidant enzyme activities, specifically under salt stress. Overall, our results indicate that it is very likely that H2O2 priming, due to its signal role, improves C. maritima tolerance to both osmotic stresses and enables the plant to memorize and to decode early signals that are rapidly activated when plants are later exposed to stress. Copyright (C) 2016. Published by Elsevier GmbH.
Duarte, B., M. T. Cabrita, et al. (2017) Disentangling the photochemical salinity tolerance in Aster tripolium L.: connecting biophysical traits with changes in fatty acid composition Plant Biology 19: 239-248. 10.1111/plb.12517A profound analysis of A.tripolium photochemical traits under salinity exposure is lacking in the literature, with very few references focusing on its fatty acid profile role in photophysiology. To address this, the deep photochemical processes were evaluated by Pulse Amplitude Modulated (PAM) Fluorometry coupled with a discrimination of its leaf fatty acid profile. Plants exposed to 125-250mm NaCl showed higher photochemical light harvesting efficiencies and lower energy dissipation rates. under higher NaCl exposure, there is evident damage of the oxygen evolving complexes (OECs). On the other hand, Reaction Centre (RC) closure net rate and density increased, improving the energy fluxes entering the PS II, in spite of the high amounts of energy dissipated and the loss of PS II antennae connectivity. Energy dissipation was mainly achieved through the auroxanthin pathway. Total fatty acid content displayed a similar trend, being also higher under 125-250mm NaCl with high levels of omega-3 and omega-6 fatty acids. The increase in oleic acid and palmitic acid allows the maintenance of the good functioning of the PS II. Also relevant was the high concentration of chloroplastic C16:1t in the individuals subjected to 125-250mm NaCl, related with a higher electron transport activity and with the organization of the Light Harvesting Complexes (LHC) and thus reducing the activation of energy dissipation mechanisms. All these new insights shed some light not only on the photophysiology of this potential cash-crop, but also highlight its important saline agriculture applications of this species as forage and potential source of essential fatty acids.
dos Santos, B. M. and T. S. Balbuena. (2017) Carbon assimilation in Eucalyptus urophylla grown under high atmospheric CO2 concentrations: A proteomics perspective Journal of Proteomics 150: 252-257. 10.1016/j.jprot.2016.09.010Photosynthetic organisms may be drastically affected by the future climate projections of a considerable increase in CO2 concentrations. Growth under a high concentration of CO2 could stimulate carbon assimilation-especially in C3-type plants. We used a proteomics approach to test the hypothesis of an increase in the abundance of the enzymes involved in carbon assimilation in Eucalyptus urophylla plants grown under conditions of high atmospheric CO2. Our strategy allowed the profiling of all Calvin-Benson cycle enzymes and associated protein species. Among the 816 isolated proteins, those involved in carbon fixation were found to be the most abundant ones. An increase in the abundance of six key enzymes out of the eleven core enzymes involved in carbon fixation was detected in plants grown at a high CO2 concentration. Proteome changes were corroborated by the detection of a decrease in the stomatal aperture and in the vascular bundle area in Eucalyptus urophylla plantlets grown in an environment of high atmospheric CO2. Our proteomics approach indicates a positive metabolic response regarding carbon fixation in a CO2-enriched atmosphere. The slight but significant increase in the abundance of the Calvin enzymes suggests that stomatal closure did not prevent an increase in the carbon assimilation rates. Biological significance: The sample enrichment strategy and data analysis used here enabled the identification of all enzymes and most protein isoforms involved in the Calvin-Benson-Bessham cycle in Eucalyptus urophylla. Upon growth in CO2-enriched chambers, Eucalyptus urophylla plantlets responded by reducing the vascular bundle area and stomatal aperture size and by increasing the abundance of six of the eleven core enzymes involved in carbon fixation. Our proteome approach provides an estimate on how a commercially important C3-type plant would respond to an increase in CO2 concentrations. Additionally, confirmation at the protein level of the predicted genes involved in carbon assimilation may be used in plant transformation strategies aiming to increase plant adaptability to climate changes or to increase plant productivity. (C) 2016 Elsevier B.V. All rights reserved.
Abdelkarim, B. T. M., V. Maranda, et al. (2017) The fate of retrotransposed processed genes in Arabidopsis thaliana Gene 609: 1-8. 10.1016/j.gene.2017.01.029Processed genes are functional genes that have arisen as a result of the retrotransposition of mRNA molecules. We found 6 genes that generated processed genes in the common ancestor of five Brassicaceae species (Arabidopsis thaliana, Arabidopsis lyrata, Capsella rubella, Brassica rapa and Thellungiella parvula). These processed genes have therefore been kept for at least 30 million years. Analyses of the Ka/Ks ratio of these genes, and of those having given rise to them, show that they evolve relatively slowly and suggest that the processed genes maintained the same function as that of their parental gene. There is a significant negative correlation between the number of ESTs and transcripts produced and the Ka/Ks ratios of the parental genes but not of the processed genes. This suggests that selection has not yet adapted the selective pressure the processed genes experience to their expression level. However, the A. thaliana processed genes tend to be expressed ill the same tissues as that of their parental genes. Furthermore, most have a CAATT-box, a TATA-box and are located about 1 kb from another protein-coding gene. Altogether, our results suggest that the processed genes found in the A. Mebane genome have been kept to produce more of the same product, and in the same tissues, as that encoded by their parental gene. (C) 2017 The Author(s). Published by Elsevier B.V.
Zhang, Y.-M., Z.-Q. Shao, et al. (2016) Uncovering the dynamic evolution of nucleotide-binding site-leucine-rich repeat (NBS-LRR) genes in Brassicaceae Journal of Integrative Plant Biology 58: 165-177. 10.1111/jipb.12365Plant genomes harbor dozens to hundreds of nucleotide-binding site-leucine-rich repeat (NBS-LRR) genes; however, the long-term evolutionary history of these resistance genes has not been fully understood. This study focuses on five Brassicaceae genomes and the Carica papaya genome to explore changes in NBS-LRR genes that have taken place in this Rosid II lineage during the past 72 million years. Various numbers of NBS-LRR genes were identified from Arabidopsis lyrata (198), A. thaliana (165), Brassica rapa (204), Capsella rubella (127), Thellungiella salsuginea (88), and C. papaya (51). In each genome, the identified NBS-LRR genes were found to be unevenly distributed among chromosomes and most of them were clustered together. Phylogenetic analysis revealed that, before and after Brassicaceae speciation events, both toll/interleukin-1 receptor-NBS-LRR (TNL) genes and non-toll/interleukin-1 receptor-NBS-LRR (nTNL) genes exhibited a pattern of first expansion and then contraction, suggesting that both subclasses of NBS-LRR genes were responding to pathogen pressures synchronically. Further, by examining the gain/loss of TNL and nTNL genes at different evolutionary nodes, this study revealed that both events often occurred more drastically in TNL genes. Finally, the phylogeny of nTNL genes suggested that this NBS-LRR subclass is composed of two separate ancient gene types: RPW8-NBS-LRR and Coiled-coil-NBS-LRR.
Zhang, K., J. Song, et al. (2016) Expression of the Thellungiella halophila vacuolar H+-pyrophosphatase gene (TsVP) in cotton improves salinity tolerance and increases seed cotton yield in a saline field Euphytica 211: 231-244. 10.1007/s10681-016-1733-zThe emergence and survival of cotton seedlings is crucial for cotton cultivation in saline fields. Limited seed cotton yield in saline fields is also a matter of concern for farmers. The expression of TsVP, a Thellungiella halophila gene encoding a vacuolar proton pumping pyrophosphatase, has been shown to improve the salinity tolerance of transgenic cotton under greenhouse conditions. However, the potential for TsVP to improve the seed cotton yield in saline fields has yet to be evaluated. In this study, the time of emergence, emergence rate, survival rate, carbon assimilation capacity during bud stage, seed cotton yield, and cotton fibre quality were determined in saline field trials using TsVP-overexpressing transgenic cotton and wild-type cotton plants. In a saline field, TsVP-overexpressing transgenic cotton emerged two days earlier than wild-type plants, and displayed greater emergence rate and survival rate. The seed cotton yield of TsVP-overexpressing transgenic cotton plants increased by an average of 14.81 % compared with that of wild-type plants, and cotton fibre quality also improved. In greenhouse conditions, TsVP-overexpressing plants also required a shorter time for 50 % emergence than wild-type plants when the NaCl concentration was greater than 100 mM. This research indicates that TsVP has the potential to improve seed cotton yield in saline fields.
Yang, Y., Z. Luo, et al. (2016) Molecular Cloning, Expression Analysis, and Functional Characterization of the H+-Pyrophosphatase from Jatropha curcas Applied Biochemistry and Biotechnology 178: 1273-1285. 10.1007/s12010-015-1944-0H+-pyrophosphatase (H+-PPase) is a primary pyrophosphate (PPi)-energized proton pump to generate electrochemical H+ gradient for ATP production and substance translocations across membranes. It plays an important role in stress adaptation that was intensively substantiated by numerous transgenic plants overexpressing H+-PPases yet devoid of any correlated studies pointing to the elite energy plant, Jatropha curcas. Herein, we cloned the full length of J. curcas H+-PPase (JcVP1) complementary DNA (cDNA) by reverse transcription PCR, based on the assembled sequence of its ESTs highly matched to Hevea brasiliensis H+-PPase. This gene encodes a polypeptide of 765 amino acids that was predicted as a K+-dependent H+-PPase evolutionarily closest to those of other Euphorbiaceae plants. Many cis-regulatory elements relevant to environmental stresses, molecular signals, or tissue-specificity were identified by promoter prediction within the 1.5-kb region upstream of JcVP1 coding sequence. Meanwhile, the responses of JcVP1 expression to several common abiotic stresses (salt, drought, heat, cold) were characterized with a considerable accordance with the inherent stress tolerance of J. curcas. Moreover, we found that the heterologous expression of JcVP1 could significantly improve the salt tolerance in both recombinant Escherichia coli and Saccharomyces cerevisiae, and this effect could be further fortified in yeast by N-terminal addition of a vacuole-targeting signal peptide from the H+-PPase of Trypanosoma cruzi.
Yang, S., C. Luo, et al. (2016) Two Groups of Thellungiella salsuginea RAVs Exhibit Distinct Responses and Sensitivity to Salt and ABA in Transgenic Arabidopsis FigshareContaining both AP2 domain and B3 domain, RAV (Related to ABI3/VP1) transcription factors are involved in diverse functions in higher plants. A total of eight TsRAV genes were isolated from the genome of Thellungiella salsuginea and could be divided into two groups (A- and B-group) based on their sequence similarity. The mRNA abundance of all Thellungiella salsuginea TsRAVs followed a gradual decline during seed germination. In Thellungiella salsuginea seedling, transcripts of TsRAVs in the group A (A-TsRAVs) were gradually and moderately reduced by salt treatment but rapidly and severely repressed by ABA treatment. In comparison, with a barely detectable constitutive expression, the transcriptional level of TsRAVs in the group B (B-TsRAVs) exhibited a moderate induction in cotyledons when confronted with ABA. We then produced the gain-of-function transgenic Arabidopsis plants for each TsRAV gene and found that only 35S:A-TsRAVs showed weak growth retardation including reduced root elongation, suggesting their roles in negatively controlling plant growth. Under normal conditions, the germination process of all TsRAVs overexpressing transgenic seeds was inhibited with a stronger effect observed in 35S:A-TsRAVs seeds than in 35S:B-TsRAVs seeds. With the presence of NaCl, seed germination and seedling root elongation of all plants including wild type and 35S:TsRAVs plants were retarded and a more severe inhibition occurred to the 35S:A-TsRAV transgenic plants. ABA treatment only negatively affected the germination rates of 35S:A-TsRAV transgenic seeds but not those of 35S:B-TsRAV transgenic seeds. All 35S:TsRAVs transgenic plants showed a similar degree of reduction in root growth compared with untreated seedlings in the presence of ABA. Furthermore, the cotyledon greening/expansion was more severely inhibited 35S:A-TsRAVs than in 35S:B-TsRAVs seedlings. Upon water deficiency, with a wider opening of stomata, 35S:A-TsRAVs plants experienced a faster transpirational water loss than wild type and 35S:B-TsRAVs lines. Taken together, our results suggest that two groups of TsRAVs perform distinct regulating roles during plant growth and abiotic defense including drought and salt, and A-TsRAVs are more likely than B-TsRAVs to act as negative regulators in the above-mentioned biological processes. Copyright: CC BY.
Yang, S., C. Luo, et al. (2016) Two Groups of Thellungiella salsuginea RAVs Exhibit Distinct Responses and Sensitivity to Salt and ABA in Transgenic Arabidopsis Plos One 11: e0153517 10.1371/journal.pone.0153517Containing both AP2 domain and B3 domain, RAV (Related to ABI3NP1) transcription factors are involved in diverse functions in higher plants. A total of eight TsRAV genes were isolated from the genome of Thellungiella salsuginea and could be divided into two groups (A and B-group) based on their sequence similarity. The mRNA abundance of all Thellungiella salsuginea TsRAVs followed a gradual decline during seed germination. In Thellungiella salsuginea seedling, transcripts of TsRAVs in the group A (A-TsRAVs) were gradually and moderately reduced by salt treatment but rapidly and severely repressed by ABA treatment. In comparison, with a barely detectable constitutive expression, the transcriptional level of TsRAVs in the group B (B-TsRAVs) exhibited a moderate induction in cotyledons when confronted with ABA. We then produced the "gain-of-function" transgenicArabidopsis plants for each TsRAV gene and found that only 35S:A-TsRAVs showed weak growth retardation including reduced root elongation, suggesting their roles in negatively controlling plant growth. Under normal conditions, the germination process of all TsRAVs overexpressing transgenic seeds was inhibited with a stronger effect observed in 35S:A-TsRAVs seeds than in 35S:B-TsRAVs seeds. With the presence of NaCI, seed germination and seedling root elongation of all plants including wild type and 35S:TsRAVs plants were retarded and a more severe inhibition occurred to the 35S:A-TsRAVtransgenic plants. ABA treatment only negatively affected the germination rates of 35S:A-TsRAV transgenic seeds but not those of 35S:B-TsRAV transgenic seeds. All 35S:TsRAVs transgenic plants showed a similar degree of reduction in root growth compared with untreated seedlings in the presence of ABA. Furthermore, the cotyledon greening/expansion was more severely inhibited 35S:A-TsRAVs than in 35S:B-TsRAVs seedlings. Upon water deficiency, with a wider opening of stomata, 35SA-TsRAVs plants experienced a faster transpirational water loss than wild type and 35S:B-TsRAVs lines. Taken together, our results suggest that two groups of TsRAVs perform distinct regulating roles during plant growth and abiotic defense including drought and salt, and A-TsRAVs are more likely than B-TsRAVs to act as negative regulators in the above -mentioned biological processes.
Wu, Y., J. Guo, et al. (2016) Genome-wide identification and characterization of Eutrema salsugineum microRNAs for salt tolerance Physiologia Plantarum 157: 453-468. 10.1111/ppl.12419Eutrema salsugineum, a close relative of Arabidopsis thaliana, is a valuable halophytic model plant that has extreme tolerance to salinity. As posttranscriptional gene regulators, microRNAs (miRNAs) control gene expression and a variety of biological processes, including plant-stress responses. To identify salt-stress responsive miRNAs in E. salsugineum and reveal their possible roles in the adaptive response to salt stress, we chose the Solexa sequencing platform to screen the miRNAs in 4-week-old E. salsugineum seedlings under salt treatment. A total of 82 conserved miRNAs belonging to 27 miRNA families and 17 novel miRNAs were identified and 11 conserved miRNA families and 4 novel miRNAs showed a significant response to salt stress. To investigate the possible biological roles of miRNAs, 1060 potential targets were predicted. Moreover, 35 gene ontology (GO) categories and 1 pathway, including a few terms that were directly and indirectly related to salt stress, were significantly enriched in the salt-stress-responsive miRNAs targets. The relative expression analysis of six target genes was analyzed using quantitative real-time polymerase chain reaction (PCR) and showed a negative correlation with their corresponding miRNAs. Many stress regulatory and phytohormone regulatory cis-regulatory elements were widely present in the promoter region of the salt-responsive miRNA precursors. This study describes the large-scale characterization of E. salsugineummiRNAs and provides a useful resource for further understanding of miRNA functions in the regulation of the E. salsugineum salt-stress response.
Wang, X., C. Bi, et al. (2016) The Whole Genome Assembly and Comparative Genomic Research of Thellungiella parvula (Extremophile Crucifer) Mitochondrion International journal of genomics 2016: 5283628-5283628. 10.1155/2016/5283628The complete nucleotide sequences of the mitochondrial (mt) genome of an extremophile species Thellungiella parvula (T. parvula) have been determined with the lengths of 255,773bp. T. parvula mt genome is a circular sequence and contains 32 protein-coding genes, 19 tRNA genes, and three ribosomal RNA genes with a 11.5% coding sequence. The base composition of 27.5% A, 27.5% T, 22.7% C, and 22.3% G in descending order shows a slight bias of 55% AT. Fifty-three repeats were identified in the mitochondrial genome of T. parvula, including 24 direct repeats, 28 tandem repeats (TRs), and one palindromic repeat. Furthermore, a total of 199 perfect microsatellites have been mined with a high A/T content (83.1%) through simple sequence repeat (SSR) analysis and they were distributed unevenly within this mitochondrial genome. We also analyzed other plant mitochondrial genomes' evolution in general, providing clues for the understanding of the evolution of organelles genomes in plants. Comparing with other Brassicaceae species, T. parvula is related to Arabidopsis thaliana whose characters of low temperature resistance have been well documented. This study will provide important genetic tools for other Brassicaceae species research and improve yields of economically important plants.
Wang, J., L. Yao, et al. (2016) Comparative Proteomic Analysis of Cultured Suspension Cells of the Halophyte Halogeton glomeratus by iTRAQ Provides Insights into Response Mechanisms to Salt Stress Frontiers in Plant Science 7: 110 10.3389/fpls.2016.00110Soil salinity severely threatens land use capability and crop yields worldwide. An analysis of the molecular mechanisms of salt tolerance in halophytes will contribute to the development of salt-tolerant crops. In this study, a combination of physiological characteristics and iTRAQ-based proteomic approaches was conducted to investigate the molecular mechanisms underlying the salt response of suspension cell cultures of halophytic Halogeton glomeratus. These cells showed halophytic growth responses comparable to those of the whole plant. In total, 97 up-regulated proteins and 192 down-regulated proteins were identified as common to both 200 and 400 mM NaCl concentration treatments. Such salinity responsive proteins were mainly involved in energy, carbohydrate metabolism, stress defense, protein metabolism, signal transduction, cell growth, and cytoskeleton metabolism. Effective regulatory protein expression related to energy, stress defense, and carbohydrate metabolism play important roles in the salt-tolerance of H. glomeratus suspension cell cultures. However, known proteins regulating Na+ efflux from the cytoplasm and its compartmentalization into the vacuole did not change significantly under salinity stress suggesting our existing knowledge concerning Na+ extrusion and compartmentalization in halophytes needs to be evaluated further. Such data are discussed in the context of our current understandings of the mechanisms involved in the salinity response of the halophyte, H. glomeratus.
Wang, C.-M., Z.-R. Xia, et al. (2016) The coordinated regulation of Na+ and K+ in Hordeum brevisubulatum responding to time of salt stress Plant Science 252: 358-366. 10.1016/j.plantsci.2016.08.009Hordeum brevisubulatum, called as wild barley, is a useful monocotyledonous halophyte for soil improvement in northern China. Although previously studied, its main salt tolerance mechanism remained controversial. The current work showed that shoot Na+ concentration was increased rapidly with stress time and significantly higher than in wheat during 0-168 h of 100 mM NaCl treatment. Similar results were also found under 25 and 50 mM NaCI treatments. Even K+ was increased from 0.01 to 50 mM in the cultural solution, no significant effect was found on tissue Na+ concentrations. Interestingly, shoot growth was improved, and stronger root activity was maintained in H. brevisubulatum compared with wheat after 7 days treatment of 100 mM NaCl. To investigate the long-term stress impact on tissue Na+, 100 mM NaCI was prolonged to 60 days. The maximum values of Na+ concentrations were observed at 7th in shoot and 14th day in roots, respectively, and then decreased gradually. Micro-electrode ion flux estimation was used and it was found that increasing Na+ efflux while maintaining K+ influx were the major strategies to reduce the Na+ concentration during long-term salt stress. Moreover, leaf Na+ secretions showed little contribution to the tissue Na+ decrease. Thereby, the physiological mechanism for H. brevisubulatum to survive from long-term salt stress was proposed that rapid Na+ accumulation occurred in the shoot to respond the initial salt shock, then Na+ efflux was triggered and K+ influx was activated to maintain a stable K+/Na+ ratio in tissues. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
Velasco, V. M. E., J. Mansbridge, et al. (2016) Acclimation of the crucifer Eutrema salsugineum to phosphate limitation is associated with constitutively high expression of phosphate-starvation genes Plant Cell and Environment 39: 1818-1834. 10.1111/pce.12750Eutrema salsugineum, a halophytic relative of Arabidopsis thaliana, was subjected to varying phosphate (Pi) treatments. Arabidopsis seedlings grown on 0.05mM Pi displayed shortened primary roots, higher lateral root density and reduced shoot biomass allocation relative to those on 0.5mM Pi, whereas Eutrema seedlings showed no difference in lateral root density and shoot biomass allocation. While a low Fe concentration mitigated the Pi deficiency response for Arabidopsis, Eutrema root architecture was unaltered, but adding NaCl increased Eutrema lateral root density almost 2-fold. Eutrema and Arabidopsis plants grown on soil without added Pi for 4 weeks had low shoot and root Pi content. Pi-deprived, soil-grown Arabidopsis plants were stunted with senescing older leaves, whereas Eutrema plants were visually indistinguishable from 2.5mM Pi-supplemented plants. Genes associated with Pi starvation were analysed by RT-qPCR. EsIPS2, EsPHT1; 4 and EsPAP17 showed up-regulated expression in Pi-deprived Eutrema plants, while EsPHR1, EsWRKY75 and EsRNS1 showed no induction. Absolute quantification of transcripts indicated that PHR1, WRKY75 and RNS1 were expressed at higher levels in Eutrema plants relative to those in Arabidopsis regardless of external Pi. The low phenotypic plasticity Eutrema displays to Pi supply is consistent with adaptation to chronic Pi deprivation in its extreme natural habitat.
van Tol, N., J. Pinas, et al. (2016) Genome interrogation for novel salinity tolerant Arabidopsis mutants Plant Cell and Environment 39: 2650-2662. 10.1111/pce.12805Soil salinity is becoming an increasingly large problem in agriculture. In this study, we have investigated whether a capacity to withstand salinity can be induced in the salinity sensitive plant species Arabidopsis thaliana, and whether it can be maintained in subsequent generations. To this end, we have used zinc finger artificial transcription factor (ZF-ATFs) mediated genome interrogation. Already within a relatively small collection Arabidopsis lines expressing ZF-ATFs, we found 41 lines that were tolerant to 100mM NaCl. Furthermore, ZF-ATF encoding gene constructs rescued from the most strongly salinity tolerant lines were indeed found to act as dominant and heritable agents for salinity tolerance. Altogether, our data provide evidence that a silent capacity to withstand normally lethal levels of salinity exists in Arabidopsis and can be evoked relatively easily by in trans acting transcription factors like ZF-ATFs.
Tiley, G. P., C. Ane, et al. (2016) Evaluating and Characterizing Ancient Whole-Genome Duplications in Plants with Gene Count Data Genome Biology and Evolution 8: 1023-1037. 10.1093/gbe/evw058Whole-genome duplications (WGDs) have helped shape the genomes of land plants, and recent evidence suggests that the genomes of all angiosperms have experienced at least two ancient WGDs. In plants, WGDs often are followed by rapid fractionation, in which many homeologous gene copies are lost. Thus, it can be extremely difficult to identify, let alone characterize, ancient WGDs. In this study, we use a new maximum likelihood estimator to test for evidence of ancient WGDs in land plants and estimate the fraction of new genes copies that are retained following a WGD using gene count data, the number of gene copies in gene families. We identified evidence of many putative ancient WGDs in land plants and found that the genome fractionation rates vary tremendously among ancient WGDs. Analyses of WGDs within Brassicales also indicate that background gene duplication and loss rates vary across land plants, and different gene families have different probabilities of being retained following a WGD. Although our analyses are largely robust to errors in duplication and loss rates and the choice of priors, simulations indicate that this method can have trouble detecting multiple WGDs that occur on the same branch, especially when the gene retention rates for ancient WGDs are very low. They also suggest that we should carefully evaluate evidence for some ancient plant WGD hypotheses.
Tao, P., W. Guo, et al. (2016) Genome-wide identification, classification, and analysis of NADP-ME family members from 12 crucifer species Molecular Genetics and Genomics 291: 1167-1180. 10.1007/s00438-016-1174-3NADP-dependent malic enzymes (NADP-MEs) play essential roles in both normal development and stress responses in plants. Here, genome-wide analysis was performed to identify 65 putative NADP-ME genes from 12 crucifer species. These NADP-ME genes were grouped into five categories of syntenic orthologous genes and were divided into three clades of a phylogenic tree. Promoter motif analysis showed that NADP-ME1 genes in Group IV were more conserved with each other than the other NADP-ME genes in Groups I and II. A nucleotide motif involved in ABA responses, desiccation and seed development was found in the promoters of most NADP-ME1 genes. Generally, the NADP-ME genes of Brassica rapa, B. oleracea and B. napus had less introns than their corresponding Arabidopsis orthologs. In these three Brassica species, the NADP-ME genes derived from the least fractionated subgenome have lost less introns than those from the medium fractionated and most fractionated subgenomes. BrNADP-ME1 showed the highest expression in petals and mature embryos. Two paralogous NADP-ME2 genes (BrNADP-ME2a and BrNADP-ME2b) shared similar expression profiles and differential expression levels. BrNADP-ME3 showed down-regulation during embryogenesis and reached its lowest expression in early cotyledonary embryos. BrNADP-ME4 was expressed widely in multiple organs and showed high expression during the whole embryogenesis process. Different NADP-ME genes of B. rapa showed differential gene expression profiles in young leaves after ABA treatment or cold stress. Our genome-wide identification and characterization of NADP-ME genes extend our understanding of the evolution or function of this family in Brassicaceae.
Soda, N., A. Sharan, et al. (2016) Evidence for nuclear interaction of a cytoskeleton protein (OsIFL) with metallothionein and its role in salinity stress tolerance Scientific Reports 6: 34762 10.1038/srep34762Soil salinity is being perceived as a major threat to agriculture. Plant breeders and molecular biologist are putting their best efforts to raise salt-tolerant crops. The discovery of the Saltol QTL, a major QTL localized on chromosome I, responsible for salt tolerance at seedling stage in rice has given new hopes for raising salinity tolerant rice genotypes. In the present study, we have functionally characterized a Saltol QTL localized cytoskeletal protein, intermediate filament like protein (OsIFL), of rice. Studies related to intermediate filaments are emerging in plants, especially with respect to their involvement in abiotic stress response. Our investigations clearly establish that the heterologous expression of OsIFL in three diverse organisms (bacteria, yeast and tobacco) provides survival advantage towards diverse abiotic stresses. Screening of rice cDNA library revealed OsIFL to be strongly interacting with metallothionein protein. Bimolecular fluorescence complementation assay further confirmed this interaction to be occurring inside the nucleus. Overexpression of OsIFL in transgenic tobacco plants conferred salinity stress tolerance by maintaining favourable K+/Na+ ratio and thus showed protection from salinity stress induced ion toxicity. This study provides the first evidence for the involvement of a cytoskeletal protein in salinity stress tolerance in diverse organisms.
Shiri, M., M. Rabhi, et al. (2016) Moderate salinity reduced phenanthrene-induced stress in the halophyte plant model Thellungiella salsuginea compared to its glycophyte relative Arabidopsis thaliana: Cross talk and metabolite profiling Chemosphere 155: 453-462. 10.1016/j.chemosphere.2016.04.080It was shown that halophytes experience higher cross-tolerance to stresses than glycophytes, which was often associated with their more powerful antioxidant systems. Moreover, salinity was reported to enhance halophyte tolerance to several stresses. The aim of the, present work was to investigate whether a moderate salinity enhances phenanthrene stress tolerance in the halophyte Thellungiella salsuginea. The model plant Arabidopsis thaliana, considered as its glycophyte relative, was used as reference. Our study was based on morpho-physiological, antioxidant, and metabolomic parameters. Results showed that T. salsuginea was more tolerant to phenanthrene stress as compared to A. thaliana. An improvement of phenanthrene-induced responses was recorded in the two plants in the presence of 25 mM NaCl, but the effect was significantly more obvious in the halophyte. This observation was particularly related to the higher antioxidant activities and the induction of more adapted metabolism in the halophyte. Gas Chromatography coupled with Mass Spectrometry (GC-MS) was used to quantify alcohols, ammonium, sugars, and organic acids. It showed the accumulation of several metabolites, many of them are known to be involved in signaling and abiotic stress tolerance. Moderate salinity and phenanthrene cross-tolerance involved in these two stresses was discussed. (C) 2016 Elsevier Ltd. All rights reserved.
Seon-Gil, D., S. Eun-Ju, et al. (2016). Pharmaceutical and food compositions for preventing or treating ulcerative colitis, containing Eutrema japonicum extract, Univera Inc.; Korea, Gachon University of Industry Academic Cooperation Foundation. Schmitz, R. J. (2016) GSE75071: On the Origin and Evolutionary Consequences of Gene Body DNA Methylation Gene Expression OmnibusIn plants, CG DNA methylation is prevalent in the transcribed regions of constitutively expressed genes (aoegene body methylation; gbMa), but the origin and function of gbM remain unknown. Here we report the discovery that Eutrema salsugineum, has lost gbM from its genome, the first known instance for a flowering plant. Of all known DNA methyltransferases, only CHROMOMETHYLTRANSFERASE 3 (CMT3) is missing from E. salsugineum, indicating that CMT3 may be required for the establishment of gbM. Detailed analyses of gene expression, the histone variant H2A.Z and various histone modifications in E. salsugineum and Arabidopsis thaliana epiRILs turned up no evidence in support of any role for gbM in regulating transcription or affecting the composition and modifications of chromatin over evolutionary time scales.
Sandoval, J. F., C. Y. Yoo, et al. (2016) Growth of Arabidopsis thaliana and Eutrema salsugineum in a closed growing system designed for quantification of plant water use Journal of Plant Physiology 193: 110-118. 10.1016/j.jplph.2016.02.010The identification of genetic determinants for water-use efficiency (WUE) and their incorporation into crop plants is critical as world water resources are predicted to become less stable over the coming decades. However, quantification of WUE in small model species such as Arabidopsis is difficult because of low plant water loss relative to root zone evaporation. Furthermore, measurements of long-term WUE are labor-intensive and time-consuming. A novel high-throughput closed-container growing system for measuring plant WUE is described. The system eliminates nearly all water loss from the media and does not require irrigation throughout the duration of a typical experiment. Using the model species Arabidopsis thaliana and Eutrema salsugineum, it was confirmed that under growth chamber conditions, this system: (1) eliminates the need for irrigation for as much as 30 days with media water content remaining above 80% full capacity; (2) allows for quantification of WUE in plants with a leaf area as small as ca. 20 cm(2); (3) does not inhibit plant growth; and (4) does not alter media conditions outside of an acceptable range for these species. The growing system provides an efficient high-throughput system for quantifying plant water loss and WUE. (c) 2016 Elsevier GmbH. All rights reserved.
Rigo, G., I. Valkai, et al. (2016) Gene mining in halophytes: functional identification of stress tolerance genes in Lepidium crassifolium Plant Cell and Environment 39: 2074-2084. 10.1111/pce.12768Extremophile plants are valuable sources of genes conferring tolerance traits, which can be explored to improve stress tolerance of crops. Lepidium crassifolium is a halophytic relative of the model plant Arabidopsis thaliana, and displays tolerance to salt, osmotic and oxidative stresses. We have employed the modified Conditional cDNA Overexpression System to transfer a cDNA library from L. crassifolium to the glycophyte A. thaliana. By screening for salt, osmotic and oxidative stress tolerance through in vitro growth assays and non-destructive chlorophyll fluorescence imaging, 20 Arabidopsis lines were identified with superior performance under restrictive conditions. Several cDNA inserts were cloned and confirmed to be responsible for the enhanced tolerance by analysing independent transgenic lines. Examples include full-length cDNAs encoding proteins with high homologies to GDSL-lipase/esterase or acyl CoA-binding protein or proteins without known function, which could confer tolerance to one or several stress conditions. Our results confirm that random gene transfer from stress tolerant to sensitive plant species is a valuable tool to discover novel genes with potential for biotechnological applications.
Ren, L., L. Xu, et al. (2016) Host Range of Plasmodiophora brassicae on Cruciferous Crops and Weeds in China Plant Disease 100: 933-939. 10.1094/pdis-09-15-1082-reClubroot caused by Plasmodiophora brassicae is an increasingly important soilborne disease in China. The host range of P. brassicae was investigated with 30 cruciferous plants, including 16 crop species, 9 ornamentals, and 5 weeds in field and pot-cultured conditions. In the field, 17 species from five genera produced visible galls, and these included radish, Capsella bursa-pastoris, Orychophragmus violaceus, Sinapis alba, and 13 Brassica crops. In pot-cultured conditions, an additional 13 plant species (11 genera) were determined to be hosts of P. brassicae. Five common weeds were found to be hosts of P. brassicae, including C. bursa-pastoris, Lepidium apetalum, Descurainia sophia, S. alba, and Thellungiella salsuginea. The infection of these plants was confirmed via polymerase chain reaction (PCR) with primers specific to P. brassicae. No galls were found on Matthiola incana roots in the field or in pots and no resting spores of P. brassicae were observed in M. incana roots, although P. brassicae was detected in M. incana roots via PCR. Microscopic examination revealed infection only in the root hairs of M. incana roots. These results suggested that M. incana was highly resistant to P. brassicae in China and could be developed as a bait crop. In total, 297 accessions of oilseed rape were tested in the field, and 3 accessions of Brassica napus and 1 accession of B. juncea were found to be highly resistant to clubroot disease. These resistant resources provide options for managing clubroot in P. brassicae-infested fields.
Rathore, P., R. Geeta, et al. (2016) Microsynteny and phylogenetic analysis of tandemly organised miRNA families across five members of Brassicaceae reveals complex retention and loss history Plant Science 247: 35-48. 10.1016/j.plantsci.2016.03.002Plant genomes are characterized by the presence of large miRNA gene families which are few in number. The expansion of miRNA families is thought to be driven by gene and genome duplication. Some members of these miRNA gene families are tandemly arranged and their analysis is of interest because such organisation may indicate origin through tandem duplication and also to investigate whether some such tandem clusters have similar expression patterns, and whether these are regulated through a common set of cis-regulatory elements (eg. promoters and enhancers). As a first step, we undertake a comprehensive study using micro-synteny analyses of tandemly organised miRNA families across the Brassicaceae spanning an evolutionary time scale of ca. 45 million years, among Arabidopsis, Capsella, Brassica and Thellungiella species, to address the following questions: Are most miRNA gene families present as tandem clusters? To what extent are these tandem patterns retained? To what extent can family sizes be ascribed to genome duplication? Our analysis of thirteen tandemly organised miRNA families revealed that synteny is largely conserved among Arabidopsis thaliana, A. lyrata and Capsella rubella, which form a clade spanning approximately between 6.2-9.8 my (Acarkan et al., 2000) [1]. On the other hand, comparison of sequences from these species with Brassica rapa, B. oleracea and Thellungiella halophila, which form a separate Glade spanning 31 my (Franzke et al., 2011) [2] reveals many differences. The latter Glade reveals several paralogous duplications that probably resulted from whole genome duplication, as well as disrupted synteny. Phylogenetic analyses of precursor sequences generally support the history inferred from synteny analysis. Synteny and phylogenetic analysis of six members of the tandemly organised miR169 family suggest that the Brassicaceae ancestral state consisted of a "dimer as a unit" which may have undergone direct local duplication to retain the transcriptional orientation followed by lineage specific changes. MiR169, to the best of our knowledge, is one of the largest tandemly organised miRNA gene family across plant kingdom and further analysis should reveal the generality of this pattern of evolution. The conserved organisation of miR395A-B-C and miR395 D-E-F as two clusters on same chromosome/scaffold across A. thaliana, B. rapa and salsuginea demonstrates retention of the large chromosomal segment across the two lineages. MiRNA family miR845 was detected only in Arabidopsis species and Thellungiella indicating a complex loss and retention history. MiR447A-B family was only found in A. thaliana indicating that it is a species-specific gene family of recent origin. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
Pilarska, M., M. Wiciarz, et al. (2016) A Different Pattern of Production and Scavenging of Reactive Oxygen Species in Halophytic Eutrema salsugineum (Thellungiella salsuginea) Plants in Comparison to Arabidopsis thaliana and Its Relation to Salt Stress Signaling Frontiers in Plant Science 7: 1179 10.3389/fpls.2016.01179Isolated thylakoids from halophytic Eutrerna salsugineurn (Thellungiella salsuginea) produces more H2O2 in comparison to glycophytic Arabidopsis thaliana. The first objective of this study was to verify whether this feature is relevant also to the intact chloroplasts and leaves. Enhanced H2O2 levels in chloroplasts and leaves of E. salsugineurn were positively verified with several methods (electron microscopy, staining with Amplex Red and with diaminobenzidine). This effect was associated with a decreased ratio of O-2(center dot) -/H2O2 in E salsugineum in comparison to A. thaliana as detected by electron paramagnetic resonance method. As a next step, we tested how this specific ROS signature of halophytic species affects the antioxidant status and down-stream components of ROS signaling. Comparison of enzymatic antioxidants revealed a decreased activity of ascorbate peroxidase (APX), enhanced activity of glutathione peroxidase, and the presence of thylakoid-bound forms of iron superoxide dismutase (FeSOD) and APX in E. salsugineum. These cues were, however, independent from application of salt stress. The typical H2O2 -dependent cellular responses, namely the levels of glucosinolates and stress related hormones were determined. The total glucosinolate content in E. salsugineurn water-treated leaves was higher than in A. thaliana and increased after salinity treatment. Treatment with salinity up-regulated all of tested stress hormones, their precursors and catabolites [abscisic acid (ABA), dihydrophaseic acid, phaseic acid, 1-aminocyclopropane-1-carboxylic acid, salicylic acid, jasmonic acid, cis-(+)-12-oxo-phytodienoic acid and jasmonoyl-L-isoleucine] in A. thaliana, whereas in E. salsugineum only a stimulation in ethylene synthesis and ABA catabolism was noted. Obtained results suggest that constitutively enhanced H2O2 generation in chloroplasts of E. salsugineum might be a crucial component of stressprepardeness of this halophytic species. It shapes a very efficient antioxidant protection (in which glucosinolates might play a specific role) and a fine tuning of hormonal signaling to suppress the cell death program directed by jasmonate pathway.
Pan, Y.-Q., H. Guo, et al. (2016) The Photosynthesis, Na+/K+ Homeostasis and Osmotic Adjustment of Atriplex canescens in Response to Salinity Frontiers in Plant Science 7: 848 10.3389/fpls.2016.00848Atriplex canescens (fourwing saltbush) is a C-4 perennial fodder shrub with excellent resistance to salinity. However, the mechanisms underlying the salt tolerance in A. canescens are poorly understood. In this study, 5-weeks-old A. canescens seedlings were treated with various concentrations of external NaCI (0-400 mM). The results showed that the growth of A, canescens seedlings was significantly stimulated by moderate salinity (100 mM NaCI) and unaffected by high salinity (200 or 400 mM NaCI). Furthermore, A. canescens seedlings showed higher photosynthetic capacity under NaCI treatments (except for 100 mM NaCI treatment) with significant increases in net photosynthetic rate and water use efficiency. Under saline conditions, the A, canescens seedlings accumulated more Na+ in either plant tissues or salt bladders, and also retained relatively constant K+ in leaf tissues and bladders by enhancing the selective transport capacity for K+ over Na+ (ST value) from stem to leaf and from leaf to bladder. External NaCI treatments on A, canescens seedlings had no adverse impact on leaf relative water content, and this resulted from lower leaf osmotic potential under the salinity conditions. The contribution of Na+ to the leaf osmotic potential (Psi s) was sharply enhanced from 2% in control plants to 49% in plants subjected to 400 mM NaCI. However, the contribution of K+ to Psi s showed a significant decrease from 34% (control) to 9% under 400 mM NaCl. Interestingly, concentrations of betaine and free proline showed significant increase in the leaves of A, canescens seedlings, these compatible solutes presented up to 12% of contribution to Psi s under high salinity. These findings suggest that, under saline environments, A. canescens is able to enhance photosynthetic capacity, increase Na+ accumulation in tissues and salt bladders, maintain relative K+ homeostasis in leaves, and use inorganic ions and compatible solutes for osmotic adjustment which may contribute to the improvement of water status in plant.
Ozfidan-Konakci, C., B. Uzilday, et al. (2016) Halophytes as a source of salt tolerance genes and mechanisms: a case study for the Salt Lake area, Turkey Functional Plant Biology 43: 575-589. 10.1071/fp15288The worst case scenario of global climate change predicts both drought and salinity would be the first environmental factors restricting agriculture and natural ecosystems, causing decreased crop yields and plant growth that would directly affect human population in the next decades. Therefore, it is vital to understand the biology of plants that are already adapted to these extreme conditions. In this sense, extremophiles such as the halophytes offer valuable genetic information for understanding plant salinity tolerance and to improve the stress tolerance of crop plants. Turkey has ecological importance for its rich biodiversity with up to 3700 endemic plants. Salt Lake (Lake Tuz) in Central Anatolia, one of the largest hypersaline lakes in the world, is surrounded by salty marshes, with one of the most diverse floras in Turkey, where arid and semiarid areas have increased due to low rainfall and high evaporation during the summer season. Consequently, the Salt Lake region has a large number of halophytic, xerophytic and xero-halophytic plants. One good example is Eutrema parvulum (Schrenk) Al-Shehbaz & Warwick, which originates from the Salt Lake region, can tolerate up to 600mM NaCl. In recent years, the full genome of E. parvulum was published and it has been accepted as a model halophyte due to its close relationship (sequence identity in range of 90%) with Arabidopsis thaliana (L. Heynh.). In this context, this review will focus on tolerance mechanisms involving hormone signalling, accumulation of compatible solutes, ion transporters, antioxidant defence systems, reactive oxygen species (ROS) signalling mechanism of some lesser-known extremophiles growing in the Salt Lake region. In addition, current progress on studies conducted with E. parvulum will be evaluated to shed a light on future prospects for improved crop tolerance.
Mandakova, T. and M. A. Lysak. (2016) Karyotype and Genome Evolution of Crucifers (Brassicaceae) Cytogenetic and Genome Research 148: 112-112.Plants are able to acclimate to their growth light environments by utilizing a number of short- and long-term mechanisms. One strategy is to prevent accumulation of excess reactive oxygen species that can lead to photoinhibition of photosynthesis. Ureides, generated from purine degradation, have been proposed as antioxidants and involved in certain abiotic stress responses. Eutrema salsugineum (Thellungiella salsuginea) is an extremophilic plant known to exhibit a high degree of tolerance to a variety of abiotic stresses that invariably generate reactive oxygen species. In the present study we have investigated the possible role of the ureide metabolic pathway during acclimation to growth irradiance and its conference of tolerance to photoinhibition in Eutrema. Ureide accumulation was greater under high light growth which also conferred tolerance to photoinhibition at low temperature as measured by the maximal quantum yield of PSII photochemistry. This may represent an adaptive plastic response contributing to the extreme tolerance exhibited by this plant. Our results would provide evidence that ureide accumulation may be involved in abiotic stress as another defence mechanism in response to oxidative stress.
Llanes, A., V. Arbona, et al. (2016) Metabolomic profiling of the halophyte Prosopis strombulifera shows sodium salt- specific response Plant Physiology and Biochemistry 108: 145-157. 10.1016/j.plaphy.2016.07.010Primary and secondary metabolite profiles were analyzed in roots and leaves of the halophytic shrub Prosopis strombulifera in response to control plants (no salt added in the growing media) and to lowering the osmotic potential to -1.0, -1.9, and -2.6 MPa generated by NaCl, Na2SO4, and the iso-osmotic combination of them at 24 h after reaching such potential. A rapid production of metabolites in response to sodium salt was found, which was correlated with modifications in growth parameters. Analysis of polar metabolite profiles by GC-MS rendered a total of 108 significantly altered compounds including 18 amino acids, 19 secondary metabolites, 23 carbohydrates, 13 organic acids, 4 indole acids, among others. Primary metabolites showed a differential response under the salt treatments, which was dependent on salt type and concentration, organ and age of plants. Most of identified compounds showed the strongest accumulation at the highest salt concentration assayed for Na2SO4-treated plants, which was correlated with damaging effects of sulfate anion on plant growth. Roots of NaCl-treated plants showed a higher number of altered metabolites (analyzed by UPLC-ESI-QqTOF-MS) compared to other treatments, while leaves of Na2SO4-treated plants showed the highest number of altered signals. A low degree of overlapping between secondary metabolites altered in roots and leaves of NaCl and Na2SO4-treated plants was found. However, when both NaCl and Na2SO4 salts were present plants always showed a lower number of altered metabolites. Three compounds were tentatively identified: tryptophan, lysophosphatidylcoline and 13-hydroxyoctadecadienoic acid. Increasing knowledge on P. strombulifera metabolism will contribute to unravel the underlying biochemical mechanism of salt tolerance. (C) 2016 Elsevier Masson SAS. All rights reserved.
Liu, X. X., C. Fu, et al. (2016) The involvement of TsFtsH8 in Thellungiella salsuginea tolerance to cold and high light stresses Acta Physiologiae Plantarum 38: 62 10.1007/s11738-016-2080-3Thellungiella salsuginea is a plant that commonly grows in harsh environments of salinity and low temperature. Although the molecular mechanism underlying salt tolerance in T. salsuginea has been extensively explored, our understanding of how this species tolerates cold stress is limited. In a previous study, Wong et al. (2006) identified a cold-inducible TsFtsH8 gene in T. salsuginea. Based on the role of AtFtsH in D1 protein turnover and in maintaining the normal function of photosystem II, we hypothesized that TsFtsH8 might be related to cold tolerance in T. salsuginea. In the present study, RNAi lines of TsFtsH8 were generated and its tolerance to cold was evaluated. The results showed that in early spring, TsFtsH8-RNAi lines underwent leaf variegation, severe chlorophyll decomposition, organelle deterioration, decrease in the maximum photochemical efficiency of photosystem II (F-v/F-m) and in the proportion of open photosystem II reaction centers (qP), and incomplete degradation of the 23 kDa fragment of the D1 protein. These findings suggest that TsFtsH8 is involved in the development of T. salsuginea in the early spring.
Li, Z., J. Zhang, et al. (2016) The Functional and Regulatory Mechanisms of the Thellungiella salsuginea Ascorbate Peroxidase 6 (TsAPX6) in Response to Salinity and Water Deficit Stresses FigshareSoil salinization is a resource and ecological problem in the world. Thellungiella salsuginea is becoming a new model plant because it resembles its relative species, Arabidopsis thaliana, in small genome and short life cycle. It is highly tolerant to salinity and drought stresses. Ascorbate peroxidase (APX) is an enzyme that clears H2O2 in plants. The function and molecular and regulation mechanisms of APX in T. salsuginea have rarely been reported. In this study, an APX gene, TsApx6, was cloned from T. salsuginea and its responses to abiotic stresses in transgenic Arabidopsis were studied. Under high salinity treatment, the expression of TsApx6 was significantly induced. Under drought treatment, overexpression of TsApx6 increased the survival rate and reduced leaf water loss rate in Arabidopsis. Compared to the wild type plants, high salinity treatment reduced the concentrations of MDA, H2O2 and proline but elevated the activities of APX, GPX, CAT and SOD in the TsApx6-overexpressing plants. Meanwhile, germination rate, cotyledon greening, and root length were improved in the transgenic plants compared to the wild type plants under salt and water deficit conditions. Based on these findings, TsApx6 has an important function in the resistance of plants to certain abiotic stresses. The TsApx6 promoter sequence was obtained using Genome Walking technology. Bioinformatics analysis indicated that it contains some cis-acting elements related to stress response. The treatments of salt, dehydration, and ABA induced the expression of Gus gene under the regulation of the TsApx6 promoter. Mutation analysis showed that the MBS motif present in the TsApx6 promoter might be a key negative regulatory element which has an important effect on the growth and developmental process of plants. Copyright: CC BY.
Li, Z., J. Zhang, et al. (2016) Putative cis-elements present in the promoter sequence of TsApx6 Figshare http://dx.doi.org/10.1371/journal.pone.0154042.t001Putative cis-elements present in the promoter sequence of TsApx6. Copyright: CC BY.
Li, Z., J. Zhang, et al. (2016) The Functional and Regulatory Mechanisms of the Thellungiella salsuginea Ascorbate Peroxidase 6 (TsAPX6) in Response to Salinity and Water Deficit Stresses Plos One 11: e0154042 10.1371/journal.pone.0154042Soil salinization is a resource and ecological problem in the world. Thellungiella salsuginea is becoming a new model plant because it resembles its relative species, Arabidopsis thaliana, in small genome and short life cycle. It is highly tolerant to salinity and drought stresses. Ascorbate peroxidase (APX) is an enzyme that clears H2O2 in plants. The function and molecular and regulation mechanisms of APX in T. salsuginea have rarely been reported. In this study, an APX gene, TsApx6, was cloned from T. salsuginea and its responses to abiotic stresses in transgenic Arabidopsis were studied. Under high salinity treatment, the expression of TsApx6 was significantly induced. Under drought treatment, overexpression of TsApx6 increased the survival rate and reduced leaf water loss rate in Arabidopsis. Compared to the wild type plants, high salinity treatment reduced the concentrations of MDA, H2O2 and proline but elevated the activities of APX, GPX, CAT and SOD in the TsApx6-overexpressing plants. Meanwhile, germination rate, cotyledon greening, and root length were improved in the transgenic plants compared to the wild type plants under salt and water deficit conditions. Based on these findings, TsApx6 has an important function in the resistance of plants to certain abiotic stresses. The TsApx6 promoter sequence was obtained using Genome Walking technology. Bioinformatics analysis indicated that it contains some cis-acting elements related to stress response. The treatments of salt, dehydration, and ABA induced the expression of Gus gene under the regulation of the TsApx6 promoter. Mutation analysis showed that the MBS motif present in the TsApx6 promoter might be a key negative regulatory element which has an important effect on the growth and developmental process of plants.
Li, J., F. Gao, et al. (2016) Cloning and stress expression of GRP7 in Thellungiella salsugineum Journal of Northwest A & F University - Natural Science Edition 44: 150-166.Objective: The glycine-rich RNA-binding protein7 (GRP7) gene was isolated from Thellungiella salsugineum to understand the role of GRPs and lay the foundation for further function analysis of GRPs in stress response. Method: In this experiment, specific primers of TsGRP7 were designed based on EST sequence and full-length cDNA of TsGRP7 gene was isolated. The conserved domain and potential cis-element in promoter region were analyzed and phylogenetic analysis was performed. Quantitative real-time PCR analysis was carried out under different stresses in different tissues. Result: The 522 bp coding region of TsGRP7 encoded 173 amino acid residues. The region between residues 9 and 82 was a typical RNA-recognition motif, containing conserved RNP-1 and RNP-2 subdomains. Multiple sequence alignment and system evolution analysis of TsGRP7 protein reveled that Thellungiella salsugineum had higher identity with homologous protein in Arabidopsis. Promoter sequence analysis by PlantCARE showed that multiple cis-elements were associated with abiotic and biotic stress localized in promoters, such as HSE, LTR, ABRE, Box-W1 and P-box, indicating that the TsGRP7 gene involved in stree response. Quantitative real-time PCR analysis revealed that the expression of TsGRP7 gene was specific under different stresses and in different tissues. Conclusion: The TsGRP7 gene involved in responses to low temperature, high salt and drought stress.
Lee, Y. P., C. Funk, et al. (2016) Salt stress responses in a geographically diverse collection of Eutrema/Thellungiella spp. accessions Functional Plant Biology 43: 590-606. 10.1071/fp15285Salinity strongly impairs plant growth and development. Natural genetic variation can be used to dissect complex traits such as plant salt tolerance. We used 16 accessions of the halophytic species Eutrema salsugineum (previously called Thellungiella salsuginea (Pallas) O.E. Schulz, Thellungiella halophila (C.A. Meyer) O.E. Schulz and Thellungiella botschantzevii D. A. German to investigate their natural variation in salinity tolerance. Although all accessions showed survival and growth up to 700mM NaCl in hydroponic culture, their relative salt tolerance varied considerably. All accessions accumulated the compatible solutes proline, sucrose, glucose and fructose and the polyamines putrescine and spermine. Relative salt tolerance was not correlated with the content of any of the investigated solutes. We compared the metabolomes and transcriptomes of Arabidopsis thaliana (L. Heynh.) Col-0 and E. salsugineum Yukon under control and salt stress conditions. Higher content of several metabolites in Yukon compared with Col-0 under control conditions indicated metabolic pre-adaptation to salinity in the halophyte. Most metabolic salt responses in Yukon took place at 200mM NaCl, whereas few additional changes were observed between 200 and 500 mM. The opposite trend was observed for the transcriptome, with only little overlap between salt-regulated genes in the two species. In addition, only about half of the salt-regulated Yukon unigenes had orthologues in Col-0.
Lee, S. J., E.-M. Jeong, et al. (2016) Oxidative defense metabolites induced by salinity stress in roots of Salicornia herbacea Journal of Plant Physiology 206: 133-142. 10.1016/j.jplph.2016.08.015High salinity is a major abiotic stress that affects the growth and development of plants. This type of stress can influence flowering, the production of crops, defense mechanisms and other physiological processes. Previous studies have attempted to elucidate salt-tolerance mechanisms to improve plant growth and productivity in the presence of sodium chloride. One such plant that has been studied in detail is Salicornia, a well-known halophyte, which has adapted to grow in the presence of high salt. To further the understanding of how Salicornia grows and develops under high saline conditions, Salicornia herbacea (S. herbacea) was grown under varying saline concentrations (0, 50, 100, 200, 300, and 400 mM), and the resulting phenotype, ion levels, and metabolites were investigated. The optimal condition for the growth of S. herbacea was determined to be 100 mM NaCl, and increased salt concentrations directly decreased the internal concentrations of other inorganic ions including Ca2+, K+, and Mg2+. Metabolomics were performed on the roots of the plant as a systematic metabolomics study has not yet been reported for Salicornia roots. Using ethylacetate and methanol extraction followed by high resolution ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS), 1793 metabolites were identified at different NaCl levels. Structural and functional analyses demonstrated that the concentration of 53 metabolites increased as the concentration of NaCl increased. These metabolites have been linked to stress responses, primarily oxidative stress responses, which increase under saline stress. Most metabolites can be classified as polyols, alkaloids, and steroids. Functional studies of these metabolites show that shikimic acid, vitamin K1, and indole-3-carboxylic acid are generated as a result of defense mechanisms, including the shikimate pathway, to protect against reactive oxygen species (ROS) generated by salt stress. This metabolite profiling provides valuable information on the salt-tolerance mechanisms of S. herbacea and may be applied to bioengineer plants with improved salt tolerance. (C) 2016 Elsevier GmbH. All rights reserved.
Khadilkar, A. S., U. P. Yadav, et al. (2016) Constitutive and Companion Cell-Specific Overexpression of AVP1, Encoding a Proton-Pumping Pyrophosphatase, Enhances Biomass Accumulation, Phloem Loading, and Long-Distance Transport Plant Physiology 170: 401-414. 10.1104/pp.15.01409Plant productivity is determined in large part by the partitioning of assimilates between the sites of production and the sites of utilization. Proton-pumping pyrophosphatases (H+-PPases) are shown to participate in many energetic plant processes, including general growth and biomass accumulation, CO2 fixation, nutrient acquisition, and stress responses. H+-PPases have a well-documented role in hydrolyzing pyrophosphate (PPi) and capturing the released energy to pump H+ across the tonoplast and endomembranes to create proton motive force (pmf). Recently, an additional role for H+-PPases in phloem loading and biomass partitioning was proposed. In companion cells (CCs) of the phloem, H+-PPases localize to the plasma membrane rather than endomembranes, and rather than hydrolyzing PPi to create pmf, pmf is utilized to synthesize PPi. Additional PPi in the CCs promotes sucrose oxidation and ATP synthesis, which the plasma membrane P-type ATPase in turn uses to create more pmf for phloem loading of sucrose via sucrose-H+ symporters. To test this model, transgenic Arabidopsis (Arabidopsis thaliana) plants were generated with constitutive and CC-specific overexpression of AVP1, encoding type 1 ARABIDOPSIS VACUOLAR PYROPHOSPHATASE1. Plants with both constitutive and CC-specific overexpression accumulated more biomass in shoot and root systems. C-14-labeling experiments showed enhanced photosynthesis, phloem loading, phloem transport, and delivery to sink organs. The results obtained with constitutive and CC-specific promoters were very similar, such that the growth enhancement mediated by AVP1 overexpression can be attributed to its role in phloem CCs. This supports the model for H+-PPases functioning as PPi synthases in the phloem by arguing that the increases in biomass observed with AVP1 overexpression stem from improved phloem loading and transport.
Kazachkova, Y., A. Khan, et al. (2016) Salt Induces Features of a Dormancy-Like State in Seeds of Eutrema (Thellungiella) salsugineum, a Halophytic Relative of Arabidopsis Frontiers in Plant Science 7: 1071 10.3389/fpls.2015.01071The salinization of land is a major factor limiting crop production worldwide. Halophytes adapted to high levels of salinity are likely to possess useful genes for improving crop tolerance to salt stress. In addition, halophytes could provide a food source on marginal lands. However, despite halophytes being salt-tolerant plants, the seeds of several halophytic species will not germinate on saline soils. Yet, little is understood regarding biochemical and gene expression changes underlying salt-mediated inhibition of halophyte seed germination. We have used the halophytic Arabidopsis relative model system, Eutrema (Thellungiella) salsugineum to explore salt-mediated inhibition of germination. We show that E. salsugineum seed germination is inhibited by salt to a far greater extent than in Arabidopsis, and that this inhibition is in response to the osmotic component of salt exposure. E. salsugineum seeds remain viable even when germination is completely inhibited, and germination resumes once seeds are transferred to non-saline conditions. Moreover, removal of the seed coat from salt treated seeds allows embryos to germinate on salt-containing medium. Mobilization of seed storage reserves is restricted in salt treated seeds, while many germination associated metabolic changes are arrested or progress to a lower extent. Salt-exposed seeds are further characterized by a reduced GA/ABA ratio and increased expression of the germination repressor genes, RGL2,AB15, and DOG1. Furthermore, a salt-mediated increase in expression of a LATE EMBRYOGENESIS ABUNDANT gene and accretion of metabolites involved in osmoprotection indicates induction of processes associated with stress tolerance, and accumulation of easily mobilized carbon reserves. Overall, our results suggest that salt inhibits E. salsugineum seed germination by inducing a seed state with molecular features of dormancy while a physical constraint to radicle emergence is provided by the seed coat layers. This seed state could facilitate survival on saline soils until a rain event(s) increases soil water potential indicating favorable conditions for seed germination and establishment of salt-tolerant E. salsugineum seedlings.
Jiang, M., Q. e. Liu, et al. (2016) Cloning and expression of a C3H-type zinc finger protein gene BoCCCH2 from Brassica oleracea var. italica Journal of Zhejiang University (Agriculture and Life Sciences) 42: 143-149.Brassica oleracea var. italica is an important vegetable crop worldwide, and in China, Taizhou City of Zhejiang Province is one of the major broccoli production areas. Downy mildew and grey mold rot are two common fungal diseases caused by Hyaloperonospora parasitica and Botrytis cinerea, respectively. In recent years, broccoli production in Taizhou was frequently affected by these two fungal diseases, resulting in yield and quality loss. Broccoli germplasm resources resistance to disease is scarce; therefore, molecular breeding is regarded as an effective solution to solve the problem. This is critically important to isolate genes associated with disease resistance, which will act as potential target genes for broccoli breeding. Zinc finger proteins are kinds of important transcription factors in eukaryotic organisms, which involve in various biological activities, such as replication, transcription, translation, repair, metabolism and signaling. According to the number and order of cysteine and histidine residues, zinc finger proteins were classified into several different types, such as C2H2, C2C2, C2C2C2, C2HC and C3H. For example, C3H-type ones contain one to six typical motifs with three cysteine residues and one histidine residue. However, their functions are little known, and no gene has been reported in broccoli. In this study, a C3H-type zinc finger protein gene BoCCCH2 was isolated from broccoli, and later the expression patterns in different organs as well as leaves infected by H. parasitica and B. cinerea were studied. Results indicated that BoCCCH2 contained no intron, and the full length of coding sequence was 1 740 bp encoding 579 amino acids. The deduced protein sequence contained two ANK domains and two CCCH zinc finger structures, respectively, and the CCCH zinc finger types were C-X8-C-X5-C-X3-H and C-X5-C-X4-C-X3-H. Reverse transcription-polymerase chain reaction results showed that the BoCCCH2 was expressed in roots, leaves, stalks, young siliques, flower buds and flowers, with highest level in roots. Expression levels increased when challenged by both H. parasitica and B. cinerea. When infected by H. parasitica, expression levels increased after 24 h, and decreased after 72 h, while infected by B. cinerea, the highest level was detected after 6 h, and slowed down in 12 h. Homologous sequences were downloaded from NCBI (National Center for Biotechnology Information) website, including Citrus sinensis, Gossypium raimondii, Populus trichocarpa, Ricinus communis, Prunus persica, P. mume, Malus domestica, Fragaria vesca, Phaseolus vulgaris, Glycine soja, B. rapa, Camelina sativa, Capsella rubella, Arabidopsis thaliana and Eutrema salsugineum. Phylogenetic analysis results revealed that BoCCCH2 was grouped with homogeneous sequences from other Cruciferae plants with bootstrap confidence of 100%, and sequences from Leguminosae, Euphorbiaceae and Rosaceae were found on different clades. In conclusion, these results indicate that the BoCCCH2 might play an important role in defense responses challenged by either H. parasitica or B. cinerea. Cloning and expression analysis of BoCCCH2 provide evidence for further studies on gene function.
Jain, A. and S. Das. (2016) Synteny and comparative analysis of miRNA retention, conservation, and structure across Brassicaceae reveals lineage- and sub-genome-specific changes Functional & Integrative Genomics 16: 253-268. 10.1007/s10142-016-0484-1The recent availability of genome sequences together with syntenic block information for Brassicaceae offers an opportunity to study microRNA (miRNA) evolution across this family. We employed a synteny-based comparative genomics strategy to unambiguously identify miRNA homologs from the genome sequence of members of Brassicaceae. Such an analysis of miRNA across Brassicaceae allowed us to classify miRNAs as conserved, lineage-, karyotype- and sub-genome-specific. The differential loss of miRNA from sub-genomes in polyploid genomes of Brassica rapa and Brassica oleracea shows that miRNA also follows the rules of gene fractionation as observed in the case of protein-coding genes. The study of mature and miR* region of precursors revealed instances of in-dels and SNPs which reflect the evolutionary history of the genomes. High level of conservation in miR* regions in some cases points to their functional relevance which needs to be further investigated. We further show that sequence and length variability in precursor sequences can affect the free energy and foldback structure of miRNA which may ultimately affect their biogenesis and expression in the biological system.
Huang, B. L., X. K. Zhang, et al. (2016) Cloning and characterization of the dehydration-responsive element-binding protein 2A gene in Eruca vesicaria subsp sativa Genetics and Molecular Research 15: 15038540 10.4238/gmr.15038540Eruca vesicaria subsp sativa is one of the most tolerant Cruciferae species to drought, and dehydration-responsive element-binding protein 2A (DREB2A) is involved in responses to salinity, heat, and particularly drought. In this study, a gene encoding EvDREB2A was cloned and characterized in E. vesicaria subsp sativa. The full-length EvDREB2A cDNA sequence contained a 388-bp 5'-untranslated region (UTR), a 348-bp 3'-UTR, and a 1002-bp open reading frame that encoded 334 amino acid residues. The theoretical isoelectric point of the EvDREB2A protein was 4.80 and the molecular weight was 37.64 kDa. The genomic sequence of EvDREB2A contained no introns. Analysis using SMART indicated that EvDREB2A contains a conserved AP2 domain, similar to other plant DREBs. Phylogenetic analysis revealed that EvDREB2A and DREB2As from Brassica rapa, Eutrema salsugineum, Arabidopsis thaliana, Arabidopsis lyrata, and Arachis hypogaea formed a small subgroup, which clustered with DREB2Bs from A. lyrata, A. thaliana, Camelina sativa, and B. rapa to form a larger subgroup. EvDREB2A is most closely related to B. rapa DREB2A, followed by DREB2As from E. salsugineum, A. thaliana, A. hypogaea, and A. lyrata. A quantitative real-time polymerase chain reaction indicated that EvDREB2A expression was highest in the leaves, followed by the roots and hypocotyls, and was lowest in the flower buds. EvDREB2A could be used to improve drought tolerance in crops.
Huang, B. L., X. K. Zhang, et al. (2016) Cloning and characterization of the dehydration-responsive element-binding protein 2A gene in Eruca vesicaria subsp sativa Genetics and molecular research : GMR 15: 10.4238/gmr.15038540Eruca vesicaria subsp sativa is one of the most tolerant Cruciferae species to drought, and dehydration-responsive element-binding protein 2A (DREB2A) is involved in responses to salinity, heat, and particularly drought. In this study, a gene encoding EvDREB2A was cloned and characterized in E. vesicaria subsp sativa. The full-length EvDREB2A cDNA sequence contained a 388-bp 5'-untranslated region (UTR), a 348-bp 3'-UTR, and a 1002-bp open reading frame that encoded 334 amino acid residues. The theoretical isoelectric point of the EvDREB2A protein was 4.80 and the molecular weight was 37.64 kDa. The genomic sequence of EvDREB2A contained no introns. Analysis using SMART indicated that EvDREB2A contains a conserved AP2 domain, similar to other plant DREBs. Phylogenetic analysis revealed that EvDREB2A and DREB2As from Brassica rapa, Eutrema salsugineum, Arabidopsis thaliana, Arabidopsis lyrata, and Arachis hypogaea formed a small subgroup, which clustered with DREB2Bs from A. lyrata, A. thaliana, Camelina sativa, and B. rapa to form a larger subgroup. EvDREB2A is most closely related to B. rapa DREB2A, followed by DREB2As from E. salsugineum, A. thaliana, A. hypogaea, and A. lyrata. A quantitative real-time polymerase chain reaction indicated that EvDREB2A expression was highest in the leaves, followed by the roots and hypocotyls, and was lowest in the flower buds. EvDREB2A could be used to improve drought tolerance in crops.
Houmani, H. and F. J. Corpas. (2016) Differential responses to salt-induced oxidative stress in three phylogenetically related plant species: Arabidopsis thaliana (glycophyte), Thellungiella salsuginea and Cakile maritima (halophytes). Involvement of ROS and NO in the control of K+/Na+ homeostasis Aims Biophysics 3: 380-397. 10.3934/biophy.2016.3.380Salinity, which is usually associated with a nitro-oxidative stress component, is one of the major environmental factors limiting plant growth and development. Plants have thus developed specific ways of dealing with this problem. The compartmentalization of sodium (Na+) ions in vacuoles and the capacity to sharply discriminate between potassium (K+) and Na+ in order to maintain high K+/Na+ ratios are two of the most effective strategies to overcome salt stress. Plants require large amounts of K+ to maximize growth and yields. This macronutrient is involved in physiological processes such as growth, photosynthesis, osmoregulation, enzyme activation, stomatal movement, water and nutrient transport via the xylem and protein synthesis. Resistance to salt stress is mainly related to the capacity of plants to maintain improved K+ uptake despite competition from Na+. The Brassicaceae family includes species such as Arabidopsis thaliana (plant model for glycophytes), Thellungiella salsuginea and Cakile maritima (plant models for halophytes), which exhibit significant variations in response to salt stress. In this review, we provide a comprehensive update with respect to differential responses to salt stress in these three plant species, with particular emphasis on the potential involvement of reactive oxygen species (ROS) and nitric oxide (NO) in maintaining K+/Na+ homeostasis and their contribution to salt tolerance.
Hou, J., P. Jiang, et al. (2016) Isolation and Functional Validation of Salinity and Osmotic Stress Inducible Promoter from the Maize Type-II H+-Pyrophosphatase Gene by Deletion Analysis in Transgenic Tobacco Plants Plos One 11: e0154041 10.1371/journal.pone.0154041Salinity and drought severely affect both plant growth and productivity, making the isolation and characterization of salinity-or drought-inducible promoters suitable for genetic improvement of crop resistance highly desirable. In this study, a 1468-bp sequence upstream of the translation initiation codon ATG of the promoter for ZmGAPP (maize Type-II H+-pyrophosphatase gene) was cloned. Nine 5' deletion fragments (D1-D9) of different lengths of the ZmGAPP promoter were fused with the GUS reporter and translocated into tobacco. The deletion analysis showed that fragments D1-D8 responded well to NaCl and PEG stresses, whereas fragment D9 and CaMV 35S did not. The D8 segment (219 bp; -219 to -1 bp) exhibited the highest promoter activity of all tissues, with the exception of petals among the D1-D9 transgenic tobacco, which corresponds to about 10% and 25% of CaMV 35S under normal and NaCl or PEG stress conditions, respectively. As such, the D8 segment may confer strong gene expression in a salinity and osmotic stress inducible manner. A 71-bp segment (-219 to -148 bp) was considered as the key region regulating ZmGAPP response to NaCl or PEG stress, as transient transformation assays demonstrated that the 71-bp sequence was sufficient for the salinity or osmotic stress response. These results enhance our understanding of the molecular mechanisms regulating ZmGAPP expression, and that the D8 promoter would be an ideal candidate for moderating expression of drought and salinity response genes in transgenic plants.
Hirata, H., M. Kashihara, et al. (2016) Genome sequence of Pectobacterium carotovorum phage PPWS1, isolated from Japanese horseradish Eutrema japonicum (Miq.) Koidz showing soft-rot symptoms Genome Announcements 4: e01625-01615.Pectobacterium carotovorum subsp. carotovorum and its lytic bacteriophage PPWS1 were isolated from a Japanese horseradish rhizome with soft rot. Sequencing of the phage genomic DNA suggested that PPWS1 is a new species of the family Podoviridae and has high similarity to the bacteriophage Peat1 infectious to P. atrosepticum.
Hincha, D. K. and Y. P. Lee. (2016) GSE71271: Salt stress responses of Arabidopsis thaliana and Eutrema salsugineum (Thellungiella salsuginea) Gene Expression OmnibusArabidopsis thaliana is a glycophyte with a low salt tolerance, while Eutrema is a halophyte with a very high salt tolerance. To elucidate the transcriptional basis of this difference, we performed hydroponis culture experiments where we grew plants under control conditions (25 mM NaCl) or under salt stress (200 mM NaCl for both species, 500 mM for Eutrema). Salt concentration was increased for the stress treatments by increments of 50 mM per day (25 mM on the first day). Plants were grown at the final NaCl concentration for an additional week, when rosettes were harvested for RNA isolation.Expression patterns were compared between treatments and between species.
Hincha, D. K. and Y. P. Lee. (2016) Salt stress responses of Arabidopsis thaliana and Eutrema salsugineum (Thellungiella salsuginea) ArrayExpress ArchiveArabidopsis thaliana is a glycophyte with a low salt tolerance, while Eutrema is a halophyte with a very high salt tolerance. To elucidate the transcriptional basis of this difference, we performed hydroponis culture experiments where we grew plants under control conditions (25 mM NaCl) or under salt stress (200 mM NaCl for both species, 500 mM for Eutrema). Salt concentration was increased for the stress treatments by increments of 50 mM per day (25 mM on the first day). Plants were grown at the final NaCl concentration for an additional week, when rosettes were harvested for RNA isolation.Expression patterns were compared between treatments and between species. In total, 15 samples were hybridized. They were derived from three independent biological experiments (replicate_1 to replicate_3). Controlds were grown at 25 mM NaCl, salt stressed plants at either 200 mM NaCl or 500 mM NaCl.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831691: 33D_old_hydroponic_grown_rosette_leaves_control_replicate_1 Gene Expression OmnibusGene expression for contorl Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831693: 33D_old_hydroponic_grown_rosette_leaves_control_replicate_3 Gene Expression OmnibusGene expression for contorl Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831694: 29D_old_hydroponic_grown_rosette_leaves_1W_acclimated_at_200mM_NaCl_repl icate_1 Gene Expression OmnibusGene expression for 1 week 200 mM NaCl salt-acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831697: 35D_old_hydroponic_grown_rosette_leaves_1W_acclimated_at_500mM_NaCl_repl icate_1 Gene Expression OmnibusGene expression for 1 week 500 mM NaCl salt-acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831698: 35D_old_hydroponic_grown_rosette_leaves_1W_acclimated_at_500mM_NaCl_repl icate_2 Gene Expression OmnibusGene expression for 1 week 500 mM NaCl salt-acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831695: 29D_old_hydroponic_grown_rosette_leaves_1W_acclimated_at_200mM_NaCl_repl icate_2 Gene Expression OmnibusGene expression for 1 week 200 mM NaCl salt-acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831696: 29D_old_hydroponic_grown_rosette_leaves_1W_acclimated_at_200mM_NaCl_repl icate_3 Gene Expression OmnibusGene expression for 1 week 200 mM NaCl salt-acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831699: 35D_old_hydroponic_grown_rosette_leaves_1W_acclimated_at_500mM_NaCl_repl icate_3 Gene Expression OmnibusGene expression for 1 week 500 mM NaCl salt-acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K. and Y. P. Lee. (2016) GSM1831692: 33D_old_hydroponic_grown_rosette_leaves_control_replicate_2 Gene Expression OmnibusGene expression for contorl Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Himabindu, Y., T. Chakradhar, et al. (2016) Salt-tolerant genes from halophytes are potential key players of salt tolerance in glycophytes Environmental and Experimental Botany 124: 39-63. 10.1016/j.envexpbot.2015.11.010Crop productivity strongly depends on several biotic and abiotic factors. Salinity is one of the most important abiotic factors, besides drought, extreme temperatures, light and metal stress. The enhanced burden of secondary salinization induced through anthropogenic activities increases pressure on glycophytic crop plants. The recent isolation and characterization of salt tolerance genes encoding signaling components from halophytes, which naturally grow in high salinity, has provided tools for the development of transgenic crop plants with improved salt tolerance and economically beneficial traits. In addition understanding of the differences between glycophytes and halophytes with respect to levels of salinity tolerance is also one of the prerequisite to achieve this goal. Based on the recent developments in mechanisms of salt tolerance in halophytes, we will explore the potential of introducing salt tolerance by choosing the available genes from both dicotyledonous and monocotyledonous halophytes, including the salt overly sensitive system (SOS)-related cation/proton antiporters of plasma (NHX/SOS1) and vacuolar membranes (NHX), energy -related pumps, such as plasma membrane and vacuolar H+ adenosine triphosphatase (PM & V-H(+)ATPase), vacuolar pyrophosphatases (V-H(+)PPase) and potassium transporter genes. Various halophyte genes responsible for other processes, such as crosstalk signaling, osmotic solutes production and reactive oxygen species (ROS) suppression, which also enhance salt tolerance will be described. In addition, the transgenic overexpression of halophytic genes in crops (rice, peanut, finger millet, soybean, tomato, alfalfa, jatropha, etc.) will be discussed as a successful mechanism for the induction of salt tolerance. Moreover, the advances in genetic engineering technology for the production of genetically modified crops to achieve the improved salinity tolerance under field conditions will also be discussed. (C) 2015 Elsevier B.V. All rights reserved.
He, Q., G. Hao, et al. (2016) The complete chloroplast genome of Schrenkiella parvula (Brassicaceae) Mitochondrial DNA Part A 27: 3527-3528. 10.3109/19401736.2015.1074202Schrenkiella parvula is an Arabidopsis-related model species used here for studying plant stress tolerance. In this study, the complete chloroplast genome sequence of S. parvula has been reported for the first time. The total length of the chloroplast genome was 153 979 bp, which had a typical quadripartite structure. The annotated plastid genome includes 87 protein-coding genes, 39 tRNA genes and 8 ribosomal RNA genes. The evolutionary relationships revealed by our phylogenetic analysis indicated that S. parvula is closer to the Brassiceae species when compared with Eutrema salsugineum.
Hao, G., H. Bi, et al. (2016) The whole chloroplast genomes of two Eutrema species (Brassicaceae) Mitochondrial DNA Part A 27: 3727-3728. 10.3109/19401736.2015.1079877In this study, we determined the complete chloroplast genomes from two crucifer species of the Eutrema genus. The sizes of the two cp genomes were 153 948 bp (E. yunnanense) and 153 876 bp (E. heterophyllum). Both genomes have the typical quadripartite structure consisting of a large single copy region, a small single copy region and two inverted repeats. Gene contents and their relative positions of the 132 individual genes (87 protein-coding genes, eight rRNA, and 37 tRNA genes) of either genome were identical to each other. Phylogenetic analysis supports the idea that the currently recognized Eutrema genus is monophyletic and that E. salsugineum and Schrenkiella parvula evolved salt tolerance independently.
Hao, G., I. A. Al-Shehbaz, et al. (2016) Eutrema tianshanense (Brassicaceae), a new species from Tian Shan Mountains of central Asia Phytotaxa 286: 23-31. 10.11646/phytotaxa.286.1.3Eutrema tianshanense, a new species of Brassicaceae growing near to the permanent glaciation area in the Tian Shan Mountains of central Asia, is described. It is quite similar morphologically to E. heterophyllum, and E. racemosum from the Qinghai- Tibet Plateau and adjacent regions, and to E. edwardsii of Qinghai-Tibet Plateau, Central and North Asia, and northern North America, but with rounder and smaller leaves. In addition to its long-distance disjunction from the ranges of the above three species, phylogenetic analyses based on sequence variations of multiple chloroplast DNA markers and nuclear ITS suggested that E. tianshanense and these species represent two independently evolved lineages in Tian Shan Mountains and the Qinghai-Tibet Plateau. Their morphological similarities may have resulted from the same selection pressures in the alpine habitats where they grow.
Guo, X., G. Hao, et al. (2016) The complete chloroplast genome of salt cress (Eutrema salsugineum) Mitochondrial DNA Part A 27: 2862-2863. 10.3109/19401736.2015.1053130The complete chloroplast (cp) sequence of the salt cress (Eutrema salsugineum), a plant well-adapted to salt stress, was presented in this study. The circular molecule is 153,407 bp in length and exhibit a typical quadripartite structure containing an 83,894 bp large single copy (LSC) region, a 17,607 bp small single copy (SSC) region, and the two 25,953 bp inverted repeats (IRs). The salt cress cp genome contains 135 known genes, including 87 protein-coding genes, 8 ribosomal RNA genes, and 40 tRNA genes; 21 of these are located in the inverted repeat region. As expected, phylogenetic analysis support the idea that E. salsugineum is sister to Brassiceae species within the Brassicaceae family.
Geng, Y., Y. Zhang, et al. (2016) Traditional knowledge and its transmission of wild edibles used by the Naxi in Baidi Village, northwest Yunnan province Journal of Ethnobiology and Ethnomedicine 12: 10 10.1186/s13002-016-0082-2Background: The collection and consumption of wild edibles is an important part in livelihood strategies throughout the world. There is an urgent need to document and safeguard the wild food knowledge, especially in remote areas. The aims of this study are to accomplish detailed investigation of wild edibles used by the Naxi in Baidi village and evaluate them to identify innovative organic food products. Also, we aim to explore the characteristics of distribution and transmission of the traditional knowledge (TK) on wild edibles among the Naxi. Methods: Data was collected through a semi-structured interview of key informants above the age of 20 years, chosen carefully by a snowball sampling. The interviews were supplemented by free lists and participatory observation methods. Informants below 20 years were interviewed to test their knowledge of traditional practices. A quantitative index like Cultural Importance Index (CI) was used to evaluate the relative importance of the different wild edibles. Linear regression and t-test were performed to test variation in the TK among the informants of different age groups and genders. Results: Altogether 173 wild edible plant species belonging to 76 families and 139 genera were recorded in the study. Cardamine macrophylla, C. tangutorum and Eutrema yunnanense, have traditionally been consumed as an important supplement to the diet, particularly during food shortages as wild vegetables. The age was found to have a significant effect on TK, but there was no significant difference between male and female informant in knowledge abundance. The traditional food knowledge was dynamic and affected by social factors. Also, it was descending partly among younger generations in Baidi. Conclusion: Baidi village is a prime example of a rapidly changing community where local traditions compete with modern ways of life. Overall, this study provides a deeper understanding of the Naxi peoples' knowledge on wild edibles. Some wild edibles might have an interesting dietary constituent, which need in-depth studies. Such detail studies can help to promote the market in one hand and protect TK in the other. Protecting TK from disappearing in succeeding generations is necessary, and understanding the dynamics of TK is one important solution to this dilemma.
Genetics, U. o. G. (2016) On the Origin and Evolutionary Consequences of Gene Body DNA Methylation European Nucleotide ArchiveIn plants, CG DNA methylation is prevalent in the transcribed regions of constitutively expressed genes (aoegene body methylation; gbMa), but the origin and function of gbM remain unknown. Here we report the discovery that Eutrema salsugineum, has lost gbM from its genome, the first known instance for a flowering plant. Of all known DNA methyltransferases, only CHROMOMETHYLTRANSFERASE 3 (CMT3) is missing from E. salsugineum, indicating that CMT3 may be required for the establishment of gbM. Detailed analyses of gene expression, the histone variant H2A.Z and various histone modifications in E. salsugineum and Arabidopsis thaliana epiRILs turned up no evidence in support of any role for gbM in regulating transcription or affecting the composition and modifications of chromatin over evolutionary time scales. Overall design: Examination of DNA methylation, gene expression, and histone variant H2A.Z between Eutrema salsugineum, A. thaliana and methylation/histone modification mutants.
Gao, Y., Y. Lu, et al. (2016) Ability to Remove Na+ and Retain K+ Correlates with Salt Tolerance in Two Maize Inbred Lines Seedlings Frontiers in Plant Science 7: 1716 10.3389/fpls.2016.01716Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Here, excellent salt-tolerant maize inbred line TL1317 and extremely salt-sensitive maize inbred line SL1303 were screened to understand the maize response to salt stress and its tolerance mechanisms. Relative water content, membrane stability index, stomatal conductance, chlorophyll content, maximum photochemical efficiency, photochemical efficiency, shoot and root fresh/dry weight, and proline and water soluble sugar content analyses were used to identify that the physiological effects of osmotic stress of salt stress were obvious and manifested at about 3 days after salt stress in maize. Moreover, the ion concentration of two maize inbred lines revealed that the salt-tolerant maize inbred line could maintain low Na+ concentration by accumulating Na+ in old leaves and gradually shedding them to exclude excessive Na+. Furthermore, the K+ uptake and retention abilities of roots were important in maintaining K+ homeostasis for salt tolerance in maize. RNA-seq and qPCR results revealed some Na+/H+ antiporter genes and Ca2(+) transport genes were up-regulated faster and higher in TL1317 than those in SL1303. Some K+ transport genes were down-regulated in SL1303 but up-regulated in TL1317. RNA-seq results, along with the phenotype and physiological results, suggested that the salt-tolerant maize inbred line TL1317 possesses more rapidly and effectively responses to remove toxic Na+ ions and maintain K+ under salt stress than the salt-sensitive maize inbred line SL1303. This response should facilitate cell homoeostasis under salt stress and result in salt tolerance in TL1317.
Gao, J., J. Sun, et al. (2016) Variation in tissue Na+ content and the activity of SOS1 genes among two species and two related genera of Chrysanthemum Bmc Plant Biology 16: 98 10.1186/s12870-016-0781-9Background: Chrysanthemum, a leading ornamental species, does not tolerate salinity stress, although some of its related species do. The current level of understanding regarding the mechanisms underlying salinity tolerance in this botanical group is still limited. Results: A comparison of the physiological responses to salinity stress was made between Chrysanthemum morifolium 'Jinba' and its more tolerant relatives Crossostephium chinense, Artemisia japonica and Chrysanthemum crassum. The stress induced a higher accumulation of Na+ and more reduction of K+ in C. morifolium than in C. chinense, C. crassum and A. japonica, which also showed higher K+/Na+ ratio. Homologs of an Na+/H+ antiporter (SOS1) were isolated from each species. The gene carried by the tolerant plants were more strongly induced by salt stress than those carried by the non-tolerant ones. When expressed heterologously, they also conferred a greater degree of tolerance to a yeast mutant lacking Na+-pumping ATPase and plasma membrane Na+/H+ antiporter activity. The data suggested that the products of AjSOS1, CrcSOS1 and CcSOS1 functioned more effectively as Na+ excluders than those of CmSOS1. Over expression of four SOS1s improves the salinity tolerance of transgenic plants and the overexpressing plants of SOS1s from salt tolerant plants were more tolerant than that from salt sensitive plants. In addition, the importance of certain AjSOS1 residues for effective ion transport activity and salinity tolerance was established by site-directed mutagenesis and heterologous expression in yeast. Conclusions: AjSOS1, CrcSOS1 and CcSOS1 have potential as transgenes for enhancing salinity tolerance. Some of the mutations identified here may offer opportunities to better understand the mechanistic basis of salinity tolerance in the chrysanthemum complex.
Eshel, G., R. Shaked, et al. (2016) Anastatica hierochuntica, an Arabidopsis Desert Relative, Is Tolerant to Multiple Abiotic Stresses and Exhibits Species-Specific and Common Stress Tolerance Strategies with Its Halophytic Relative, Eutrema (Thellungiella) salsugineum Frontiers in Plant Science 7: 1992-1992. 10.3389/fpls.2016.01992The search for novel stress tolerance determinants has led to increasing interest in plants native to extreme environments - so called "extremophytes." One successful strategy has been comparative studies between Arabidopsis thaliana and extremophyte Brassicaceae relatives such as the halophyte Eutrema salsugineum located in areas including cold, salty coastal regions of China. Here, we investigate stress tolerance in the desert species, Anastatica hierochuntica (True Rose of Jericho), a member of the poorly investigated lineage III Brassicaceae. We show that A. hierochuntica has a genome approximately 4.5-fold larger than Arabidopsis, divided into 22 diploid chromosomes, and demonstrate that A. hierochuntica exhibits tolerance to heat, low N and salt stresses that are characteristic of its habitat. Taking salt tolerance as a case study, we show that A. hierochuntica shares common salt tolerance mechanisms with E. salsugineum such as tight control of shoot Na+ accumulation and resilient photochemistry features. Furthermore, metabolic profiling of E. salsugineum and A. hierochuntica shoots demonstrates that the extremophytes exhibit both species-specific and common metabolic strategies to cope with salt stress including constitutive up-regulation (under control and salt stress conditions) of ascorbate and dehydroascorbate, two metabolites involved in ROS scavenging. Accordingly, A. hierochuntica displays tolerance to methyl viologen-induced oxidative stress suggesting that a highly active antioxidant system is essential to cope with multiple abiotic stresses. We suggest that A. hierochuntica presents an excellent extremophyte Arabidopsis relative model system for understanding plant survival in harsh desert conditions.
Cong, M., J. Zhao, et al. (2016) Homologous cloning, characterization and expression of a new halophyte phytochelatin synthase gene in Suaeda salsa Chinese Journal of Oceanology and Limnology 34: 1034-1043. 10.1007/s00343-016-4382-0The halophyte Suaeda salsa can grow in heavy metal-polluted areas along intertidal zones having high salinity. Since phytochelatins can effectively chelate heavy metals, it was hypothesized that S. salsa possessed a phytochelatin synthase (PCS) gene. In the present study, the cDNA of PCS was obtained from S. salsa (designated as SsPCS) using homologous cloning and the rapid amplification of cDNA ends (RACE). A sequence analysis revealed that SsPCS consisted of 1 916 bp nucleotides, encoding a polypeptide of 492 amino acids with one phytochelatin domain and one phytochelatin C domain. A similarity analysis suggested that SsPCS shared up to a 58.6% identity with other PCS proteins and clustered with PCS proteins from eudicots. There was a new kind of metal ion sensor motif in its C-terminal domain. The SsPCS transcript was more highly expressed in elongated and fibered roots and stems (P < 0.05) than in leaves. Lead and mercury exposure significantly enhanced the mRNA expression of SsPCS (P < 0.05). To the best of our knowledge, SsPCS is the second PCS gene cloned from a halophyte, and it might contain a different metal sensing capability than the first PCS from Thellungiella halophila. This study provided a new view of halophyte PCS genes in heavy metal tolerance.
Bewick, A. J., L. Ji, et al. (2016) On the origin and evolutionary consequences of gene body DNA methylation Proceedings of the National Academy of Sciences of the United States of America 113: 9111-9116. 10.1073/pnas.1604666113In plants, CG DNA methylation is prevalent in the transcribed regions of many constitutively expressed genes (gene body methylation; gbM), but the origin and function of gbM remain unknown. Here we report the discovery that Eutrema salsugineum has lost gbM from its genome, to our knowledge the first instance for an angiosperm. Of all known DNA methyltransferases, only CHROMOMETHYLASE 3 (CMT3) is missing from E. salsugineum. Identification of an additional angiosperm, Conringia planisiliqua, which independently lost CMT3 and gbM, supports that CMT3 is required for the establishment of gbM. Detailed analyses of gene expression, the histone variant H2A.Z, and various histone modifications in E. salsugineum and in Arabidopsis thaliana epigenetic recombinant inbred lines found no evidence in support of any role for gbM in regulating transcription or affecting the composition and modification of chromatin over evolutionary timescales.
Bedre, R., V. R. Mangu, et al. (2016) Transcriptome analysis of smooth cordgrass (Spartina alterniflora Loisel), a monocot halophyte, reveals candidate genes involved in its adaptation to salinity Bmc Genomics 17: 657 10.1186/s12864-016-3017-3Background: Soil salinity affects growth and yield of crop plants. Plants respond to salinity by physiological and biochemical adjustments through a coordinated regulation and expression of a cascade of genes. Recently, halophytes have attracted attention of the biologists to understand their salt adaptation mechanisms. Spartina alterniflora (smooth cordgrass) is a Louisiana native monocot halophyte that can withstand salinity up to double the strength of sea water. To dissect the molecular mechanisms underlying its salinity adaptation, leaf and root transcriptome of S. alterniflora was sequenced using 454/GS-FLX. Results: Altogether, 770,690 high quality reads with an average length 324-bp were assembled de novo into 73,131 contigs (average 577-bp long) with 5.9X sequence coverage. Most unigenes (95 %) annotated to proteins with known functions, and had more than 90 % similarity to rice genes. About 28 % unigenes were considered specific to S. alterniflora. Digital expression profiles revealed significant enrichment (P < 0.01) of transporters, vacuolar proton pump members and transcription factors under salt stress, which suggested the role of ion homeostasis and transcriptional regulation in the salinity adaptation of this grass. Also, 10,805 SSRs markers from 9457 unigenes were generated and validated through genetic diversity analysis among 13 accessions of S. alterniflora. Conclusions: The present study explores the transcriptome of S. alterniflora to understand the gene regulation under salt stress in halophytes. The sequenced transcriptome (control and salt-regulated) of S. alterniflora provides a platform for further gene finding studies in grasses. This study and our previously published studies suggested that S. alterniflora is a rich reservoir of salt tolerance genes that can be used to develop salt tolerant cereal crops, especially rice, a major food crop of global importance.
Banerjee, A. and A. Roychoudhury. (2016) Group II late embryogenesis abundant (LEA) proteins: structural and functional aspects in plant abiotic stress Plant Growth Regulation 79: 1-17. 10.1007/s10725-015-0113-3Group II late embryogenesis abundant (LEA) proteins are crucial phytomolecules which accumulate mainly in the late phases of seed development and also in the vegetative tissues in response to exogenous stress. In spite of considerable research, their mechanism of action to generate plant tolerance against abiotic stresses still remains obscure. The present review focuses on the varied structural aspects which ultimately dictate the multifarious functions of the Group II LEA proteins when the plants are exposed to intense desiccation. Currently, several reports have been documented regarding newer in silico approaches in predicting LEA protein structure and the corresponding cis-elements. Coupled to recent transgenic approaches, these reports need to be properly structured to further characterize the physico-chemical and functional importance of LEA proteins in regulating tolerance against multiple abiotic stresses.
Azri, W., Z. Barhoumi, et al. (2016) Proteomic responses in shoots of the facultative halophyte Aeluropus littoralis (Poaceae) under NaCl salt stress Functional Plant Biology 43: 1028-1047. 10.1071/fp16114Salinity is an environmental constraint that limits agricultural productivity worldwide. Studies on the halophytes provide valuable information to describe the physiological and molecular mechanisms of salinity tolerance. Therefore, because of genetic relationships of Aeluropus littoralis (Willd) Parl. with rice, wheat and barley, the present study was conducted to investigate changes in shoot proteome patterns in response to different salt treatments using proteomic methods. To examine the effect of salinity on A. littoralis proteome pattern, salt treatments (0, 200 and 400mM NaCl) were applied for 24h and 7 and 30 days. After 24h and 7 days exposure to salt treatments, seedlings were fresh and green, but after 30 days, severe chlorosis was established in old leaves of 400mM NaCl-salt treated plants. Comparative proteomic analysis of the leaves revealed that the relative abundance of 95 and 120 proteins was significantly altered in 200 and 400mM NaCl treated plants respectively. Mass spectrometry-based identification was successful for 66 out of 98 selected protein spots. These proteins were mainly involved in carbohydrate, energy, amino acids and protein metabolisms, photosynthesis, detoxification, oxidative stress, translation, transcription and signal transduction. These results suggest that the reduction of proteins related to photosynthesis and induction of proteins involved in glycolysis, tricarboxylic acid (TCA) cycle, and energy metabolism could be the main mechanisms for salt tolerance in A. littoralis. This study provides important information about salt tolerance, and a framework for further functional studies on the identified proteins in A. littoralis.
Ali, A. and D.-J. Yun. (2016) Differential selection of sodium and potassium ions by TsHKT1;2 Plant signaling & behavior 11: e1206169 10.1080/15592324.2016.1206169Among abiotic stresses, soil salinity is a major threat to agriculture. To address and control the effects of high salinity on plants, it is important to understand their responses to salt stress that disturbs the homeostatic equilibrium at cellular and molecular levels. To deal and control effects of high salinity on plants, it is important to understand their responses to salt stress that disturbs the homeostatic equilibrium at cellular and molecular levels. In this regard, halophytes (salt tolerant plants) can provide superior models for the study of salt stress defense parameters compared to glycophytes (salt sensitive species). TsHKT1; 2 one of the 3 copies of HKT1 in the Arabidopsis relative halophyte, Thellungiella salsuginea acts as a potassium transporter, even under salt stress. TsHKT1; 2 includes a conserved Asp (D) residue in the 2nd pore-loop domain. Most other HKT1 sequences, including AtHKT1, contain Asn (N) in this position. We found that athkt1-1 plants complemented by TsHKT1; 2 under native AtHKT1 promoter were more tolerant to salt stress, while substitution of Asp (D207) by Asn (N) significantly reduced resistance to salinity. We suggest that the presence of Asn or Asp is the essential feature that defines and establishes cation selectivity in dicot HKT1-type transporters.
Ali, A., N. Raddatz, et al. (2016) A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance Plant Physiology 171: 2112-2126. 10.1104/pp.16.00569A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K+ TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na+ from the transpiration stream. However, TsHKT1; 2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K+ transporter in the presence of Na+ in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1; 2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (N) in this position. Wild-type TsHKT1; 2 and altered AtHKT1 (AtHKT1(N-D)) complemented K+-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1(N-D) and TsHKT1; 2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na+ and K+ based on the N/D variance in the pore region. This change also dictated inward-rectification for Na+ transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats.
Al-Shehbaz, I. A. (2016). Brassicaceae: Volume 30. Flora of the Pan-Himalaya. in Brassicaceae: Volume 30. Flora of the Pan-Himalaya (I. A. Al-Shehbaz eds.) Zhu, J.-K. (2015) The Next Top Models Cell 163: 18-18.Previous studies have indicated that homeodomain-leucine zipper (HD-Zip) transcription factors play important roles during abiotic stress, but there is no information on the functions of HD-Zip genes in a new model plant Eutrema salsugineum for studying plant abiotic stress tolerance. Here, EsHdzip1 (GenBank No. XM_006390503) belonging to the Class IV subgroup of HD-Zip transcription factor family was isolated from E. salsugineum and characterized for its physiological roles under drought stress conditions. Transgenic tobacco plants overexpressing EsHdzip1 exhibited increased drought resistance with promoted root growth and reduction of water loss. Furthermore, these transgenic plants had lower ion leakage (IL), malondialdehyde (MDA), and reactive oxygen species (ROS) accumulation, but higher content of osmotic solutes (proline and total soluble sugars) and activities of antioxidant enzymes including superoxide dismutase (SOD) and ascorbate peroxidase (APX) relative to wild-type (WT) plants when subjected to drought stress treatments. The content of abscisic acid (ABA) was also observed to be remarkably higher in the transgenic lines than WT plants under drought stress conditions. In addition, the expression levels of three important stress-related genes (NtP5CS, NtERD10C, and NtLEA5) involved in the osmotic adjustment and water maintenance were significantly higher than WT plants under drought stress conditions. Therefore, we have revealed important roles of the EsHdzip1 gene in response to drought stress, suggesting that this gene has a great potential for improving plant drought tolerance by engineering manipulation.
Zhou, C., Y. Sun, et al. (2015) Heterologous expression of EsSPDS1 in tobacco plants improves drought tolerance with efficient reactive oxygen species scavenging systems South African Journal of Botany 96: 19-28. 10.1016/j.sajb.2014.10.008It has previously been indicated that polyamines (PM) are involved in the response to adverse environmental stresses in various plant species. Increased cellular PA levels or exogenous PA application can reduce the accumulation of reactive oxygen species (ROS) imposed by multiple abiotic stresses via increasing antioxidant enzyme activities. In this study, a novel spermidine synthase gene, designated as EsSPDS1, was cloned and characterized from the halophytic plant Eutrema salsugitteum. Analyses of tissue-specific expression profiles revealed that EsSPDS1 was expressed in almost all tested organs including leaves, stems, flowers, roots and siliques. The expression of EsSPDS1 was obviously induced by polyethylene glycol (PEG) and high salinity treatments. Furthermore, the EsSPDS1 transcripts rapidly accumulated upon exposure to abscisic acid (ABA) treatments, implying that this gene was involved in ABA-mediated abiotic stress response. Trangenic tobacco plants harboring EsSPDS1 exhibited enhanced drought tolerance relative to wild-type (WT) plants. These transgenic plants had lower levels of malondialdehyde (MDA), less ion leakage (IL) and reactive oxygen species (ROS). However, relative water content (RWC) and activities of antioxidant enzymes including SOD and CAT of the transgenic plants was remarkably higher than those of WT plants under drought stress conditions. Collectively, our data suggested that the activation of EsSPDS1 expression in tobacco plants conferred drought tolerance, which might be attributed to enhance the ability to scavenge ROS levels. (C) 2014 SAAB. Published by Elsevier B.V. All rights reserved.
Zhou, C., Y. Sun, et al. (2015) OVEREXPRESSION OF EsDHAR1 IMPROVED TOLERANCE IN TRANSGENIC TOBACCO WITH INCREASED ASCORBIC ACID LEVELS Oxidation Communications 38: 677-688.Vitamin C (ascorbic acid, AsA) is a pivotal antioxidant that alleviates oxidative damage imposed by various environmental stresses such as drought, cold and salinity. The dehydroascorbate reductase (DHAR) has recently been shown to play an essential role in the regeneration of AsA. In this work, a novel cDNA encoding DHAR, designated as EsDHAR1, was isolated from Eutrema salsugineum. To investigate the protective role of EsDHAR1 against oxidative stress, a constructed plasmid carrying its coding region was introduced into tobacco plants. Our results revealed that the EsDHAR1-overexpressing lines had higher content of AsA and glutathione (GSH) relative to wild type (WT) plants under well-watered and drought stress conditions. When plants were subjected to drought stress or in vitro leaf discs were treated with NaCl or mannitol, the transgenic lines exhibited a greater tolerance to these stresses compared with WT plants. Furthermore, these transgenic lines accumulated lower reactive oxygen species (ROS) including H2O2 and O-2(-) than WT plants under drought stress. Collectively, our study demonstrated that overexpression of EsDHAR1 enhanced the AsA biosynthesis in transgenic tobacco plants and provided important evidence that this gene could be used to improve plant adaptation to adverse environments.
Zhou, C., Z. Y. Ma, et al. (2015) Overexpression of EsMcsu1 from the halophytic plant Eutrema salsugineum promotes abscisic acid biosynthesis and increases drought resistance in alfalfa (Medicago sativa L.) Genetics and Molecular Research 14: 17204-17218. 10.4238/2015.December.16.20The stress phytohormone abscisic acid (ABA) plays pivotal roles in plants' adaptive responses to adverse environments. Molybdenum cofactor sulfurases influence aldehyde oxidase activity and ABA biosynthesis. In this study, we isolated a novel EsMcsu1 gene encoding a molybdenum cofactor sulfurase from Eutrema salsugineum. EsMcus1 transcriptional patterns varied between organs, and its expression was significantly upregulated by abiotic stress or ABA treatment. Alfalfa plants that overexpressed EsMcsu1 had a higher ABA content than wild-type (WT) plants under drought stress conditions. Furthermore, levels of reactive oxygen species (ROS), ion leakage, and malondialdehyde were lower in the transgenic plants than in the WT plants after drought treatment, suggesting that the transgenic plants experienced less ROS-mediated damage. However, the expression of several stress-responsive genes, antioxidant enzyme activity, and osmolyte (proline and total soluble sugar) levels in the transgenic plants were higher than those in the WT plants after drought treatment. Therefore, EsMcsu1 overexpression improved drought tolerance in alfalfa plants by activating a series of ABA-mediated stress responses.
Zhou, C., Z. Ma, et al. (2015) Activated expression of EsHD1 enhances drought tolerance in tobacco plants via mitigation of reactive oxygen species-mediated membrane damage Turkish Journal of Botany 39: 941-+. 10.3906/bot-1506-15It is well documented that the homeodomain-leucine zipper (HD-Zip) transcription factors play diverse roles during plant growth and development. The Class I HD-Zip genes are shown to be involved in the regulation of abiotic stress responses and tolerance. Herein, a novel Class I HD-Zip gene, EsHD1, was isolated from Eutrema salsugineum, and an investigation was performed of its physiological functions in response to drought stress. The analyses of gene expression profiles revealed that the EsHD1 transcripts quickly accumulated upon exposure to various abiotic stress conditions or abscisic acid treatments. Furthermore, the overexpression of EsHD1 in tobacco plants conferred improved tolerance to drought stress. The EsHD1-overexpressing lines had lower levels of reactive oxygen species (ROS), ion leakage, and malondialdehyde, but they manifested higher activities of antioxidant enzymes and the transcription of pathogenic-related genes as compared to wild-type plants under drought stress conditions. Therefore, our findings demonstrated that EsHD1 positively regulated plant drought tolerance via alleviation of ROS-mediated membrane damage.
Zhang, J., Z. Liu, et al. (2015) Three genes encoding AOP2, a protein involved in aliphatic glucosinolate biosynthesis, are differentially expressed in Brassica rapa Journal of Experimental Botany 66: 6205-6218. 10.1093/jxb/erv331The glucosinolate biosynthetic gene AOP2 encodes an enzyme that plays a crucial role in catalysing the conversion of beneficial glucosinolates into anti-nutritional ones. In Brassica rapa, three copies of BrAOP2 have been identified, but their function in establishing the glucosinolate content of B. rapa is poorly understood. Here, we used phylogenetic and gene structure analyses to show that BrAOP2 proteins have evolved via a duplication process retaining two highly conserved domains at the N-terminal and C-terminal regions, while the middle part has experienced structural divergence. Heterologous expression and in vitro enzyme assays and Arabidopsis mutant complementation studies showed that all three BrAOP2 genes encode functional BrAOP2 proteins that convert the precursor methylsulfinyl alkyl glucosinolate to the alkenyl form. Site-directed mutagenesis showed that His356, Asp310, and Arg376 residues are required for the catalytic activity of one of the BrAOP2 proteins (BrAOP2.1). Promoter-beta-glucuronidase lines revealed that the BrAOP2.3 gene displayed an overlapping but distinct tissue- and cell-specific expression profile compared with that of the BrAOP2.1 and BrAOP2.2 genes. Quantitative real-time reverse transcription-PCR assays demonstrated that BrAOP2.1 showed a slightly different pattern of expression in below-ground tissue at the seedling stage and in the silique at the reproductive stage compared with BrAOP2.2 and BrAOP2.3 genes in B. rapa. Taken together, our results revealed that all three BrAOP2 paralogues are active in B. rapa but have functionally diverged.
Yeo, M. T. S., P. Carella, et al. (2015) Development of a Pseudomonas syringae-Eutrema salsugineum pathosystem to investigate disease resistance in a stress tolerant extremophile model plant Plant Pathology 64: 297-306. 10.1111/ppa.12271To improve the ability to understand how plants respond to multiple and/or concurrent stresses, disease resistance was investigated in Eutrema salsugineum, an extremophile model plant that is highly tolerant of abiotic stress. Compared to Arabidopsis (Col-0), both Yukon and Shandong Eutrema accessions exhibit increased resistance to Pseudomonas syringae pv. tomato DC3000 (Pst) and pv. maculicola (Psm), with Shandong Eutrema exhibiting greater resistance to Pst than Yukon Eutrema. RT-PCR of the EsPR1 (Pathogenesis-related 1) defence marker gene confirmed RNA-Seq data that healthy Shandong Eutrema constitutively expresses EsPR1. The data suggests that Shandong Eutrema exists in a highly primed state of defence preparedness, as it displays heightened resistance compared to defence-primed natural accessions of Arabidopsis (Can-0, Bur-0). Pathogen-triggered PR1 expression was delayed in Yukon Eutrema; however, these plants were resistant to Pst suggesting that Yukon Eutrema employs a PR1-independent mechanism to resist Pst. This study demonstrates that Eutrema is an excellent model to investigate biotic stress tolerance. The Eutrema-P.syringae pathosystem will facilitate future studies to understand how this extremophile tolerates both abiotic and biotic stress, and will allow exploration of the interplay of these responses to inform efforts to improve stress tolerance in crops.
Yang, Z., J. Li, et al. (2015) Identification of Non-HIV Immunogens That Bind to Germline b12 Predecessors and Prime for Elicitation of Cross-clade Neutralizing HIV-1 Antibodies Plos One 10: e0126428 10.1371/journal.pone.0126428A fundamental challenge for developing an effective and safe HIV-1 vaccine is to identify vaccine immunogens that can initiate and maintain immune responses leading to elicitation of broadly neutralizing HIV-1 antibodies (bnAbs) through complex maturation pathways. We have previously found that HIV-1 envelope glycoproteins (Env) lack measurable binding to putative germline predecessors of known bnAbs and proposed to search for non-HIV immunogens that could initiate their somatic maturation. Using bnAb b12 as a model bnAb and yeast display technology, we isolated five (poly) peptides from plant leaves, insects, E. coli strains, and sea water microbes that bind to b12 putative germline and intermediate antibodies. Rabbit immunization with the (poly) peptides alone induced high titers of cross-reactive antibodies that neutralized HIV-1 isolates SF162 and JRFL. Priming rabbits with the (poly) peptides followed by boosts with trimeric gp140(SF162) and then resurfaced Env (RSC3) induced antibodies that competed with mature b12 and neutralized tier 1 and 2 viruses from clade B, C and E, while control rabbits without (poly) peptide priming induced antibodies that did not compete with mature b12 and neutralized fewer isolates. The degree of competition with mature b12 for binding to gp140SF162 correlated with the neutralizing activity of the rabbit IgG. Reversing the order of the two boosting immunogens significantly affected the binding profile and neutralization potency of the rabbit IgG. Our study is the first to provide evidence that appears to support the concept that non-HIV immunogens may initiate immune responses leading to elicitation of cross-clade neutralizing antibodies.
Yang, Y., R. J. Tang, et al. (2015) Overexpression of a Populus trichocarpa H+-pyrophosphatase gene PtVP1.1 confers salt tolerance on transgenic poplar Tree Physiology 35: 663-677. 10.1093/treephys/tpv027The Arabidopsis vacuolar H+-pyrophosphatase (AVP1) has been well studied and subsequently employed to improve salt and/or drought resistance in herbaceous plants. However, the exact function of H+-pyrophosphatase in woody plants still remains unknown. In this work, we cloned a homolog of type I H+-pyrophosphatase gene, designated as PtVP1.1, from Populus trichocarpa, and investigated its function in both Arabidopsis and poplar. The deduced translation product PtVP1.1 shares 89.74% identity with AVP1. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR analyses revealed a ubiquitous expression pattern of PtVP1.1 in various tissues, including roots, stems, leaves and shoot tips. Heterologous expression of PtVP1.1 rescued the retarded-root-growth phenotype of avp1, an Arabidopsis knock out mutant of AVP1, on low carbohydrate medium. Overexpression of PtVP1.1 in poplar (P. davidiana x P. bolleana) led to more vigorous growth of transgenic plants in the presence of 150 mM NaCl. Microsomal membrane vesicles derived from PtVP1.1 transgenic plants exhibited higher H+-pyrophosphatase hydrolytic activity than those from wild type (WT). Further studies indicated that the improved salt tolerance was associated with a decreased Na+ and increased K+ accumulation in the leaves of transgenic plants. Na+ efflux and H+ influx in the roots of transgenic plants were also significantly higher than those in the WT plants. All these results suggest that PtVP1.1 is a functional counterpart of AVP1 and can be genetically engineered for salt tolerance improvement in trees.
Yamamoto, N., O. Takano, et al. (2015) Comprehensive analysis of transcriptome response to salinity stress in the halophytic turf grass Sporobolus virginicus Frontiers in Plant Science 6: 241 10.3389/fpls.2015.00241The turf grass Sporobolus virginicus is halophyte and has high salinity tolerance. To investigate the molecular basis of its remarkable tolerance, we performed Illumina high throughput RNA sequencing on roots and shoots of a S. virginicus genotype under normal and saline conditions. The 130 million short reads were assembled into 444,242 unigenes. A comparative analysis of the transcriptome with rice and Arabidopsis transcriptome revealed six turf grass-specific unigenes encoding transcription factors. Interestingly, all of them showed root specific expression and five of them encode bZIP type transcription factors. Another remarkable transcriptional feature of S. virginicus was activation of specific pathways under salinity stress. Pathway enrichment analysis suggested transcriptional activation of amino acid, pyruvate, and phospholipid metabolism. Up-regulation of several unigenes, previously shown to respond to salt stress in other halophytes was also observed. Gene Ontology enrichment analysis revealed that unigenes assigned as proteins in response to water stress, such as dehydrin and aquaporin, and transporters such as cation, amino acid, and citrate transporters, and H-F-ATPase, were up-regulated in both shoots and roots under salinity. A correspondence analysis of the enriched pathways in turf grass cells, but not in rice cells, revealed two groups of unigenes similarly up-regulated in the turf grass in response to salt stress; one of the groups, showing excessive up-regulation under salinity, included unigenes homologos to salinity responsive genes in other halophytes. Thus, the present study identified candidate genes involved in salt tolerance of S. virginicus. This genetic resource should be valuable for understanding the mechanisms underlying high salt tolerance in S. virginicus. This information can also provide insight into salt tolerance in other halophytes.
Xiao, Y., C. Li, et al. (2015) Eutrema bulbiferum (Brassicaceae), a new species with bulbils from Hunan, China Phytotaxa 219: 233-242.Eutrema bulbiferum, a unique new species of Brassicaceae found in the limestone areas of Longshan and Jishou, Hunan, China, is described and illustrated. This species is most similar to E. tenue and E. yunnanense, but can be easily distinguished by its rosulate fleshy bulbils in the leaf axil or near the stem base, fewer ovules per ovary, slightly 4-angled short wand-like silique, and bended silique apex with a beak. E. bulbiferum is categorized into Eutrema by phylogenetic analysis based on the nuclear internal transcribed spacer (ITS). It is also clearly separated from E. tenue and E. yunnanense by the results of both phylogenetic analysis and Principal Component Analysis (PCA) based on morphometric characters.
Wiciarz, M., B. Gubernator, et al. (2015) Enhanced chloroplastic generation of H2O2 in stress-resistant Thellungiella salsuginea in comparison to Arabidopsis thaliana Physiologia Plantarum 153: 467-476. 10.1111/ppl.12248In order to find some basis of salinity resistance in the chloroplastic metabolism, a halophytic Thellungiella salsuginea was compared with glycophytic Arabidopsis thaliana. In control T.s. plants the increased ratios of chlorophyll a/b and of fluorescence emission at 77 K (F-730/F-685) were documented, in comparison to A.t.. This was accompanied by a higher Y-II and lower NPQ (non-photochemical quenching) values, and by a more active PSI (photosystem I). Another prominent feature of the photosynthetic electron transport (PET) in T.s. was the intensive production of H2O2 from PQ (plastoquinone) pool. Salinity treatment (0.15 and 0.30 MNaCl for A.t. and T.s., respectively) led to a decrease in ratios of chl a/b and F-730/F-685. In A.t., a salinity-driven enhancement of Y-II and NPQ was found, in association with the stimulation of H2O2 production from PQ pool. In contrast, in salinity-treated T.s., these variables were similar as in controls. The intensive H2O2 generation was accompanied by a high activity of PTOX (plastid terminal oxidase), whilst inhibition of this enzyme led to an increased H2O2 formation. It is hypothesized, that the intensive H2O2 generation from PQ pool might be an important element of stress preparedness in Thellungiella plants. In control T.s. plants, a higher activation state of carboxylase ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) was also documented in concert with the attachment of Rubisco activase (RCA) to the thylakoid membranes. It is supposed, that a closer contact of RCA with PSI in T.s. enables a more efficient Rubisco activation than in A.t.
Werbrouck, S. P. O. and G. Zhang. (2015) Plant growth regulators involved in abiotic stress: preface Plant Growth Regulation 76: 1-2. 10.1007/s10725-015-0057-7Eutrema salsugineum (= Thellungiella salsuginea Brassicaceae), a species growing in highly saline habitats, is a good model for use in salt-stress research. However, its evolutionary migrations and genetic variations within and between disjunct regions from central Asia to northern China and North America remain largely unknown. We examined genetic variations and phylogeographic patterns of this species by sequencing ITS, 9 chloroplast (cp) DNA fragments (4379 bp) and 10 unlinked nuclear loci (6510 bp) of 24 populations across its distributional range. All markers suggested the high genetic poverty of this species and the limited number of genetic variations recovered was congruently partitioned between central Asia, northern China and North America. Further modelling of nuclear population-genetic data based on approximate bayesian computation (ABC) analyses indicated that the long-distance dispersals after the recent origin of E. salsugineum may have occurred from central Asia to the other two regions respectively within 20000 years. The fast demographic expansions should have occurred in northern China in a more recent past. Our study highlights the importance of using ABC analyses and nuclear population genetic data to trace evolutionary migrations of the disjunct distributions of the plants in the recent past.
Wang, X., J. Wu, et al. (2015) Brassica database (BRAD) version 2.0: integrating and mining Brassicaceae species genomic resources Database : the journal of biological databases and curation 2015: 10.1093/database/bav093The Brassica database (BRAD) was built initially to assist users apply Brassica rapa and Arabidopsis thaliana genomic data efficiently to their research. However, many Brassicaceae genomes have been sequenced and released after its construction. These genomes are rich resources for comparative genomics, gene annotation and functional evolutionary studies of Brassica crops. Therefore, we have updated BRAD to version 2.0 (V2.0). In BRAD V2.0, 11 more Brassicaceae genomes have been integrated into the database, namely those of Arabidopsis lyrata, Aethionema arabicum, Brassica oleracea, Brassica napus, Camelina sativa, Capsella rubella, Leavenworthia alabamica, Sisymbrium irio and three extremophiles Schrenkiella parvula, Thellungiella halophila and Thellungiella salsuginea. BRAD V2.0 provides plots of syntenic genomic fragments between pairs of Brassicaceae species, from the level of chromosomes to genomic blocks. The Generic Synteny Browser (GBrowse_syn), a module of the Genome Browser (GBrowse), is used to show syntenic relationships between multiple genomes. Search functions for retrieving syntenic and non-syntenic orthologs, as well as their annotation and sequences are also provided. Furthermore, genome and annotation information have been imported into GBrowse so that all functional elements can be visualized in one frame. We plan to continually update BRAD by integrating more Brassicaceae genomes into the database. Database URL: http://brassicadb.org/brad/.
Wang, X., J. Wu, et al. (2015) Brassica database (BRAD) version 2.0: integrating and mining Brassicaceae species genomic resources Database-the Journal of Biological Databases and Curation bav093 10.1093/database/bav093The Brassica database (BRAD) was built initially to assist users apply Brassica rapa and Arabidopsis thaliana genomic data efficiently to their research. However, many Brassicaceae genomes have been sequenced and released after its construction. These genomes are rich resources for comparative genomics, gene annotation and functional evolutionary studies of Brassica crops. Therefore, we have updated BRAD to version 2.0 (V2.0). In BRAD V2.0, 11 more Brassicaceae genomes have been integrated into the database, namely those of Arabidopsis lyrata, Aethionema arabicum, Brassica oleracea, Brassica napus, Camelina sativa, Capsella rubella, Leavenworthia alabamica, Sisymbrium irio and three extremophiles Schrenkiella parvula, Thellungiella halophila and Thellungiella salsuginea. BRAD V2.0 provides plots of syntenic genomic fragments between pairs of Brassicaceae species, from the level of chromosomes to genomic blocks. The Generic Synteny Browser (GBrowse_syn), a module of the Genome Browser (GBrowse), is used to show syntenic relationships between multiple genomes. Search functions for retrieving syntenic and non-syntenic orthologs, as well as their annotation and sequences are also provided. Furthermore, genome and annotation information have been imported into GBrowse so that all functional elements can be visualized in one frame. We plan to continually update BRAD by integrating more Brassicaceae genomes into the database.
Wang, L., D. Pan, et al. (2015) Proteomic analysis of changes in the Kandelia candel chloroplast proteins reveals pathways associated with salt tolerance Plant Science 231: 159-172. 10.1016/j.plantsci.2014.11.013The plant chloroplast is one of the most sensitive organelles in response to salt stress. Chloroplast proteins extracted from seedling leaves were separated by two-dimensional gel electrophoresis (2-DE). More than 600 protein spots could be distinguished on each gel. Fifty-eight differentially expressed protein spots were detected, of which 46 could be identified through matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). These proteins were found to be involved in multiple aspects of chloroplast metabolism pathways such as photosynthesis, ATP synthesis, detoxification and antioxidation processes, nitrogen assimilation and fixation, protein metabolism, and tetrapyrrole biosynthesis. The results indicated that K. candel could withstand up to 500 mM NaCl stress for a measured period of 3 days, by maintaining normal or high photosynthetic electron transfer efficiency and an only slightly stimulated Calvin cycle. Meanwhile, we found that ROS scavenging, nitrogen assimilation, protein degradation and chaperone function in chloroplasts were also of importance for salt tolerance of K. candel. The ultrastructural and physiological data agree with chloroplast proteome results. These findings allow further exploration of our knowledge on salt adaptation in woody halophytes and may contribute to the development of more salt-tolerant plants in the future. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
Wang, J., Y. Meng, et al. (2015) Physiological and proteomic analyses of salt stress response in the halophyte Halogeton glomeratus Plant Cell and Environment 38: 655-669. 10.1111/pce.12428Very little is known about the adaptation mechanism of Chenopodiaceae Halogeton glomeratus, a succulent annual halophyte, under saline conditions. In this study, we investigated the morphological and physiological adaptation mechanisms of seedlings exposed to different concentrations of NaCl treatment for 21d. Our results revealed that H.glomeratus has a robust ability to tolerate salt; its optimal growth occurs under approximately 100mm NaCl conditions. Salt crystals were deposited in water-storage tissue under saline conditions. We speculate that osmotic adjustment may be the primary mechanism of salt tolerance in H.glomeratus, which transports toxic ions such as sodium into specific salt-storage cells and compartmentalizes them in large vacuoles to maintain the water content of tissues and the succulence of the leaves. To investigate the molecular response mechanisms to salt stress in H.glomeratus, we conducted a comparative proteomic analysis of seedling leaves that had been exposed to 200mm NaCl for 24h, 72h and 7d. Forty-nine protein spots, exhibiting significant changes in abundance after stress, were identified using matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS/MS) and similarity searches across EST database of H.glomeratus. These stress-responsive proteins were categorized into nine functional groups, such as photosynthesis, carbohydrate and energy metabolism, and stress and defence response.
Volkov, V. (2015) Salinity tolerance in plants. Quantitative approach to ion transport starting from halophytes and stepping to genetic and protein engineering for manipulating ion fluxes Frontiers in Plant Science 6: 873 10.3389/fpls.2015.00873Ion transport is the fundamental factor determining salinity tolerance in plants. The Review starts from differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes. The comparison provides introductory information for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion fluxes. Further steps require knowledge about mechanisms of ion transport and individual genes of ion transport proteins. Initially, the Review describes methods to measure ion fluxes, the independent set of techniques ensures robust and reliable basement for quantitative approach. The Review briefly summarizes current data concerning Na+ and K+ concentrations in cells, refers to primary thermodynamics of ion transport and gives special attention to individual ion channels and transporters. Simplified scheme of a plant cell with known transport systems at the plasma membrane and tonoplast helps to imagine the complexity of ion transport and allows choosing specific transporters for modulating ion transport. The complexity is enhanced by the influence of cell size and cell wall on ion transport. Special attention is given to ion transporters and to potassium and sodium transport by HKT, HAK, NHX, and SOS1 proteins. Comparison between non-selective cation channels and ion transporters reveals potential importance of ion transporters and the balance between the two pathways of ion transport. Further on the Review describes in detail several successful attempts to overexpress or knockout ion transporters for changing salinity tolerance. Future perspectives are questioned with more attention given to promising candidate ion channels and transporters for altered expression. Potential direction of increasing salinity tolerance by modifying ion channels and transporters using single point mutations is discussed and questioned. An alternative approach from synthetic biology is to create new regulation networks using novel transport proteins with desired properties for transforming agricultural crops. The approach had not been widely used earlier; it leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis. Summarizing, several potential ways are aimed at required increase in salinity tolerance of plants of interest.
Uzilday, B., R. Ozgur, et al. (2015) Changes in the alternative electron sinks and antioxidant defence in chloroplasts of the extreme halophyte Eutrema parvulum (Thellungiella parvula) under salinity Annals of Botany 115: 449-463. 10.1093/aob/mcu184Background and Aims Eutrema parvulum (synonym, Thellungiella parvula) is an extreme halophyte that thrives in high salt concentrations (100-150 mM) and is closely related to Arabidopsis thaliana. The main aim of this study was to determine how E. parvulum uses reactive oxygen species (ROS) production, antioxidant systems and redox regulation of the electron transport system in chloroplasts to tolerate salinity. Methods Plants of E. parvulum were grown for 30 d and then treated with either 50, 200 or 300 mM NaCl. Physiological parameters including growth and water relationships were measured. Activities of antioxidant enzymes were determined in whole leaves and chloroplasts. In addition, expressions of chloroplastic redox components such as ferrodoxin thioredoxin reductases (FTR), NADPH thioredoxin reductases (NTRC), thioredoxins (TRXs) and peroxiredoxins (PRXs), as well as genes encoding enzymes of the water-water cycle and proline biosynthesis were measured. Key Results Salt treatment affected water relationships negatively and the accumulation of proline was increased by salinity. E. parvulum was able to tolerate 300 mM NaCl over long periods, as evidenced by H2O2 content and lipid peroxidation. While Ca2+ and K+ concentrations were decreased by salinity, Na+ and Cl-concentrations increased. Efficient induction of activities and expressions of water-water cycle enzymes might prevent accumulation of excess ROS in chloroplasts and therefore protect the photosynthetic machinery in E. parvulum. The redox homeostasis in chloroplasts might be achieved by efficient induction of expressions of redox regulatory enzymes such as FTR, NTRC, TRXs and PRXs under salinity. Conclusions E. parvulum was able to adapt to osmotic stress by an efficient osmotic adjustment mechanism involving proline and was able to regulate its ion homeostasis. In addition, efficient induction of water-water cycle enzymes and other redox regulatory components such as TRXs and PRXs in chloroplasts were able to protect the chloroplasts from salinity-induced oxidative stress.
Theerawitaya, C., R. Tisarum, et al. (2015) Physio-biochemical and morphological characters of halophyte legume shrub, Acacia ampliceps seedlings in response to salt stress under greenhouse Frontiers in Plant Science 6: 630 10.3389/fpls.2015.00630Acacia ampliceps (salt wattle), a leguminous shrub, has been introduced in salt-affected areas in the northeast of Thailand for the remediation of saline soils. However, the defense mechanisms underlying salt tolerance A. ampliceps are unknown. We investigated various physio-biochemical and morphological attributes of A. ampliceps in response to varying levels of salt treatment (200-600 mM NaCl). Seedlings of A. ampliceps (25 2 cm in plant height) raised from seeds were treated with 200 mM (mild stress), 400 and 600 mM (extreme stress) of salt treatment (NaCl) under greenhouse conditions. Na+ and Ca2+ contents in the leaf tissues increased significantly under salt treatment, whereas K+ content declined in salt-stressed plants. Free proline and soluble sugar contents in plants grown under extreme salt stress (600 mM NaCl) for 9 days significantly increased by 28.7 (53.33 mu mol g(-1) FW) and 3.2 (42.11 mg g(-1) DW) folds, respectively over the control, thereby playing a major role as osmotic adjustment. Na+ enrichment in the phyllode tissues of salt-stressed seedlings positively related to total chlorophyll (TC) degradation (R-2 = 0.72). Photosynthetic pigments and chlorophyll fluorescence in salt-stressed plants increased under mild salt stress (200 mM NaCl). However, these declined under high levels of salinity (400-600 mM NaCl), consequently resulting in a reduced net photosynthetic rate (R-2 = 0.81) and plant dry weight (R-2 = 0.91). The study concludes that A. ampliceps has an osmotic adjustment and Na+ compartmentation as effective salt defense mechanisms, and thus it could be an excellent species to grow in salt-affected soils.
Tajetdinova, D. M. (2015) Records of Brassicaceae in the flora of Ustyurt Botanicheskii Zhurnal 100: 406-411.Thellungiella toxophylla (Bieb.) V. I. Dorof. (=Arabidopsis toxophylla (Bieb.) N. Busch) and Sisymbrium polymorphum (Murr.) Roth are reported as new to Ustyurt. The occurrence of Rorippa brachycarpa (C. A. Mey.) Hayek is confirmed. New localities were found for 16 species, among them Isatis minima Bunge, I. violascens Bunge and Matthiola chenopodiifolia Fisch. et C. A. Mey. being recorded for the first time in the Turkmen part of Ustyurt.
Sun, Y.-S., J.-Q. Liu, et al. (2015) Demographic tests based on mismatch distribution and LAMARC Figshare http://dx.doi.org/10.1371/journal.pone.0124010.t002θ0 and θ1 are pre-expansion and post-expansion populations sizes; SSD, sum of squared deviations; RAG, the Harpending’s Raggedness indexa, with populations from northern China and Buriatia (Group B)b, without populations from northern China and Buriatiac, with populations from Xinjiang and Altai, both of which have the same sequence (Group A)d, with populations from Tuva,Yakutsk and Canada (Group C)-, no data.Demographic tests based on mismatch distribution and LAMARC.
Sun, Y.-S., J.-Q. Liu, et al. (2015) Nucleotide variation, haplotype diversity for 10 nuclear loci and 9 cpDNA from E. salsuginea populations Figshare http://dx.doi.org/10.1371/journal.pone.0124010.t001N, sample size; L, length in base pairs; S, number of segregating sizes; pi, nucleotide diversity (pit, πa and πsil are in total locus, nonsynonymous site and silent site respectively); θ, Watterson’s parameter (θwt, θwa and θsil are in total locus, nonsynonymous site and silent site respectively); Nh, number of haplotypes; He, Nei’ s haplotype diversity; Rm, minimum number of recombinant events¶, no polymorphisms-, no data§, 8 cpDNA fragments with no variations (see S3 Table) were not shown.Nucleotide variation, haplotype diversity for 10 nuclear loci and 9 cpDNA from E. salsuginea populations.
Sun, Y.-S., J.-Q. Liu, et al. (2015) Evolutionary Migration of the Disjunct Salt Cress Eutrema salsugineum (= Thellungiella salsuginea, Brassicaceae) between Asia and North America FigshareEutrema salsugineum (= Thellungiella salsuginea Brassicaceae), a species growing in highly saline habitats, is a good model for use in salt-stress research. However, its evolutionary migrations and genetic variations within and between disjunct regions from central Asia to northern China and North America remain largely unknown. We examined genetic variations and phylogeographic patterns of this species by sequencing ITS, 9 chloroplast (cp) DNA fragments (4379 bp) and 10 unlinked nuclear loci (6510 bp) of 24 populations across its distributional range. All markers suggested the high genetic poverty of this species and the limited number of genetic variations recovered was congruently partitioned between central Asia, northern China and North America. Further modelling of nuclear population-genetic data based on approximate bayesian computation (ABC) analyses indicated that the long-distance dispersals after the recent origin of E. salsugineum may have occurred from central Asia to the other two regions respectively within 20000 years. The fast demographic expansions should have occurred in northern China in a more recent past. Our study highlights the importance of using ABC analyses and nuclear population genetic data to trace evolutionary migrations of the disjunct distributions of the plants in the recent past.
Sun, W., Y. Li, et al. (2015) The TsnsLTP4, a Nonspecific Lipid Transfer Protein Involved in Wax Deposition and Stress Tolerance Plant Molecular Biology Reporter 33: 962-974. 10.1007/s11105-014-0798-xNonspecific lipid transfer proteins (nsLTPs), a group of small, basic proteins that are ubiquitously distributed throughout the plant kingdom, are thought to participate in cutin formation as well as in defense reactions against abiotic and biotic stresses. However, whether nsLTPs are involved in cuticular wax deposition remains unknown. We identified a salt-induced gene, TsnsLTP4, encoding an nsLTP from Thellungiella salsuginea. TsnsLTP4 expression was significantly induced by salt, polyethylene glycol (PEG), abscisic acid (ABA), and high (37 degrees C) and low (4 degrees C) temperatures. Transgenic onion epidermal cells transiently expressing a TsnsLTP4-DsRed fusion protein demonstrated that TsnsLTP4 was targeted to the cell wall. Overexpression of TsnsLTP4 in transgenic Arabidopsis plants resulted in increased epicuticular wax deposition, particularly of wax components with a carbon chain length of more than C27. Moreover, the amount of wax deposited was strongly reduced in RNA interference (RNAi)-knockdown TsnsLTP4 transgenic T. salsuginea lines. Cuticle permeability was inversely related to the expression level of TsnsLTP4. Further analyses indicated that overexpression of TsnsLTP4 resulted in significantly enhanced drought and salt tolerance in transgenic Arabidopsis. In summary, our studies suggested that TsnsLTP4 may play a role in wax deposition and in plant tolerance against abiotic stresses.
Sun, L., G. Yu, et al. (2015) TsMIP6 enhances the tolerance of transgenic rice to salt stress and interacts with target proteins Journal of Plant Biology 58: 285-292. 10.1007/s12374-015-0069-xAquaporins (AQPs), a large family of channel proteins in plants, play an important role in regulating the balance of osmotic potential in cells. We isolated an AQP gene, TsMIP6, from the halophyte Thellungiella salsuginea and functionally characterized it in transgenic rice (Oryza sativa). This gene belongs to a subfamily of tonoplast intrinsic proteins and is localized at the plasma membrane. Real-time PCR showed that expression of TsMIP6 in shoots or roots of T. salsuginea was markedly induced by salinity, whereas its ectopic expression in 'Kitaake' lines of rice significantly increased plant tolerance to salt stress. Physiological data suggested that TsMIP6 is involved in regulating ion homeostasis and water channel activity in salt-stressed transgenic rice. Heterologous expression analysis indicated that TsMIP6 specifically interacts with a member of the glycoside hydrolase family 64 protein #617 in yeast cells. This suggests that the relationship between TsMIP6 and #617 has a crucial role in mediating osmotic balance in plant cells. Moreover, TsMIP6 might help to modulate the transport of some neutral molecules and may function through a pathway regulating solute equilibrium to maintain osmotic potential.
Shiri, M., M. Rabhi, et al. (2015) The Halophyte Cakile maritima Reduces Phenanthrene Phytotoxicity International Journal of Phytoremediation 17: 925-928. 10.1080/15226514.2014.1003784In a previous study, we showed that the halophyte plant model Thellungiella salsuginea was more tolerant to phenanthrene (Polycyclic Aromatic Hydrocarbon: PAH) than its relative glycophyte Arabidopsis thaliana. In the present work, we investigated the potential of another halophyte with higher biomass production, Cakile maritma, to reduce phenanthrene phytotoxicity. Sand was used instead of arable soil with the aim to avoid pollutant degradation by microorganisms or their interaction with the plant. After 6 weeks of treatment by 500ppm phenanthrene (Phe), stressed plants showed a severe reduction (-73%) in their whole biomass, roots being more affected than leaves and stems. In parallel, Guaiacol peroxidase (GPX) activity was increased by 185 and 62% in leaves and roots, respectively. Non-enzymatic antioxidant capacity (assayed by ABTS test) was maintained unchanged in all plant organs. The model halophytic plant Thellungiella salsuginea was used as a biomarker of phenanthrene stress severity and was grown at 0 (control), 125, 250, and 375ppm. T. salsuginea plants grown on the sand previously contaminated by 500ppm Phe then treated by C. maritma culture (phytoremediation culture) showed similar biomass production as plants subjected to 125ppm Phe. This suggests that the phytotoxic effects of phenanthrene were reduced by 75% by the 6-week treatment by C. maritima. Our findings indicate that C. maritima can constitute a potentially good candidate for PAH phytoremediation.
Shiri, M., M. Rabhi, et al. (2015) The halophytic model plant Thellungiella salsuginea exhibited increased tolerance to phenanthrene-induced stress in comparison with the glycophitic one Arabidopsis thaliana: Application for phytoremediation Ecological Engineering 74: 125-134. 10.1016/j.ecoleng.2014.09.123Polycyclic aromatic hydrocarbons constitute a large family of organic environmental pollutants. Hence, a particular attention has been attributed to all approaches involved in the reduction of their contamination in water and natural ecosystems. Plant tolerance, absorption, accumulation, and likely biodegradation of these pollutants, known as phytoremediation, have emerged as an efficient technique to remediate environments contaminated with polycyclic aromatic hydrocarbons. The present work was aimed to compare the tolerance to phenanthrene (a polycyclic aromatic hydrocarbon) in the two model plants: Arabidopsis thaliana (glycophyte) and Thellungiella salsuginea (halophyte). Our study showed that the development of these two species was reduced under phenanthrene stress, the effect being more pronounced in A. thaliana than in T. salsuginea. In parallel, results from the intrinsic quantum yield of photosystem II and chlorophyll concentrations were concomitant with those of growth and phenotypic changes, and confirmed the higher tolerance of T. salsuginea compared to that of A. thaliana. The intrinsic quantum yield of photosystem II was drastically decreased in the glycophyte, which indicates a marked disturbance in photosystem II performance. This induced a severe oxidative stress as shown by the utilization of specific reactive oxygen species probes. In parallel, the activities of glutathione reductase, gaiacol peroxidase, and superoxide dismutase were increased by 95, 73, and 36%, respectively, which indicates a marked phenanthrene-induced oxidative stress. In T. salsuginea, photosystem II performance was not significantly affected. This species showed less accumulated reactive oxygen species than A. thaliana. Its enzymatic antioxidant system showed few changes as superoxide dismutase was the only enzyme whose activity was enhanced (+34%). A much higher capacity of recovery was also noticed in this halophyte as compared to the glycophyte. Indeed, it seems that T. salsuginea accumulated phenanthrene in stomata, which suggests its possible volatilization. All these data, taken together, add new insight to the mechanisms involved in halophytic plant tolerance to abiotic stresses and their potential use in phytoremediation. (C) 2014 Elsevier B.V. All rights reserved.
Roychoudhury, A., A. Banerjee, et al. (2015) Metabolic and molecular-genetic regulation of proline signaling and its cross-talk with major effectors mediates abiotic stress tolerance in plants Turkish Journal of Botany 39: 887-910. 10.3906/bot-1503-27Proline (Pro) accumulation is a common response of several plant species to combat abiotic stresses. Under stress conditions, Pro acts as an excellent compatible solute in the plant system, participating in the alleviation of stress sensitivity. Though the metabolic pathways associated with Pro are well studied, parts of its regulatory cascades are still not properly known. It has also been conjectured that epigenetic modifications regulate Pro metabolism during abiotic stress. Apart from Pro, the plant abiotic stress responses are essentially mediated by multiple effectors. Hence, proper analysis of the cross-talks of Pro with the other components of the abiotic stress response has turned out to be mandatory in order to design multistress-tolerant transgenic lines. Highlighting the relation between Pro and seed germination is also essential to understand the notion behind plant susceptibility and survival during stress. Generally, Pro has a universal mechanism to generate abiotic stress tolerance through stabilization of structural components, enzyme structures, and regulation of osmotic adjustments. The success achieved through recent transgenic approaches leading to more accumulation of Pro in the sink has also been focused on in the present review.
Qiang, X.-j., G.-h. Yu, et al. (2015) Thellungiella halophila ThPIP1 gene enhances the tolerance of the transgenic rice to salt stress Journal of Integrative Agriculture 14: 1911-1922. 10.1016/s2095-3119(15)61045-0Aquaporin proteins were demonstrated to play an important regulatory role in transporting water and other small molecules. To better understand physiological functions of aquaporins in extremophile plants, a novel ThPIP1 gene from the Thellungiella halophila was isolated and functionally characterized in the transgenic rice. Data showed that the ThPIP1 protein encoded 284 amino acids, and was identified to be located on the plasma membrane. The expression of ThPIP1 gene in the shoots and roots of T halophila seedlings were induced by high salinity. The transgenic rice overexpressing ThPIP1 gene significantly increased plants tolerance to salt stress through the pathway regulating the osmotic potentials, accumulation of organic small molecules substances and the ratio of K+/Na+ in the plant cells. Moreover, split-ubiquitin yeast two-hybrid assay showed that ThPIP1 protein specifically interacted with ThPIP2 and a non-specific lipid-transfer protein 2, suggesting that ThPIP1 probably play a key role in responding to the reactions of multiple external stimulus and in participating in different physiological processes of plants exposed to salt stress.
Plant Science, T. U. M. (2015) Substantial Reprogramming of the Thellungiella salsuginea Transcriptome in Response to UV and Silver Nitrate Challenge European Nucleotide ArchiveThe transcriptional response of T. salsuginea to UV irradiation and AgNO3 was monitored by microarray analysis. Most transcripts (respectively 70% and 78%) were significantly differentially regulated and a large overlap between the two treatments was observed (54% of total). While core genes of the biosynthesis of aliphatic glucosinolates were repressed, tryptophan and indole glucosinolate biosynthetic genes, as well as defence-related WRKY transcription factors, were consistently upregulated. Overall design: Microarray analysis of four biological replicates was conducted with Agilent arrays. Statistically robust differential regulation was observed for the majority of transcripts.
Nian, F. and L. Zhao. (2015) MOLECULAR CHARACTERIZATION AND EXPRESSION PATTERN OF A NOVEL CADMIUM RESISTANCE GENE OF TOBACCO Bioscience Journal 31: 1024-1029.Cadmium (Cd) of tobacco is a pollutant that is extremely toxic to the health of humans. Protein plant cadmium resistance 8 gene has been characterized to increase the plant Cd resistance. In present experiment, the complete mRNA sequence of tobacco protein plant cadmium resistance 8 gene was amplified using the rapid amplification of cDNA ends methods. The full-length tobacco protein plant cadmium resistance 8 gene mRNA was 887bp containing an 555 bp open reading frame, which encodes a protein of 184 amino acids. BLAST analysis revealed that tobacco protein plant cadmium resistance 8 protein shares high homology with the protein plant cadmium resistance 8 of potato (81%), Lycopersicon esculentum (80%), Eutrema salsugineum (60%), Capsella rubella (58%) and thale cress (57%). Results also showed that tobacco protein plant cadmium resistance 8 gene has a closer genetic relationship with the protein plant cadmium resistance 8 gene of Lycopersicon esculentum. The expression profile was studied and the results indicated that tobacco protein plant cadmium resistance 8 gene was highly expressed in root, moderately expressed in stem, and hardly expressed in flower and leaf. These results established the primary foundation of utilizing tobacco protein plant cadmium resistance 8 gene to decrease the cadmium content of tobacco and benefit the health of humans in the future.
Murat, F., A. Louis, et al. (2015) Understanding Brassicaceae evolution through ancestral genome reconstruction Genome Biology 16: 262 10.1186/s13059-015-0814-yBackground: Brassicaceae is a family of green plants of high scientific and economic interest, including thale cress (Arabidopsis thaliana), cruciferous vegetables (cabbages) and rapeseed. Results: We reconstruct an evolutionary framework of Brassicaceae composed of high-resolution ancestral karyotypes using the genomes of modern A. thaliana, Arabidopsis lyrata, Capsella rubella, Brassica rapa and Thellungiella parvula. The ancestral Brassicaceae karyotype (Brassicaceae lineages I and II) is composed of eight protochromosomes and 20,037 ordered and oriented protogenes. After speciation, it evolved into the ancestral Camelineae karyotype (eight protochromosomes and 22,085 ordered protogenes) and the proto-Calepineae karyotype (seven protochromosomes and 21,035 ordered protogenes) genomes. Conclusions: The three inferred ancestral karyotype genomes are shown here to be powerful tools to unravel the reticulated evolutionary history of extant Brassicaceae genomes regarding the fate of ancestral genes and genomic compartments, particularly centromeres and evolutionary breakpoints. This new resource should accelerate research in comparative genomics and translational research by facilitating the transfer of genomic information from model systems to species of agronomic interest.
Muenchen, T. U. (2015) Eutrema salsugineum cultivar:Shandong Transcriptome or Gene expression European Nucleotide Archiveaka Eutrema salsugineum UV-irradiation, Silver nitrate application, Botrytis cinerea infection.
Mucha, S., D. Walther, et al. (2015) Substantial reprogramming of the Eutrema salsugineum (Thellungiella salsuginea) transcriptome in response to UV and silver nitrate challenge Bmc Plant Biology 15: 137 10.1186/s12870-015-0506-5Background: Cruciferous plants synthesize a large variety of tryptophan-derived phytoalexins in response to pathogen infection, UV irradiation, or high dosages of heavy metals. The major phytoalexins of Eutrema salsugineum (Thellungiella salsuginea), which has recently been established as an extremophile model plant, are probably derivatives of indole glucosinolates, in contrast to Arabidopsis, which synthesizes characteristic camalexin from the glucosinolate precursor indole-3-acetaldoxime. Results: The transcriptional response of E. salsugineum to UV irradiation and AgNO3 was monitored by RNAseq and microarray analysis. Most transcripts (respectively 70% and 78%) were significantly differentially regulated and a large overlap between the two treatments was observed (54% of total). While core genes of the biosynthesis of aliphatic glucosinolates were repressed, tryptophan and indole glucosinolate biosynthetic genes, as well as defence-related WRKY transcription factors, were consistently upregulated. The putative Eutrema WRKY33 ortholog was functionally tested and shown to complement camalexin deficiency in Atwrky33 mutant. Conclusions: In E. salsugineum, UV irradiation or heavy metal application resulted in substantial transcriptional reprogramming. Consistently induced genes of indole glucosinolate biosynthesis and modification will serve as candidate genes for the biosynthesis of Eutrema-specific phytoalexins.
Msilini, N., J. Ferhi, et al. (2015) ARABIDOPSIS THALIANA TOLERATES IRON DEFICIENCY MORE THAN THELLUNGIELLA SALSUGINEA BY INDUCING METABOLIC CHANGES AT THE ROOT LEVEL Acta Biologica Cracoviensia Series Botanica 57: 44-50. 10.1515/abcsb-2015-0003Several studies have used A. thaliana as a model to identify the physiological and molecular mechanisms underlying iron deficiency tolerance in plants. Here, Arabidopsis thaliana and Thellungiella salsuginea were used to investigate the differential responses to iron deficiency of these two species. Plants were cultivated in hydroponic medium containing 5 or 0 mu M Fe, for 10 days. Results showed that rosette biomass was more reduced in T. salsuginea than in A. thaliana when grown on Fe-deficient medium. As a marker for iron deficiency tolerance, the induction of ferric chelate reductase (FCR) and phosphoenolpyruvate carboxylase (PEPC) activities was observed only in A. thaliana roots. In addition, we found that the accumulation of phenolic acids in roots of N1438 ecotype of A. thaliana was stimulated by Fe deficiency. Furthermore, an increase of flavonoids content in the root and exudates was observed under Fe-deficiency in this ecotype. Unlike other abiotic stresses, it appears that iron deficiency effects were more pronounced in Thellungiella than in Arabidopsis. The higher tolerance of the Arabidopsis plant to iron deficiency may be due to the metabolic changes occurring in the roots.
Milia, G., S. Camiolo, et al. (2015) The dynamic loss and gain of introns during the evolution of the Brassicaceae Plant Journal 82: 915-924. 10.1111/tpj.12860Sequence comparison allows the detailed analysis of evolution at the nucleotide and amino acid levels, but much less information is known about the structural evolution of genes, i.e. how the number, length and distribution of introns change over time. We constructed a parsimonious model for the evolutionary rate of intron loss (IL) and intron gain (IG) within the Brassicaceae and found that IL/IG has been highly dynamic, with substantial differences between and even within lineages. The divergence of the Brassicaceae lineages I and II marked a dramatic change in the IL rate, with the common ancestor of lineage I losing introns three times more rapidly than the common ancestor of lineage II. Our data also indicate a subsequent declining trend in the rate of IL, although in Arabidopsis thaliana introns continue to be lost at approximately the ancestral rate. Variations in the rate of IL/IG within lineage II have been even more remarkable. Brassica rapa appears to have lost introns approximately 15 times more rapidly than the common ancestor of B.rapa and Schenkiella parvula, and approximately 25 times more rapidly than its sister species Eutrema salsugineum. Microhomology was detected at the splice sites of several dynamic introns suggesting that the non-homologous end-joining and double-strand break repair is a common pathway underlying IL/IG in these species. We also detected molecular signatures typical of mRNA-mediated IL, but only in B.rapa. Significance Statement We used phylogeny and parsimony to investigate the dynamic rate of intron loss and gain (IL/IG) among six Brassicaceae species. Variation in the IL rate did not follow established evolutionary branches but changed in a species-dependent manner. The analysis of several features of lost introns indicated that the non-homologous end joining of double-strand breaks is a common repair pathway underlying IL/IG in these species, whereas signatures for mRNA-mediated IL were found only in Brassica rapa.
MacLeod, M. J. R., J. Dedrick, et al. (2015) Exposure of two Eutrema salsugineum (Thellungiella salsuginea) accessions to water deficits reveals different coping strategies in response to drought Physiologia Plantarum 155: 267-280. 10.1111/ppl.12316Eutrema salsugineum is an extremophile related to Arabidopsis. Accessions from Yukon, Canada and Shandong, China, were evaluated for their tolerance to water deficits. Plants were exposed to two periods of water deficit separated by an interval of re-watering and recovery. All plants took the same time to wilt during the first drought exposure but Yukon plants took 1day longer than Shandong plants following the second drought treatment. Following re-watering and turgor recovery, solute potentials of Shandong leaves returned to predrought values while those of Yukon leaves were lower than predrought levels consistent with having undergone osmotic adjustment. Polar metabolites profiled in re-watered plants showed that different metabolites are accumulated by Yukon and Shandong plants recovering from a water deficit with glucose more abundant in Yukon and fructose in Shandong leaves. The drought-responsive expression of dehydrin genes RAB18, ERD1, RD29A and RD22 showed greater changes in transcript abundance in Yukon relative to Shandong leaves during both water deficits and recovery with the greatest difference in expression appearing during the second drought. We propose that the initial exposure of Yukon plants to drought renders them more resilient to water loss during a subsequent water deficit leading to delayed wilting. Yukon plants also established a high leaf water content and increased specific leaf area during the second deficit. Shandong plants undergoing the same treatment regime do not show the same beneficial drought tolerance responses and likely use drought avoidance to cope with water deficits.
Ma, Y., J. Wang, et al. (2015) Genome-wide analysis of the cation/proton antiporter (CPA) super family genes in grapevine (Vitis vinifera L.) Plant Omics 8: 300-311.Grapevine (Vitis vinifera L.) is sensitive to salinity. Cation/proton antiporter genes function in regulating ions and pH homeostasis in organisms, enhance salt resistance/tolerance of plants through the vacuolar compartmentalization of Na+, Na+ efflux from the cell, and affecting K+ concentrations. Two previous general bioinformatics studies on CPA gene families, including that of grapevine, showed different numbers of grapevine CPA genes because of using different genome assemblies. In this report, we employed comprehensive bioinformatics and annotation analysis and carefully re-evaluated the previous studies characterizing the CPA proteins. We resolved the discordance of CPA family genes in grapevine, and revealed that duplications contribute contributing to expansion of CPA family genes in grapevine. Furthermore, we identified motifs between grapevine and Arabidopsis and found some motifs are subgroup subgroup-specific motifs. In addition, we investigated the gene structure among the CPA1 subfamily genes in six species. In our analysis 29 CPA genes were identified in the grapevine reference genome. This detailed information on the CPA superfamily in the physiological responses to salinity and osmotic stress and for potential development of salt resistant cultivars.
Luo, J., S. Tang, et al. (2015) Elucidation of Cross-Talk and Specificity of Early Response Mechanisms to Salt and PEG-Simulated Drought Stresses in Brassica napus Using Comparative Proteomic Analysis Plos One 10: e0138974 10.1371/journal.pone.0138974To understand the cross-talk and specificity of the early responses of plants to salt and drought, we performed physiological and proteome analyses of Brassica napus seedlings pretreated with 245 mM NaCl or 25% polyethylene glycol (PEG) 6000 under identical osmotic pressure (-1.0 MPa). Significant decreases in water content and photosynthetic rate and excessive accumulation of compatible osmolytes and oxidative damage were observed in response to both stresses. Unexpectedly, the drought response was more severe than the salt response. We further identified 45 common differentially expressed proteins (DEPs), 143 salt-specific DEPs and 160 drought-specific DEPs by isobaric tags for relative and absolute quantitation (iTRAQ) analysis. The proteome quantitative data were then confirmed by multiple reaction monitoring (MRM). The differences in the proteomic profiles between drought-treated and salt-treated seedlings exceeded the similarities in the early stress responses. Signal perception and transduction, transport and membrane trafficking, and photosynthesis-related proteins were enriched as part of the molecular cross-talk and specificity mechanism in the early responses to the two abiotic stresses. The Ca2+ signaling, G protein-related signaling, 14-3-3 signaling pathway and phosphorylation cascades were the common signal transduction pathways shared by both salt and drought stress responses; however, the proteins with executive functions varied. These results indicate functional specialization of family proteins in response to different stresses, i.e., CDPK21, TPR, and CTR1 specific to phosphorylation cascades under early salt stress, whereas STN7 and BSL were specific to phosphorylation cascades under early drought stress. Only the calcium-binding EF-hand family protein and ZKT were clearly identified as signaling proteins that acted as cross-talk nodes for salt and drought signaling pathways. Our study provides new clues and insights for developing strategies to improve the tolerance of crops to complex, multiple environmental stresses.
Louisiana State, U. (2015) Comparison of basal gene expression strengths between Schrenkiella parvula and Arabidopsis thaliana European Nucleotide ArchiveSchrenkiella parvula is a wild relative of brassica crops and the model plant Arabidopsis thaliana, and is adapted to multi-ion salt stress. This project compare basal level expression strengths of orthologous genes between the two species, in root and shoot tissues under a non-stress condition, using RNA-seq.
Li, Z. Q., J. X. Li, et al. (2015) Overexpression of TsApx1 from Thellungiella salsuginea improves abiotic stress tolerance in transgenic Arabidopsis thaliana Biologia Plantarum 59: 497-506. 10.1007/s10535-015-0533-yThe halophyte Thellungiella salsuginea is a new model plants due to its small genome size, short life cycle, and copious seed production. Although T. salsuginea shares a high sequence identity with its close relative Arabidopsis thaliana, it shows a greater tolerance to salinity, drought, freezing, heat, and cold. To elucidate the mechanism of abiotic stress resistance in T. salsuginea, we characterized its cytosolic Apx1 gene (TsApx1) and established A. thaliana transgenic lines overexpressing TsApx1. Under 300 mM NaCl, the content of H2O2, malondialdehyde, and proline were lower and the activities of superoxide dismutase, catalase, glutathione peroxidase, and ascorbate peroxidase were all higher in the transgenic plants overexpressing TsApx1 (35S:TsApx1-GFP) than in the wild-type plants. The atapx1 mutant plants of A. thaliana had a NaCl/mannitol-sensitive phenotype. The ectopic expression of TsApx1 in the atapx1 mutant effectively remedied the phenotype. These results suggest that TsApx1 plays an important role in scavenging reactive oxygen species in the cytoplasm under salinity or drought. Although TsApx1 in T. salsuginea was constantly expressed at a high level, this gene was clearly inducible. In summary, the high constitutive expression and rapid induction of TsApx1 may contribute to the tolerance to abiotic stresses in T. salsuginea.
Li, W., M. A. Khan, et al. (2015) Hormonal and environmental regulation of seed germination in salt cress (Thellungiella halophila) Plant Growth Regulation 76: 41-49. 10.1007/s10725-014-0007-9Thellungiella halophila (salt cress) is a salt tolerant species with high genetic and morphological similarity to model plant Arabidopsis thaliana. The role of growth regulators in imposing seed dormancy and a release from it while responding to environmental signals has been examined. Seeds of salt cress possess a deep dormancy at maturity which decreased during after-ripening and cold stratification. After-ripened seeds of salt cress failed to germinate in dark and in strong light (134 A mu mol m(-2) s(-1)) while best seed germination was obtained in weak white light (1-10 A mu mol m(-2) s(-1)) at 22 A degrees C. The germination of non-dormant salt cress seeds was also regulated by red and far-red light. Light enhanced the sensitivity to gibberellin in dark-imbibed salt cress seeds and strong light inhibited biosynthesis of gibberellins. The endogenous abscisic acid was not affected by strong light implying that inhibition of seed germination is not mediated through ABA signals. Higher seed germination was recorded at a constant temperature of 20 A degrees C and a thermoperiod of 15/25 A degrees C (12 h strong light/12 h dark). Seeds of salt cress when exposed to 400 mM NaCl for 10 days maintain their viability however there was a heavy mortality among Arbidopsis seeds under similar conditions. Our data indicates that seed germination in salt cress is highly regulated by environmental and hormonal signals to provide opportunities to germinate under natural conditions.
Lee, S. B. and M. C. Suh. (2015) Advances in the understanding of cuticular waxes in Arabidopsis thaliana and crop species Plant Cell Reports 34: 557-572. 10.1007/s00299-015-1772-2The aerial parts of plants are covered with a cuticle, a hydrophobic layer consisting of cutin polyester and cuticular waxes that protects them from various environmental stresses. Cuticular waxes mainly comprise very long chain fatty acids and their derivatives such as aldehydes, alkanes, secondary alcohols, ketones, primary alcohols, and wax esters that are also important raw materials for the production of lubricants, adhesives, cosmetics, and biofuels. The major function of cuticular waxes is to control non-stomatal water loss and gas exchange. In recent years, the in planta roles of many genes involved in cuticular wax biosynthesis have been characterized not only from model organisms like Arabidopsis thaliana and saltwater cress (Eutrema salsugineum), but also crop plants including maize, rice, wheat, tomato, petunia, Medicago sativa, Medicago truncatula, rapeseed, and Camelina sativa through genetic, biochemical, molecular, genomic, and cell biological approaches. In this review, we discuss recent advances in the understanding of the biological functions of genes involved in cuticular wax biosynthesis, transport, and regulation of wax deposition from Arabidopsis and crop species, provide information on cuticular wax amounts and composition in various organs of nine representative plant species, and suggest the important issues that need to be investigated in this field of study.
Khanal, N., B. A. Moffatt, et al. (2015) Acquisition of freezing tolerance in Arabidopsis and two contrasting ecotypes of the extremophile Eutrema salsugineum (Thellungiella salsuginea) Journal of Plant Physiology 180: 35-44. 10.1016/j.jplph.2015.03.011Eutrema salsugineum (Thellungiella salsuginea) is an extremophile, a close relative of Arabidopsis, but possessing much higher constitutive levels of tolerance to abiotic stress. This study aimed to characterize the freezing tolerance of Arabidopsis (Columbia ecotype) and two ecotypes of Eutrema (Yukon and Shandong) isolated from contrasting geographical locations. Under our growth conditions, maximal freezing tolerance was observed after two-and three-weeks of cold acclimation for Arabidopsis and Eutrema, respectively. The ecotypes of Eutrema and Arabidopsis do not differ in their constitutive level of freezing tolerance or short-term cold acclimation capacity. However Eutrema remarkably outperforms Arabidopsis in long-term acclimation capacity suggesting a wider phenotypic plasticity for the trait of freezing tolerance. The combination of drought treatment and one-week of cold acclimation was more effective than long-term cold acclimation in achieving maximum levels of freezing tolerance in Eutrema, but not Arabidopsis. Furthermore, it was demonstrated growth conditions, particularly irradiance, are determinates of the level of freezing tolerance attained during cold acclimation suggesting a role for photosynthetic processes in adaptive stress responses. (C) 2015 Elsevier GmbH. All rights reserved.
Katschnig, D., T. Bliek, et al. (2015) Constitutive high-level SOS1 expression and absence of HKT1;1 expression in the salt-accumulating halophyte Salicornia dolichostachya Plant Science 234: 144-154. 10.1016/j.plantsci.2015.02.011We investigated the effects of salinity on ion accumulation and expression of candidate salt tolerance genes in the highly tolerant salt accumulating halophyte Salicornia dolichostachya and the taxonomically related glycophytic Spinacia oleracea. S. dolichostachya, in comparison with S. oleracea, constitutively expressed SOS1 at a high level, but did not detectably express HKT1;1. These findings suggest that the constitutive high level of shoot salt accumulation in S. dolichostachya is accomplished through enhancement of SOS 1-mediated Na+ xylem loading, in combination with complete suppression of HKT1;1-mediated Na+ retrieval from the xylem. Our findings demonstrate the importance of gene expression comparisons between highly tolerant halophytes and taxonomically related glycophytes to improve the understanding of mechanisms of Na+ movement and salt tolerance in plants. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
Jiang, Y., W. Chen, et al. (2015) Bioinformatics analysis for ICE1 and ICE2 genes of transcription factors related to plant cold resistance Guizhou Agricultural Sciences 43: 24-30.The complete sequences of ICE1 and ICE2 genes of different plants from NCBI were analyzed to provide the theoretical basis for studying structure and biological function of ICE gene, then the phylogenetic trees were established based on multiple alignments of amino acid sequences of ICE1 and ICE2 genes from the different plants by Clustal W2 and Mega 5.0 software, and finally the primary, secondary and tertiary structures of these ICE1 and ICE2 proteins were analyzed by different bioinformatics software. The results showed that ICE1 and ICE2 genes both have four different structural domains of S-rich, nuclear localization signal (NLS), basic helix-loop-helix (bHLH) and transmembrane, but there is difference between bHLH structural domain and S-rich domain in monocotyledon. The amino acid of ICE1 and ICE2 gene code is aliphatic amino acid (Ser and Leu) mainly. The isoelectric points are acidity and the value of the isoelectric points is isoelectric points > dicotyledon. ICE1 and ICE2 genes both are hydrophilic unstable protein. C and H are major elements of secondary structure of ICE1 and ICE2 protein but E and T distribute in whole protein sporadically. There are differences in content of H, T, E and C and the difference in their content and fold patterns results in difference of protein's tertiary structure. ICE1 and ICE2 genes have the similar structural domain in gene sequence but there is difference in protein structure.
Jiang, M., B. Chen, et al. (2015) Cloning and expression analysis of a transcription factor gene BoWRKY2 from broccoli Journal of Zhejiang University (Agriculture and Life Sciences) 41: 153-159.Broccoli (Brassica oleracea var. italica), which belongs to Cruciferae family, is a cash crop widely cultivated in China, and it is regarded as one of the most consumed vegetables in the world. The flower head of broccoli is rich in minerals, vitamins, fibers as well as anti-oxidants, so it is recognized as a healthy vegetable with anti-cancer properties. As a major broccoli production center in China, the average plantation areas reach to 8 000 hm2 in Taizhou of Zhejiang Province. However, broccoli cultivation suffered from plant diseases of downy mildew and stalk break which were caused by Hyaloperonospora parasitica and Sclerotinia sclerotiorum, respectively, resulting in yield and quality loss. WRKY transcription factors played important roles in plant stress responses, and WRKY domains were defined as an approximately 60-amino acid motif named WRKYGQK as well as a zinc finger structure of C-X4-5-C-X22-23-H-X1-H at their C-terminus. The WRKY domain binds specifically to DNA sequence of (T)(T)TGAC(C/T) known as the W-box which exists in defense-related promoters. Enhanced disease resistance by overexpression of WRKY genes in different crop plants has been reported in recent years. In this study, a WRKY gene designated as BoWRKY2, was isolated from B. oleracea var. italica. Based on sequence analysis, expression patterns of BoWRKY2 were detected using reverse transcription-polymerase chain reaction (RT-PCR) method while challenged by H. parasitica and S. sclerotioruni, respectively. The results showed that the genome DNA sequence was 1 507 bp in length with two introns and a complete coding sequence of 987 bp, and the length of two introns were 425 and 95 bp, respectively; BoWRKY2 encoded 328 amino acids with a WRKYGQK residue and a zinc finger structure of C-X5-C-X23-H-X1-H. The WRKY domain located between 247 and 313 residues, and several DNA binding sites were found at sites of 66, 67, 69, 71, 74, 281, 282, 283 and 317. The WRKY domain was similar to that of oilseed rape with only one amino acid residue difference between them. Phylogenetic analysis indicated the BoWRKY2 was grouped with other Cruciferae plants such as B. napus, Arabidopsis thaliana, A. lyrata, Capsella rubella and Eutrema salsugineum, with 97% confidence. RT-PCR results revealed that the BoWRKY2 was induced by both H. parasitica and S. sclerotiorum with similar expression patterns. The expression level both increased at 6 h and 12 h, and decreased after 24 h, indicating the resistance responses of BoWRKY2 against two plant fungi. In a word, the cloning and expression analysis of BoWRKY2 gene lay the foundation for further studies in gene function identification and molecular breeding of broccoli.
Hou, Q. and D. Bartels. (2015) Comparative study of the aldehyde dehydrogenase (ALDH) gene superfamily in the glycophyte Arabidopsis thaliana and Eutrema halophytes Annals of Botany 115: 465-479. 10.1093/aob/mcu152Background and Aims Stresses such as drought or salinity induce the generation of reactive oxygen species, which subsequently cause excessive accumulation of aldehydes in plant cells. Aldehyde dehydrogenases (ALDHs) are considered as 'aldehyde scavengers' to eliminate toxic aldehydes caused by oxidative stress. The completion of the genome sequencing projects of the halophytes Eutrema parvulum and E. salsugineum has paved the way to explore the relationships and the roles of ALDH genes in the glycophyte Arabidopsis thaliana and halophyte model plants. Methods Protein sequences of all plant ALDH families were used as queries to search E. parvulum and E. salsugineum genome databases. Evolutionary analyses compared the phylogenetic relationships of ALDHs from A. thaliana and Eutrema. Expression patterns of several stress-associated ALDH genes were investigated under different salt conditions using reverse transcription-PCR. Putative cis-elements in the promoters of ALDH10A8 from A. thaliana and E. salsugineum were compared in silico. Key Results Sixteen and 17 members of ten ALDH families were identified from E. parvulum and E. salsugineum genomes, respectively. Phylogenetic analysis of ALDH protein sequences indicated that Eutrema ALDHs are closely related to those of Arabidopsis, and members within these species possess nearly identical exon-intron structures. Gene expression analysis under different salt conditions showed that most of the ALDH genes have similar expression profiles in Arabidopsis and E. salsugineum, except for ALDH7B4 and ALDH10A8. In silico analysis of promoter regions of ALDH10A8 revealed different distributions of cis-elements in E. salsugineum and Arabidopsis. Conclusions Genomic organization, copy number, sub-cellular localization and expression profiles of ALDH genes are conserved in Arabidopsis, E. parvulum and E. salsugineum. The different expression patterns of ALDH7B4 and ALDH10A8 in Arabidopsis and E. salsugineum suggest that E. salsugineum uses modified regulatory pathways, which may contribute to salinity tolerance.
Hohmann, N., E. M. Wolf, et al. (2015) A Time-Calibrated Road Map of Brassicaceae Species Radiation and Evolutionary History Plant Cell 27: 2770-2784. 10.1105/tpc.15.00482The Brassicaceae include several major crop plants and numerous important model species in comparative evolutionary research such as Arabidopsis, Brassica, Boechera, Thellungiella, and Arabis species. As any evolutionary hypothesis needs to be placed in a temporal context, reliably dated major splits within the evolution of Brassicaceae are essential. We present a comprehensive time-calibrated framework with important divergence time estimates based on whole-chloroplast sequence data for 29 Brassicaceae species. Diversification of the Brassicaceae crown group started at the Eocene-to-Oligocene transition. Subsequent major evolutionary splits are dated to; 20 million years ago, coinciding with the Oligocene-to-Miocene transition, with increasing drought and aridity and transient glaciation events. The age of the Arabidopsis thaliana crown group is 6 million years ago, at the Miocene and Pliocene border. The overall species richness of the family is well explained by high levels of neopolyploidy (43% in total), but this trend is neither directly associated with an increase in genome size nor is there a general lineage-specific constraint. Our results highlight polyploidization as an important source for generating new evolutionary lineages adapted to changing environments. We conclude that species radiation, paralleled by high levels of neopolyploidization, follows genome size decrease, stabilization, and genetic diploidization.
Hao, G., I. A. Al-Shehbaz, et al. (2015) Eutrema racemosum (Eutremeae, Brassicaceae), a new tetraploid species from southwest China Phytotaxa 224: 185-195. 10.11646/phytotaxa.224.2.5The new species Eutrema racemosum is described, and its relationship to the closely related E. heterophyllum and E. edwardsii are discussed based on morphological, cytological, and molecular data. The novelty differs from E. heterophyllum by having elongated racemes and from E. edwardsii by somewhat reflexed fruiting pedicels. Four chloroplast DNA fragments and nuclear ITS region were sequenced for multiple individuals of each species. Three species show distinct and stable sequence variations. Eutrema racemosum and E. heterophyllum form a clade sister to that of E. edwardsii in phylogenetic analyses of sequence variations. Our cytological studies revealed that E. heterophyllum is a diploid with the small genome size, while E. racemosum is a tetraploid with duplicate genomes. These available data support the recognition of E. racemosum as a distinct species well differentiated morphologically and genetically, as well as well-isolated reproductively from its sister species E. heterophyllum. We further found some interspecific triploid hybrids between tetraploid E. racemosum and diploid E. heterophyllum, which seem to be sterile according to our germination experiments.
Guo, Q., L. Meng, et al. (2015) Salt tolerance in two tall wheatgrass species is associated with selective capacity for K+ over Na+ Acta Physiologiae Plantarum 37: 1708 10.1007/s11738-014-1708-4Decaploid Elytrigia elongata (tall wheatgrass) is a halophytic relative of wheat that is used to improve salt tolerance of wheat in China. However, the physiological mechanisms for the salt tolerance of decaploid E. elongata remain elusive. To further gain insights into mechanisms important for salt tolerance, we present here a comparative study of salt tolerance in salt-sensitive tetraploid E. elongata (PI578686) and salt-tolerant decaploid E. elongata (PI276399). Results showed that compared with PI578686, PI276399 exhibited a higher relative growth rate and a stronger selective absorption and -transport capacity for K+ over Na+ under high salt conditions (100-200 mM NaCl). This contributed to maintain lower net Na+ uptake rates and more efficiently control Na+ transport to the shoot in PI276399 than in PI578686. Meanwhile, this also resulted in lower reductions of tissue K+ concentrations as well as of net K+ uptake rates in PI276399 compared to PI578686. Taken together, our findings indicate that PI276399 has the stronger selectivity for K+ over Na+ contributing it to maintain lower Na+ uptake and K+ loss compared with PI578686 in the presence of high salt, and hence endowing the higher salt tolerance of PI276399.
Grafi, G. and S. Barak. (2015) Stress induces cell dedifferentiation in plants Biochimica Et Biophysica Acta-Gene Regulatory Mechanisms 1849: 378-384. 10.1016/j.bbagrm.2014.07.015Accumulating evidence lends support to the proposal that a major theme in plant responses to stresses is dedifferentiation, whereby mature cells acquire stem cell features (e.g. open chromatin conformation) prior to acquisition of a new cell fate. In this review, we discuss data addressing plant cell plasticity and provide evidence linking stress, dedifferentiation and a switch in cell fate. We emphasize the epigenetic modifications associated with stress-induced global changes in chromatin structure and conclude with the implications for genetic variation and for induced pluripotent stem cells in animals. It appears that stress is perceived as a signal that directs plant cells to undergo reprogramming (dedifferentiation) as a means for adaptation and in preparation for a stimulus-based acquisition of a new cell fate. This article is part of a Special Issue entitled: Stress as a fundamental theme in cell plasticity. (C) 2014 Elsevier B.V. All rights reserved.
German, D. A. and I. A. Al-Shehbaz. (2015) Typification of miscellaneous Brassicaceae (Cruciferae) from Central and Middle Asia Phytotaxa 221: 57-65.The present paper deals with the typification of 25 names (11 species, 13 varieties, and one form) in the Brassicaceae, of which the majority (19 names) is in Draba. In addition, Arabis tibetica var. bucharica, A. tibetica var. pinnatifida, Eutrema potaninii, Pseudobraya kizyl-arti, Sisymbrium mollissimum f. pamiricum, and Winklera patrinoides, which are currently treated as synonyms in the genera Crucihimalaya (3 names), Draba, Eutrema, and Lepidium (one name each), are also typified. Most of the original material was collected from the five Middle Asian republics of the Former Soviet Union (especially Kyrgyzstan and Tajikistan), and some other was from China, with a few syntypes of three Draba taxa originating from Asian Russia, Mongolia, Kashmir, and Sikkim.
German, D. A. and I. A. Al-Shehbaz. (2015) (2369) Proposal to conserve the name Sisymbrium pumilum Stephan, non Lam. (Calymmatium pumilum, Olimarabidopsis pumila, Thellungiella pumila) (Cruciferae) Taxon 64: 849-850.Background Most of the water on Earth is seawater, each kilogram of which contains about 35 g of salts, and yet most plants cannot grow in this solution; less than 0.2 % of species can develop and reproduce with repeated exposure to seawater. These 'extremophiles' are called halophytes. Scope Improved knowledge of halophytes is of importance to understanding our natural world and to enable the use of some of these fascinating plants in land re-vegetation, as forages for livestock, and to develop salt-tolerant crops. In this Preface to a Special Issue on halophytes and saline adaptations, the evolution of salt tolerance in halophytes, their life-history traits and progress in understanding the molecular, biochemical and physiological mechanisms contributing to salt tolerance are summarized. In particular, cellular processes that underpin the ability of halophytes to tolerate high tissue concentrations of Na+ and Cl-, including regulation of membrane transport, their ability to synthesize compatible solutes and to deal with reactive oxygen species, are highlighted. Interacting stress factors in addition to salinity, such as heavy metals and flooding, are also topics gaining increased attention in the search to understand the biology of halophytes. Conclusions Halophytes will play increasingly important roles as models for understanding plant salt tolerance, as genetic resources contributing towards the goal of improvement of salt tolerance in some crops, for re-vegetation of saline lands, and as 'niche crops' in their own right for landscapes with saline soils.
Feng, J., J. Wang, et al. (2015) High-throughput deep sequencing reveals that microRNAs play important roles in salt tolerance of euhalophyte Salicornia europaea Bmc Plant Biology 15: 63 10.1186/s12870-015-0451-3Background: microRNAs (miRNAs) are implicated in plant development processes and play pivotal roles in plant adaptation to environmental stresses. Salicornia europaea, a salt mash euhalophyte, is a suitable model plant to study salt adaptation mechanisms. S. europaea is also a vegetable, forage, and oilseed that can be used for saline land reclamation and biofuel precursor production on marginal lands. Despite its importance, no miRNA has been identified from S. europaea thus far. Results: Deep sequencing was performed to investigate small RNA transcriptome of S. europaea. Two hundred and ten conserved miRNAs comprising 51 families and 31 novel miRNAs (including seven miRNA star sequences) belonging to 30 families were identified. About half (13 out of 31) of the novel miRNAs were only detected in salt-treated samples. The expression of 43 conserved and 13 novel miRNAs significantly changed in response to salinity. In addition, 53 conserved and 13 novel miRNAs were differentially expressed between the shoots and roots. Furthermore, 306 and 195 S. europaea unigenes were predicted to be targets of 41 conserved and 29 novel miRNA families, respectively. These targets encoded a wide range of proteins, and genes involved in transcription regulation constituted the largest category. Four of these genes encoding laccase, F-box family protein, SAC3/GANP family protein, and NADPH cytochrome P-450 reductase were validated using 5'-RACE. Conclusions: Our results indicate that specific miRNAs are tightly regulated by salinity in the shoots and/or roots of S. europaea, which may play important roles in salt tolerance of this euhalophyte. The S. europaea salt-responsive miRNAs and miRNAs that target transcription factors, nucleotide binding site-leucine-rich repeat proteins and enzymes involved in lignin biosynthesis as well as carbon and nitrogen metabolism may be applied in genetic engineering of crops with high stress tolerance, and genetic modification of biofuel crops with high biomass and regulatable lignin biosynthesis.
Feki, K., F. Brini, et al. (2015) Comparative functional analysis of two wheat Na+/H+ antiporter SOS1 promoters in Arabidopsis thaliana under various stress conditions Journal of Applied Genetics 56: 15-26. 10.1007/s13353-014-0228-7The bread wheat TaSOS1 has been previously shown to be induced by salt stress treatment. To further investigate the regulation of the TaSOS1 gene, the two genomic fragments Pr (SOS1-AB) and Pr (SOS1-D) have been isolated and sequenced. Pr (SOS1-AB) and Pr (SOS1-D) are the promoter regions of SOS1 alleles, which are localised on genomes A and/or B, and on genome D, respectively. Sequence analysis of these two promoters revealed the presence of cis-regulatory elements which could be required for abiotic stress and abscisic acid (ABA) responsiveness. Histochemical assays of stably transformed Arabidopsis T3 plants showed that Pr (SOS1-AB) and Pr (SOS1-D) are active in this heterologous system, and their activities were almost the same at early developmental stages (4-, 8- and 12-day-old transgenic Arabidopsis seedlings). Nevertheless, beta-glucuronidase (GUS) activity was detected only in plants carrying the Pr (SOS1-AB) -gusA construct grown for 20 or 30 days. Furthermore, in these plants, the application of abiotic stress produced an accumulation in gusA transcripts. Taken together, these results show that, in this heterologous dicot system and under normal growth conditions, Pr (SOS1-AB) and Pr (SOS1-D) are age-dependent and organ-specific promoters. However, in the presence of different stress conditions, the activities of these two promoters became different and only Pr (SOS1-AB) is an abiotic stress-inducible promoter at different developmental stages. Thus, Pr (SOS1-AB) can be used for the development of abiotic stress-tolerant transgenic plants.
Dorn, K. M., J. D. Fankhauser, et al. (2015) A draft genome of field pennycress (Thlaspi arvense) provides tools for the domestication of a new winter biofuel crop DNA Research 22: 121-131. 10.1093/dnares/dsu045Field pennycress (Thlaspi arvense L.) is being domesticated as a new winter cover crop and biofuel species for the Midwestern United States that can be double-cropped between corn and soybeans. A genome sequence will enable the use of new technologies to make improvements in pennycress. To generate a draft genome, a hybrid sequencing approach was used to generate 47 Gb of DNA sequencing reads from both the Illumina and PacBio platforms. These reads were used to assemble 6,768 genomic scaffolds. The draft genome was annotated using the MAKER pipeline, which identified 27,390 predicted protein-coding genes, with almost all of these predicted peptides having significant sequence similarity to Arabidopsis proteins. A comprehensive analysis of pennycress gene homologues involved in glucosinolate biosynthesis, metabolism, and transport pathways revealed high sequence conservation compared with other Brassicaceae species, and helps validate the assembly of the pennycress gene space in this draft genome. Additional comparative genomic analyses indicate that the knowledge gained from years of basic Brassicaceae research will serve as a powerful tool for identifying gene targets whose manipulation can be predicted to result in improvements for pennycress.
Diray-Arce, J., M. Clement, et al. (2015) Transcriptome assembly, profiling and differential gene expression analysis of the halophyte Suaeda fruticosa provides insights into salt tolerance Bmc Genomics 16: 353 10.1186/s12864-015-1553-xBackground: Improvement of crop production is needed to feed the growing world population as the amount and quality of agricultural land decreases and soil salinity increases. This has stimulated research on salt tolerance in plants. Most crops tolerate a limited amount of salt to survive and produce biomass, while halophytes (salt-tolerant plants) have the ability to grow with saline water utilizing specific biochemical mechanisms. However, little is known about the genes involved in salt tolerance. We have characterized the transcriptome of Suaeda fruticosa, a halophyte that has the ability to sequester salts in its leaves. Suaeda fruticosa is an annual shrub in the family Chenopodiaceae found in coastal and inland regions of Pakistan and Mediterranean shores. This plant is an obligate halophyte that grows optimally from 200-400 mM NaCl and can grow at up to 1000 mM NaCl. High throughput sequencing technology was performed to provide understanding of genes involved in the salt tolerance mechanism. De novo assembly of the transcriptome and analysis has allowed identification of differentially expressed and unique genes present in this non-conventional crop. Results: Twelve sequencing libraries prepared from control (0 mM NaCl treated) and optimum (300 mM NaCl treated) plants were sequenced using Illumina Hiseq 2000 to investigate differential gene expression between shoots and roots of Suaeda fruticosa. The transcriptome was assembled de novo using Velvet and Oases k-45 and clustered using CDHIT-EST. There are 54,526 unigenes; among these 475 genes are downregulated and 44 are upregulated when samples from plants grown under optimal salt are compared with those grown without salt. BLAST analysis identified the differentially expressed genes, which were categorized in gene ontology terms and their pathways. Conclusions: This work has identified potential genes involved in salt tolerance in Suaeda fruticosa, and has provided an outline of tools to use for de novo transcriptome analysis. The assemblies that were used provide coverage of a considerable proportion of the transcriptome, which allows analysis of differential gene expression and identification of genes that may be involved in salt tolerance. The transcriptome may serve as a reference sequence for study of other succulent halophytes.
Chidambaram, R., G. Venkataraman, et al. (2015) Analysis of transcriptional regulation and tissue-specific expression of Avicennia marina Plasma Membrane Protein 3 suggests it contributes to Na+ transport and homoeostasis in A-marina Plant Science 236: 89-102. 10.1016/j.plantsci.2015.03.013Plasma membrane proteins (PMP3) play a role in cation homoeostasis. The 5' flanking sequence of stress inducible, Avicennia marina PMP3 (AmPMP3prom) was transcriptionally fused to (a) GUS or (b) GFP-AmPMP3 and analyzed in transgenic tobacco. Tissue-histochemical GUS and GFP:AmPMP3 localization are co-incident under basal and stress conditions. AmPMP3prom directed GUS activity is highest in roots. Basal transcription is conferred by a 388 bp segment upstream of the translation start site. A 463 bp distal enhancer in the AmPMP3prom confers enhanced expression under salinity in all tissues and also responds to increases in salinity. The effect of a central, stem-specific negative regulatory region is suppressed by the distal enhancer. The A. marina rhizosphere encounters dynamic changes in salinity at the inter-tidal interface. The complex, tissue-specific transcriptional responsiveness of AmPMP3 to salinity appears to have evolved in response to these changes. Under salinity, guard cell and phloem-specific expression of GFP:AmPMP3 is highly enhanced. Mesophyll, trichomes, bundle sheath, parenchymatous cortex and xylem parenchyma also show GFP:AmPMP3 expression. Cis-elements conferring stress, root and vascular-specific expression are enriched in the AmPMP3 promoter. Pronounced vascular-specific AmPMP3 expression suggests a role in salinity induced Na+ transport, storage, and secretion in A. marina. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
Chen, Q., Y. Qu, et al. (2015) Cloning and sequence analysis of HRD transcription factors gene from two kinds of ephemeral plants Bulletin of Botanical Research 35: 250-258.We isolated two transcription factor genes, named as CpHRD and SaHRD, from two kinds of ephemeral Conringia planisiliqua L. and Sisybrium altissimum L. by RT-PCR, respectively. By bioinformatics, both of CpHRD and SaHRD are possessing an intact complete open reading frame of 564 bp and sharing 88%, 87%, 87% and 86% of sequence identity with Eutrema salsugineum, Arabidopsis lyrata, Capsella rubella and Arabidopsis thaliana, respectively. The deduced polypeptide sequence of CpHRD and SaHRD are 187 amino acid residues with a predicted molecular weight of 20 kD with secondary protein structure of the polypeptide chains contain including 2 beta-sheets, 5 alpha-helixs and random coils, belonging to hydrophilicity and stable of transmembrane protein. By phylogenetic tree analysis, CpHRD and SaHRD mainly exist in the nucleus contains, and have a typical AP2/EREBP domain function structure, which may be involved in plant stresses response process of ABA, drought and low temperature. Our results can provide useful information about the molecular mechanism of HRD genetic mechanism of drought resistance, and will contribute a valuable resource for development and utilization of germplasm resources of ephemeral plant.
Chang, L., A. Guo, et al. (2015) The beta subunit of glyceraldehyde 3-phosphate dehydrogenase is an important factor for maintaining photosynthesis and plant development under salt stress-Based on an integrative analysis of the structural, physiological and proteomic changes in chloroplasts in Thellungiella halophila Plant Science 236: 223-238. 10.1016/j.plantsci.2015.04.010Thellungiella halophila, a new model halophyte, can survive under highly saline conditions. We performed comparative proteomics of chloroplasts from plants grown under different saline conditions. Seventy-five salt-responsive proteins were positively identified by mass spectrometry, which represented 43 unique ones. These proteins were categorized into 7 main pathways: light reaction, carbon fixation, energy metabolism, antenna proteins, cell structure, and protein degradation and folding. Saline conditions increased the abundance of proteins involved in photosynthesis, energy metabolism and cell structure. The results indicated that Thellungiella could withstand high salinity by maintaining normal or high photosynthetic capacity, reducing ROS production, as well as enhancing energy usage. Meanwhile, the ultrastructural and physiological data also agree with chloroplast proteomics results. Subsequently, the glyceraldehydes 3-phosphate dehydrogenase beta subunit (GAPB) involved in carbon fixation was selected and its role in salt tolerance was clarified by over-expressing it in Arabidopsis. ThGAPB-overexpressing plants had higher total chlorophyll contents, dry weights, water contents and survival rates than that of wild type plants. These results indicated that ThGAPB might improve plant salt tolerance by maintaining higher recycling rates of ADP and NADV(+) to decrease ROS production, helping to maintain photosynthetic efficiency and plant development under saline conditions. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
Bush, S. J., P. X. Kover, et al. (2015) Data from: Lineage-specific sequence evolution and exon edge conservation partially explain the relationship of evolutionary rate and expression level in A. thaliana Dryad http://dx.doi.org/10.5061/DRYAD.905SQRapidly evolving proteins can aid the identification of genes underlying phenotypic adaptation across taxa, but functional and structural elements of genes can also affect evolutionary rates. In plants, the edges' of exons, flanking intron junctions, are known to contain splice enhancers and to have a higher degree of conservation compared to the remainder of the coding region. However, the extent to which these regions may be masking indicators of positive selection or account for the relationship between dN/dS and other genomic parameters is unclear. We investigate the effects of exon edge conservation on the relationship of dN/dS to various sequence characteristics and gene expression parameters in the model plant Arabidopsis thaliana. We also obtain lineage-specific dN/dS estimates, making use of the recently sequenced genome of Thellungiella parvula, the second closest sequenced relative after the sister species Arabidopsis lyrata. Overall, we find that the effect of exon edge conservation, as well as the use of lineage-specific substitution estimates, upon dN/dS ratios partly explains the relationship between the rates of protein evolution and expression level. Furthermore, the removal of exon edges shifts dN/dS estimates upwards, increasing the proportion of genes potentially under adaptive selection. We conclude that lineage-specific substitutions and exon edge conservation have an important effect on dN/dS ratios and should be considered when assessing their relationship with other genomic parameters.
Bose, J., A. Rodrigo-Moreno, et al. (2015) Rapid regulation of the plasma membrane H+-ATPase activity is essential to salinity tolerance in two halophyte species, Atriplex lentiformis and Chenopodium quinoa Annals of Botany 115: 481-494. 10.1093/aob/mcu219Background and Aims The activity of H+-ATPase is essential for energizing the plasma membrane. It provides the driving force for potassium retention and uptake through voltage-gated channels and for Na+ exclusion via Na+/H+ exchangers. Both of these traits are central to plant salinity tolerance; however, whether the increased activity of H+-ATPase is a constitutive trait in halophyte species and whether this activity is upregulated at either the transcriptional or post-translation level remain disputed. Methods The kinetics of salt-induced net H+, Na+ and K+ fluxes, membrane potential and AHA1/2/3 expression changes in the roots of two halophyte species, Atriplex lentiformis (saltbush) and Chenopodium quinoa (quinoa), were compared with data obtained from Arabidopsis thaliana roots. Key Results Intrinsic (steady-state) membrane potential values were more negative in A. lentiformis and C. quinoa compared with arabidopsis (-144 +/- 3.3, -138 +/- 5.4 and -128 +/- 3.3mV, respectively). Treatment with 100mM NaCl depolarized the root plasma membrane, an effect that was much stronger in arabidopsis. The extent of plasma membrane depolarization positively correlated with NaCl-induced stimulation of vanadate-sensitive H+ efflux, Na+ efflux and K+ retention in roots (quinoa > saltbush > arabidopsis). NaCl-induced stimulation of H+ efflux was most pronounced in the root elongation zone. In contrast, H+-ATPase AHA transcript levels were much higher in arabidopsis compared with quinoa plants, and 100mM NaCl treatment led to a further 3-fold increase in AHA1 and AHA2 transcripts in arabidopsis but not in quinoa. Conclusions Enhanced salinity tolerance in the halophyte species studied here is not related to the constitutively higher AHA transcript levels in the root epidermis, but to the plant's ability to rapidly upregulate plasma membrane H+-ATPase upon salinity treatment. This is necessary for assisting plants to maintain highly negative membrane potential values and to exclude Na+, or enable better K+ retention in the cytosol under saline conditions.
Bacha, H., R. Rodenas, et al. (2015) High Ca2+ reverts the repression of high-affinity K+ uptake produced by Na+ in Solanum lycopersycum L. (var. microtom) plants Journal of Plant Physiology 180: 72-79. 10.1016/j.jplph.2015.03.014Potassium (K+) is an essential nutrient for plants which is acquired by plant roots through the operation of specific transport systems. Abiotic stress conditions such as salinity impair K+ nutrition because, in addition to other effects, high salt concentrations in the solution bathing the roots inhibit K+ uptake systems. This detrimental effect of salinity is exacerbated when external K+ is very low and the only system capable of mediating K+ uptake is one with high-affinity for K+, as that mediated by transporters of the HAK5 type. Increasing external Ca2+ has been shown to improve K+ nutrition under salinity and, although the specific mechanisms for this beneficial effect are largely unknown, they are beginning to be understood. The genes encoding the HAK5 transporters are induced by K+ starvation and repressed by long-term exposure to high Na+. This occurs in parallel with the hyperpolarization and depolarization of root cell membrane potential. In the present study it is shown in tomato plants that the presence of high Ca2+ during the K+ starvation period that leads to LeHAK5 induction, counteracts the repression exerted by high Na+. High Ca2+ reduces the Na+-induced plasma membrane depolarization of root cells, resorting one of the putative first steps in the low-K+ signal cascade. This allows proper LeHAK5 expression and functional high-affinity K+ uptake at the roots. Thus, the maintenance of HAK5-mediated K+ nutrition under salinity by high Ca2+ can be regarded as a specific beneficial effect of Ca2+ contributing to salt tolerance in plants. (C) 2015 Elsevier GmbH. All rights reserved.
Ariga, H., T. Tanaka, et al. (2015) CSP41b, a protein identified via FOX hunting using Eutrema salsugineum cDNAs, improves heat and salinity stress tolerance in transgenic Arabidopsis thaliana Biochemical and Biophysical Research Communications 464: 318-323. 10.1016/j.bbrc.2015.06.151Eutrema salsugineum (also known as Thellungiella salsuginea and formerly Thellungiella halophila), a species closely related to Arabidopsis thaliana, shows tolerance not only to salt stress, but also to chilling, freezing, and high temperatures. To identify genes responsible for stress tolerance, we conducted Full-length cDNA Over-eXpressing gene (FOX) hunting among a collection of E. salsugineum cDNAs that were stress-induced according to gene ontology analysis or over-expressed in E. salsugineum compared with A. thaliana. We identified E. salsugineum CSP41b (chloroplast stem-loop-binding protein of 41 kDa; also known as CRB, chloroplast RNA binding; named here as EsCSP41b) as a gene that can confer heat and salinity stress tolerance on A. thaliana. A. thaliana CSP41 b is reported to play an important role in the proper functioning of the chloroplast: the atcsp41b mutant is smaller and paler than wild-type plants and shows altered chloroplast morphology and photosynthetic performance. We observed that AtCSP41b-overexpressing transgenic A. thaliana lines also exhibited marked heat tolerance and significant salinity stress tolerance. The EsCSP41b-overexpressing transgenic A. thaliana lines showed significantly higher photosynthesis activity than wild-type plants not only under normal growth conditions but also under heat stress. In wild-type plants, the expression levels of both EsCSP41b and AtCSP41b were significantly reduced under heat or salinity stress. We conclude that maintenance of CSP41b expression under abiotic stresses may alleviate photoinhibition and improve survival under such stresses. (C) 2015 Elsevier Inc. All rights reserved.
Amparo Asensi-Fabado, M., A. Ammon, et al. (2015) Tocopherol deficiency reduces sucrose export from salt-stressed potato leaves independently of oxidative stress and symplastic obstruction by callose Journal of Experimental Botany 66: 957-971. 10.1093/jxb/eru453Tocopherol cyclase, encoded by the gene SUCROSE EXPORT DEFECTIVE1, catalyses the second step in the synthesis of the antioxidant tocopherol. Depletion of SXD1 activity in maize and potato leaves leads to tocopherol deficiency and a 'sugar export block' phenotype that comprises massive starch accumulation and obstruction of plasmodesmata in paraveinal tissue by callose. We grew two transgenic StSXD1:RNAi potato lines with severe tocopherol deficiency under moderate light conditions and subjected them to salt stress. After three weeks of salt exposure, we observed a strongly reduced sugar exudation rate and a lack of starch mobilization in leaves of salt-stressed transgenic plants, but not in wild-type plants. However, callose accumulation in the vasculature declined upon salt stress in all genotypes, indicating that callose plugging of plasmodesmata was not the sole cause of the sugar export block phenotype in tocopherol-deficient leaves. Based on comprehensive gene expression analyses, we propose that enhanced responsiveness of SnRK1 target genes in mesophyll cells and altered redox regulation of phloem loading by SUT1 contribute to the attenuation of sucrose export from salt-stressed SXD:RNAi source leaves. Furthermore, we could not find any indication that elevated oxidative stress may have served as a trigger for the salt-induced carbohydrate phenotype of SXD1: RNAi transgenic plants. In leaves of the SXD1: RNAi plants, sodium accumulation was diminished, while proline accumulation and pools of soluble antioxidants were increased. As supported by phytohormone contents, these differences seem to increase longevity and prevent senescence of SXD: RNAi leaves under salt stress.
Al-Shehbaz, I. A. (2015) TYPIFICATION OF HIMALAYAN TAXA OF BRASICACEAE (CRUCIFERAE) Harvard Papers in Botany 20: 5-28. 10.3100/hpib.v20iss1.2015.n2The type status of 146 names of Himalayan taxa is discussed, of which the lectotypes of 133 names are designated here for the first time, including a few that were incompletely lectotypified due to the existence of more than one sheet in the institution where the type was said to be. These 133 species and infraspecfic names were originally described in the genera Arabis (15), Chorispora (4), Cochlearia (4), Dilophia (2), Draba (64), Ermania (2), Erysimum (5), Eutrema (4), Nasturtium (3), Sisymbrium (9), and Thlaspi (2). In addition, lectotypes are designated for one name each in the 15 other genera: Barbarea, Brassica, Capsella, Cardamine, Cheiranthus, Dipoma, Goldbachia, Hemilophia, Hutchinsia, Lepidostemon, Martinella, Megacarpaea, Microsisymbrium, Sinapis, and Sophiopsis. The type status of 13 additional names in Arabis (1), Buchingera (1), Draba (8), Erysimum (2), Parlatoria (1), Parrya (2), Sisymbrium (1), and Torularia (1) are discussed.
Adwy, W., M. Laxa, et al. (2015) A simple mechanism for the establishment of C-2-specific gene expression in Brassicaceae Plant Journal 84: 1231-1238. 10.1111/tpj.13084The transition of C-3, via C-2 towards C4 photosynthesis is an important example of stepwise evolution of a complex genetic trait. A common feature that was gradually emphasized during this trajectory is the evolution of a CO2 concentration mechanism around Rubisco. In C-2 plants, this mechanism is based on tissue- specific accumulation of glycine decarboxylase (GDC) in bundle sheath (BS) cells, relative to global expression in the cells of C-3 leaves. This limits photorespiratory CO2 release to BS cells. Because BS cells are surrounded by photosynthetically active mesophyll cells, this arrangement enhances the probability of re-fixation of CO2. The restriction of GDC to BS cells was mainly achieved by confinement of its P-subunit (GLDP). Here, we provide a mechanism for the establishment of C-2-type gene expression by studying the upstream sequences of C-3 Gldp genes in Arabidopsis thaliana. Deletion of 59 bp in the upstream region of AtGldp1 restricted expression of a reporter gene to BS cells and the vasculature without affecting diurnal variation. This region was named the ` M box'. Similar results were obtained for the AtGldp2 gene. Fusion of the M box to endogenous or exogenous promoters supported mesophyll expression. Nucleosome densities at the M box were low, suggesting an open chromatin structure facilitating transcription factor binding. In silico analysis defined a possible consensus for the element that was conserved across the Brassicaceae, but not in Moricandia nitens, a C-2 plant. Collective results provide evidence that a simple mutation is sufficient for establishment of C-2-specific gene expression in a C-3 plant.
Zhu, L., J. Guo, et al. (2014) Enhanced expression of EsWAX1 improves drought tolerance with increased accumulation of cuticular wax and ascorbic acid in transgenic Arabidopsis Plant Physiology and Biochemistry 75: 24-35. 10.1016/j.plaphy.2013.11.028Drought can activate several stress responses in plants, such as stomatal closure, accumulation of cuticular wax and ascorbic acid (AsA), which have been correlated with improvement of drought tolerance. In this study, a novel MYB gene, designed as EsWAX1, was isolated and characterized from Eutrema salsugineum. EsWAX1 contained a full-length open reading frame (ORF) of 1068 bp, which encoding 355 amino acids. Transcript levels of EsWAX1 were quickly inducible by drought stress and ABA treatment, indicating that EsWAX1 may act as a positive regulator in response to drought stress. Ectopic expression of EsWAX1 increased accumulation of cuticular wax via modulating the expression of several wax-related genes, such as CER1, KCS2 and KCR1. Scanning electron microscopy further revealed higher densities of wax crystalline structures on the adaxial surfaces of leaves in transgenic Arabidopsis plants. In addition, the expression of several AsA biosynthetic genes (VTC1, GLDH and MIOX4) was significantly up-regulated in EsWAX1-overexpressing lines and these transgenic plants have approximately 23-27% more total AsA content than WT plants. However, the high-level expression of EsWAX1 severely disrupted plant normal growth and development. To reduce negative effects of EsWAX1 over-expression on plant growth, we generated transgenic Arabidopsis plants expressing EsWAX1 driven by the stress-inducible RD29A promoter. Our data indicated the RD29A::EsWAX1 transgenic plants had greater tolerance to drought stress than wild-type plants. Taken together, the EsWAX1 gene is a potential regulator that may be utilized to improve plant drought tolerance by genetic manipulation. (C) 2013 Elsevier Masson SAS. All rights reserved.
Zhang, L., C. Zhang, et al. (2014) Global Analysis of Gene Expression Profiles in Physic Nut (Jatropha curcas L.) Seedlings Exposed to Salt Stress Plos One 9: e97878 10.1371/journal.pone.0097878Background: Salt stress interferes with plant growth and production. Plants have evolved a series of molecular and morphological adaptations to cope with this abiotic stress, and overexpression of salt response genes reportedly enhances the productivity of various crops. However, little is known about the salt responsive genes in the energy plant physic nut (Jatropha curcas L.). Thus, excavate salt responsive genes in this plant are informative in uncovering the molecular mechanisms for the salt response in physic nut. Methodology/Principal Findings: We applied next-generation Illumina sequencing technology to analyze global gene expression profiles of physic nut plants (roots and leaves) 2 hours, 2 days and 7 days after the onset of salt stress. A total of 1,504 and 1,115 genes were significantly up and down-regulated in roots and leaves, respectively, under salt stress condition. Gene ontology (GO) analysis of physiological process revealed that, in the physic nut, many "biological processes'' were affected by salt stress, particular those categories belong to "metabolic process'', such as "primary metabolism process'', "cellular metabolism process'' and "macromolecule metabolism process''. The gene expression profiles indicated that the associated genes were responsible for ABA and ethylene signaling, osmotic regulation, the reactive oxygen species scavenging system and the cell structure in physic nut. Conclusions/Significance: The major regulated genes detected in this transcriptomic data were related to trehalose synthesis and cell wall structure modification in roots, while related to raffinose synthesis and reactive oxygen scavenger in leaves. The current study shows a comprehensive gene expression profile of physic nut under salt stress. The differential expression genes detected in this study allows the underling the salt responsive mechanism in physic nut with the aim of improving its salt resistance in the future.
Yu, B. and W. Li. (2014) Comparative profiling of membrane lipids during water stress in Thellungiella salsuginea and its relative Arabidopsis thaliana Phytochemistry 108: 77-86. 10.1016/j.phytochem.2014.09.012The remodelling of membrane lipids contributes to the tolerance of plants to stresses, such as freezing and deprivation of phosphorus. However, whether and how this remodelling relates to tolerance of PEG-induced osmotic stress has seldom been reported. Thellungiella salsuginea is a popular extremophile model for studies of stress tolerance. In this study, it was demonstrated that T. salsuginea was more tolerant to PEG-induced osmotic stress than its close relative Arabidopsis thaliana. Lipidomic analysis indicated that plastidic lipids are more sensitive to PEG-induced osmotic stress than extra-plastidic ones in both species, and that the changes in plastidic lipids differed markedly between them. PEG-induced osmotic stress led to a dramatic decrease in levels of plastidic lipids in A. thaliana, whereas the change in plastidic lipid in T. salsuginea involved an adaptive remodelling shortly after the onset of PEG-induced osmotic stress. The two aspects of this remodelling involved increases in (1) the level of plastidic lipids, especially digalactosyl diacylglycerol, and (2) the double bond index of plastidic lipids. These remodelling steps could maintain the integrity and improve the fluidity of plastidic membranes and this may contribute to the PEG-induced osmotic stress tolerance of T. salsuginea. (c) 2014 Elsevier Ltd. All rights reserved.
Yi, X., Y. Sun, et al. (2014) Quantitative proteomics of Sesuvium portulacastrum leaves revealed that ion transportation by V-ATPase and sugar accumulation in chloroplast played crucial roles in halophyte salt tolerance Journal of Proteomics 99: 84-100. 10.1016/j.jprot.2014.01.017Physiological and proteomic responses of Sesuvium portulacastrum leaves under salinity were investigated. Different from glycophytes, this halophyte had optimal growth at 200-300 mM NaCl and accumulated more starch grains in chloroplasts under high salinity. Increased contents of soluble sugars, proline, and Na+ were observed upon salinity. X-ray microanalysis revealed that Na+ was mainly compartmentalized into cell vacuole. Quantitative proteomics produced 96 salt responsive proteins, and the majority was chloroplast-located proteins. Gene ontology analysis revealed that proteins involved in ion binding, proton transport, photosynthesis and ATP synthesis were overrepresented. The expressions of a Na+/H+ antiporter and several ATP synthase subunits were activated upon high salinity. ATP hydrolysis assay demonstrated that V-ATPase activity at tonoplast was dramatically increased upon NaCl whereas vacuolar H+-pyrophosphatase and plasma membrane P-ATPase activities were not increased, which indicated that sodium compartmentalization was mainly performed by enhancing V-ATPase activity rather than P-ATPase and H+-pyrophosphatase. Accumulation of soluble sugars as well as sodium compartmentalization maintained the osmotic balance between vacuole and cytoplasm, which finally established ionic homeostasis in saline cells in true halophytes. Biological significance Physiological and proteomic analyses of S. portulacastrum leaves under different salinities were investigated. This true halophyte accumulated more soluble sugars, starch, proline and Na+ under high salinity. Differential proteomics produced 96 salt responsive proteins and the majority was involved in ion binding, proton transport, photosynthesis, and ATP synthesis. A Na+/H+ antiporter and several ATP synthase subunits were induced upon high salinity. ATP hydrolysis assay demonstrated that V-ATPase activity at tonoplast was dramatically increased whereas vacuolar H+-pyrophosphatase and plasma membrane ATPase activities were stable upon NaCl. These findings demonstrated that the increased Na+ was compartmentalized into vacuole by enhancing V-ATPase activity rather than H+-ATPase. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.
Yadav, N. S., V. K. Singh, et al. (2014) A Novel Gene SbSI-2 Encoding Nuclear Protein from a Halophyte Confers Abiotic Stress Tolerance in E-coli and Tobacco Plos One 9: e101926 10.1371/journal.pone.0101926Salicornia brachiata is an extreme halophyte that grows luxuriantly in coastal marshes. Previously, we have reported isolation and characterization of ESTs from Salicornia with large number of novel/unknown salt-responsive gene sequences. In this study, we have selected a novel salt-inducible gene SbSI-2 (Salicornia brachiata salt-inducible-2) for functional characterization. Bioinformatics analysis revealed that SbSI-2 protein has predicted nuclear localization signals and a strong protein-protein interaction domain. Transient expression of the RFP: SbSI2 fusion protein confirmed that SbSI-2 is a nuclear localized protein. Genomic organization study showed that SbSI-2 is intronless and has a single copy in Salicornia genome. Quantitative RT-PCR analysis revealed higher SbSI-2 expression under salt stress and desiccation conditions. The SbSI-2 gene was transformed in E. coli and tobacco for functional characterization. pET28a-SbSI-2 recombinant E. coli cells showed higher tolerance to desiccation and salinity compared to vector alone. Transgenic tobacco plants overexpressing SbSI-2 have improved salt-and osmotic tolerance, accompanied by better growth parameters, higher relative water content, elevated accumulation of compatible osmolytes, lower Na+ and ROS accumulation and lesser electrolyte leakage than the wild-type. Overexpression of the SbSI-2 also enhanced transcript levels of ROS-scavenging genes and some stress-related transcription factors under salt and osmotic stresses. Taken together, these results demonstrate that SbSI-2 might play an important positive modulation role in abiotic stress tolerance. This identifies SbSI-2 as a novel determinant of salt/osmotic tolerance and suggests that it could be a potential bioresource for engineering abiotic stress tolerance in crop plants.
Xu, X. J., Y. J. Zhou, et al. (2014) Cloning and characterization of gene encoding a Mn-containing superoxide dismutase in Eutrema halophilum Biologia Plantarum 58: 105-113. 10.1007/s10535-013-0363-8A gene encoding Mn-containing superoxide dismutase (Mn-SOD), designated as ThMSD, was cloned from salt cress (Eutrema halophilum) by reverse transcriptase - polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The full length of ThMSD (acc. No. EF413171) is 1 047 bp with an open reading frame (ORF) of 693 bp. The deduced 231-amino acid polypeptide had a predicted molecular mass of 25.5 kDa, an estimated pI of 9.08, and a putative Mn-binding site. Recombinant ThMSD protein was expressed in Escherichia coli and characterized. The SOD activity of ThMSD was inactivated by sodium azide but not by potassium cyanide or hydrogen peroxide confirming that ThMSD is a Mn-SOD. Real-time PCR revealed that ThMSD was expressed in roots, rosette leaves, stems, stem leaves, flowers, and siliques. ThMSD mRNA reached the highest content in roots and its content increased when plants were treated with NaCl (in a concentration dependent manner), ABA, and subjected to drought. ThMSD was transformed into Arabidopsis and the stress tolerance properties of transgenic lines were assayed. The seeds of transgenic lines exhibited significantly higher germination rate under 100 and 150 mM NaCl than the wild type. The root growth of transgenic lines was affected less obviously than the wild type under 100 mM NaCl. The above results indicate that ThMSD played an important role in E. halophilum tolerance to environmental stresses, especially NaCl stress.
Xu, X., J. Feng, et al. (2014) Leaf cuticular lipids on the Shandong and Yukon ecotypes of saltwater cress, Eutrema salsugineum, and their response to water deficiency and impact on cuticle permeability Physiologia Plantarum 151: 446-458. 10.1111/ppl.12127The impact of water-deficit stress on leaf cuticular waxes and cutin monomers, and traits associated with cuticle permeability were examined in Shandong and Yukon ecotypes of Eutrema salsugineum (syn. Thellungiella salsuginea). Although Shandong exhibits glaucous leaves, and Yukon is non-glaucous, wax amounts on non-stressed Yukon leaves were 4.6-fold higher than on Shandong, due mainly to Yukon's eightfold higher wax fatty acids, especially the C-22 and C-24 acid homologues. Water deficit caused a 26.9% increase in total waxes on Shandong leaves, due mainly to increased C-22 and C-24 acids; and caused 10.2% more wax on Yukon, due mainly to an increase in wax alkanes. Total cutin monomers on non-stressed leaves of Yukon were 58.3% higher than on Shandong. Water deficit caused a 28.2% increase in total cutin monomers on Shandong, whereas total cutin monomers were not induced on Yukon. With or without stress, more abundant cuticle lipids were generally associated with lower water loss rates, lower chlorophyll efflux rates and an extended time before water deficit-induced wilting. In response to water deficit, Shandong showed elevated transcription of genes encoding elongase subunits, consistent with the higher stress induction of acids by Shandong. Yukon's higher induction of CER1 and CER3 transcripts may explain why alkanes increased most on Yukon after water deficit. Eutrema, with its diverse cuticle lipids and responsiveness, provides a valuable genetic resource for identifying new genes and alleles effecting cuticle metabolism, and lays groundwork for studies of the cuticle's role in extreme stress tolerance.
Wang, L.-L., A.-P. Chen, et al. (2014) The Thellungiella salsuginea Tonoplast Aquaporin TsTIP1;2 Functions in Protection Against Multiple Abiotic Stresses Plant and Cell Physiology 55: 148-161. 10.1093/pcp/pct166Examination of aquaporin (AQP) membrane channels in extremophile plants may increase our understanding of plant tolerance to high salt, drought or other conditions. Here, we cloned a tonoplast AQP gene (TsTIP1;2) from the halophyte Thellungiella salsuginea and characterized its biological functions. TsTIP1;2 transcripts accumulate to high levels in several organs, increasing in response to multiple external stimuli. Ectopic overexpression of TsTIP1;2 in Arabidopsis significantly increased plant tolerance to drought, salt and oxidative stresses. TsTIP1;2 had water channel activity when expressed in Xenopus oocytes. TsTIP1;2 was also able to conduct H2O2 molecules into yeast cells in response to oxidative stress. TsTIP1;2 was not permeable to Na+ in Xenopus oocytes, but it could facilitate the entry of Na+ ions into plant cell vacuoles by an indirect process under high-salinity conditions. Collectively, these data showed that TsTIP1;2 could mediate the conduction of both H2O and H2O2 across membranes, and may act as a multifunctional contributor to survival of T. salsuginea in highly stressful habitats.
Wang, B., Y. Zhang, et al. (2014) Identification of nuclear low-copy genes and their phylogenetic utility in rosids Genome 57: 547-554. 10.1139/gen-2014-0138By far, the interordinal relationships in rosids remain poorly resolved. Previous studies based on chloroplast, mitochondrial, and nuclear DNA has produced conflicting phylogenetic resolutions that has become a widely concerned problem in recent phylogenetic studies. Here, a total of 96 single-copy nuclear gene loci were identified from the KOG (eukaryotic orthologous groups) database, most of which were first used for phylogenetic analysis of angiosperms. The orthologous sequence datasets from completely sequenced genomes of rosids were assembled for the resolution of the position of the COM (Celastrales-Oxalidales-Malpighiales) clade in rosids. Our analysis revealed strong and consistent support for CM topology (the COM clade as sister to the malvids). Our results will contribute to further exploring the underlying cause of conflict between chloroplast, mitochondrial, and nuclear data. In addition, our study identified a few novel nuclear molecular markers with potential to investigate the deep phylogenetic relationship of plants or other eukaryotic taxonomical groups.
Vera-Estrella, R., B. J. Barkla, et al. (2014) Comparative 2D-DIGE analysis of salinity responsive microsomal proteins from leaves of salt-sensitive Arabidopsis thaliana and salt-tolerant Thellungiella salsuginea Journal of Proteomics 111: 113-127. 10.1016/j.jprot.2014.05.018Halophytes have evolved unique molecular strategies to overcome high soil salinity but we still know very little about the main mechanisms that these plants use to complete their lifecycle under salinity stress. One useful approach to further our understanding in this area is to directly compare the response to salinity of two closely related species which show diverse levels of salt tolerance. Here we present a comparative proteomic study using DIGE of leaf microsomal proteins to identify salt-responsive membrane associated proteins in Arabidopsis thaliana (a glycophyte) and Thellungiella salsuginea (a halophyte). While a small number of distinct protein abundance changes were observed upon salt stress in both species, the most notable differences were observed between species and specifically, in untreated plants with a total of 36 proteins displaying significant abundance changes. Gene ontology (GO) term enrichment analysis showed that the majority of these proteins were distributed into two functional categories; transport (31%) and carbohydrate metabolism (17%). Results identify several novel salt responsive proteins in this system and support the theory that T. salsuginea shows a high degree of salt-tolerance because molecular mechanisms are primed to deal with the stress. This intrinsic ability to anticipate salinity stress distinguishes it from the glycophyte A. thaliana. Biological significance There is significant interest in understanding the molecular mechanisms that plants use to tolerate salinity as soil salinization is becoming an increasing concern for agriculture with high soil Na+ levels leading to reduced yields and economic loss. Much of our knowledge on the molecular mechanisms employed by plants to combat salinity stress has come from work on salt-sensitive plants, but studies on naturally occurring highly salt-resistant plants, halophytes, and direct comparisons between closely related glycophytes and halophytes, could help to further our understanding of salinity tolerance mechanisms. In this study, employing two closely related species which differ markedly in their salt-tolerance, we carried out a quantitative proteomic approach using 2D-DIGE to identify salt-responsive proteins and compare and contrast the differences between the two plant species. Our work complements a previous study using iTRAQ technology (34) and highlights the benefits of using alternative technologies and approaches to gain a broader representation of the salt-responsive proteome in these species. This article is part of a Special Issue entitled: Proteomics, mass spectrometry and peptidomics, Cancun 2013. Guest Editors: Cesar Lopez-Camarillo, Victoria Pando-Robles and Bronwyn Jane Barkla. (C) 2014 Elsevier B.V. All rights reserved.
Transcript Profiling, M. P. I. o. M. P. P. (2014) Transcriptome sequencing and microarray design for functional genomics in the extremophile Arabidopsis relative Thellungiella salsuginea European Nucleotide ArchiveArabidopsis thaliana is not particularly stress tolerant and may lack protective mechanisms required to survive extreme environmental conditions. Thellungiella salsuginea has therefore attracted increasing interest as an alternative plant model species that possesses high tolerance of various abiotic stresses. While the T. salsuginea genome has recently been sequenced, its annotation is still far from complete and, due to the low number of ESTs available, evidence for actual transcriptional activity is lacking for most genes. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from plant samples from different developmental stages and grown under abiotic stress conditions. The ESTs of Thellungiella was sequenced by 454 pyrosequencing method. More than 1 million sequence reads were assembled into 42,810 unigenes, approximately 50% of which could be functionally annotated. From this sequence information, we constructed a 44k Agilent oligonucleotide microarray. A comparison of same-species and cross-species hybridization results showed the superior performance of the newly designed array for Thellungiella samples. In addition, the array was validated in a cold acclimation experiment that used the appropriately adapted MapMan software for analysis and visualization. Overall design: To examine the quality of the Thellungiella array and to assess whether hybridization results from a dedicated array are superior to cross-species hybridization using the Arabidopsis array from the same manufacturer, we performed reciprocal array hybridizations. In this experiment, RNA from the Yukon accession of Thellungiella and RNA from the Col-0 accession of Arabidopsis were both hybridized on the Agilent Thellungiella and Arabidopsis expression arrays. For both species, RNA was extracted from acclimated and non-acclimated plants from three independent biological replicates.
Sun, Y., L. Zhu, et al. (2014) Heterologous expression of EsABA1 enhances salt tolerance with increased accumulation of endogenous ABA in transgenic tobacco Turkish Journal of Botany 38: 1067-1079. 10.3906/bot-1403-105Salt stress can trigger several physiological responses in plants such as increased accumulation of ABA and antioxidant enzyme activities, which have been closely associated with the tolerance of plants to salt stress. In the present study a novel zeaxanthin epoxidase gene, designated EsABA1, was isolated from Eutrema salsugineum. EsABA1 contained a full-length open reading frame (ORF) of 2001 bp, encoding 666 amino acids. Transcription of EsABA1 rapidly accumulated after exposure to various abiotic stresses, suggesting that the EsABA1 gene was involved in multiple stress responses and tolerance. To further investigate the roles of EsABA1 under salt-stress conditions, transgenic tobacco lines that ectopically overexpressed EsABA1 were obtained. These transgenic lines exhibited more tolerance to salt stress than wild-type (WT) plants, and overexpression of EsABA1 increased the contents of ABA and proline as compared to WT plants under salt-stress conditions. Moreover, the expression levels of stress responsive genes and activities of antioxidant enzymes were much higher in the EsABA1-overexpressing lines than in WT plants. Therefore, our findings indicated that the elevated expression of EsABA1 enhanced the tolerance of transgenic tobacco plants to high salinity stress.
Sui, N. and G. Han. (2014) Increases of unsaturated fatty acids in membrane lipids protects photosystem II from photoinhibition under salinity in different halophytes Journal of Agricultural Science (Toronto) 6: 251-264.For the purpose of testing the function of unsaturated fatty acids in different halophytes in the process of photosynthesis under salt stress, the impact of saline stress on plant development, content of chlorophyll, the PSII photochemistry efficiency, content of membrane lipid and composition of fatty acid were investigated in the three halophytes Thellungiella halophila, Limonium bicolor and Suaeda salsa and non-halophyte Arabidopsis thaliana. Salinity (200 mM NaCl) did not reduce the value of Fv/Fm, PhiPSII, and chlorophyll content in the halophytes. While all of them decreased by 200 mM NaCl treatment in A. thaliana. In the non-halophytic, A. thaliana, when treated with NaCl, the content of unsaturated fatty acid and the DBI of membrane lipids MGDG, SQDG, PG and PC decreased. While the unsaturated fatty acid content and the DBI of T. halophila, L. bicolor and S. salsa increased. The DBI of total lipids increased in all halophytes but decreased in the non-halophyte, A. thaliana. The proportion of PG increased in T. halophila and S. salsa. It decreased in L. bicolor and A. thaliana. The DGDG (digalactosyldiacylglycerols)/MGDG (monogalactosyldiacylglycerols) ratio of S. salsa increased from 1.20 to 1.35, while it decreased in T. halophila, L. bicolor and A. thaliana under salt stress. These results suggest that unsaturated fatty acid levels increase in the halophytes under salt stress relative to the non-halophyte A. thaliana. The proportion of membrane lipids and unsaturated fatty acids is related to different levels of salt tolerance among different halophytes.
Sui, N. and G. Han. (2014) Salt-induced photoinhibition of PSII is alleviated in halophyte Thellungiella halophila by increases of unsaturated fatty acids in membrane lipids Acta Physiologiae Plantarum 36: 983-992. 10.1007/s11738-013-1477-5The effect of salinity on plant growth, chlorophyll content, photosynthetic parameters, photochemical efficiency of PSII, membrane lipid content and fatty-acid composition of halophyte Thellungiella halophila and glycophyte Arabidopsis thaliana was investigated to examine the possible role of unsaturated fatty acids in photosynthesis under saline conditions. The growth of Arabidopsis was significantly decreased by the 100 and 200 mM NaCl treatments; however, there was no significant difference in the fresh and dry weight of Thellungiella at different concentrations of NaCl. Exposure of Arabidopsis to salt resulted in a progressive decline in chlorophyll content, while there was no significant change in that of Thellungiella. The net photosynthetic rate, maximal photochemical efficiency of PSII (F (v)/F (m)) and actual PSII efficiency were significantly reduced in Arabidopsis but remained unaffected in Thellungiella. Arabidopsis under NaCl treatment showed decreased PG levels and decreased values for the unsaturated fatty acid content and the double bond index (DBI) of monogalactosyldiacylglycerols and phosphatidylglycerols; these values significantly increased in Thellungiella under NaCl treatment, as did the DBI values of digalactosyldiacylglycerols and sulphoquinovosyldiacylglycerols. These results suggest that Thellungiella under salt stress displays high resistance to photoinhibition and that increased concentrations of unsaturated fatty acids in membrane lipids enhances the tolerance of photosystem II to salt stress.
Saski, C. and H. Luo (2014). Switchgrass Genomic Resources Development. in Compendium of Bioenergy Plants: Switchgrass. H. Luo, Y. Wu and C. Kole (eds): 214-227. Rubio, F., M. Fon, et al. (2014) A low K+ signal is required for functional high-affinity K+ uptake through HAK5 transporters Physiologia Plantarum 152: 558-570. 10.1111/ppl.12205The high-affinity K+ transporter HAK5 is a key system for root K+ uptake and, under very low external K+, the only one capable of supplying K+ to the plant. Functional HAK5-mediated K+ uptake should be tightly regulated for plant adaptation to different environmental conditions. Thus, it has been described that the gene encoding the transporter is transcriptionally regulated, being highly induced under K+ limitation. Here we show that environmental conditions, such as the lack of K+, NO3- or P, that induced a hyperpolarization of the plasma membrane of root cells, induce HAK5 transcription. However, only the deprivation of K+ produces functional HAK5-mediated K+ uptake in the root. These results suggest on the one hand the existence of a posttranscriptional regulation of HAK5 elicited by the low K+ signal and on the other that HAK5 may be involved in yet-unknown functions related to NO3- and P deficiencies. These results have been obtained here with Solanum lycopersicum (cv. Micro-Tom) as well as Arabidopsis thaliana plants, suggesting that the posttranscriptional regulation of high-affinity HAK transporters take place in all plant species.
Rohini, G., V. Mohit, et al. (2014) Deep Transcriptome Sequencing of Wild Halophyte Rice, Porteresia coarctata, Provides Novel Insights into the Salinity and Submergence Tolerance Factors DNA Research 21: 69-84. 10.1093/dnares/dst042Porteresia coarctata is a wild relative of rice with capability of high salinity and submergence tolerance. The transcriptome analyses of Porteresia can lead to the identification of candidate genes involved in salinity and submergence tolerance. We sequenced the transcriptome of Porteresia under different conditions using Illumina platform and generated about 375 million high-quality reads. After optimized assembly, a total of 152 367 unique transcript sequences with average length of 794 bp were obtained. Many of these sequences might represent fragmented transcripts. Functional annotation revealed the presence of genes involved in diverse cellular processes and 2749 transcription factor (TF)-encoding genes in Porteresia. The differential gene expression analyses identified a total of 15 158 genes involved in salinity and/or submergence response(s). The stress-responsive members of different TF families, including MYB, bHLH, AP2-EREBP, WRKY, bZIP and NAC, were identified. We also revealed key metabolic pathways, including amino acid biosynthesis, hormone biosynthesis, secondary metabolite biosynthesis, carbohydrate metabolism and cell wall structures, involved in stress tolerance in Porteresia. The transcriptome analyses of Porteresia are expected to highlight genes/pathways involved in salinity and submergence tolerance of this halophyte species. The data can serve as a resource for unravelling the underlying mechanism and devising strategies to engineer salinity and submergence tolerance in rice.
Peele, H. M., N. Guan, et al. (2014) Loss and retention of resistance genes in five species of the Brassicaceae family Bmc Plant Biology 14: 298 10.1186/s12870-014-0298-zBackground: Plants have evolved disease resistance (R) genes encoding for nucleotide-binding site (NB) and leucine-rich repeat (LRR) proteins with N-terminals represented by either Toll/Interleukin-1 receptor (TIR) or coiled-coil (CC) domains. Here, a genome-wide study of presence and diversification of CC-NB-LRR and TIR-NB-LRR encoding genes, and shorter domain combinations in 19 Arabidopsis thaliana accessions and Arabidopsis lyrata, Capsella rubella, Brassica rapa and Eutrema salsugineum are presented. Results: Out of 528 R genes analyzed, 12 CC-NB-LRR and 17 TIR-NB-LRR genes were conserved among the 19 A. thaliana genotypes, while only two CC-NB-LRRs, including ZAR1, and three TIR-NB-LRRs were conserved when comparing the five species. The RESISTANCE TO LEPTOSPHAERIA MACULANS 1 (RLM1) locus confers resistance to the Brassica pathogen L. maculans the causal agent of blackleg disease and has undergone conservation and diversification events particularly in B. rapa. On the contrary, the RLM3 locus important in the immune response towards Botrytis cinerea and Alternaria spp. has recently evolved in the Arabidopsis genus. Conclusion: Our genome-wide analysis of the R gene repertoire revealed a large sequence variation in the 23 cruciferous genomes. The data provides further insights into evolutionary processes impacting this important gene family.
Oh, D.-H., H. Hong, et al. (2014) Genome Structures and Transcriptomes Signify Niche Adaptation for the Multiple-Ion-Tolerant Extremophyte Schrenkiella parvula1 C W OPEN Plant Physiology 164: 2123-2138. 10.1104/pp.113.233551Schrenkiella parvula (formerly Thellungiella parvula), a close relative of Arabidopsis (Arabidopsis thaliana) and Brassica crop species, thrives on the shores of Lake Tuz, Turkey, where soils accumulate high concentrations of multiple-ion salts. Despite the stark differences in adaptations to extreme salt stresses, the genomes of S. parvula and Arabidopsis show extensive synteny. S. parvula completes its life cycle in the presence of Na+, K+, Mg2(+), Li+, and borate at soil concentrations lethal to Arabidopsis. Genome structural variations, including tandem duplications and translocations of genes, interrupt the colinearity observed throughout the S. parvula and Arabidopsis genomes. Structural variations distinguish homologous gene pairs characterized by divergent promoter sequences and basal-level expression strengths. Comparative RNA sequencing reveals the enrichment of ion-transport functions among genes with higher expression in S. parvula, while pathogen defense-related genes show higher expression in Arabidopsis. Key stress-related ion transporter genes in S. parvula showed increased copy number, higher transcript dosage, and evidence for subfunctionalization. This extremophyte offers a framework to identify the requisite adjustments of genomic architecture and expression control for a set of genes found in most plants in a way to support distinct niche adaptation and lifestyles.
Oh, D.-h., M. Dassanayake, et al. (2014). Genomics of plant abiotic stress tolerance. in Plant Abiotic Stress, 2nd Edition (M. A. Jenks and P. M. Hasegawa eds.) Nieves-Cordones, M., F. Aleman, et al. (2014) K+ uptake in plant roots. The systems involved, their regulation and parallels in other organisms Journal of Plant Physiology 171: 688-695. 10.1016/j.jplph.2013.09.021Potassium (K+) is an essential macronutrient for plants. It is taken into the plant by the transport systems present in the plasma membranes of root epidermal and cortical cells. The identity of these systems and their regulation is beginning to be understood and the systems of K+ transport in the model species Arabidopsis thaliana remain far better characterized than in any other plant species. Roots can activate different K+ uptake systems to adapt to their environment, important to a sessile organism that needs to cope with a highly variable environment. The mechanisms of K+ acquisition in the model species A. thaliana are the best characterized at the molecular level so far. According to the current model, nonselective channels are probably the main pathways for K+ uptake at high concentrations (>10 mM), while at intermediate concentrations (1 mM), the inward rectifying channel AKT1 dominates K+ uptake. Under lower concentrations of external K+ (100 mu M), AKT1 channels, together with the high-affinity K+ uptake system HAK5 contribute to K+ acquisition, and at extremely low concentrations (<10 mu M) the only system capable of taking up K+ is HAK5. Depending on the species the high-affinity system has been named HAK5 or HAK1, but in all cases it fulfills the same functions. The activation of these systems as a function of the K+ availability is achieved by different mechanisms that include phosphorylation of AKT1 or induction of HAK5 transcription. Some of the characteristics of the systems for root K+ uptake are shared by other organisms, whilst others are specific to plants. This indicates that some crucial properties of the ancestral of K+ transport systems have been conserved through evolution while others have diverged among different kingdoms. (C) 2013 Elsevier GmbH. All rights reserved.
Nazima, B., S. Armghan, et al. (2014) Plants and salt stress International Journal of Agriculture and Crop Sciences (IJACS) 7: 1439-1446.Soil salinity is one of the major environmental problems affecting agricultural production in arid and semi-arid regions of the world, both in irrigated and dry land agriculture. The deleterious effects of salinity on plant growth are associated with low osmotic potential of soil solution causing physiological drought, nutritional imbalances and specific ion toxicity or combination of all these factors. Plant growth responds to salinity in two phases: osmotic phase that inhibits growth of young leaves and ionic phase that accelerates senescence of mature leaves. Plant adaptations to salt stress are of three diverse types: osmotic tolerance, sodium, chloride exclusion and the tolerance of tissue to accumulated sodium. Ability of plant cells to keep low cytosolic sodium concentrations is an essential process associated with the capacity of plants to grow in high salt concentrations. Traditional breeding programs trying to improve abiotic stress tolerance have had some success but are limited by the multigenic nature of the trait. Number of tolerant plants is reported in recent years such as Mesembryanthemum crystallinum and Thellungiella halophila. Arabidopsis thaliana is a genetic model plant, and widely used for unravelling the molecular basis of stress tolerance. Molecular genetics and functional genomics provide a new way to synthesize molecular and physiological knowledge to improve the salinity tolerance of plants. The aim of this review is to provide a basic biological understanding of salt stress and plant responses.
Nawaz, I., M. Iqbal, et al. (2014) Expression levels and promoter activities of candidate salt tolerance genes in halophytic and glycophytic Brassicaceae Environmental and Experimental Botany 99: 59-66. 10.1016/j.envexpbot.2013.10.006We compared six Brassicaceae glycophytes and halophytes for salt tolerance and the expression levels in roots and shoots of the candidate salt tolerance genes, NHX1, SOS1, and VATD, encoding the tonoplast Na+/H+ antiporter, the plasma-membrane-located Na+/H+ antiporter, and subunitD of the tonoplast W-ATPase, respectively. Salt tolerance decreased in the order of Cochlearia x hollandica >> Cochlearia danica/Thellungiella botschantzevii > Brassica oleracea> Thlaspi arvense > Arabidopsis thaliana. The highest expression levels of NHX1, SOS1, and VATD were consistently found in C. x hollandica, both in shoots and roots, and both in control plants and salt-treated ones. Salt-imposed induction of NHX1 was observed in C. danica (shoot and root) and B. oleracea (shoot). SOS1 was up-regulated by salt treatment in the shoots of C. x hollandica and C. danica, and VATD in the shoot of T. arvense. Expression of NHX1 genomic DNA under the C x hollandica NHX1 promoter in the A.t.nhx1 mutant background yielded, irrespective of the genomic DNA source, 20-fold and 2-fold enhanced expression levels, in comparison with those in wild-type A. thaliana and C x hollandica, respectively. This suggests that the high expression level in C. x hollandica is completely explained by altered cis-regulation of this gene. Promoter swap experiments showed that the C x hollandica SOS1 and VATD promoters were fivefold and two-fold more active than the corresponding A. thaliana promoters, respectively. However, particularly in the case of VATD, this is not sufficient to explain the difference in the wild-type expression levels between C. x hollandica and A. thaliana. (C) 2013 Elsevier B.V. All rights reserved.
Moshaei, M. R., G. A. Nematzadeh, et al. (2014) Quantitative gene expression analysis of some sodium ion transporters under salinity stress in Aeluropus littoralis Saudi Journal of Biological Sciences 21: 394-399. 10.1016/j.sjbs.2014.05.001Plant sodium transporters activity is one of the most important salt tolerance mechanisms to keep normal status of cytosolic sodium content. In the present study, expression pattern of genes encoding Na+/H+ antiporters in the plasma membrane (SOS1 gene), vacuolar membrane (NHX1 gene) and H+-ATPase pump (VHA gene) in Aeluropus littoralis under different treatments of NaCl was measured by the semi-quantitative RT-PCR method. Our results indicated that root and shoot sodium contents were increased along with increasing salinity pressure. In response to 200 and 400 mM NaCl, mRNA level of SOS1 and NHX1 was increased in the shoot and root tissues, while VHA transcripts were increased only under 400 mM of NaCl. Transcripts of VHA-c and NHX1 in root were higher than shoot in all treatments. In general, our results indicated that transcriptional level of SOS1, and NHX1 genes induced in parallel with VHA expression may be involved in controlling cytosolic Na+ concentration in A. littoralis. (C) 2014 Production and hosting by Elsevier B.V. on behalf of King Saud University.
Mironova, V. V., N. A. Omelyanchuk, et al. (2014) Computational analysis of auxin responsive elements in the Arabidopsis thaliana L. genome Bmc Genomics 15: S4 10.1186/1471-2164-15-s12-s4Auxin responsive elements (AuxRE) were found in upstream regions of target genes for ARFs (Auxin response factors). While Chip-seq data for most of ARFs are still unavailable, prediction of potential AuxRE is restricted by consensus models that detect too many false positive sites. Using sequence analysis of experimentally proven AuxREs, we revealed both an extended nucleotide context pattern for AuxRE itself and three distinct types of its coupling motifs (Y-patch, AuxRE-like, and ABRE-like), which together with AuxRE may form the composite elements. Computational analysis of the genome-wide distribution of the predicted AuxREs and their impact on auxin responsive gene expression allowed us to conclude that: (1) AuxREs are enriched around the transcription start site with the maximum density in 5'UTR; (2) AuxREs mediate auxin responsive up-regulation, not down-regulation. (3) Directly oriented single AuxREs and reverse multiple AuxREs are mostly associated with auxin responsiveness. In the composite AuxRE elements associated with auxin response, ABRE-like and Y-patch are 5'-flanking or overlapping AuxRE, whereas AuxRE-like motif is 3'-flanking. The specificity in location and orientation of the coupling elements suggests them as potential binding sites for ARFs partners.
Merilo, E., I. Joesaar, et al. (2014) To open or to close: species-specific stomatal responses to simultaneously applied opposing environmental factors New Phytologist 202: 499-508. 10.1111/nph.12667 Plant stomatal responses to single environmental factors are well studied; however, responses to a change in two (or more) factors - a common situation in nature - have been less frequently addressed. We studied the stomatal responses to a simultaneous application of opposing environmental factors in six evolutionarily distant mono- and dicotyledonous herbs representing different life strategies (ruderals, competitors and stress-tolerators) to clarify whether the crosstalk between opening- and closure-inducing pathways leading to stomatal response is universal or species-specific. Custom-made gas exchange devices were used to study the stomatal responses to a simultaneous application of two opposing factors: decreased/increased CO2 concentration and light availability or reduced air humidity. The studied species responded similarly to changes in single environmental factors, but showed species-specific and nonadditive responses to two simultaneously applied opposing factors. The stomata of the ruderals Arabidopsis thaliana and Thellungiella salsuginea (previously Thellungiella halophila) always opened, whereas those of competitor-ruderals either closed in all two-factor combinations (Triticum aestivum), remained relatively unchanged (Nicotiana tabacum) or showed a response dominated by reduced air humidity (Hordeum vulgare). Our results, indicating that in changing environmental conditions species-specific stomatal responses are evident that cannot be predicted from studying one factor at a time, might be interesting for stomatal modellers, too.
Global climatic changes as high temperatures and low precipitation contribute to increase cultivated areas affected by high salt soil content. Soil salinity is well known to reduce the ability of plants to take up water and this quickly causes reduction in their growth rate. V-ATPase (EC 3.6.3.14) and V-PPase (EC 3.6.1.1) hydrolytic and proton transport activities, and gene expression were evaluated in hypocotyls of 3-, 5-, 7-day-old Vigna unguiculata (L.) Walp cv. Vita 3 germinated in 100 mM NaCl in order to highlight their differential regulation and activity modulation under salt stress. Semi-quantitative RT-PCR revealed that both genes were up-regulated by salt stress in all salt exposition times studied. Up-regulation was correlated with the increase in protein content at 5 and 7-day-old seedlings. Co-expression between A and E V-ATPase subunits was also observed. The hydrolytic and proton transport activities showed that these enzymes presented a differential modulation of their activities in the presence of 100 mM NaCl. These results suggest that V-ATPase and V-PPase activities are modulated by salt stress and a multi-step regulation is exerted in order to re-establish homeostasis.
Maumus, F. and H. Quesneville. (2014) Ancestral repeats have shaped epigenome and genome composition for millions of years in Arabidopsis thaliana Nature Communications 5: 4104 10.1038/ncomms5104Little is known about the evolution of repeated sequences over long periods of time. Using two independent approaches, we show that the majority of the repeats found in the Arabidopsis thaliana genome are ancient and likely to derive from the retention of fragments deposited during ancestral bursts that occurred early in the Brassicaceae evolution. We determine that the majority of young repeats are found in pericentromeric domains, while older copies are frequent in the gene-rich regions. Our results further suggest that the DNA methylation of repeats through small RNA-mediated pathways can last over prolonged periods of time. We also illustrate the way repeated sequences are composted by mutations towards genomic dark matter over time, probably driven by the deamination of methylcytosines, which also have an impact on epigenomic landscapes. Overall, we show that the ancient proliferation of repeat families has long-term consequences on A. thaliana biology and genome composition.
Lopez-Camarillo, C., V. Pando-Robles, et al. (2014) Untitled Journal of Proteomics 111: 1-5. 10.1016/j.jprot.2014.10.016In this research,a full-length cDNA sequence of 4CL related to flax lignin synthesis is cloned by RACE-PCR technique on the basis of the segment of this gene cloned freviously. The complete cDNA sequence of 4CL is 1 957 bp in length,with a complete open reading frame of 1 650 bp. The encoded protein contains 549 amino acids,with a molecular mass of 60 kD and a pI of 5. 3. Random coil and a-helix are the main secondary structure of the protein. Phylogenetic analysis indicated that there is high similarity between flax 4CL gene and that of Thellungiella halophila. The full-length cDNA sequence has been registered in GenBank, with an accession number of KC832864. A 413 bp CDS fragment of 4CL is amplified by PCR to construct the RNA interference vector p1301M-4CL, which is transformed to flax by agrobacterium-mediated method. Seven transgenic seedlings selected randomly are detected by GUS and PCR. The results showed that the RNAi vector construction has been integrated into flax genome, which leads to evidently depression of the expression of 4CL gene in flax.
Li, X., C. Guo, et al. (2014) Overexpression of VP, a vacuolar H-pyrophosphatase gene in wheat (Triticum aestivum L.), improves tobacco plant growth under Pi and N deprivation, high salinity, and drought (Retracted article. See vol. 67, pg. 2913, 2016) Journal of Experimental Botany 65: 683-696. 10.1093/jxb/ert442Establishing crop cultivars with strong tolerance to P and N deprivation, high salinity, and drought is an effective way to improve crop yield and promote sustainable agriculture worldwide. A vacuolar H-pyrophosphatase (V-H-PPase) gene in wheat (TaVP) was functionally characterized in this study. TaVP cDNA is 2586-bp long and encodes a 775-amino-acid polypeptide that contains 10 conserved membrane-spanning domains. Transcription of TaVP was upregulated by inorganic phosphate (Pi) and N deprivation, high salinity, and drought. Transgene analysis revealed that TaVP overexpression improved plant growth under normal conditions and specifically under Pi and N deprivation stresses, high salinity, and drought. The improvement of growth of the transgenic plants was found to be closely related to elevated V-H-PPase activities in their tonoplasts and enlarged root systems, which possibly resulted from elevated expression of auxin transport-associated genes. TaVP-overexpressing plants showed high dry mass, photosynthetic efficiencies, antioxidant enzyme activities, and P, N, and soluble carbohydrate concentrations under various growth conditions, particularly under the stress conditions. The transcription of phosphate and nitrate transporter genes was not altered in TaVP-overexpressing plants compared with the wild type, suggesting that high P and N concentrations regulated by TaVP were caused by increased root absorption area instead of alteration of Pi and NO3 acquisition kinetics. TaVP is important in the tolerance of multiple stresses and can serve as a useful genetic resource to improve plant P- and N-use efficiencies and to increase tolerance to high salinity and drought.
Li, Q., Z. Tang, et al. (2014) Functional analyses of a putative plasma membrane Na+/H+ antiporter gene isolated from salt tolerant Helianthus tuberosus Molecular Biology Reports 41: 5097-5108. 10.1007/s11033-014-3375-3Jerusalem artichokes (Helianthus tuberosus L.) can tolerate relatively higher salinity, drought and heat stress. In this paper, we report the cloning of a Salt Overly Sensitive 1 (SOS1) gene encoding a plasma membrane Na+/H+ antiporter from a highly salt-tolerant genotype of H. tuberosus, NY1, named HtSOS1 and characterization of its function in yeast and rice. The amino acid sequence of HtSOS1 showed 83.4 % identity with the previously isolated SOS1 gene from the Chrysanthemum crassum. The mRNA level in the leaves of H. tuberosus was significantly up-regulated by presence of high concentrations of NaCl. Localization analysis using rice protoplast expression showed that the protein encoded by HtSOS1 was located in the plasma membrane. HtSOS1 partially suppressed the salt sensitive phenotypes of a salt sensitive yeast strain. In comparison with wild type (Oryza sativa L., ssp. Japonica. cv. Nipponbare), the transgenic rice expressed with HtSOS1 could exclude more Na+ and accumulate more K+. Expression of HtSOS1 decreased Na+ content much larger in the shoot than in the roots, resulting in more water content in the transgenic rice than WT. These data suggested that HtSOS1 may be useful in transgenic approaches to improving the salinity tolerance of glycophyte.
Krasavina, M. S., N. A. Burmistrova, et al. (2014). The Role of Carbohydrates in Plant Resistance to Abiotic Stresses. in Emerging Technologies and Management of Crop Stress Tolerance, Vol 1: Biological Techniques (P. Ahmad and S. Rasool eds.) Korolkova, D. V., N. L. Radyukina, et al. (2014) Effect of spermine treatment on the functioning of Thellungiella salsuginea antioxidant system Russian Journal of Plant Physiology 61: 63-69. 10.1134/s1021443714010075The effect of spermine (Spm) treatment on the content of polyamines (PAs) and activities of antioxidant enzymes in the roots and leaves of Thellungiella salsuginea (Pall.) O.E. Schulz plants grown under optimal conditions were studied. The genes encoding three forms of ascorbate peroxidase (APX; APX1, APX2, and APX4) and genes of key enzymes of proline metabolism (Pro, P5CS1, 1P5CD) were identified, and their expression intensity was measured. Six-day-old plants were treated with Spm (1 and 2 mM) and with the inhibitor of polyamine oxidase (PAO) activity, N,N-(2-hydroxyethyl)hydrazine (HEH, 1 and 2 mM) separately or in combination by adding these compounds to nutrient medium. Roots and leaves responded differently to Spm treatment. In the leaves, the content of PAs reduced due to a decreased in the spermidine (Spd) content, whereas in the roots the total pool of PAs increased due to putrescine (Put) and Spd accumulation. Treatment with Spm activated PAO in the roots but not in the leaves; HEH removed this increase, but the intercellular Spm concentration was not substantially changed. It was suggested that treatment with Spm suppressed the biosynthesis of intracellular Spm and, on the other hand, stimulated the reverse conversion of Spm into Spd and further into Put due to the activation of one of the PAO isoforms. Plant treatment with Spm was not accompanied by a noticeable activation enzymes degrading hydrogen peroxide in the roots: APX, (except of peroxidase II), and catalase. However, the activity of Cu/Zn-SOD doubled and the activity of Mn-SOD reduced. In the leaves, slight activation of peroxidases I and III, the inhibition of Cu/Zn- and Mn-SOD, differential changes in the time-coursed of gene expression of three APX isoforms, and activated gene expression of key enzymes of Pro metabolism were observed. At the same time, the level of MDA did not increase either in the leaves or in the roots. This indicates that treatment of Th. salsuginea plants with Spm under optimal growing conditions did not enhance ROS generation and did not manifest prooxidant properties.
Kononenko, N. V., T. G. Leonova, et al. (2014) Use of cytophotometry for determination of salt resistance of wild plants Russian Agricultural Sciences 40: 408-410.In determination of salt resistance of wild plants, cytophotometry has been used for evaluation of distribution of nuclei of the root meristem cells. Salt resistant and salt sensitive plants of two Thellungiella species whose seeds were collected at the places of their vegetation, as well as of two Aegilops L. species from the collection of the All-Russia Research Institute of Plant Industry (VIR), have been analyzed in the experiments. Salt resistant cells of Thel. botschantzevii and Ae. taushii (k-677) were accumulated in the G1 period of the interphase, which indicates high adaptation of these plants to high concentrations of salts. It has been demonstrated that cytophotometry can be used for determination of salt resistance of wild plants growing in the climatic zones appropriate for their natural propagation.
Kononenko, N. V., T. G. Leonova, et al. (2014) THE USE OF THE METHOD CYTOPHOTOMETRY FOR DETERMINATION OF SALT RESISTANCE OF WILD PLANTS Doklady Rossiiskoi Akademii Sel'skokhozyaistvennykh Nauk 13-15.For determination of salt resistance of wild plants used cytophotometry method for evaluating the distribution of nuclei of cells root meristem. In experiments analyzed the salt resistance and salt sensitive plant two kinds of Thellungiella which seeds were collected on the ground, as well as two species Aegilops L. from the collection of VIR. It is shown that the salt resistance Thel. botschantzevii and Ae.taushii (k-677) accumulated cells in G(1) period interphasa, which testifies to high cells adaptation of these plants to high concentrations of salts. Thus, the method of cytophotometry can be used to determine the salt resistance of wild plants growing in the climatic zones that are appropriate for the dissemination of natural distribution.
Kim, Y. S., I. S. Kim, et al. (2014) Overexpression of the Arabidopsis vacuolar H+-pyrophosphatase AVP1 gene in rice plants improves grain yield under paddy field conditions Journal of Agricultural Science 152: 941-953. 10.1017/s0021859613000671The Arabidopsis gene AVP1 encodes a vacuolar H+-translocating inorganic pyrophosphatase (enzyme classification (EC) 3.6.1.1) that functions as an electronic proton pump in the vacuolar membrane and affects growth development and the stress response in plants. The current study was conducted to evaluate the molecular properties of the Arabidopsis thaliana vacuolar H+-pyrophosphatase (AVP1) gene in rice (Oryza sativa L.). Incorporation and expression of the transgene was confirmed by semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR. Expression of the AVP1 gene in transgenic rice plants (TRP1 and TRP2) resulted in a significantly enhanced tolerance to 5.8 g/l NaCl under greenhouse conditions when compared with the control wild-type (WT) rice plants. Augmented AVP1 expression in the transgenic rice plants (TRP) also affected total biomass and improved ion homoeostasis through increased accumulation of Na+ ions in whole tissues when compared with control WT rice plants under high salinity conditions. The photochemical yield (Fv/Fm) values of TRP were higher than those of the WT rice plants, even though the values decreased over time in both the WT and transgenic (TRP1 to TRP8) rice plants. Furthermore, rice grain yield and biomass of the TRP were at least 15% higher based on culm and root weights, and panicle and spikelet numbers when compared with those of the WT rice plants during the 2010 and 2010 growing seasons in South Korea. Thus, these results suggest that ectopic AVP1 expression conferred tolerance and stress resistance to genetically modified transgenic crop plants by improving cellular ion homoeostasis in response to saline conditions, which enhanced rice yield and biomass under natural conditions in paddy fields.
Jarvis, D. E., C.-H. Ryu, et al. (2014) Distinct Roles for SOS1 in the Convergent Evolution of Salt Tolerance in Eutrema salsugineum and Schrenkiella parvula Molecular Biology and Evolution 31: 2094-2107. 10.1093/molbev/msu152Eutrema salsugineum and Schrenkiella parvula are salt-tolerant relatives of the salt-sensitive species Arabidopsis thaliana. An important component of salt tolerance is the regulation of Na+ ion homeostasis, which occurs in part through proteins encoded by the Cation/Proton Antiporter-1 (CPA1) gene family. We used a combination of evolutionary and functional analyses to examine the role of CPA1 genes in the salt tolerance of E. salsugineum and Sc. parvula, and found evidence that changes in CPA1-mediated Na+ extrusion may contribute to the salt tolerance of both species. Specifically, we found that a member of the CPA1 family, the Na+/H+ antiporter gene Salt Overly Sensitive 1 (SOS1), evolved under positive selection in E. salsugineum. In the absence of activation by the SOS2 kinase/SOS3 calcium-binding protein complex, SOS1 from E. salsugineum (EsSOS1) confers greater salt tolerance than SOS1 from Sc. parvula (SpSOS1) and Ar. thaliana (AtSOS1) when expressed in a salt-sensitive strain of Saccharomyces cerevisiae. A single amino acid change in the putative autoinhibitory domain is required but not sufficient for the enhanced salt tolerance conferred by EsSOS1. When activated by SOS2 and SOS3, both EsSOS1 and SpSOS1 confer greater salt tolerance than AtSOS1. Enhanced SOS1-mediated Na+ extrusion therefore appears to contribute to the salt tolerance of both E. salsugineum and Sc. parvula, although through apparently different mechanisms.
Jabeen, Z., N. Hussain, et al. (2014) The differences in physiological responses, ultrastructure changes, and Na+ subcellular distribution under salt stress among the barley genotypes differing in salt tolerance Acta Physiologiae Plantarum 36: 2397-2407. 10.1007/s11738-014-1613-xPlants adopt several strategies to maintain cellular ion homeostasis, including physiological, biochemical, cellular, subcellular, and molecular mechanisms for fighting against salt stress. We investigated the responses of tolerant Tibetan wild barley (XZ16), tolerant (CM72) and sensitive (Gairdner) barley cultivars at physiological, cellular, and molecular levels. The results revealed that salinity induced a significantly greater reduction in total root length, surface area, diameter, and total volume in Gairdner than in CM72 and XZ16. Analysis of gene expression using quantitative RT-PCR showed that transcripts of vacuolar H+-ATPase and inorganic pyrophosphatase (HvHVA/68 and HvHVP1) were more abundant in leaves and roots of XZ16 and CM72 than those of Gairdner. Observation of electron microscopy detected the difference in the damage of leaf and root ultrastructure among the three genotypes under salt stress, with XZ16 and Gairdner being least and most affected, respectively. Subcellular study showed that a primary strategy to protect the cytosol against sodium toxicity was compartmentalization of sodium ions into soluble fraction (vacuoles). Gairdner showed drastically stronger sodium-specific fluorescence visualized by CoroNa-Green, a sodium-specific fluorophore, than CM72 and XZ16.
Huerta-Ocampo, J. A., A. Barrera-Pacheco, et al. (2014) Salt Stress-Induced Alterations in the Root Proteome of Amaranthus cruentus L Journal of Proteome Research 13: 3607-3627. 10.1021/pr500153mSalt stress is one of the major factors limiting crop productivity worldwide. Amaranth is a highly nutritious pseudocereal with remarkable nutraceutical properties; it is also a stress-tolerant plant, making it an alternative crop for sustainable food production in semiarid conditions. A two-dimensional electrophoresis gel coupled with a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) approach was applied in order to analyze the changes in amaranth root protein accumulation in plants subjected to salt stress under hydroponic conditions during the osmotic phase (1 h), after recovery (24 h), and during the ionic phase of salt stress (168 h). A total of 101 protein spots were differentially accumulated in response to stress, in which 77 were successfully identified by LC-MS/MS and a database search against public and amaranth transcriptome databases. The resulting proteins were grouped into different categories of biological processes according to Gene Ontology. The identification of several protein isoforms with a change in pI and/or molecular weight reveals the importance of the salt-stress-induced posttranslational modifications in stress tolerance. Interestingly stress-responsive proteins unique to amaranth, for example, Ah24, were identified. Amaranth is a stress-tolerant alternative crop for sustainable food production, and the understanding of amaranth's stress tolerance mechanisms will provide valuable input to improve stress tolerance of other crop plants.
Graether, S. P. and K. F. Boddington. (2014) Disorder and function: a review of the dehydrin protein family Frontiers in Plant Science 5: 576 10.3389/fpls.2014.00576Dehydration proteins (dehydrins) are group 2 members of the late embryogenesis abundant (LEA) protein family. The protein architecture of dehydrins can be described by the presence of three types of conserved sequence motifs that have been named the K-, Y-, and S-segments. By definition, a dehydrin must contain at least one copy of the lysine-rich K-segment. Abiotic stresses such as drought, cold, and salinity cause the upregulation of dehydrin mRNA and protein levels. Despite the large body of genetic and protein evidence of the importance of these proteins in stress response, the in vivo protective mechanism is not fully known. In vitro experimental evidence from biochemical assays and localization experiments suggests multiple roles for dehydrins, including membrane protection, cryoprotection of enzymes, and protection from reactive oxygen species. Membrane binding by dehydrins is likely to be as a peripheral membrane protein, since the protein sequences are highly hydrophilic and contain many charged amino acids. Because of this, dehydrins in solution are intrinsically disordered proteins, that is, they have no well-defined secondary or tertiary structure. Despite their disorder, dehydrins have been shown to gain structure when bound to ligands such as membranes, and to possibly change their oligomeric state when bound to ions. We review what is currently known about dehydrin sequences and their structures, and examine the various ligands that have been shown to bind to this family of proteins.
Gong, W.-f., L.-n. Zhao, et al. (2014) Identifying novel salt-tolerant genes from Dunaliella salina using a Haematococcus pluvialis expression system Plant Cell Tissue and Organ Culture 117: 113-124. 10.1007/s11240-014-0425-4Dunaliella salina (Dunal) Teod, a unicellular eukaryotic green alga, is a highly salt-tolerant organism. To identify novel genes with potential roles in salinity tolerance, a salt stress-induced D. salina cDNA library was screened based on the expression in Haematococcus pluvialis, an alga also from Volvocales but one that is hypersensitive to salt. Five novel salt-tolerant clones were obtained from the library. Among them, Ds-26-16 and Ds-A3-3 contained the same open reading frame (ORF) and encoded a 6.1 kDa protein. Transgenic tobacco overexpressing Ds-26-16 and Ds-A3-3 exhibited increased leaf area, stem height, root length, total chlorophyll, and glucose content, but decreased proline content, peroxidase activity, and ascorbate content, and enhanced transcript level of Na+/H+ antiporter salt overly sensitive 1 gene (NtSOS1) expression, compared to those in the control plants under salt condition, indicating that Ds-26-16 enhanced the salt tolerance of tobacco plants. The transcript of Ds-26-16 in D. salina was upregulated in response to salt stress. The expression of Ds-26-16 in Escherichia coli showed that the ORF contained the functional region and changed the protein(s) expression profile. A mass spectrometry assay suggested that the most abundant and smallest protein that changed is possibly a DNA-binding protein or Cold shock-like protein. Subcellular localization analysis revealed that Ds-26-16 was located in the nuclei of onion epidermal cells or nucleoid of E. coli cells. In addition, the possible use of shoots regenerated from leaf discs to quantify the salt tolerance of the transgene at the initial stage of tobacco transformation was also discussed.
Gao, F., J. Chen, et al. (2014) The Glutathione Peroxidase Gene Family in Thellungiella salsuginea: Genome- Wide Identification, Classification, and Gene and Protein Expression Analysis under Stress Conditions International Journal of Molecular Sciences 15: 3319-3335. 10.3390/ijms15023319Glutathione peroxidases (GPX) catalyze the reduction of H2O2 or organic hydroperoxides to water or corresponding alcohols using reduced glutathione, which plays an essential role in ROS (reactive oxygen species) homeostasis and stress signaling. Thellungiella salsuginea (Eutrema salsugineum), a relative of Arabidopsis thaliana, displays an extremely high level of tolerance to salt, drought, cold and oxidative stresses. The enzymatic antioxidant systems may contribute to the stress tolerance of T. salsuginea. In the present study, we aimed at understanding the roles of the antioxidant enzymes in T. salsuginea by focusing on the GPX family. We identified the eight GPX genes in T. salsuginea, and the structure of the N-terminal domains indicated their putative chloroplastic, mitochondrial and cytoplasmic location. The exon-intron organization of these genes exhibited a conserved pattern among plant GPX genes. Multiple environmental stresses and hormone response related cis-acting elements were predicted in the promoters of TsGPX genes. The gene and protein expression profiles of TsGPXs in response to high level of salinity and osmotic stresses, in leaves and roots of T. salsuginea were investigated using real-time RT-PCR and western blotting analysis. Our result showed that different members of the GPX gene family were coordinately regulated under specific environmental stress conditions, and supported the important roles of TsGPXs in salt and drought stress response in T. salsuginea.
Gan, Q. and X. Li. (2014) A New Species of Eutrema (Brassicaceae) from Central China Novon 23: 162-164. 10.3417/2011045A new species of the genus Eutrema R. Br. (Brassicaceae) is described and illustrated from Hubei Province in China. This species is similar to E. yungshunensis (W. T. Wang) Al-Shehbaz & Warwick in its leafy stems and ovaries with more than 10 ovules, but the new species differs in having glaucous stems, larger leaves abaxially purplish, larger sepals and petals, and fewer seeds per fruit.
Gamburg, K. Z., N. E. Korotaeva, et al. (2014) The relationship between the differences in frost resistance of Arabidopsis and Thellungiella and heat shock proteins and dehydrins Russian Journal of Plant Physiology 61: 318-323. 10.1134/s1021443714030054Plants of extremophile Thellungiella (Thellungiella salsuginea (Pall.) OE Schulz) withstood freezing at -15A degrees C for 2 h without hardening, whereas plants of Arabidopsis (Arabidopsis thaliana (L.) Heinh.) were damaged at -10A degrees C and died at -15A degrees C under these conditions. The content of heat shock proteins (HSPs) HSP101, HSP60 and constitutive HSC70 was significantly higher in unhardened Thellungiella plants than in unhardened Arabidopsis plants. The spectrum of dehydrins (DHNs) in unhardened Thellungiella plants was more diverse and their total content was higher than in unhardened Arabidopsis plants. Frost resistance of Arabidopsis increased after hardening (4A degrees C, 7 days), and there was an increase in the content of HSP101 and HSP60, as well as in the content of the DHN with a mol wt of 70 kD. Thellungiella plants survived after hardening at -18A degrees C, and the increase in the content of HSP101, HSP70, and HSP60 was significantly less pronounced than in Arabidopsis. At the same time, the content of DHNs in Thellungiella increased significantly during the hardening primarily because of the appearance of two DHNs (mol wts of 42 and 45 kD). It is assumed that an increased content of HSPs and DHNs and their greater diversity can be one of the factors of Thellungiella resistance to low temperatures as compared to Arabidopsis.
Fukami-Kobayashi, K., Y. Nakamura, et al. (2014) SABRE2: A Database Connecting Plant EST/Full-Length cDNA Clones with Arabidopsis Information Plant and Cell Physiology 55: 10.1093/pcp/pct177The SABRE (Systematic consolidation of Arabidopsis and other Botanical REsources) database cross-searches plant genetic resources through publicly available Arabidopsis information. In SABRE, plant expressed sequence tag (EST)/cDNA clones are related to TAIR (The Arabidoposis Information Resource) gene models and their annotations through sequence similarity. By entering a keyword, SABRE searches and retrieves TAIR gene models and annotations, together with homologous gene clones from various plant species. SABRE thus facilitates using TAIR annotations of Arabidopsis genes for research on homologous genes from other model plants. To expand the application range of SABRE to crop breeding, we have recently upgraded SABRE to SABRE2 (http://sabre.epd.brc.riken.jp/SABRE2.html), by newly adding six model plants (including the major crops barley, soybean, tomato and wheat), and by improving the retrieval interface. The present version has integrated information on > 1.5 million plant EST/cDNA clones from the National BioResource Project (NBRP) of Japan. All clones are actual experimental resources from 14 plant species (Arabidoposis, barley, cassava, Chinese cabbage, lotus, morning glory, poplar, Physcomitrella patens, Striga hermonthica, soybean, Thellungiella halophila, tobacco, tomato and wheat), and are available from the core facilities of the NBRP. SABRE2 is thus a useful tool that can contribute towards the improvement of important crop breeds by connecting basic research and crop breeding.
Eppel, A., R. Shaked, et al. (2014) Low induction of non-photochemical quenching and high photochemical efficiency in the annual desert plant Anastatica hierochuntica Physiologia Plantarum 151: 544-558. 10.1111/ppl.12146Non-photochemical quenching (NPQ) plays a major role in photoprotection. Anastatica hierochuntica is an annual desert plant found in hot deserts. We compared A. hierochuntica to three other different species: Arabidopsis thaliana, Eutrema salsugineum and Helianthus annuus, which have different NPQ and photosynthetic capacities. Anastatica hierochuntica plants had very different induction kinetics of NPQ and, to a lesser extent, of photosystem II electron transport rate (PSII ETR), in comparison to all other plants species in the experiments. The major components of the unusual photosynthetic and photoprotective response in A. hierochuntica were: (1) Low NPQ at the beginning of the light period, at various light intensities and CO2 concentrations. The described low NPQ cannot be explained by low leaf absorbance or by low energy distribution to PSII, but was related to the de-epoxidation state of xanthophylls. (2) Relatively high PSII ETR at various CO2 concentrations in correlation with low NPQ. PSII ETR responded positively to the increase of CO2 concentrations. At low CO2 concentrations PSII ETR was mostly O-2 dependent. At moderate and high CO2 concentrations the high PSII ETR in A. hierochuntica was accompanied by relatively high CO2 assimilation rates. We suggest that A. hierochuntica have an uncommon NPQ and PSII ETR response. These responses in A. hierochuntica might represent an adaptation to the short growing season of an annual desert plant.
Ellouzi, H., K. Ben Hamed, et al. (2014) A comparative study of the early osmotic, ionic, redox and hormonal signaling response in leaves and roots of two halophytes and a glycophyte to salinity Planta 240: 1299-1317. 10.1007/s00425-014-2154-7Salt stress is one of the most important abiotic stress factors affecting plant growth and productivity in natural ecosystems. In this study, we aimed at determining possible differences between salt tolerant and salt sensitive species in early (within 72 h) salt stress response in leaves and roots. To this purpose, we subjected three Brassicaceae species, namely two halophytes-Cakile maritima and Thellungiella salsuginea-and a glycophyte-Arabidopsis thaliana- to short-term salt stress (400 mM NaCl). The results indicate that the halophytes showed a differential osmotic and ionic response together with an early and transient oxidative burst, which was characterized by enhanced hydrogen peroxide levels and subsequent activation of antioxidant defenses in both leaves and roots. In addition, the halophytes displayed enhanced accumulation of abscisic acid, jasmonic acid (JA) and ACC (aminocyclopropane-1-carboxylic acid, the precursor of ethylene) in leaves and roots, as compared to A. thaliana under salt stress. Moreover, the halophytes showed enhanced expression of ethylene response factor1 (ERF1), the convergence node of the JA and ethylene signaling pathways in both leaves and roots upon exposure to salt stress. In conclusion, we show that the halophytes C. maritima and T. salsuginea experience an early oxidative burst, improved antioxidant defenses and hormonal response not only in leaves but also in roots, in comparison to the glycophyte A. thaliana. This differential signaling response converging, at least in part, into increased ERF1 expression in both above- and underground tissues seems to underlay, at least in part, the enhanced tolerance of the two studied halophytes to salt stress.
Duarte, B., N. Sleimi, et al. (2014) Biophysical and biochemical constraints imposed by salt stress: learning from halophytes Frontiers in Plant Science 5: 746 10.3389/fpls.2014.00746Soil salinization is one of the most important factors impacting plant productivity. About 3.6 billion of the world's 5.2 billion ha of agricultural dry land, have already suffered erosion, degradation, and salinization. Halophytes are typically considered as plants able to complete their life cycle in environments where the salt concentration is above 200 mM NaCl. Salinity adjustment is a complex phenomenon but essential mechanism to overcome salt stress, with both biophysical and biochemical implications. At this level, halophytes evolved in several directions, adopting different strategies. Otherwise, the lack of adaptation to a salt environment would negatively affect their electron transduction pathways and the entire energetic metabolism, the foundation of every plant photosynthesis and biomass production.The maintenance of ionic homeostasis is in the basis of all cellular counteractive measures, in particular in terms of redox potential and energy transduction. In the present work the biophysical mechanisms underlying energy capture and transduction in halophytes are discussed alongside with their relation with biochemical counteractive mechanisms, integrating data from photosynthetic light harvesting complexes, electron transport chains to the quinone pools, carbon fixation, and energy dissipation metabolism.
Dae-Jin, Y., 백동원, et al. (2014) Screening of salt-tolerance plants using transgenic Arabidopsis that express a salt cress cDNA library Journal of Plant Biotechnology 41: 81-88.Salt cress (Thellungiella halophila or Thellungiellaparvula), species closely related to Arabidopsis thaliana,represents an extremophile adapted to harsh saline environments.To isolate salt-tolerance genes from this species, we constructeda cDNA library from roots and leaves of salt cress plantstreated with 200 mM NaCl. This cDNA library was subsequentlyshuttled into the destination binary vector [drivenby the cauliflower mosaic virus (CaMV) 35S promoter]designed for plant transformation and expression via recombination-assisted cloning. In total, 305,400 pools of transgenicBASTA-resistant lines were generated in Arabidopsis usingeither T. halophila or T. parvula cDNA libraries. These wereused for functional screening of genes involved in salttolerance. Among these pools, 168,500 pools were used forprimary screening to date from which 7,157 lines showedapparent salt tolerant-phenotypes in the initial screen. Asecondary screen has now identified 165 salt tolerant transgeniclines using 1,551 (10.6%) lines that emerged in the firstscreen. The prevalent phenotype in these lines includes acceleratedseed germination often accompanied by faster root growthcompared to WT Arabidopsis under salt stress condition. Inaddition, other lines showed non-typical development of stemsand flowers compared to WT Arabidopsis. Based on the closerelationship of the tolerant species to the target species wesuggest this approach as an appropriate method for the largescaleidentification of salt tolerance genes from salt cress.
Castaings, L., S. Bergonzi, et al. (2014) Evolutionary conservation of cold-induced antisense RNAs of FLOWERING LOCUS C in Arabidopsis thaliana perennial relatives Nature Communications 5: 4457 10.1038/ncomms5457Antisense RNA (asRNA) COOLAIR is expressed at A. thaliana FLOWERING LOCUS C (FLC) in response to winter temperatures. Its contribution to cold-induced silencing of FLC was proposed but its functional and evolutionary significance remain unclear. Here we identify a highly conserved block containing the COOLAIR first exon and core promoter at the 3' end of several FLC orthologues. Furthermore, asRNAs related to COOLAIR are expressed at FLC loci in the perennials A. alpina and A. lyrata, although some splicing variants differ from A. thaliana. Study of the A. alpina orthologue, PERPETUAL FLOWERING 1 (PEP1), demonstrates that AaCOOLAIR is induced each winter of the perennial life cycle. Introduction of PEP1 into A. thaliana reveals that AaCOOLAIR cis-elements confer cold-inducibility in this heterologous species while the difference between PEP1 and FLC mRNA patterns depends on both cis-elements and species-specific trans-acting factors. Thus, expression of COOLAIR is highly conserved, supporting its importance in FLC regulation.
Biology, M. U. (2014) Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat European Nucleotide ArchiveBackground: Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm. Results: To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen media suggests that Thellungiella shows metabolic plasticity in response to environmental stress and that resource availability can influence the expression of stress tolerance traits under field conditions. Conclusion: Comparisons between Thellungiella plants responding to stress in cabinets and in their natural habitats showed differences but also overlap between transcript and metabolite profiles. The traits in common offer potential targets for improving crops that must respond appropriately to multiple, concurrent stresses. Overall design: A custom cDNA mcroarray was used for transcript profiling. Cauline leaves from individual plants collected at a Yukon, Canada field site were used in this study. Three samples were obtained in 2003 (Field 2003 A, B and C) and three harvested in 2005 (Field 2005 A, B and D). Cauline leaves from 12 week old chamber grown plants served as controls. For each microarray experiment a technical replicate (dye swap) was performed resulting in a total of 12 hybridizations.
Ben Rejeb, K., C. Abdelly, et al. (2014) How reactive oxygen species and proline face stress together Plant Physiology and Biochemistry 80: 278-284. 10.1016/j.plaphy.2014.04.007Reactive oxygen species (ROS) are continuously generated as a consequence of plant metabolic processes due to incomplete reduction of O-2. Previously considered to be only toxic by-products of metabolism, ROS are now known to act as second messengers in intracellular signalling cascades to trigger tolerance of various abiotic and biotic stresses. The accumulation of proline is frequently observed during the exposure of plants to adverse environmental conditions. Interestingly proline metabolism may also contribute to ROS formation in mitochondria, which play notably a role in hypersensitive response in plants, life-span extension in worms and tumor suppression in animals. Here we review current knowledge about the regulation of proline metabolism in response to environmental constraints and highlight the key role of ROS in the regulation of this metabolism. The impact of proline on ROS generation is also investigated. Deciphering and integrating these relationships at the whole plant level will bring new perspectives on how plants adapt to environmental stresses. (C) 2014 Elsevier Masson SAS. All rights reserved.
Batelli, G., D.-H. Oh, et al. (2014). Using Arabidopsis-Related Model Species (ARMS): Growth, Genetic Transformation, and Comparative Genomics. in Arabidopsis Protocols, 3rd Edition. J. J. SanchezSerrano and J. Salinas (eds). 1062: 27-51. Bao, A.-K., Y.-W. Wang, et al. (2014) Co-expression of xerophyte Zygophyllum xanthoxylum ZxNHX and ZxVP1-1 enhances salt and drought tolerance in transgenic Lotus corniculatus by increasing cations accumulation Functional Plant Biology 41: 203-214. 10.1071/fp13106Lotus corniculatus L. is an important legume for forage, but is sensitive to salinity and drought. To develop salt-and drought-resistant L. corniculatus, ZxNHX and ZxVP1-1 genes encoding tonoplast Na+/H+ antiporter and H+-pyrophosphatase (H+-PPase) from a succulent xerophyte Zygophyllum xanthoxylum L., which is well adapted to arid environments through accumulating Na+ in its leaves, were transferred into this forage. We obtained the transgenic lines co-expressing ZxNHX and ZxVP1-1 genes (VX) as well as expressing ZxVP1-1 gene alone (VP). Compared with wild-type, both VX and VP transgenic lines grew better at 200 mM NaCl, and also exhibited higher tolerance and faster recovery from water-deficit stress: these performances were associated with more Na+, K+ and Ca2+ accumulation in their leaves and roots, which caused lower leaf solute potential and thus retained more water. Moreover, the transgenic lines maintained lower relative membrane permeability and higher net photosynthesis rate under salt or water-deficit stress. These results indicate that expression of tonoplast Na+/H+ antiporter and H+-PPase genes from xerophyte enhanced salt and drought tolerance of L. corniculatus. Furthermore, compared with VP, VX showed higher shoot biomass, more cations accumulation, higher water retention, lesser cell membrane damage and higher photosynthesis capacity under salt or water-deficit condition, suggesting that co-expression of ZxVP1-1 and ZxNHX confers even greater performance to transgenic L. corniculatus than expression of the single ZxVP1-1.
Aleman, F., F. Caballero, et al. (2014) The F130S point mutation in the Arabidopsis high-affinity K transporter AtHAK5 increases K+ over Na+ and Cs+ selectivity and confers Na+ and Cs+ tolerance to yeast under heterologous expression Frontiers in Plant Science 5: 430 10.3389/fpls.2014.00430Potassium (K+) is an essential macronutrient required for plant growth, development and high yield production of crops. Members of group I of the KT/HAK/KUP family of transporters, such as HAK5, are key components for K+ acquisition by plant roots at low external K+ concentrations. Certain abiotic stress conditions such as salinity or Cs+-polluted soils may jeopardize plant K+ nutrition because HAK5-mediated K+ transport is inhibited by Na+ and Cs+. Here, by screening in yeast a randomly-mutated collection of AtHAK5 transporters, a new mutation in AtHAK5 sequence is identified that greatly increases Na+ tolerance. The single point mutation F130S, affecting an amino acid residue conserved in HAK5 transporters from several species, confers high salt tolerance, as well as Cs+ tolerance. This mutation increases more than 100-fold the affinity of AtHAK5 for K+ and reduces the K, values for Na+ and Cs+, suggesting that the F130 residue may contribute to the structure of the pore region involved in K+ binding. In addition, this mutation increases the Vmax for K+. All this changes occur without increasing the amount of the AtHAK5 protein in yeast and support the idea that this residue is contributing to shape the selectivity filter of the AtHAK5 transporter.
Ait Hammou, K., L. Rubio, et al. (2014) Potassium uptake in the halophyte Halimione portulacoides L. Aellen Environmental and Experimental Botany 107: 15-24. 10.1016/j.envexpbot.2014.05.001The characteristics of root Kt uptake in the halophyte Halimione portulacoides have been studied using electrophysiological techniques. Plantlets grown in the absence of both K+ and Na+ are able to take up K+ at micromolar external concentrations and root cells of these plants depolarize in response to these K+ concentrations. Depolarizations show saturation kinetics with a K-m around 300 mu M K+. Rubidium also induces membrane depolarizations and inhibits K+ transport at low micromolar concentrations whereas Cs+ hardly depolarizes the membrane. The addition of millimolar Na+ reduces both the affinity for K+ and the maximum transport rates, and membrane potentials become more positive only when Na+ concentration reaches 300 mM. Plantlets grown at high Na+ show the same effects on K+ transport but membrane potentials are maintained at highly negative values. Plantlets grown in the absence or the presence of Na+ show similar responses to different inhibitors of le uptake. TEA(+) does not affect K+ transport, Cs+ produces a partial inhibition whereas Ba2+ completely blocks the process. Besides, the external pH does not affect K+ transport. However, NH4+ inhibits partially this process in plants grown without Na+ but has no effect on plants grown at 300 mM Na+. Altogether these results point out that the transport of K+ in this species is mediated mainly by channels, most probably of the AKT-1 type, both in plants grown with or without Na+; however, the operation of potassium transporters cannot be excluded in plants grown in the absence of Na+. Cytosolic K+ activities were also measured in plantlets grown without or with 300 mM Na+, showing lower values at high Na+. Calculation of the electrochemical potential gradient for K+ in these plants indicates that the transport would be passive, i.e. mediated by channels, at concentrations higher than 20 mu M or 120 mu M, in the absence or the presence of 300 mM Na+, respectively. (C) 2014 Elsevier B.V. All rights reserved.
Zhou, C., H. Wang, et al. (2013) Molecular Cloning, Subcellular Localization and Functional Analysis of ThCLC-a from Thellungiella halophila Plant Molecular Biology Reporter 31: 783-790. 10.1007/s11105-012-0545-0Often, nitrate is the major source of available nitrogen for plants. Nitrate can accumulate in central vacuoles via tonoplast transporters. In the present study, a gene termed ThCLC-a that encodes a chloride channel protein was isolated from Thellungiella halophila. Deduced amino acid sequence analysis revealed high identity with AtCLC-a. RT-PCR analysis showed that the ThCLC-a gene was expressed ubiquitously in all major organs and its expression was induced by nitrate treatment. Confocal microscopy using green fluorescent fusion proteins revealed that ThCLC-a was localized specifically to the tonoplast membrane. Furthermore, an RNAi construct expressing a ThCLC-a cDNA fragment was used to silence the endogenous ThCLC-a in T. halophila. HPLC analysis showed that the nitrate content in shoots or roots of silenced plants was 19-36 % lower than in wild-type plants. Transgenic Arabidopsis plants ectopically expressing the ThCLC-a gene could accumulate 15-21 % more nitrate content than wild type plants under limited nitrogen conditions. Finally, our results suggest ThCLC-a may play an important role in the transport of nitrate via the vacuolar membrane.
Zhao, Y.-X., Y.-L. Wei, et al. (2013) Construction of a cDNA Library from the Ephemeral Plant Olimarabidopsis pumila and Preliminary Analysis of Expressed Sequence Tags Zeitschrift Fur Naturforschung Section C-a Journal of Biosciences 68: 499-508.Olimarabidopsis pumila is a close relative of the model plant Arabidopsis thaliana but, unlike A. thaliana, it is a salt-tolerant ephemeral plant that is widely distributed in semi-arid and semi-salinized regions of the Xinjiang region of China, thus providing an ideal candidate plant system for salt tolerance gene mining. A good-quality cDNA library was constructed using cap antibody to enrich full-length cDNA with the gateway technology allowing library construction without traditional methods of cloning by use of restriction enzymes. A preliminary analysis of expressed sequence tags (ESTs) was carried out. The titers of the primary and the normalized cDNA library were 1.6 . 10(6) cfu/mL and 6.7 . 10(6) cfu/mL, respectively. A total of 1093 clones were randomly selected from the normalized library for EST sequencing. By sequence analysis, 894 high-quality ESTs were generated and assembled into 736 unique sequences consisting of 72 contigs and 664 singletons. The resulting unigenes were categorized according to the gene ontology (GO) hierarchy. The potential roles of gene products associated with stress-related ESTs are discussed. The 736 unigenes were similar to A. thaliana, A. lyrata, or Thellungiella salsuginea. This research provides an overview of the mRNA expression profile and first-hand information of gene sequence expressed in young leaves of O. pumila.
Zhao, Q., H. Zhang, et al. (2013) Proteomics-based investigation of salt-responsive mechanisms in plant roots Journal of Proteomics 82: 230-253. 10.1016/j.jprot.2013.01.024Salinity is one of the major abiotic stresses that limits agricultural productivity worldwide. Plant roots function as the primary site of salinity perception. Salt responses in roots are essential for maintaining root functionality, as well as for transmitting the salt signal to shoot for proper salt response and adaptation in the entire plant. Therefore, a thorough understanding of signaling and metabolic mechanisms of salt response in roots is critical for improving plant salt tolerance. Current proteomic studies have provided salt-responsive expression patterns of 905 proteins in 14 plant species. Through integrative analysis of salt-responsive proteins and previous physiological and molecular findings, this review summarizes current understanding of salt responses in roots and highlights proteomic findings on the molecular mechanisms in the fine-tuned salt-responsive networks. At the proteome level, the following processes become dominant in root salt response: (i) salt signal perception and transduction; (ii) detoxification of reactive oxygen species (ROS); (iii) salt uptake/exclusion and compartmentalization; (iv) protein translation and/or turnover dynamics; (v) cytoskeleton/cell wall dynamics; (vi) carbohydrate and energy metabolism; and (vii) other salt-responsive metabolisms. These processes work together to gain cellular homeostasis in roots and determine the overall phenotype of plant growth and development under salt stress. (C) 2013 Elsevier B.V. All rights reserved.
Zhang, Z., X. Sui, et al. (2013) Cloning and prokaryotic expression of ThGPX8 from Thellungiella salsuginea Journal of Northwest A & F University - Natural Science Edition 41: 165-172.Objective: In the study, ThGPX8 (Thellungiella salsuginea GPX8) was isolated and analyzed using bioinformatics tools to improve the structural and functional analysis of ThGPX8. Method: ThGPX8 was cloned from T. salsuginea by RT-PCR. The structure and phylogenetic tree of ThGPX8 were analyzed by bioinformatics software. ThGPX8 was ligated into pET28a vector, and transferred into E. coli strain BL21(DE3) for heterologous expression. Result: Nucleotide analysis showed that ThGPX8 sequence contained a 504 bp open reading frame (ORF), which encoded 167 amino acid residues. Amino sequence analysis demonstrated that the deduced ammo sequences of ThGPXS had characteristic domain of GPXs ThGPXS was not a trans-membrane protein. The secondary structure of ThGPXS mainly included random coils, and its tertiary structure was a dimer. The phylogenetic analysis of ThGPXS revealed that ThGPXS shared higher homology with AlyGPX8, AtGPX8 and BnGPX8. There were differences in physicochemical properties between ThGPX8 and ThGPX6, but they were similar in secondary and tertiary structure. After being induced by IPTG, a 23 ku recombinant protein was highly expressed in 37°C for 5 h. Conclusion: ThGPX8 was cloned from T. salsuginea, and the deduced amino sequence of ThGPX8 belonged to glutathione peroxidases in plant. pET-ThGPX8 was constructed and transferred into E. coli strain BL21(DE3), and a 23 ku recombinant protein was expressed.
Zhang, X. D., R. P. Wang, et al. (2013) Lipid profiling and tolerance to low-temperature stress in Thellungiella salsuginea in comparison with Arabidopsis thaliana Biologia Plantarum 57: 149-153. 10.1007/s10535-012-0137-8Changes in membrane lipid composition is a fundamental strategy for plants to resist low-temperature stress. We compared members of 11 membrane glycerolipid classes in Thellungiella salsuginea and its close relative Arabidopsis thaliana at normal growth temperature, and during cold acclimation (CA), freezing (FR), and post-freezing recovery (PFR). The results showed several properties of T. salsuginea distinct from that in A. thaliana, which included: 1) low relative content of phosphatidic acid (PA) and a rapid increase and decrease of PA during FR and PFR respectively; 2) insensitivity of lyso-phospholipids to freezing; and 3) high ratio of phosphatidylcholine to phosphatidylethanolamine. All these properties were in favour of maintaining membrane integrity and stability and therefore enable T. salsuginea to be more tolerant to freezing than A. thaliana.
Zhang, X., L. Wei, et al. (2013) Physiological and Molecular Features of Puccinellia tenuiflora Tolerating Salt and Alkaline-Salt Stress Journal of Integrative Plant Biology 55: 262-276. 10.1111/jipb.12013Saline-alkali soil seriously threatens agriculture productivity; therefore, understanding the mechanism of plant tolerance to alkaline-salt stress has become a major challenge. Halophytic Puccinellia tenuiflora can tolerate salt and alkaline-salt stress, and is thus an ideal plant for studying this tolerance mechanism. In this study, we examined the salt and alkaline-salt stress tolerance of P. tenuiflora, and analyzed gene expression profiles under these stresses. Physiological experiments revealed that P. tenuiflora can grow normally with maximum stress under 600 mmol/L NaCl and 150 mmol/L Na2CO3 (pH 11.0) for 6 d. We identified 4,982 unigenes closely homologous to rice and barley. Furthermore, 1,105 genes showed differentially expressed profiles under salt and alkaline-salt treatments. Differentially expressed genes were overrepresented in functions of photosynthesis, oxidation reduction, signal transduction, and transcription regulation. Almost all genes downregulated under salt and alkaline-salt stress were related to cell structure, photosynthesis, and protein synthesis. Comparing with salt stress, alkaline-salt stress triggered more differentially expressed genes and significantly upregulated genes related to H+ transport and citric acid synthesis. These data indicate common and diverse features of salt and alkaline-salt stress tolerance, and give novel insights into the molecular and physiological mechanisms of plant salt and alkaline-salt tolerance.
Zhang, Q., C. Zhao, et al. (2013) Genome-wide identification of Thellungiella salsuginea microRNAs with putative roles in the salt stress response Bmc Plant Biology 13: Unsp 180 10.1186/1471-2229-13-180Background: MicroRNAs are key regulators of plant growth and development with important roles in environmental adaptation. The microRNAs from the halophyte species Thellungiella salsuginea (salt cress), which exhibits extreme salt stress tolerance, remain to be investigated. The sequenced genome of T. salsuginea and the availability of high-throughput sequencing technology enabled us to discover the conserved and novel miRNAs in this plant species. It is interesting to identify the microRNAs from T. salsuginea genome wide and study their roles in salt stress response. Results: In this study, two T. salsuginea small RNA libraries were constructed and sequenced using Solexa technology. We identified 109 miRNAs that had previously been reported in other plant species. A total of 137 novel miRNA candidates were identified, among which the miR* sequence of 26 miRNAs was detected. In addition, 143 and 425 target mRNAs were predicted for the previously identified and Thellungiella-specific miRNAs, respectively. A quarter of these putative targets encode transcription factors. Furthermore, numerous signaling factor encoding genes, defense-related genes, and transporter encoding genes were amongst the identified targets, some of which were shown to be important for salt tolerance. Cleavage sites of seven target genes were validated by 5' RACE, and some of the miRNAs were confirmed by qRT-PCR analysis. The expression levels of 26 known miRNAs in the roots and leaves of plants subjected to NaCl treatment were determined by Affymetrix microarray analysis. The expression of most tested miRNA families was up-or down-regulated upon NaCl treatment. Differential response patterns between the leaves and roots were observed for these miRNAs. Conclusions: Our results indicated that diverse set of miRNAs of T. salsuginea were responsive to salt stress and could play an important role in the salt stress response.
Zhang, J. (2013) Comprehensive evaluation of landscape exploitation and application of wild herbaceous plant resources of Yuntai mountain Journal of Nanjing Forestry University (Natural Sciences Edition) 37: 37-43.In order to exploit different wild ornamental plants of Lianyungang city effectively, a synthetical assessment was established to evaluate the potential landscape application value of 108 wild herbaceous plants of Yuntai mountain in Lianyungang based on the Analytical Hierarchy Process (AHP), which included criteria adaptability, ornamental value, exploitation value as three principal levels and 13 evaluation factors, among that the saline-alkaline tolerance was especially concerned. According to this evaluation system, 32 species of plants, such as Glehnia littoralis, Scutellaria strigillosa, Peucedanum japonicum, ect., most of which are seaside herbaceous plants with high saline-alkaline tolerance and have higher ornamental values, were attributed to the first level, 33 species of plants included Asplenium castaneo-viride, Thellungiella salsuginea, Cyrtomium falcatum, ect., and 43 species Elsholtzia splendens, Allium thunbergii, Lilium brownii, etc. belonged to second and third level respectively.
Yao, B. Q., C. M. Zhao, et al. (2013) Phenotypic plasticity of Thellungiella salsaginea in response to saline stress Evolutionary Ecology Research 15: 829-846.Background: Theoretical and empirical studies have shown that phenotypic plasticity can contribute to plant fitness by augmenting the ability of a plant to adapt to or tolerate novel conditions. Genetic analysis of Thellungiella salsaginea (alt cress, Brassicaceae) with neutral nuclear markers revealed no genetic variation within or among populations despite the wide variety of phenotypes in this species. Phenotypic variation is likely due to plasticity. Goal: To examine the characteristics of phenotypic plasticity and its intrinsic constraint (i.e. trait integration) of several phenotypic traits in response to salt stress in populations of T. salsaginea with a homogeneous, neutral genetic background. Organism: Thellungiella salsaginea is a halophyte that is widely distributed in the saline regions of northern China. Methods: Seeds were collected from seven natural populations at distantly separated locations along a saline gradient. Plants were grown from seeds in a growth chamber, and growth and physiological traits were measured under conditions of saline stress. Experiments were performed in a greenhouse at Lanzhou University, China. Results: All traits exhibited considerable plasticity in response to the various levels of salinity. Moreover, various patterns in plasticity were found among the seven populations. The degrees of trait integration were relatively low (mean difference of the correlation coefficients = 0.711). Moreover, the integration patterns varied between individual traits and treatments among populations. Thus, the ability of this species to adapt should be attributed to high plasticity and low integration, as well as to the various patterns of plasticity and integration among populations, which probably resulted from epigenetic changes among the populations.
Yang, R., D. E. Jarvis, et al. (2013) The Reference Genome of the Halophytic Plant Eutrema salsugineum. Frontiers in Plant Science 4: 46. 10.3389/fpls.2013.00046Halophytes are plants that can naturally tolerate high concentrations of salt in the soil, and their tolerance to salt stress may occur through various evolutionary and molecular mechanisms. Eutrema salsugineum is a halophytic species in the Brassicaceae that can naturally tolerate multiple types of abiotic stresses that typically limit crop productivity, including extreme salinity and cold. It has been widely used as a laboratorial model for stress biology research in plants. Here, we present the reference genome sequence (241 Mb) of E. salsugineum at 8× coverage sequenced using the traditional Sanger sequencing-based approach with comparison to its close relative Arabidopsis thaliana. The E. salsugineum genome contains 26,531 protein-coding genes and 51.4% of its genome is composed of repetitive sequences that mostly reside in pericentromeric regions. Comparative analyses of the genome structures, protein-coding genes, microRNAs, stress-related pathways, and estimated translation efficiency of proteins between E. salsugineum and A. thaliana suggest that halophyte adaptation to environmental stresses may occur via a global network adjustment of multiple regulatory mechanisms. The E. salsugineum genome provides a resource to identify naturally occurring genetic alterations contributing to the adaptation of halophytic plants to salinity and that might be bioengineered in related crop species.
Yang, F., J. Liu, et al. (2013) Molecular Evolutionary Analysis of the Alfin-Like Protein Family in Arabidopsis lyrata, Arabidopsis thaliana, and Thellungiella halophila Figshare 1: http://dx.doi.org/10.1371/journal.pone.0066838.s001In previous studies, the Alfin1 gene, a transcription factor, enhanced salt tolerance in alfalfa, primarily through altering gene expression levels in the root. Here, we examined the molecular evolution of the Alfin-like (AL) proteins in two Arabidopsis species (A. lyrata and A. thaliana) and a salt-tolerant close relative Thellungiella halophila. These AL-like proteins could be divided into four groups and the two known DUF3594 and PHD-finger domains had co-evolved within each group of genes, irrespective of species, due to gene duplication events in the common ancestor of all three species while gene loss was observed only in T. halophila. To detect whether natural selection acted in the evolution of AL genes, we calculated synonymous substitution ratios (dn/ds) and codon usage statistics, finding positive selection operated on four branches and significant differences in biased codon usage in the AL family between T. halophila and A. lyrata or A. thaliana. Distinctively, only the AL7 branch was under positive selection on the PHD-finger domain and the three members on the branch showed the smallest difference when codon bias was evaluated among the seven clusters. Functional analysis based on transgenic overexpression lines and T-DNA insertion mutants indicated that salt-stress-induced AtAL7 could play a negative role in salt tolerance of A. thaliana, suggesting that adaptive evolution occurred in the members of AL gene family.
Yamaguchi, T., S. Hamamoto, et al. (2013) Sodium transport system in plant cells Frontiers in Plant Science 4: 410 10.3389/fpls.2013.00410Since sodium, Na, is a non-essential element for the plant growth, the molecular mechanism of Na+ transport system in plants has remained elusive for the last two decades. The accumulation of Na+ in soil through irrigation for sustainable agricultural crop production, particularly in arid land, and by changes in environmental and climate conditions leads to the buildup of toxic level of salts in the soil. Since the latter half of the twentieth century, extensive molecular research has identified several classes of Na+ transporters that play major roles in the alleviation of ionic stress by excluding toxic Na+ from the cytosol or preventing Na+ transport to the photosynthetic organs, and also in osmotic stress by modulating intra/extracellular osmotic balance. In this review, we summarize the current knowledge of three major Na+ transporters, namely NHX, SOS1, and HKT transporters, including recently revealed characteristics of these transporters.
Weretilnyk, E. A., M. J. Champigny, et al. (2013) GSE49378: RNA-Seq effectively monitors gene expression in Eutrema salsuginuem plants growing in an extreme natural habitat and in controlled growth cabinet conditions Gene Expression OmnibusBackground: The investigation of extremophile plant species growing in their natural environment offers certain advantages, chiefly that plants adapted to severe habitats have a repertoire of stress tolerance genes that are regulated to maximize plant performance under physiologically challenging conditions. Accordingly, transcriptome sequencing offers a powerful approach to address questions concerning the influence of natural habitat on the physiology of an organism. We used RNA sequencing of Eutrema salsuginuem, an extremophile relative of Arabidopsis thaliana, to investigate the extent to which genetic variation and controlled versus natural environments contribute to differences between transcript profiles.Results: Using 10 million cDNA reads, we compared transcriptomes from two natural Eutrema accessions (originating from Yukon Territory, Canada and Shandong Province, China) grown under controlled conditions in cabinets and those from Yukon plants collected at a Yukon field site. We assessed the genetic heterogeneity between individuals using single-nucleotide polymorphisms (SNPs) and the expression patterns of 27,016 genes. Over 39,000 SNPs distinguish the Yukon from the Shandong accessions but only 4,475 SNPs differentiated transcriptomes of Yukon field plants from an inbred Yukon line. We found 2,898 genes that were differentially expressed between the three sample groups and multivariate statistical analyses showed that transcriptomes of individual plants from a Yukon field site were as reproducible as those from inbred plants grown under controlled conditions. Predicted functions based upon gene ontology classifications show that the transcriptomes of field plants were enriched by the differential expression of light- and stress-related genes, an observation consistent with the habitat where the plants were found.Conclusion: Our expectation that comparative RNA-Seq analysis of transcriptomes from plants originating in natural habitats would be confounded by uncontrolled genetic and environmental factors was not borne out. Moreover, the transcriptome data shows little genetic variation between laboratory Yukon Eutrema plants and those found at a field site. Transcriptomes were reproducible and biological associations meaningful whether plants were grown in cabinets or found in the field. Thus RNA-Seq is a valuable approach to study native plants in natural environments and this technology can be exploited to discover new gene targets for improved crop performance under adverse conditions.Funding Acknowledgement: This work was sponsored by an Ontario Research Fund-Research Excellence award 03-043 to EAW and RKC with support from by Viterra Inc. and Sigma-Aldrich.
Wei, S., Y. Wu, et al. (2013) Cloning and Function Analysis of ThDREB2B Gene Encoding a Putative DRE-binding Transcription Factor from Thellungiella halophila Xibei Zhiwu Xuebao 33: 215-222.A DREB-like gene,designated as ThDREB2B (NCBI Accession No. EF653377) was isolated from Thellungiella halophila,a model plant for stress tolerance research. The result showed that: (1) The cDNA of ThDREB2B was 1 486 bp in full length,contained an open reading frame (ORF) of 954 bp that encoded 316 amino acid residues. The deduced protein was predicted to be 36.0 kD in molecular mass and pI 4.81. The region between residues 76 and 135 was a typical AP2/EREBP DNA-binding domain. (2) The phylogenetic analysis showed that ThDREB2B belonged to the A-2 group of DREB transcription factor subfamily. (3)The expression level of ThDREB2B was relative low in normal growth conditions, and was up-regulated under low temperature, salty, or drought stress. (4) The yeast one-hybrid analysis showed that ThDREB2B could bind to DRE element very specifically, but the transcriptional activate activity was very low. A post-translation modification might be necessary for ThDREB2B to activate the transcription of target genes.
Wang, X., L. Chang, et al. (2013) Comparative Proteomics of Thellungiella halophila Leaves from Plants Subjected to Salinity Reveals the Importance of Chloroplastic Starch and Soluble Sugars in Halophyte Salt Tolerance Molecular & Cellular Proteomics 12: 2174-2195. 10.1074/mcp.M112.022475Thellungiella halophila, a close relative of Arabidopsis, is a model halophyte used to study plant salt tolerance. The proteomic/physiological/transcriptomic analyses of Thellungiella plant leaves subjected to different salinity levels, reported herein, indicate an extraordinary ability of Thellungiella to adapt to large concentrations of exogenous saline by compartmentalizing Na+ into cell vacuoles and accumulating proline and soluble sugars as organic osmolytes. Salinity stress stimulated the accumulation of starch in chloroplasts, which resulted in a greatly increased content of starch and total sugars in leaves. Comparative proteomics of Thellungiella leaves identified 209 salt-responsive proteins. Among these, the sequences of 108 proteins were strongly homologous to Arabidopsis protein sequences, and 30 had previously been identified as Thellungiella proteins. Functional classification of these proteins into 16 categories indicated that the majority are involved in carbohydrate metabolism, followed by those involved in energy production and conversion, and then those involved in the transport of inorganic ions. Pathway analysis revealed that most of the proteins are involved in starch and sucrose metabolism, carbon fixation, photosynthesis, and glycolysis. Of these processes, the most affected were starch and sucrose metabolism, which might be pivotal for salt tolerance. The gene expression patterns of the 209 salt-responsive proteins revealed through hierarchical clustering of microarray data and the expression patterns of 29 Thellungiella genes evaluated via quantitative RT-PCR were similar to those deduced via proteomic analysis, which underscored the possibility that starch and sucrose metabolism might play pivotal roles in determining the salt tolerance ability of Thellungiella. Our observations enabled us to propose a schematic representation of the systematic salt-tolerance phenotype in Thellungiella and suggested that the increased accumulation of starch, soluble sugars, and proline, as well as subcellular compartmentalization of sodium, might collectively denote important mechanisms for halophyte salt tolerance.
Wang, R., J. Huang, et al. (2013) Effects of high concentration salt on contents of IAA and GAs in the roots of Thellungiella halophilla and Arabidopsis thaliana Journal of Northwest A & F University - Natural Science Edition 41: 178-182.Objective: Arabidopsis thaliana and Thellungiella halophilla, are Brassicaceae species closely relate to Arabidopsis thaliana. The effects of high salinity on their root growth, and endogenous gibberellins (GAs) and growth hormone (IAA) levels were compared to improve the understanding of salt tolerance mechanism. Method: After growing on MS medium for one week, Arabidopsis thaliana and Thellungiella halophilla seedlings with similar root length were selected for the salt tolerance experiment. Concentrations of NaCl solutions for Arabidopsis seedlings were 0, 50, 100, 150, 200, 250, 300 mmol/L and for Thellungiella seedlings were 0, 50, 100, 150, 200, 300, 500 mmol/L. Simultaneously, Same Arabidopsis thaliana and Thellungiella halophilla seedlings were selected to be transplanted in the vermiculite/perlite (vol. is 1:1) medium. After 4 weeks, these seedlings were treated with salinity as well (150 and 300 mmol/L NaCl). Root samples were taken from these seedlings on 0 (control), 1, 4, 7, and 10 d, and their endogenous GAs and IAA contents in both species were measured by enzyme-linked immunosorbent assay (ELISA). Result: We found that Thellungiella root growth rate was lower than that of Arabidopsis in the normal condition. With salt stress, root growths of both species were inhibited. The Thellungiella root exhibited a higher tolerance. In addition, IAA contents in both plants decreased initially and then increased, while the contents of GAs gradually increased in the whole process. Conclusion: Salt stress appears to impact the properties of both species by increasing the overall IAA and GAs contents. IAA and GAs accumulation of Thellungiella halophilla was higher than that of Arabidopsis thaliana in high salt stress.
Vysotskii, D. A., I. J. de Vries-van Leeuwen, et al. (2013) ABF transcription factors of Thellungiella salsuginea: Structure, expression profiles and interaction with 14-3-3 regulatory proteins Plant signaling & behavior 8: e22672-e22672. 10.4161/psb.22672ABF transcription factors are the key regulators of ABA signaling. Using RACE-PCR, we identified and sequenced the coding regions of four genes that encode ABF transcription factors in the extremophile plant Thellungiella salsuginea, a close relative of Arabidopsis thaliana that possesses high tolerance to abiotic stresses. An analysis of the deduced amino acid sequences revealed that the similarity between Thellungiella and Arabidopsis ABFs ranged from 71% to 88%. Similar to their Arabidopsis counterparts, Thellungiella ABFs share a bZIP domain and four conservative domains, including a highly conservative motif at the C-terminal tail, which was reported to be a canonical site for binding by 14-3-3 regulatory proteins. Gene expression analysis by real-time PCR revealed a rapid transcript induction of three of the ABF genes in response to salt stress. To check whether Thellungiella ABF transcription factors can interact with abundant 14-3-3 proteins, multiple constructs were designed, and yeast two-hybrid experiments were conducted. Six of the eight tested Ts14-3-3 proteins were able to bind the TsABFs in an isoform-specific manner. A serine-to-alanine substitution in the putative 14-3-3 binding motif resulted in the complete loss of interaction between the 14-3-3 proteins and the ABFs. The role of 14-3-3 interaction with ABFs in the salt and ABA signaling pathways is discussed in the context of Thellungiella survivability.
Verbruggen, N., M. Hanikenne, et al. (2013) A more complete picture of metal hyperaccumulation through next-generation sequencing technologies Frontiers in Plant Science 4: 388 10.3389/fpls.2013.00388The mechanistic understanding of metal hyperaccumulation has benefitted immensely from the use of molecular genetics tools developed for Arabidopsis thaliana. The revolution in DNA sequencing will enable even greater strides in the near future, this time not restricted to the family Brassicaceae. Reference genomes are within reach for many ecologically interesting species including heterozygous outbreeders. They will allow deep RNA-seq transcriptome studies and the re-sequencing of contrasting individuals to unravel the genetic basis of phenotypic variation. Cell-type specific transcriptome analyses, which will be essential for the dissection of metal translocation pathways in hyperaccumulators, can be achieved through the combination of RNA-seq and translatome approaches. Affordable high-resolution genotyping of many individuals enables the elucidation of quantitative trait loci in intra- and interspecific crosses as well as through genome-wide association mapping across large panels of accessions. Furthermore, genome-wide scans have the power to detect loci under recent selection. Together these approaches will lead to a detailed understanding of the evolutionary path towards the emergence of hyperaccumulation traits.
Taranov, V. V., M. V. Berdnikova, et al. (2013) Usage of cold shock domain proteins for improvement of frost hardiness in plant biotechnology Russian Agricultural Sciences 39: 315-317. 10.3103/s1068367413040204We have discovered that overexpression of the gene TsCSDP3 that encodes the cold-shock domain protein from the extremophile plant Thellungiella salsuginea in the test plant A. thaliana considerably improves frost hardiness of the latter, which is promising for use of this gene and, perhaps, of other CDS protein genes in biotechnology of cultivated plants in order to enhance cold stress resistance.
Taranov, V. V., M. V. Berdnikova, et al. (2013) Cold shock domain proteins in biotechnology and their usage in improvement of plant cold hardiness Doklady Rossiiskoi Akademii Sel'skokhozyaistvennykh Nauk 22-24.It is shown that the overexpression of TsCSDP3 gene encoding a cold shock domain protein from an extremophyte Thellungiella salsuginea, significantly increased the A. thaliana model plant frost tolerance. This result indicates the efficiency of TsCSDP3 gene and possibly other CSDP genes in crop plant biotechnology in order to increase their resistance to cold stress.
Sun, Z., X. Qi, et al. (2013) Overexpression of TsGOLS2, a galactinol synthase, in Arabidopsis thaliana enhances tolerance to high salinity and osmotic stresses Plant Physiology and Biochemistry 69: 82-89. 10.1016/j.plaphy.2013.04.009Galactinol synthase (GOLS, EC 2.4.1.123), a key enzyme in the synthesis of raffinose family oligosaccharides (RFOs), catalyzes the condensation of UDP-galactose with myo-inositol to produce galactinol as the sole donor for the synthesis of RFOs. RFOs have been implicated in mitigating effects of environmental stresses on plants. TsGOLS2, was cloned from Thellungiella salsuginea with high homology to AtGOLS2. TsGOLS2 was up-regulated by several abiotic stresses. We overexpressed TsGOLS2 in Arabidopsis thaliana. The contents of galactinol, raffinose, and alpha-ketoglutaric acid were significantly increased in transgenic plants. Compared to wild type plants, salt-stressed transgenic A. thaliana exhibited higher germination rate, photosynthesis ability, and seedling growth. After being treated with osmotic stress by high concentration of sorbitol, transgenic plants retained high germination rates and grew well during early development. These results indicated that overexpression of TsGOLS2 in A. thaliana improved the tolerance of transgenic plants to high salinity and osmotic stress. (C) 2013 Elsevier Masson SAS. All rights reserved.
Soshinkova, T. N., N. L. Radyukina, et al. (2013) Proline and functioning of the antioxidant system in Thellungiella salsuginea plants and cultured cells subjected to oxidative stress Russian Journal of Plant Physiology 60: 41-54. 10.1134/s1021443713010093The effects of proline on the functioning of antioxidant enzymes - superoxide dismutase (SOD) and ascorbate peroxidase (APO) - in Thellungiella salsuginea plants and cultured cells under normal conditions of culturing and under the influence of hydrogen peroxide (500 mu M) were studied. Proline addition (0.2, 2, or 5 mM) to the medium for suspension culture or nutrient medium for plant growing resulted in the increase in the content of intracellular proline in both cultured cells and intact plant leaves and also in the activation of proline dehydrogenase, i.e., the enzyme degrading proline. Under normal conditions, treatment with proline exerted prooxidant action on both cellular and organismal levels. This was manifested in MDA accumulation and changes in APO and SOD activities. The amino acid alanine, used as a control, did not exert similar strong effect as proline. Application of 500 mu M H2O2 on plant leaves resulted in the development of oxidative stress, whereas hydrogen peroxide addition into the culture medium - to the death of 50% of suspension cells. When plants and cultured cells were treated with 2 mM proline and than with H2O2, the number of dead cells in suspension was 35%, the content of MDA was decreased, APO was activated, and SOD activity was decreased in both cell culture and plant leaves. Thus, an increase in the intracellular proline concentration changed the redox balance and induced functioning of APO and SOD at both normal conditions of plant growing and cell culturing and under stress.
Song, Y., J. Gao, et al. (2013) Molecular Evolutionary Analysis of the Alfin-Like Protein Family in Arabidopsis lyrata, Arabidopsis thaliana, and Thellungiella halophila Plos One 8: e66838 10.1371/journal.pone.0066838In previous studies, the Alfin1 gene, a transcription factor, enhanced salt tolerance in alfalfa, primarily through altering gene expression levels in the root. Here, we examined the molecular evolution of the Alfin-like (AL) proteins in two Arabidopsis species (A. lyrata and A. thaliana) and a salt-tolerant close relative Thellungiella halophila. These AL-like proteins could be divided into four groups and the two known DUF3594 and PHD-finger domains had co-evolved within each group of genes, irrespective of species, due to gene duplication events in the common ancestor of all three species while gene loss was observed only in T. halophila. To detect whether natural selection acted in the evolution of AL genes, we calculated synonymous substitution ratios (dn/ds) and codon usage statistics, finding positive selection operated on four branches and significant differences in biased codon usage in the AL family between T. halophila and A. lyrata or A. thaliana. Distinctively, only the AL7 branch was under positive selection on the PHD-finger domain and the three members on the branch showed the smallest difference when codon bias was evaluated among the seven clusters. Functional analysis based on transgenic overexpression lines and T-DNA insertion mutants indicated that salt-stress-induced AtAL7 could play a negative role in salt tolerance of A. thaliana, suggesting that adaptive evolution occurred in the members of AL gene family.
Shandong Academy of Agricultural, S. (2013) Thellungiella salsuginea miRNA European Nucleotide ArchiveTo identify miRNAs and investigate their possible roles in salt-tolerance of Thellungiella two small RNA libraries were constructed in this study. One library was used as control derived from tissues of 40 d old plants under non-stress condition, and the other library was constructed using 40 d old plants treated with 200 mM NaCl for 24 h.
Shandong Academy of Agricultural, S. (2013) Eutrema salsugineum European Nucleotide ArchiveTo identify miRNAs and investigate their possible roles in salt-tolerance of Thellungiella two small RNA libraries were constructed in this study. One library was used as control derived from tissues of 40 d old plants under non-stress condition, and the other library was constructed using 40 d old plants treated with 200 mM NaCl for 24 h.
Ryzhova, N. N., M. A. Filiushin, et al. (2013) Identification and nucleotide polymorphisms in Brassica rapa genes coding cold shock domain proteins (CSDP) Molekuliarnaia biologiia 47: 107-115.Full-length BrCSDP2 and BrCSDP4 cold shock gene sequences of Brassica rapa are obtained. It is shown that the isolated genes belong to a group AtCSP2/AtCSP4 of Arabidopsis thaliana and TsCSDP2/TsCSDP4 of Thellungiella salsuginea genes encoding proteins with a cold shock domain (CSD) and two zinc finger motives. The structure and the allelic variants of these genes are described and characterized. It is shown that the identified allelic polymorphism is due to both of point substitutions and small indels. Coefficients of total genetic similarity ranged from 1.0 to 0.53. In tern the genetic similarity coefficient for BrCSDP2 and AtCSDP2 was 0.89, and for BrCSDP4 and AtCSDP4 was 0.85.Translation in silico of gene sequences has revealed amino acid substitutions in the protein sequence, but no significant correlation between the detected polymorphism and signs of resistance to cold stress were found.
Ryzhova, N. N., M. A. Filiushin, et al. (2013) Identification and nucleotide polymorphisms in Brassica rapa genes coding cold-shock domain proteins Molecular Biology 47: 97-104. 10.1134/s0026893312060143Full-length BrCSDP2 and BrCSDP4 cold-shock gene sequences of Brassica rapa have been obtained. The isolated genes were shown to belong to a group AtCSP2/AtCSP4 of Arabidopsis thaliana and TsCSDP2/TsCSDP4 of Thellungiella salsuginea genes that encode proteins with a cold-shock domain and two zinc finger motifs. The structure and the allelic variants of these genes have been described and characterized. The identified allelic polymorphism was shown to result both from point substitutions and small indels. Coefficients of total genetic similarity ranged from 1.0 to 0.53. For BrCSDP2 and AtCSDP2, the genetic similarity coefficient was 0.89 and, for BrCSDP4 and AtCSDP4, it was 0.85. The in silico translation of gene sequences has revealed amino acid substitutions in the protein sequence, but no significant correlation between the detected polymorphism and signs of resistance to cold stress were found.
Rozema, J. and H. Schat. (2013) Salt tolerance of halophytes, research questions reviewed in the perspective of saline agriculture Environmental and Experimental Botany 92: 83-95. 10.1016/j.envexpbot.2012.08.004Halophytes of the lower coastal salt Marsh show increased salt tolerance, and under high salinity they grow faster than upper marsh species. We could not show reduced growth rate of halophytes compared with glycophytes when grown under non-saline conditions. This indicates limited energy costs associated with high-salt tolerance in plants of genera such as Salicornia, providing a good perspective of saline agriculture cultivating Salicornia as a vegetable crop. We show that halophytes do not occur on non-saline or inland sites because of a reduced growth rate at low soil salinity, but probably due to other ecological traits of glycophytic upper marsh species. These traits provide competitive advantage over lower salt marsh halophytes, such as earlier germination and increased growing season length. Some halophytic Amaranthaceae (Salicornioideae, Chenopodioideae and Suaedoideae) are not just highly salt tolerant, their growth rate is stimulated at a salinity range of 150-300 mM NaCl. Alternatively this may be described as depressed growth at low salinity. Selective pressure for such high-salt tolerance and salt stimulated growth likely occurred with prevailing arid climate and saline soil conditions. Under such conditions highly-salt tolerant succulent Salicornioideae, Chenopodioidea and Suaedoideae may have evolved about 65 Mya. In the context of evolution and diversication of land plants this origin of highly-salt tolerant succulent plants is relatively recent. Such high-salt tolerance might be characterized as constitutive in comparison with inducible (lower) salt tolerance of other dicotyledonae and monocotyledonae (Poaceae) species. Levels of salt tolerance of the latter type span a large range of low, intermediate to high-salt tolerance, but do not include salt stimulated growth. Salt tolerant traits of the latter inducible type appear to have evolved repeatedly and independently. Early highly-salt tolerant succulent Salicornioideae, Chenopodioidea and Suaedoideae were perennial and frost sensitive and occurred in warm temperate and Mediterranean regions. A shift from the perennial Sarcocornia to an annual life form has been phylogenetically dated circa 9.4-4.2 Mya and enabled evolution of annual hygrohalophytes in more northern coastal locations up to boreal and subarctic coastal sites avoiding damage of winter frost. Diversification of such hygrohalophytes was facilitated by polyploidization (e.g. occurrence of tetraploid and diploid Salicornia species), and a high degree of inbreeding allowing sympatric occurrence of Salicornia species in coastal salt marshes. High-level salt tolerance is probably a very complex polygenic trait. It is unlikely that glycophytes would accommodate the appropriate allelic variants at all the loci involved in halophyte salt tolerance. This might explain why attempts to improve crop salt tolerance through conventional breeding and selection have been unsuccessful to date. Genetic engineering provides a viable alternative, but the choice for the appropriate transgenes is hampered by a fundamental lack of knowledge of the mechanisms of salt tolerance in halophytes. The chances to identify the determinant genes through QTL analyses, or comparisons among near isogenic lines (NILS) are limited. Salt-tolerance is usually a species-wide trait in halophytes, and intra-specific divergence in salt tolerance in facultative halophytes seems to be often associated with chromosomal incompatibility. A variety of candidate salt tolerance genes been identified in Arabidopsis thaliana, among which genes encoding Na+ and K+ transporters, and genes involved in the general stress or anti-oxidant response, or in compatible solute metabolism. Many of these genes have been over-expressed in different glycophytic hosts, which usually appeared to alleviate, to some degree, the response to high salinity levels. However, with few exceptions, there are no indications that the same genes would be responsible for the superior salt tolerance in (eu)halophytes. Comparisons of gene expression and gene promoter activity patterns between halophytes and glycophytes are, with few exceptions, virtually lacking, which is a major omission in current day salt tolerance research. Full-genome transcriptomic comparisons between halophytes and related glycophytes through deep sequencing seem to be the most promising strategy to identify candidate genetic determinants of the difference in salt tolerance between halophytes and glycophytes. The most reliable validation of any candidate gene is through silencing the gene in the halophytic genetic background, preferably down to the level at which it is expressed in the glycophyte reference species. This requires genetically accessible halophyte models, which are not available to date, with the exception of Thellungiella halophila. However, more models are required, particularly because T. halophila is not a typical halophyte. Eventually, the pyramiding of validated salt tolerance genes under suitable promoters may be expected to be a viable strategy for crop salt tolerance improvement. (C) 2012 Elsevier B.V. All rights reserved.
Rolin, D., C. Deborde, et al. (2013). High-Resolution H-1-NMR Spectroscopy and Beyond to Explore Plant Metabolome. in Metabolomics Coming of Age with Its Technological Diversity. D. Rolin (eds). 67: 1-66. Reinhardt, R., D. K. Hincha, et al. (2013) Transcriptome sequencing and microarray design for functional genomics in the extremophile Arabidopsis relative Thellungiella salsuginea ArrayExpress ArchiveArabidopsis thaliana is not particularly stress tolerant and may lack protective mechanisms required to survive extreme environmental conditions. Thellungiella salsuginea has therefore attracted increasing interest as an alternative plant model species that possesses high tolerance of various abiotic stresses. While the T. salsuginea genome has recently been sequenced, its annotation is still far from complete and, due to the low number of ESTs available, evidence for actual transcriptional activity is lacking for most genes. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from plant samples from different developmental stages and grown under abiotic stress conditions. The ESTs of Thellungiella was sequenced by 454 pyrosequencing method. More than 1 million sequence reads were assembled into 42,810 unigenes, approximately 50% of which could be functionally annotated. From this sequence information, we constructed a 44k Agilent oligonucleotide microarray. A comparison of same-species and cross-species hybridization results showed the superior performance of the newly designed array for Thellungiella samples. In addition, the array was validated in a cold acclimation experiment that used the appropriately adapted MapMan software for analysis and visualization. To examine the quality of the Thellungiella array and to assess whether hybridization results from a dedicated array are superior to cross-species hybridization using the Arabidopsis array from the same manufacturer, we performed reciprocal array hybridizations. In this experiment, RNA from the Yukon accession of Thellungiella and RNA from the Col-0 accession of Arabidopsis were both hybridized on the Agilent Thellungiella and Arabidopsis expression arrays. For both species, RNA was extracted from acclimated and non-acclimated plants from three independent biological replicates.
Rahman, L. N., F. McKay, et al. (2013) Interactions of Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 with membranes at cold and ambient temperatures-Surface morphology and single-molecule force measurements show phase separation, and reveal tertiary and quaternary associations Biochimica Et Biophysica Acta-Biomembranes 1828: 967-980. 10.1016/j.bbamem.2012.11.031Dehydrins (group 2 late embryogenesis abundant proteins) are intrinsically-disordered proteins that are expressed in plants experiencing extreme environmental conditions such as drought or low temperature. Their roles include stabilizing cellular proteins and membranes, and sequestering metal ions. Here, we investigate the membrane interactions of the acidic dehydrin TsDHN-1 and the basic dehydrin TsDHN-2 derived from the crucifer Thellungiella salsuginea that thrives in the Canadian sub-Arctic. We show using compression studies with a Langmuir-Blodgett trough that both dehydrins can stabilize lipid monolayers with a lipid composition mimicking the composition of the plant outer mitochondrial membrane, which had previously been shown to induce ordered secondary structures (disorder-to-order transitions) in the proteins. Ellipsometry of the monolayers during compression showed an increase in monolayer thickness upon introducing TsDHN-1 (acidic) at 4 C and TsDHN-2 (basic) at room temperature. Atomic force microscopy of supported lipid bilayers showed temperature-dependent phase transitions and domain formation induced by the proteins. These results support the conjecture that acidic dehydrins interact with and potentially stabilize plant outer mitochondrial membranes in conditions of cold stress. Single-molecule force spectroscopy of both proteins pulled from supported lipid bilayers indicated the induced formation of tertiary conformations in both proteins, and potentially a dimeric association for TsDHN-2. (C) 2012 Elsevier B.V. All rights reserved.
Physiol, M. P. I. M. P. (2013) Eutrema salsugineum Transcriptome or Gene expression European Nucleotide ArchiveThellungiella salsuginea has attracted increasing interest as an alternative to Arabidopsis as a plant model species that possesses high tolerance of various abiotic stresses. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from plant samples from different developmental stages and grown under abiotic stress conditions.
Physiol, M. P. I. M. P. (2013) Eutrema salsugineum strain:Yukon Transcriptome or Gene expression European Nucleotide ArchiveThellungiella salsuginea has attracted increasing interest as an alternative to Arabidopsis as a plant model species that possesses high tolerance of various abiotic stresses. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from plant samples from different developmental stages and grown under abiotic stress conditions.
Panahi, B., S. A. Mohammadi, et al. (2013) Identification of miRNAs and their potential targets in halophyte plant Thellungiella halophila Biotechnologia (Poznan) 94: 285-290.MicroRNAs (miRNAs) are a class of non-coding RNAs with important role in gene regulation in various organisms. These RNAs regulate gene expression at the post-transcriptional level. To date, several hundred plant miRNAs have been deposited in the miRBase database. Many of them are conserved during the evolution of terrestrial plants, suggesting that the well-conserved miRNAs may also retain homologous target interactions. So far, there has been no experimental or computational identification of miRNAs and their target genes in Thellungiella halophila. Here, using a computational homology based search approach and according to a series of filtering criteria, a total of 8 miRNAs belonging to 4 miRNA families were detected from the Expressed Sequence Tags (EST) databases. Potential target genes of these predicted miRNAs were subsequently assessed. Our findings showed that among the target genes, most of them encode transcription factors and enzymes that participate in regulation of development, growth and other physiological processes.
Ozgur, R., B. Uzilday, et al. (2013) Reactive oxygen species regulation and antioxidant defence in halophytes Functional Plant Biology 40: 832-847. 10.1071/fp12389Production of reactive oxygen species (ROS), which are a by-product of normal cell metabolism in living organisms, is an inevitable consequence of aerobic life on Earth, and halophytes are no exception to this rule. The accumulation of ROS is elevated under different stress conditions, including salinity, due to a serious imbalance between their production and elimination. These ROS are highly toxic and, in the absence of protective mechanisms, can cause oxidative damage to lipids, proteins and DNA, leading to alterations in the redox state and further damage to the cell. Besides functioning as toxic by-products of stress metabolism, ROS are also important signal transduction molecules in controlling growth, development and responses to stress. Plants control the concentrations of ROS by an array of enzymatic and nonenzymatic antioxidants. Although a relation between enzymatic and non-enzymatic antioxidant defence mechanisms and tolerance to salt stress has been reported, little information is available on ROS-mediated signalling, perception and specificity in different halophytic species. Hence, in this review, we describe recent advances in ROS homeostasis and signalling in response to salt, and discuss current understanding of ROS involvement in stress sensing, stress signalling and regulation of acclimation responses in halophytes. We also highlight the role of genetic, proteomic and metabolic approaches for the successful study of the complex relationship among antioxidants and their functions in halophytes, which would be critical in increasing salt tolerance in crop plants.
Ncbi. (2013) Eutrema parvulum overview European Nucleotide ArchiveEutrema parvulum, also called Thellungiella parvula, is one of several extremophile relatives of Arabidopsis, is notable for its tolerance to high salinity, freezing temperatures, water deficit and resource-poor environments. Under saline conditions, for example, its LD50 in NaCl is 600 mM for mature plants; below that, while Na+ gradually accumulates, K+ levels are maintained. With a small nuclear genome of ~140Mb in 7 chromosomes (N), Eutrema parvulum represents an extremophile model species.
Ncbi. (2013) Thellungiella overview European Nucleotide ArchiveThis work aimed to study the regulation of K+/Na+ homeostasis and the physiological responses of salt-treated sorghum plants [Sorghum bicolor (L.) Moench] grown with different inorganic nitrogen (N) sources. Four days after sowing (DAS), the plants were transferred to complete nutrient solutions containing 0.75 mM K+ and 5 mM N, supplied as either NO3 (-) or NH4 (+). Twelve DAS, the plants were subjected to salt stress with 75 mM NaCl, which was applied in two doses of 37.5 mM. The plants were harvested on the third and seventh days after the exposure to NaCl. Under the salt stress conditions, the reduction of K+ concentrations in the shoot and roots was higher in the culture with NO3 (-) than with NH4 (+). However, the more conspicuous effect of N was on the Na+ accumulation, which was severely limited in the presence of NH4 (+). This ionic regulation had a positive influence on the K+/Na+ ratio and the selective absorption and transport of K+ in the plants grown with NH4 (+). Under control and salt stress conditions, higher accumulation of free amino acids and soluble proteins was promoted in NH4 (+) grown roots than NO3 (-) grown roots at both harvesting time, whereas higher accumulation of soluble sugars was observed only at 7 days of salt stress exposure. Unlike the NH4 (+) grown plants, the gas exchanges of the NO3 (-) grown plants were reduced after 7 days of salt stress. These results suggest that external NH4 (+) may limit Na+ accumulation in sorghum, which could contribute to improving its physiological and metabolic responses to salt stress.
Minzu University of, C. (2013) Eutrema halophilum Transcriptome or Gene expression European Nucleotide ArchiveAs a salt tolerant relative of Arabidopsis, Thellungiella salsuginea has increasingly been used in studies of plant salinity tolerance. In the past years, large-scale screening of salt stress-related gene was hindered by lack of sufficient transcriptomic and genomic data in public databases. Thus, high throughput transcriptome sequencing and subsequent digital gene expression analysis is helpful to generate a large amount of transcript sequences for gene discovery and perform high-throughput profiling of high salinity regulated genes in Thellungiella.
Minzu University of, C. (2013) Eutrema halophilum strain:Ecotype Shandong Transcriptome or Gene expression European Nucleotide ArchiveAs a salt tolerant relative of Arabidopsis, Thellungiella salsuginea has increasingly been used in studies of plant salinity tolerance. In the past years, large-scale screening of salt stress-related gene was hindered by lack of sufficient transcriptomic and genomic data in public databases. Thus, high throughput transcriptome sequencing and subsequent digital gene expression analysis is helpful to generate a large amount of transcript sequences for gene discovery and perform high-throughput profiling of high salinity regulated genes in Thellungiella.
Li, J., Y. Liu, et al. (2013) Cloning and Sequence Analysis of EIN2 in Malus domestica Xibei Zhiwu Xuebao 33: 684-691.The DNA sequence and cDNA sequence of Mains domestica EIN2 were amplified by PCR and RT-PCR,respectively. Bioinformatic analysis of the nucleotide and sequence of EIN2 was performed. The results showed that : (1)The sequences of M. clomestica EIN2 amplified by PCR and RT-PCR both are the same,without intron in it. The M. domestica EIN2 was 4 378 bp,containing one opening reading frame of 3 282 bp and coding 1 093 amino acid residues. The molecular weight of M. dornestica EIN2 is 118. 9 kD,and its theoretical pI is 5. 52,and the protein probably is a liposoluble and lyophobic protein. (2)The multiple sequence alignment indicated that the deduced amino acid sequence of M. domestica EIN2 shared 52%, 79% and 62% identity with EIN2 of Arabiclopsis thaliana (AAD41077. 1),Prunits persica (ACY78397. 1) and Vitis vinifera (CAN66374. 1). respectively. (3) The constructed phylogenetic tree shows that A. thaliana,Thellungiella halophila,Cucumis melo and Po pulus trichocarpa were clustered together, while P. persica,Petunia hvbricla and Solcinum lycopersicum were clustered to another group. V. vini fera, M. domestica and Medicago truncatula were clustered in separate groups, respectively. And M. clomesticu EIN2 is closely related with the homologous genes of P. persica,et al, and the relationships of it with the homologous EIN2 genes in A. thaliana and T. halophila were remote.
Lee, Y. P., F. M. Giorgi, et al. (2013) Transcriptome sequencing and microarray design for functional genomics in the extremophile Arabidopsis relative Thellungiella salsuginea (Eutrema salsugineum) Bmc Genomics 14: 793 10.1186/1471-2164-14-793Background: Most molecular studies of plant stress tolerance have been performed with Arabidopsis thaliana, although it is not particularly stress tolerant and may lack protective mechanisms required to survive extreme environmental conditions. Thellungiella salsuginea has attracted interest as an alternative plant model species with high tolerance of various abiotic stresses. While the T. salsuginea genome has recently been sequenced, its annotation is still incomplete and transcriptomic information is scarce. In addition, functional genomics investigations in this species are severely hampered by a lack of affordable tools for genome-wide gene expression studies. Results: Here, we report the results of Thellungiella de novo transcriptome assembly and annotation based on 454 pyrosequencing and development and validation of a T. salsuginea microarray. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from samples covering different tissues and abiotic stress conditions. Both libraries yielded partially unique sequences, indicating their necessity to obtain comprehensive transcriptome coverage. More than 1 million sequence reads were assembled into 42,810 unigenes, approximately 50% of which could be functionally annotated. These unigenes were compared to all available Thellungiella genome sequence information. In addition, the groups of Late Embryogenesis Abundant (LEA) proteins, Mitogen Activated Protein (MAP) kinases and protein phosphatases were annotated in detail. We also predicted the target genes for 384 putative miRNAs. From the sequence information, we constructed a 44 k Agilent oligonucleotide microarray. Comparison of same-species and cross-species hybridization results showed superior performance of the newly designed array for T. salsuginea samples. The developed microarrays were used to investigate transcriptional responses of T. salsuginea and Arabidopsis during cold acclimation using the MapMan software. Conclusions: This study provides the first comprehensive transcriptome information for the extremophile Arabidopsis relative T. salsuginea. The data constitute a more than three-fold increase in the number of publicly available unigene sequences and will greatly facilitate genome annotation. In addition, we have designed and validated the first genome-wide microarray for T. salsuginea, which will be commercially available. Together with the publicly available MapMan software this will become an important tool for functional genomics of plant stress tolerance.
Lai, J.-S. and K.-Y. Lue. (2013) Microhabitat Preference of the Alishan Salamander (Hynobius arisanensis) Current Herpetology 32: 125-134. 10.5358/hsj.32.125An analysis of the microhabitat preference of the Alishan salamander (Hynobius arisanensis) was conducted in the Alishan area of Taiwan from 2003 to 2006. The study consisted of two parts: one to record microhabitat use of salamanders, and the other to quantify suitable microhabitat in the study site. The salamanders were found to use most of the microhabitat types available to them in the study site. However, they used rocks as shelters at a high frequency (77.7%). Although decayed logs were less available than rocks, the salamanders seemed to choose the logs as shelters. The decayed logs can keep moisture for a longer time and provide more prey than rocks, which probably causes the salamanders to choose less-available logs. The salamander preferred large rocks, but showed no preference for the size of logs. They also liked the cover objects with mosses growing on them. As for substrates, soil and plant debris were used most frequently. Salamanders were found negatively associated with live plant roots. Plant roots growing profusely under the cover objects are difficult for the salamanders to pass. The Alishan salamander preferred substrates with neutral substrate pH (6.2-7.0), high substrate moisture (70%-90%), and moderate substrate hardness (10-15). These results show that when information on microhabitat availability is taken into consideration, the real microhabitat preference of the salamanders does not agree with the descriptive results. We suggest that a quantitative approach should be taken for a habitat preference study, and that this information will be very useful for habitat restoration.
Kranner, I. and C. E. Seal. (2013) Salt stress, signalling and redox control in seeds Functional Plant Biology 40: 848-859. 10.1071/fp13017Abiotic stresses, including salt stress, can impair electron transport chains, thereby increasing the production of reactive oxygen species (ROS). An excess of ROS can damage macromolecular and cellular structure, but ROS are also key components of signalling networks, through which they regulate developmental processes. Surprisingly little is known about the effects of salt stress upon seeds given their pivotal role in plant reproduction and dispersal. This review provides information on tolerance mechanisms and redox control in relation to seed metabolism and performance. First, the effects of salt stress throughout the seed life cycle are discussed, comprising salt effects on the mother plant and its implications on seed development, salt uptake upon seed imbibition and effects on seed germination. Then, responses to elevated salt concentrations are discussed according to a recently proposed triphasic seed stress model comprising the phases alarm, resistance and exhaustion. Implications of redox control in seeds on the physiological, biochemical and molecular level are considered and the review concludes with a perspective on future research in relation to salt stress and seed biology.
Koyro, H.-W., C. Zoerb, et al. (2013) The effect of hyper-osmotic salinity on protein pattern and enzyme activities of halophytes Functional Plant Biology 40: 787-804. 10.1071/fp12387Studies of the convergence of the expression of enzymes and the physiology of salt resistance are rare, and give the general impression of a jigsaw puzzle with many missing pieces. To date, only minor responses of plasma membrane and tonoplast proteins of halophytes have been reported. Mostly, subunits of the catalytic portions of ATPases were found to change. In succulent plants such as Salicornia europea the abundance of V-type ATPase subunits has been correlated with growth performance. This stresses the physiological strategy to sequester incoming salt into vacuoles, which may also benefit osmotic regulation and further promote growth. A considerable amount of information is available on the responses of proteins involved in photosynthesis and detoxification of reactive oxygen species (ROS) under saline conditions. Two aspects deserve special attention: (i) salt responsive multiple spot patterns of individual proteins (due to protein modification, phosphorylation, for instance); and (ii) correlations between salt-mediated protein abundance and plant performance. Relevant observations underline that there exists a tightly knit metabolic network underlying physiological observations. Although the exact functioning of control and signalling sequences remains elusive, another aspect becomes very obvious from the publications analysed: stress responses of halophytes are multi-variant and include not only an increase in abundance of enzymes, but also of chaperones and proteins controlling organisation of the cytoplasm.
Kosova, K., P. Vitamvas, et al. (2013) Plant proteome responses to salinity stress - comparison of glycophytes and halophytes Functional Plant Biology 40: 775-786. 10.1071/fp12375The review discusses impacts of salinity on proteome composition in both salinity-sensitive (glycophytic) and salinity-tolerant (halophytic) plants. Salinity response with respect to proteome changes is compared in glycophytes and halophytes with a special focus on specific strategies employed by halophytes to cope with high (above 200 mM NaCl) salt concentrations. The results of comparative proteomic studies aimed at determination of the differences in salinity response between related plant species with contrasting salinity tolerance (Arabidopsis thaliana vs Thellungiella salsuginea, common wheat vs its hybrid, rice vs Porteresia coarctata) are analysed. The comparative studies have revealed that salt-tolerant plants display an enhanced constitutive expression of several salt-responsive genes and fewer salinity-related disturbances in energy metabolism with respect to the salt-sensitive plants. In conclusion, recent results of comparative proteomic studies are summarised and possible ways of utilisation of the obtained results for an improvement of plant (crop) salt tolerance are discussed.
Kosova, K., I. T. Prasil, et al. (2013) Protein Contribution to Plant Salinity Response and Tolerance Acquisition International Journal of Molecular Sciences 14: 6757-6789. 10.3390/ijms14046757The review is focused on plant proteome response to salinity with respect to physiological aspects of plant salt stress response. The attention is paid to both osmotic and ionic effects of salinity stress on plants with respect to several protein functional groups. Therefore, the role of individual proteins involved in signalling, changes in gene expression, protein biosynthesis and degradation and the resulting changes in protein relative abundance in proteins involved in energy metabolism, redox metabolism, stress- and defence-related proteins, osmolyte metabolism, phytohormone, lipid and secondary metabolism, mechanical stress-related proteins as well as protein posttranslational modifications are discussed. Differences between salt-sensitive (glycophytes) and salt-tolerant (halophytes) plants are analysed with respect to differential salinity tolerance. In conclusion, contribution of proteomic studies to understanding plant salinity tolerance is summarised and discussed.
Koch, M. A. and D. A. German. (2013) Taxonomy and systematics are key to biological information: Arabidopsis, Eutrema (Thellungiella), Noccaea and Schrenkiella (Brassicaceae) as examples Frontiers in Plant Science 4: 10.3389/fpls.2013.00267Taxonomy and systematics provide the names and evolutionary framework for any biological study. Without these names there is no access to a biological context of the evolutionary processes which gave rise to a given taxon: close relatives and sister species (hybridization), more distantly related taxa (ancestral states), for example. This is not only true for the single species a research project is focusing on, but also for its relatives, which might be selected for comparative approaches and future research. Nevertheless, taxonomical and systematic knowledge is rarely fully explored and considered across biological disciplines. One would expect the situation to be more developed with model organisms such as Noccaea, Arabidopsis, Schrenkiella and Eutrema (Thellungiella). However, we show the reverse. Using Arabidopsis hallen and Noccaea caerulescens, two model species among metal accumulating taxa, we summarize and reflect past taxonomy and systematics of Arabidopsis and Noccaea and provide a modern synthesis of taxonomic, systematic and evolutionary perspectives. The same is presented for several species of Eutrema s. I. and Schrenkiella recently appeared as models for studying stress tolerance in plants and widely known under the name Thellungiella.
Kazachkova, Y., A. Batushansky, et al. (2013) Growth Platform-Dependent and -Independent Phenotypic and Metabolic Responses of Arabidopsis and Its Halophytic Relative, Eutrema salsugineum, to Salt Stress Plant Physiology 162: 1583-1598. 10.1104/pp.113.217844Comparative studies of the stress-tolerant Arabidopsis (Arabidopsis thaliana) halophytic relative, Eutrema salsugineum, have proven a fruitful approach to understanding natural stress tolerance. Here, we performed comparative phenotyping of Arabidopsis and E. salsugineum vegetative development under control and salt-stress conditions, and then compared the metabolic responses of the two species on different growth platforms in a defined leaf developmental stage. Our results reveal both growth platform-dependent and -independent phenotypes and metabolic responses. Leaf emergence was affected in a similar way in both species grown in vitro but the effects observed in Arabidopsis occurred at higher salt concentrations in E. salsugineum. No differences in leaf emergence were observed on soil. A new effect of a salt-mediated reduction in E. salsugineum leaf area was unmasked. On soil, leaf area reduction in E. salsugineum was mainly due to a fall in cell number, whereas both cell number and cell size contributed to the decrease in Arabidopsis leaf area. Common growth platform-independent leaf metabolic signatures such as high raffinose and malate, and low fumarate contents that could reflect core stress tolerance mechanisms, as well as growth platform-dependent metabolic responses were identified. In particular, the in vitro growth platform led to repression of accumulation of many metabolites including sugars, sugar phosphates, and amino acids in E. salsugineum compared with the soil system where these same metabolites accumulated to higher levels in E. salsugineum than in Arabidopsis. The observation that E. salsugineum maintains salt tolerance despite growth platform-specific phenotypes and metabolic responses suggests a considerable degree of phenotypic and metabolic adaptive plasticity in this extremophile.
Joint Genome, I. (2013) Eutrema salsugineum Genome sequencing European Nucleotide ArchiveGenome of Eutrema salsugineum has been sequenced to 8x coverage by JGI. It contains 26,531 protein-coding genes and 51.4% of its genome is composed of repetitive sequences that mostly reside in pericentromeric regions.
Jgi. (2013) A halophytic relative of Arabidopsis European Nucleotide ArchiveThe build-up of salt in agricultural soils is a widespread problem that limits the growth and yield of important crop species worldwide. With few exceptions, crop plants are glycophytes, unable to adapt to the ionic, osmotic, and oxidative stresses induced by elevated levels of salt in the soil. Halophytes are plants that are capable of maintaining growth in extremely saline environments. Sequencing of Eutrema halophilum (Thellungiella halophila), a halophytic relative of both the genetic model Arabidopsis thaliana (Arabidopsis) and agriculturally important members of the genus Brassica (e.g., Oilseed Rape) will be critical for understanding the molecular mechanisms underlying halophyte success during growth in salt and discovery of the associated determinants. Achieving these goals will be an essential part of strategies to engineer and breed more salt-tolerant crop plants.
Jaarsma, R., R. S. M. de Vries, et al. (2013) Effect of Salt Stress on Growth, Na+ Accumulation and Proline Metabolism in Potato (Solanum tuberosum) Cultivars Plos One 8: e60183 10.1371/journal.pone.0060183Potato (Solanum tuberosum) is a major crop world-wide and the productivity of currently used cultivars is strongly reduced at high soil salt levels. We compared the response of six potato cultivars to increased root NaCl concentrations. Cuttings were grown hydroponically and treated with 0 mM, 60 mM and 180 mM NaCl for one week. Growth reduction on salt was strongest for the cultivars Mozart and Mona Lisa with a severe senescence response at 180 mM NaCl and Mozart barely survived the treatment. The cultivars Desiree and Russett Burbank were more tolerant showing no senescence after salt treatment. A clear difference in Na+ homeostasis was observed between sensitive and tolerant cultivars. The salt sensitive cultivar Mozart combined low Na+ levels in root and stem with the highest leaf Na+ concentration of all cultivars, resulting in a high Na+ shoot distribution index (SDI) for Mozart as compared to Desiree. Overall, a positive correlation between salt tolerance and stem Na+ accumulation was found and the SDI for Na+ points to a role of stem Na+ accumulation in tolerance. In stem tissue, Mozart accumulated more H2O2 and less proline compared to the tolerant cultivars. Analysis of the expression of proline biosynthesis genes in Mozart and Desiree showed a clear reduction in proline dehydrogenase (PDH) expression in both cultivars and an increase in pyrroline-5-carboxylate synthetase 1 (P5CS1) gene expression in Desiree, but not in Mozart. Taken together, current day commercial cultivars show promising differences in salt tolerance and the results suggest that mechanisms of tolerance reside in the capacity of Na+ accumulation in stem tissue, resulting in reduced Na+ transport to the leaves.
Hughes, S. L., V. Schart, et al. (2013) The Importance of Size and Disorder in the Cryoprotective Effects of Dehydrins Plant Physiology 163: 1376-1386. 10.1104/pp.113.226803Dehydrins protect plant proteins and membranes from damage during drought and cold. Vitis riparia K-2 is a 48-residue protein that can protect lactate dehydrogenase from freeze-thaw damage by preventing the aggregation and denaturation of the enzyme. To further elucidate its mechanism, we used a series of V. riparia K-2 concatemers (K-4, K-6, K-8, and K-10) and natural dehydrins (V. riparia YSK2, 60 kilodalton peach dehydrin [PCA60], barley dehydrin5 [Dhn5], Thellungiella salsuginea dehydrin2 [TsDHN-2], and Opuntia streptacantha dehydrin1 [OpsDHN-1]) to test the effect of the number of K-segments and dehydrin size on their ability to protect lactate dehydrogenase from freeze-thaw damage. The results show that the larger the hydrodynamic radius of the dehydrin, the more effective the cryoprotection. A similar trend is observed with polyethylene glycol, which would suggest that the protection is simply a nonspecific volume exclusion effect that can be manifested by any protein. However, structured proteins of a similar range of sizes did not show the same pattern and level of cryoprotection. Our results suggest that with respect to enzyme protection, dehydrins function primarily as molecular shields and that their intrinsic disorder is required for them to be an effective cryoprotectant. Lastly, we show that the cryoprotection by a dehydrin is not due to any antifreeze protein-like activity, as has been reported previously.
Huertas, R., L. Rubio, et al. (2013) The K+/H+ antiporter LeNHX2 increases salt tolerance by improving K+ homeostasis in transgenic tomato Plant Cell and Environment 36: 2135-2149. 10.1111/pce.12109The endosomal LeNHX2 ion transporter exchanges H+ with K+ and, to lesser extent, Na+. Here, we investigated the response to NaCl supply and K+ deprivation in transgenic tomato (Solanum lycopersicumL.) overexpressing LeNHX2 and show that transformed tomato plants grew better in saline conditions than untransformed controls, whereas in the absence of K+ the opposite was found. Analysis of mineral composition showed a higher K+ content in roots, shoots and xylem sap of transgenic plants and no differences in Na+ content between transgenic and untransformed plants grown either in the presence or the absence of 120mm NaCl. Transgenic plants showed higher Na+/H+ and, above all, K+/H+ transport activity in root intracellular membrane vesicles. Under K+ limiting conditions, transgenic plants enhanced root expression of the high-affinity K+ uptake system HAK5 compared to untransformed controls. Furthermore, tomato overexpressing LeNHX2 showed twofold higher K+ depletion rates and half cytosolic K+ activity than untransformed controls. Under NaCl stress, transgenic plants showed higher uptake velocity for K+ and lower cytosolic K+ activity than untransformed plants. These results indicate the fundamental role of K+ homeostasis in the better performance of LeNHX2 overexpressing tomato under NaCl stress.
Huchzermeyer, B. and T. Flowers. (2013) Putting halophytes to work - genetics, biochemistry and physiology Functional Plant Biology 40: V-VIII. 10.1071/FPv40n9_FOHalophytes are a small group of plants able to tolerate saline soils whose salt concentrations can reach those found in ocean waters and beyond. Since most plants, including many of our crops, are unable to survive salt concentrations one sixth those in seawater (about 80 mM NaCl), the tolerance of halophytes to salt has academic and economic importance. In 2009 the COST Action Putting halophytes to work - from genes to ecosystems was established and it was from contributions to a conference held at the Leibniz University, Hannover, Germany, in 2012 that this Special Issue has been produced. The 17 contributions cover the fundamentals of salt tolerance and aspects of the biochemistry and physiology of tolerance in the context of advancing the development of salt-tolerant crops.
Hofmann, N. R. (2013) Reconstruction of the Brassica rapa Ancestral Genome Plant Cell 25: 1484-1484. 10.1105/tpc.113.250511Arabidopsis thaliana is not particularly stress tolerant and may lack protective mechanisms required to survive extreme environmental conditions. Thellungiella salsuginea has therefore attracted increasing interest as an alternative plant model species that possesses high tolerance of various abiotic stresses. While the T. salsuginea genome has recently been sequenced, its annotation is still far from complete and, due to the low number of ESTs available, evidence for actual transcriptional activity is lacking for most genes. ESTs were generated from a non-normalized and a normalized library synthesized from RNA pooled from plant samples from different developmental stages and grown under abiotic stress conditions. The ESTs of Thellungiella was sequenced by 454 pyrosequencing method. More than 1 million sequence reads were assembled into 42,810 unigenes, approximately 50% of which could be functionally annotated. From this sequence information, we constructed a 44k Agilent oligonucleotide microarray. A comparison of same-species and cross-species hybridization results showed the superior performance of the newly designed array for Thellungiella samples. In addition, the array was validated in a cold acclimation experiment that used the appropriately adapted MapMan software for analysis and visualization.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033666: 6W T. salsuginea rosette leaves 2W cold acclimated replicate 2 Gene Expression OmnibusGene expression for 2 weeks cold acclimated Col-0 rosette leaves at 4 A°C. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033667: 6W T. salsuginea rosette leaves non acclimated replicate 2 Gene Expression OmnibusGene expression for non acclimated Col-0 rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033665: 6W T. salsuginea rosette leaves non acclimated replicate 1 Gene Expression OmnibusGene expression for non acclimated Col-0 rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033664: 6W T. salsuginea rosette leaves 2W cold acclimated replicate 1 Gene Expression OmnibusGene expression for 2 weeks cold acclimated Col-0 rosette leaves at 4 A°C. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033670: 8W T. salsuginea rosette leaves 2W cold acclimated replicate 1 Gene Expression OmnibusGene expression for 2 weeks cold acclimated Yukon rosette leaves at 4 A°C. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033669: 6W T. salsuginea rosette leaves non acclimated replicate 3 Gene Expression OmnibusGene expression for non acclimated Col-0 rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033668: 6W T. salsuginea rosette leaves 2W cold acclimated replicate 3 Gene Expression OmnibusGene expression for 2 weeks cold acclimated Col-0 rosette leaves at 4 A°C. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033672: 8W T. salsuginea rosette leaves 2W cold acclimated replicate 2 Gene Expression OmnibusGene expression for 2 weeks cold acclimated Yukon rosette leaves at 4 A°C. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033671: 8W T. salsuginea rosette leaves non acclimated replicate 1 Gene Expression OmnibusGene expression for non acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033674: 8W T. salsuginea rosette leaves 2W cold acclimated replicate 3 Gene Expression OmnibusGene expression for 2 weeks cold acclimated Yukon rosette leaves at 4 A°C. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033673: 8W T. salsuginea rosette leaves non acclimated replicate 2 Gene Expression OmnibusGene expression for non acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Hincha, D. K., Y. P. Lee, et al. (2013) GSM1033675: 8W T. salsuginea rosette leaves non acclimated replicate 3 Gene Expression OmnibusGene expression for non acclimated Yukon rosette leaves. RNA was hybridized on custom made Agilent Thellungiella salsuginea expression array The scanned images were analyzed with Feature Extraction Software 10.5.1.1 (Agilent) using default parameters (protocol GE1_105_Dec08 and Grid: 031554_D_F_20101207) to obtain background subtracted and spatially detrended Processed Signal intensities. Features flagged in Feature Extraction as Feature Non-uniform outliers were excluded.
Higashi, Y., N. Ohama, et al. (2013) HsfA1d, a Protein Identified via FOX Hunting Using Thellungiella salsuginea cDNAs Improves Heat Tolerance by Regulating Heat-Stress-Responsive Gene Expression Molecular Plant 6: 411-422. 10.1093/mp/sst024Thellungiella salsuginea, a species closely related to Arabidopsis, is tolerant not only to high salt levels, but also to high temperature. We identified T. salsuginea HsfA1d (TsHsfA1d) as a gene that can confer marked heat tolerance on Arabidopsis via FOX hunting.Thellungiella salsuginea (formerly T. halophila), a species closely related to Arabidopsis (Arabidopsis thaliana), is tolerant not only to high salt levels, but also to chilling, freezing, and ozone. Here, we report that T. salsuginea also shows greater heat tolerance than Arabidopsis. We identified T. salsuginea HsfA1d (TsHsfA1d) as a gene that can confer marked heat tolerance on Arabidopsis. TsHsfA1d was identified via Full-length cDNA Over-eXpressing gene (FOX) hunting from among a collection of heat-stress-related T. salsuginea cDNAs. Transgenic Arabidopsis overexpressing TsHsfA1d showed constitutive up-regulation of many genes in the Arabidopsis AtHsfA1 regulon under normal growth temperature. In Arabidopsis mesophyll protoplasts, TsHsfA1d was localized in both the nucleus and the cytoplasm. TsHsfA1d also interacted with AtHSP90, which negatively regulates AtHsfA1s by forming HsfA1HSP90 complexes in the cytoplasm. It is likely that the partial nuclear localization of TsHsfA1d induced the expression of the AtHsfA1d regulon in the transgenic plants at normal temperature. We also discovered that transgenic Arabidopsis plants overexpressing AtHsfA1d were more heat-tolerant than wild-type plants and up-regulated the expression of the HsfA1d regulon, as was observed in TsHsfA1d-overexpressing plants. We propose that the products of both TsHsfA1d and AtHsfA1d function as positive regulators of Arabidopsis heat-stress response and would be useful for the improvement of heat-stress tolerance in other plants.
Goyal, E., R. S. Singh, et al. (2013) Isolation and functional characterization of Salt overly sensitive 1 (SOS1) gene promoter from Salicornia brachiata Biologia Plantarum 57: 465-473. 10.1007/s10535-013-0309-1Soil salinity is a major abiotic stress and salt overly sensitive (SOS) pathway plays an important role in imparting tolerance to salinity by reinstating cellular ionic equilibrium. Salt overly sensitive 1 (SOS1) gene of SOS pathway has been implicated in increasing salt tolerance in plants. In this study, a 734 bp fragment of SOS1 promoter (SbUSOS1) was isolated from a halophyte Salicornia brachiata Roxb. In silico analysis of SbUSOS1 predicted several cis-acting regulatory elements such as DOF motif, GT elements, ABRE-like sequence, and root specific motifs. Functional validation of SbUSOS1 into tobacco stems and leaves using the GUS reporter gene showed that this promoter is induced by salt stress (250 mM NaCl) but not by ABA (500 mu M) and cold (4 A degrees C) stresses. This study indicated that SbUSOS1 was functional with predicted cis-acting elements that could be responsible for its salt-inducible nature. It can be used for the development of salt stress tolerant transgenic plants.
Golldack, D. (2013). Cellular Mechanisms of Environmental Adaptation: Learning from Non-Arabidopsis Model Species. in Progress in Botany 74. U. Luttge, W. Beyschlag, D. Francis and J. Cushman (eds). 74: 137-151. Gamboa, M. C., F. Baltierra, et al. (2013) Drought and salt tolerance enhancement of transgenic Arabidopsis by overexpression of the vacuolar pyrophosphatase 1 (EVP1) gene from Eucalyptus globulus Plant Physiology and Biochemistry 73: 99-105. 10.1016/j.plaphy.2013.09.005Vacuolar solute accumulation has been shown to be a mechanism by which plants are capable of increasing drought and salt tolerance. The exposure of plants to NaCl induces H+ transport into the vacuole by specialized pumps. One of them corresponds to the vacuolar H+-pyrophosphatase, which generates a H+ gradient across the vacuolar membrane. In our laboratory we isolated the first cDNA sequence of a vacuolar pyrophosphatase type I (EVP1) from Eucalyptus globulus. Using real-time PCR we confirmed that EVP1 participates in Eucalyptus plants' response to drought and salt stress through an ABA independent pathway. Additionally, the overexpression of EVP1 in transgenic Arabidopsis resulted in an enhancement of drought and salt tolerance. Interestingly we established that the transgenic plants had a higher number of root hairs, which may have a positive effect on the plant's response to drought and salt stress. These results suggest that EVP1 plays an active role in abiotic stress tolerance in E. globulus, and that it may be potentially used to enhance drought and stress tolerance of plants. (C) 2013 Elsevier Masson SAS. All rights reserved.
Debez, A., K. Ben Rejeb, et al. (2013) Ecophysiological and genomic analysis of salt tolerance of Cakile maritima Environmental and Experimental Botany 92: 64-72. 10.1016/j.envexpbot.2012.12.002Arabidopsis thaliana L. (Brassicaceae) and its close relative Thellungiella salsuginea (Pallas) O.E. Schulz have been widely used as genetic models by researchers in their quest of understanding salt tolerance mechanisms in plants. Despite the fact that significant knowledge has been gained, both of these plants present some limitations mainly in relation to their response to salinity. Indeed, Arabidopsis is a glycophyte, whereas Thellungiella is a facultative halophyte. Among the Brassicaceae, Cakile maritima Scop. is an annual succulent obligate halophyte with a small size genome (1C=719 Mb) and short life cycle. With these attributes, C. maritima presents a potential as a genetic model system to address salt stress adaptations at the molecular level in the quest to identify salt stress tolerance mechanisms. Beside their potential as promising model species, halophytes might also be valued for their potential as cash crops themselves. The present paper aims to highlight the main results gained on C. maritima using multidisciplinary approaches in complement to those obtained on plant model species of the Brassicaceae family. (C) 2013 Elsevier B.V. All rights reserved.
de Vos, A. C., R. Broekman, et al. (2013) Developing and testing new halophyte crops: A case study of salt tolerance of two species of the Brassicaceae, Diplotaxis tenuifolia and Cochlearia officinalis Environmental and Experimental Botany 92: 154-164. 10.1016/j.envexpbot.2012.08.003Diplotaxis tenuifolia (L.) and Cochlearia officinalis (L.) were presumed to be salt tolerant with potential as vegetable halophyte crops. The response to increasing salinity was analysed by means of the relative growth rate (RGR) and its components and mineral composition. No growth reductions occurred up to 100 mM NaCl for D. tenuifolia, whereas C officinalis showed a 37% decrease in total dry weight at this concentration of NaCl, corresponding to a 9% decrease in RGR. The RGR at higher salinity levels (>= 200 mM NaCl) showed reductions around 20% for both species, largely due to changes of leaf morphology (decrease in specific leaf area, increase in leaf succulence) rather than toxic leaf Na+ concentrations. In comparison to seven other species of the Brassicaceae, including salt sensitive and highly salt tolerant species, both D. tenuifolia and C. officinalis showed an intermediate response to increasing salinity. Both species were able to survive the highest salinity treatment (300 mM NaCl for D. tenuifolia and 400 mM NaCl for C. officinalis) and can be classified as salt tolerant with potential as vegetable crops for saline agriculture. Since D. tenuifolia is already in use as an agricultural crop, little constraints are foreseen for its introduction as a saline crop. Before C. officinalis can be used as a saline crop, agricultural practices and marketing still have to be addressed. A hands-on tool is provided for this process, which combines science, agronomy, the social system, and the business sector. (C) 2012 Elsevier B.V. All rights reserved.
Cheeseman, J. M. (2013) The integration of activity in saline environments: problems and perspectives Functional Plant Biology 40: 759-774. 10.1071/fp12285The successful integration of activity in saline environments requires flexibility of responses at all levels, from genes to life cycles. Because plants are complex systems, there is no 'best' or 'optimal' solution and with respect to salt, glycophytes and halophytes are only the ends of a continuum of responses and possibilities. In this review, I briefly examine seven major aspects of plant function and their responses to salinity including transporters, secondary stresses, carbon acquisition and allocation, water and transpiration, growth and development, reproduction, and cytosolic function and 'integrity'. I conclude that new approaches are needed to move towards understanding either organismal integration or 'salt tolerance', especially cessation of protocols dependent on sudden, often lethal, shock treatments and the embracing of systems level resources. Some of the tools needed to understand the integration of activity and even 'salt stress' are already in hand, such as those for whole-transcriptome analysis. Others, ranging from discovery studies of the nature of the cytosol to expanded tool kits for proteomic, metabolomic and epigenomic studies, still need to be further developed. After resurrecting the distinction between applied stress and the resultant strain and noting that with respect to salinity, the strain is manifest in changes at all -omic levels, I conclude that it should be possible to model and quantify stress responses.
Champigny, M. J., W. W. L. Sung, et al. (2013) RNA-Seq effectively monitors gene expression in Eutrema salsugineum plants growing in an extreme natural habitat and in controlled growth cabinet conditions Bmc Genomics 14: 578 10.1186/1471-2164-14-578Background: The investigation of extremophile plant species growing in their natural environment offers certain advantages, chiefly that plants adapted to severe habitats have a repertoire of stress tolerance genes that are regulated to maximize plant performance under physiologically challenging conditions. Accordingly, transcriptome sequencing offers a powerful approach to address questions concerning the influence of natural habitat on the physiology of an organism. We used RNA sequencing of Eutrema salsugineum, an extremophile relative of Arabidopsis thaliana, to investigate the extent to which genetic variation and controlled versus natural environments contribute to differences between transcript profiles. Results: Using 10 million cDNA reads, we compared transcriptomes from two natural Eutrema accessions (originating from Yukon Territory, Canada and Shandong Province, China) grown under controlled conditions in cabinets and those from Yukon plants collected at a Yukon field site. We assessed the genetic heterogeneity between individuals using single-nucleotide polymorphisms (SNPs) and the expression patterns of 27,016 genes. Over 39,000 SNPs distinguish the Yukon from the Shandong accessions but only 4,475 SNPs differentiated transcriptomes of Yukon field plants from an inbred Yukon line. We found 2,989 genes that were differentially expressed between the three sample groups and multivariate statistical analyses showed that transcriptomes of individual plants from a Yukon field site were as reproducible as those from inbred plants grown under controlled conditions. Predicted functions based upon gene ontology classifications show that the transcriptomes of field plants were enriched by the differential expression of light- and stress-related genes, an observation consistent with the habitat where the plants were found. Conclusion: Our expectation that comparative RNA-Seq analysis of transcriptomes from plants originating in natural habitats would be confounded by uncontrolled genetic and environmental factors was not borne out. Moreover, the transcriptome data shows little genetic variation between laboratory Yukon Eutrema plants and those found at a field site. Transcriptomes were reproducible and biological associations meaningful whether plants were grown in cabinets or found in the field. Thus RNA-Seq is a valuable approach to study native plants in natural environments and this technology can be exploited to discover new gene targets for improved crop performance under adverse conditions.
Buhmann, A. and J. Papenbrock. (2013) An economic point of view of secondary compounds in halophytes Functional Plant Biology 40: 952-967. 10.1071/fp12342Salt tolerance of halophytes relies on several strategies, among them, the production of species-specific secondary metabolites. Chemically, a broad variety of secondary compounds of economic interest is present in halophytes. Several of these secondary compounds are restricted to halophytic species or are found in higher concentrations than in glycophytes. For their exploitation, optimal plant cultivation conditions and extraction, fractionation and isolation processes need to be identified. On the one hand, the function of single compounds can be more precisely determined and controlled; on the other hand the mixture of compounds in crude extracts might have synergistic effects. Also, different plant organs and plants in different developmental stages contain highly varying amounts and compositions of secondary compounds. Secondary compounds from halophytes have potential uses in various fields such as pharmacognosy, functional foods, nutraceuticals and technical implementations. Many of the potential applications are still in the research and development phase; some products are already on the market. We describe and evaluate the economic potential of several halophytes such as Salicornia spp. and Crithmum maritimum containing valuable compounds used in different applications.
Bressan, R. A., H. C. Park, et al. (2013) Biotechnology for mechanisms that counteract salt stress in extremophile species: a genome-based view Plant Biotechnology Reports 7: 27-37. 10.1007/s11816-012-0249-9Molecular genetics has confirmed older research and generated new insights into the ways how plants deal with adverse conditions. This body of research is now being used to interpret stress behavior of plants in new ways, and to add results from most recent genomics-based studies. The new knowledge now includes genome sequences of species that show extreme abiotic stress tolerances, which enables new strategies for applications through either molecular breeding or transgenic engineering. We will highlight some physiological features of the extremophile lifestyle, outline emerging features about halophytism based on genomics, and discuss conclusions about underlying mechanisms.
Biology, M. U. (2013) RNA-Seq effectively monitors gene expression in Eutrema salsuginuem plants growing in an extreme natural habitat and in controlled growth cabinet conditions European Nucleotide ArchiveBackground: The investigation of extremophile plant species growing in their natural environment offers certain advantages, chiefly that plants adapted to severe habitats have a repertoire of stress tolerance genes that are regulated to maximize plant performance under physiologically challenging conditions. Accordingly, transcriptome sequencing offers a powerful approach to address questions concerning the influence of natural habitat on the physiology of an organism. We used RNA sequencing of Eutrema salsuginuem, an extremophile relative of Arabidopsis thaliana, to investigate the extent to which genetic variation and controlled versus natural environments contribute to differences between transcript profiles. Results: Using 10 million cDNA reads, we compared transcriptomes from two natural Eutrema accessions (originating from Yukon Territory, Canada and Shandong Province, China) grown under controlled conditions in cabinets and those from Yukon plants collected at a Yukon field site. We assessed the genetic heterogeneity between individuals using single-nucleotide polymorphisms (SNPs) and the expression patterns of 27,016 genes. Over 39,000 SNPs distinguish the Yukon from the Shandong accessions but only 4,475 SNPs differentiated transcriptomes of Yukon field plants from an inbred Yukon line. We found 2,898 genes that were differentially expressed between the three sample groups and multivariate statistical analyses showed that transcriptomes of individual plants from a Yukon field site were as reproducible as those from inbred plants grown under controlled conditions. Predicted functions based upon gene ontology classifications show that the transcriptomes of field plants were enriched by the differential expression of light- and stress-related genes, an observation consistent with the habitat where the plants were found. Conclusion: Our expectation that comparative RNA-Seq analysis of transcriptomes from plants originating in natural habitats would be confounded by uncontrolled genetic and environmental factors was not borne out. Moreover, the transcriptome data shows little genetic variation between laboratory Yukon Eutrema plants and those found at a field site. Transcriptomes were reproducible and biological associations meaningful whether plants were grown in cabinets or found in the field. Thus RNA-Seq is a valuable approach to study native plants in natural environments and this technology can be exploited to discover new gene targets for improved crop performance under adverse conditions. Funding Acknowledgement: This work was sponsored by an Ontario Research Fund-Research Excellence award 03-043 to EAW and RKC with support from by Viterra Inc. and Sigma-Aldrich. Overall design: The set of nine transcriptomes is 3 repeats of 3 different 'Treatments'. Each transcriptome was obtained from a different plant.
Benina, M., T. Obata, et al. (2013) Comparative metabolic profiling of Haberlea rhodopensis, Thellungiella halophyla, and Arabidopsis thaliana exposed to low temperature Frontiers in Plant Science 4: 499 10.3389/fpls.2013.00499Haberlea rhodopensis is a resurrection species with extreme resistance to drought stress and desiccation but also with ability to withstand low temperatures and freezing stress. In order to identify biochemical strategies which contribute to Haberlea's remarkable stress tolerance, the metabolic reconfiguration of H. rhodopensis during low temperature (4 degrees C) and subsequent return to optimal temperatures (21 degrees C) was investigated and compared with that of the stress tolerant Thellungiella halophyla and the stress sensitive Arabidopsis thaliana. Metabolic analysis by GC-MS revealed intrinsic differences in the metabolite levels of the three species even at 21 degrees C. H. rhodopensis had significantly more raffinose, melibiose, trehalose, rhamnose, myo-inositol, sorbitol, galactinol, erythronate, threonate, 2-oxoglutarate, citrate, and glycerol than the other two species. A. thaliana had the highest levels of putrescine and fumarate, while T halophila had much higher levels of several amino acids, including alanine, asparagine, beta-alanine, histidine, isoleucine, phenylalanine, serine, threonine, and valine. In addition, the three species responded differently to the low temperature treatment and the subsequent recovery, especially with regard to the sugar metabolism. Chilling induced accumulation of maltose in H. rhodopensis and raffinose in A. thaliana but the raffinose levels in low temperature exposed Arabidopsis were still much lower than these in unstressed Haberlea. While all species accumulated sucrose during chilling, that accumulation was transient in H. rhodopensis and A. thaliana but sustained in T halophila after the return to optimal temperature. Thus, Haberlea's metabolome appeared primed for chilling stress but the low temperature acclimation induced additional stress-protective mechanisms. A diverse array of sugars, organic acids, and polyols constitute Haberlea's main metabolic defence mechanisms against chilling, while accumulation of amino acids and amino acid derivatives contribute to the low temperature acclimation in Arabidopsis and Thellungiella. Collectively, these results show inherent differences in the metabolomes under the ambient temperature and the strategies to respond to low temperature in the three species.
Bartels, D. and C. Dinakar. (2013) Balancing salinity stress responses in halophytes and non-halophytes: a comparison between Thellungiella and Arabidopsis thaliana Functional Plant Biology 40: 819-831. 10.1071/fp12299Salinity is one of the major abiotic stress factors that drastically reduces agricultural productivity. In natural environments salinity often occurs together with other stresses such as dehydration, light stress or high temperature. Plants cope with ionic stress, dehydration and osmotic stress caused by high salinity through a variety of mechanisms at different levels involving physiological, biochemical and molecular processes. Halophytic plants exist successfully in stressful saline environments, but most of the terrestrial plants including all crop plants are glycophytes with varying levels of salt tolerance. An array of physiological, structural and biochemical adaptations in halophytes make them suitable models to study the molecular mechanisms associated with salinity tolerance. Comparative analysis of plants that differ in their abilities to tolerate salinity will aid in better understanding the phenomenon of salinity tolerance. The halophyte Thellungiella salsuginea has been used as a model for studying plant salt tolerance. In this review, T. salsuginea and the glycophyte Arabidopsis thaliana are compared with regards to their biochemical, physiological and molecular responses to salinity. In addition recent developments are presented for improvement of salinity tolerance in glycophytic plants using genes from halophytes.
Arif, A., Y. Zafar, et al. (2013) Improved Growth, Drought Tolerance, and Ultrastructural Evidence of Increased Turgidity in Tobacco Plants Overexpressing Arabidopsis Vacuolar Pyrophosphatase (AVP1) Molecular Biotechnology 54: 379-392. 10.1007/s12033-012-9577-9An increasing volume of evidence indicating the mechanisms of drought tolerance of AVP1-overexpressing transgenic plants has been reported. In the present study, we are reporting the experiments conducted for the drought tolerance of AVP1 overexpressing plants and WT tobacco plants in three water regimes named as "fully watered," "less-watered," and "desiccated". Results suggest that AVP1 plants exhibited greater vigor and drought tolerance in quantitative terms i.e., increase in size and weight of shoots and capsules. AVP1 plants produced more seeds than WT across all three water regimes. The less-watered regime was found to produce the greatest contrast. AVP1 overexpression enhanced solute accumulation in vacuoles resulting in an increase in water retention and turgor of the cell. The ultrastructure study of AVP1 overexpressing cells and WT leaf cells revealed that AVP1 plants displayed more turgid and hyperosmotic cells than WT. Moreover, guard cells in the AVP1 plants exhibited thick cell walls, few vacuoles, and deep and close stomata, whereas WT plants showed larger vacuoles and relatively open stomata aperture with no significant difference in size and number of the cells per unit area.
Arasan, S. K. T., J.-I. Park, et al. (2013) Characterization and expression analysis of dirigent family genes related to stresses in Brassica Plant Physiology and Biochemistry 67: 144-153. 10.1016/j.plaphy.2013.02.030The dirigent (DIR) genes are playing a vital role in enhancing stress resistance in different crop plants. In this study, we collected 29 DIR like genes, two from a Brassica rapa cv. Osome full length cDNA library and 27 from the B. rapa database designated as B. rapa Dirigent (BrDIR) like genes. Sequence analysis and a comparison study of these genes confirmed that seven were dirigent and the remaining 22 were dirigent like genes. Expression analysis revealed an organ specific expression of these genes. BrDIR2 showed differential responses after Fusarium oxysporum f.sp. conglutinans infection in cabbage. Four Brassica oleracea dirigent like genes highly homologous to BrDIR2 also showed similar responses in cabbage plants infected with this fungus. Moreover, several BrDIR like genes showed significant responses after water, ABA and cold stress treatments in Chinese cabbage. Under water stress, most responsive genes showed the highest expression at 24 h, at which time the acid soluble lignin content of samples under the same stress condition were also highest, indicating a possible relationship between BrDIR like genes and lignin content. Taken together, our results indicate a protective role of BrDIR genes against biotic and abiotic stresses in Brassica. (C) 2013 Elsevier Masson SAS. All rights reserved.
An, H., X. Xu, et al. (2013) Callus induction and culture characteristics of suspension cells of Thellungiella halophila Journal of Henan Agricultural Sciences 42: 46-50.In order to establish a stable suspension cell line of Thellungiela halophila, petioles and leaves from T. halophila (Shandong ecotype) were used as explants to investigate the effect of different hormones and the concentration on callus induction, and then the effect of diluting ratio on the growth of suspension cells was discussed. The results showed that MS+6-BA+2,4-D and MS+6-BA+NAA both induced massive callus. The petioles had higher callus induction ratio than leaves, even up to 100%, and callus from leaves formed later than that from petioles. It was indicated that MS+6-BA+NAA could also help petioles and leaves to differentiate adventitious buds, with 57% petiole differentiation ratio. In the growth of suspension cells, it was found that the inoculation volume of 10.0 mL suspension cells into 50 mL liquid medium was advisable in the subculture experiment once a week.
Ali, A., H. Park, et al. (2013) Role of HKT1 in Thellungiella salsuginea, a model extremophile plant Plant Signaling and Behavior 8: e25196-e25196.Maintenance of the cytosolic Na+/K+ ratio under saline conditions is crucial for plants. HKT-type Na+ transporters play a key role in keeping low cytosolic Na+ concentrations thus retaining a low Na+/K+ ratio, that reduces Na+ toxicity and causing high salinity stress tolerance. Two HKT-type transporters, AtHKT1 from Arabidopsis and TsHKT1;2 from Thellungiella salsuginea, that share high DNA and protein sequence identities, are distinguished by fundamentally different ion selection and salinity stress behavior. On the level of transcription, TsHKT1;2 is dramatically induced upon salt stress, whereas AtHKT1 is downregulated. TsHKT1;2-RNAi lines show severe potassium deficiency and are also sensitive to high [Na+]. We have validated the ability of the TsHKT1;2 protein to act as an efficient K+ transporter in the presence of high [Na+] by expression in yeast cells. K+ specificity is based on amino acid differences in the pore of the transporter protein relative to AtHKT1.
Ali, A., H. Cheol Park, et al. (2013) Role of HKT1 in Thellungiella salsuginea, a model extremophile plant Plant signaling & behavior 8: 10.4161/psb.25196Maintenance of the cytosolic Na(+)/K(+) ratio under saline conditions is crucial for plants. HKT-type Na(+) transporters play a key role in keeping low cytosolic Na(+) concentrations thus retaining a low Na(+)/K(+) ratio, that reduces Na(+) toxicity and causing high salinity stress tolerance. Two HKT-type transporters, AtHKT1 from Arabidopsis and TsHKT1;2 from Thellungiella salsuginea, that share high DNA and protein sequence identities, are distinguished by fundamentally different ion selection and salinity stress behavior. On the level of transcription, TsHKT1;2 is dramatically induced upon salt stress, whereas AtHKT1 is downregulated. TsHKT1;2-RNAi lines show severe potassium deficiency and are also sensitive to high [Na(+)]. We have validated the ability of the TsHKT1;2 protein to act as an efficient K(+) transporter in the presence of high [Na(+)] by expression in yeast cells. K(+) specificity is based on amino acid differences in the pore of the transporter protein relative to AtHKT1.
Abreu, I. A., A. P. Farinha, et al. (2013) Coping with abiotic stress: Proteome changes for crop improvement Journal of Proteomics 93: 145-168. 10.1016/j.jprot.2013.07.014Plant breeders need new and more precise tools to accelerate breeding programs that address the increasing needs for food, feed, energy and raw materials, while facing a changing environment in which high salinity and drought have major impacts on crop losses worldwide. This review covers the achievements and bottlenecks in the identification and validation of proteins with relevance in abiotic stress tolerance, also mentioning the unexpected consequences of the stress in allergen expression. While addressing the key pathways regulating abiotic stress plant adaptation, comprehensive data is presented on the proteins confirmed as relevant to confer tolerance. Promising candidates still to be confirmed are also highlighted, as well as the specific protein families and protein modifications for which detection and characterization is still a challenge. This article is part of a Special Issue entitled: Translational Plant Proteomics. (C) 2013 Elsevier B.V. All rights reserved.
Zhou, C., J. S. Guo, et al. (2012) Molecular characterization of a novel AP2 transcription factor ThWIND1-L from Thellungiella halophila Plant Cell Tissue and Organ Culture 110: 423-433. 10.1007/s11240-012-0163-4Several AP2/ERF transcription factors are wound-induced regulators, which play key roles in controlling cell dedifferentiation. In this study, a novel AP2/ERF transcription factor, the WIND1-like gene (ThWIND1-L), was isolated and characterized from Thellungiella halophila. ThWIND1-L cDNA clone contained a full open reading frame (ORF) of 1,068 bp encoding 356 amino acids. The predicted amino acid sequence of ThWIND1-L cDNA shared remarkably high degree of identity with the Arabidopsis RAP2.4 (WIND1). The expression of ThWIND1-L rapidly responded to the wound signals, ectopic expression of ThWIND1-L in Arabidopsis plants promoted callus tissue formation without the presence of exogenous hormones. Furthermore, overexpression of ThWIND1-L influenced some primary transcription factors (TFs), which have been shown to be involved in cell dedifferentiation and shoot regeneration. These results indicated ThWIND1-L might be a wound-induced regulator, which played an important role in the control of cell dedifferentiation.
Zhang, Y. Y., Y. Li, et al. (2012) Ectopic expression of a LEA protein gene TsLEA1 from Thellungiella salsuginea confers salt-tolerance in yeast and Arabidopsis Molecular Biology Reports 39: 4627-4633. 10.1007/s11033-011-1254-8Thellungiella salsuginea is a valuable halophytic genetic model plant in the Brassicaceae family. Based on previous construction of a salt treated Thellungiella cDNA library carried by pGAD-GH shuttle vector which could directly express in Saccharomyces cerevisiae, a putative salt-tolerance gene TsLEA1 was identified by large-scale stress-tolerance screen in salt sensitive yeast strain G19. The longest 483 bp ORF of TsLEA1 cDNA coding a 160 amino acids protein with a predicted conserved pfam domain shared an 89% amino acid sequence similarity to Arabidopsis LEA group 4 proteins. The transcription level of TsLEA1 gene in T. salsuginea seedlings increased upon salt treatment and its transcript accumulated more in roots than in aerial parts. The ability of the TsLEA1 to facilitate salinity tolerance was analyzed in yeast and transgenic Arabidopsis. It was confirmed that TsLEA1 exhibits conserved salt tolerance in plant as well as in yeast. The results suggested that the TsLEA1 may participate in response to stresses in over expressed circumstance, protecting yeast and plant cells under stress conditions.
Zhang, Y.-M., Z.-H. Liu, et al. (2012) The vacuolar Na+-H+ antiport gene TaNHX2 confers salt tolerance on transgenic alfalfa (Medicago sativa) Functional Plant Biology 39: 708-716. 10.1071/fp12095TaNHX2, a vacuolar Na+-H+ antiport gene from wheat (Triticum aestivum L.), was transformed into alfalfa (Medicago sativa L.) via Agrobacterium-mediated transformation to evaluate the role of vacuolar energy providers in plant salt stress responses. PCR and Southern blotting analysis showed that the target gene was integrated into the Medicago genome. Reverse transcription-PCR indicated that gene TaNHX2 was expressed at the transcriptional level. The relative electrical conductivity in the T-2 transgenic plants was lower and the osmotic potential was higher compared to the wild-type plants under salt stress conditions. The tonoplast H+-ATPase, H+-pyrophosphatase (PPase) hydrolysis activities and ATP-dependent proton pump activities in transgenic plants were all higher than those of wild-type plants, and the enzyme activities could be induced by salt stress. The PPi-dependent proton pump activities decreased when NaCl concentrations increased from 100mM to 200mM, especially in transgenic plants. The vacuolar Na+-H+ antiport activities of transgenic plants were 2-3 times higher than those of the wild -type plants under 0mM and 100mM NaCl stress. Na+-H+ antiport activity was not detectable for wild-type plants under 200mM NaCl, but for transgenic plants, it was further increased with an increment in salt stress intensity. These results demonstrated that expression of the foreign TaNHX2 gene enhanced salt tolerance in transgenic alfalfa.
Yao, M., Y. Zeng, et al. (2012) Overexpression of the halophyte Kalidium foliatum H+-pyrophosphatase gene confers salt and drought tolerance in Arabidopsis thaliana Molecular Biology Reports 39: 7989-7996. 10.1007/s11033-012-1645-5According to sequences of H+-pyrophosphatase genes from GenBank, a new H+-pyrophosphatase gene (KfVP1) from the halophyte Kalidium foliatum, a very salt-tolerant shrub that is highly succulent, was obtained by using reverse transcription PCR and rapid amplification of cDNA ends methods. The obtained KfVP1 cDNA contained a 2295 bp ORF and a 242 bp 3'-untranslated region. It encoded 764 amino acids with a calculated molecular mass of 79.78 kDa. The deduced amino acid sequence showed high identity to those of H+-PPase of some Chenopodiaceae plant species. Semi-quantitative PCR results revealed that transcription of KfVP1 in K. foliatum was induced by NaCl, ABA and PEG stress. Transgenic lines of A. thaliana with 35S::KfVP1 were generated. Three transgenic lines grew more vigorous than the wild type (ecotype Col-0) under salt and drought stress. Moreover, the transgenic plants accumulated more Na+ in the leaves compared to wild type plants. These results demonstrated that KfVP1 from K. foliatum may be a functional tonoplast H+-pyrophosphatase in contributing to salt and drought tolerance.
Yadav, N. S., P. S. Shukla, et al. (2012) The SbSOS1 gene from the extreme halophyte Salicornia brachiata enhances Na+ loading in xylem and confers salt tolerance in transgenic tobacco Bmc Plant Biology 12: 188 10.1186/1471-2229-12-188Background: Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1) gene encodes a plasma membrane Na+/H+ antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. Results: The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC), chlorophyll, K+/Na+ ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT) plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS) and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na+ content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na+ content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na+ loading to xylem from root and leaf tissues. Transgenic lines also showed increased K+ and Ca2+ content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. Conclusions: Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na+ efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na+ content in different organs and also affect the other transporters activity indirectly. These results broaden the role of SbSOS1 in planta and suggest that this gene could be used to develop salt-tolerant transgenic crops.
Wu, H. J., Z. H. Zhang, et al. (2012) Insights into salt tolerance from the genome of Thellungiella salsuginea Proceedings of the National Academy of Sciences of the United States of America 109: 12219-12224. 10.1073/pnas.1209954109Thellungiella salsuginea, a close relative of Arabidopsis, represents an extremophile model for abiotic stress tolerance studies. We present the draft sequence of the T. salsuginea genome, assembled based on similar to 134-fold coverage to seven chromosomes with a coding capacity of at least 28,457 genes. This genome provides resources and evidence about the nature of defense mechanisms constituting the genetic basis underlying plant abiotic stress tolerance. Comparative genomics and experimental analyses identified genes related to cation transport, abscisic acid signaling, and wax production prominent in T. salsuginea as possible contributors to its success in stressful environments.
Wu, F., M. Yu, et al. (2012) Cloning and Functional Characterization of Three Superoxide Dismutases Genes from Halophyte Salicornia europaea and Thellungiella halophila Xibei Zhiwu Xuebao 32: 1957-1964.In order to study the halophyte salt-tolerance mechanism and compare the salt tolerance of superoxide dismutase (SOD) from different halophytes, we cloned the full-length cDNAs of manganese (Mn) and Cu/Zn SOD from Salicornia europaea by RACE method. Sequence analysis indicated that the S. europaea MnSOD gene (SeMSD) (GenBank accession number: JQ061158) comprised an open reading frame of 699 bp,encoding a polypeptide of 233 amino acids with a predicted molecular mass of 25.7 kD. Correspondingly, the Cu/ZnSOD gene (SeCSD, GenBank accession number: JQ061160) consisted of an open reading frame of 684 bp which encoded a protein of 228 amino acids with a predicted molecular mass of 23.3 kD. According to these two obtained cDNA sequences and Thellungiella halophila MnSOD gene (ThMSD) published on GenBank (EF140719), the prokaryotic expression vectors pET30a-SeMSD, pET30a-SeCSD and pET30a-ThMSD were constructed,and the target proteins were expressed successfully in BL21 Escherichia coli. Through optimizating the concentration of Isopropyl beta-D-Thiogalactopyranoside (IPTG), the salt tolerance of these bacteria with the three superoxide dismutases were tested under 6.5 % and 7.5% NaCl. The results demonstrated that the recombinants BL21 (pET30a-SeMSD) and BL21 (pET30a-ThMSD) strains showed better tolerance to salinity stress in comparison with the control stains BL21 (pET30a), but the recombinant BL21 (pET30a-SeCSD) strains displayed no salt tolerance increase.
Wiszniewski, A. A. G., S. M. Smith, et al. (2012) Conservation of two lineages of peroxisomal (Type I) 3-ketoacyl-CoA thiolases in land plants, specialization of the genes in Brassicaceae, and characterization of their expression in Arabidopsis thaliana Journal of Experimental Botany 63: 6093-6103. 10.1093/jxb/ers260Arabidopsis thaliana has three genes encoding type I 3-ketoacyl-CoA thiolases (KAT1, KAT2, and KAT5), one of which (KAT5) is alternatively transcribed to produce both peroxisomal and cytosolic proteins. To evaluate the potential importance of these four gene products, their evolutionary history in plants and their expression patterns in Arabidopsis were investigated. Land plants as a whole have gene lineages corresponding to KAT2 and KAT5, implying conservation of distinct functions for these two genes. By contrast, analysis of synteny shows that KAT1 arose by duplication of the KAT2 locus. KAT1 is found in the Brassicaceae family, including in the genera Arabidopsis, Capsella, Thellungiella (Eutrema) and Brassica, but not in the more distantly related Caricaceae (order Brassicales), or other plants. Gene expression analysis using qRT-PCR and -glucuronidase reporter genes showed strong expression of KAT2 during germination and in many plant tissues throughout the life cycle, consistent with its observed dominant function in fatty acid -oxidation. KAT1 was expressed very weakly while KAT5 was most strongly expressed during flower development and in seedlings after germination. Isoform-specific qRT-PCR analysis and promoter -glucuronidase reporters revealed that the two splicing variants of KAT5 have similar expression profiles. Alternative splicing of KAT5 to produce cytosolic and peroxisomal proteins is specific to and ubiquitous in the Brassicaceae, and possibly had an earlier origin in the order Brassicales. This implies that an additional function for KAT5 arose between 43 and 115 mybp. We speculate that this KAT5 mutation was recruited for a cytosolic function in secondary metabolism.
Weretilnyk, E. A., B. Moffatt, et al. (2012) GSE41182: Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat Gene Expression OmnibusBackground: Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm.Results: To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen media suggests that Thellungiella shows metabolic plasticity in response to environmental stress and that resource availability can influence the expression of stress tolerance traits under field conditions.Conclusion: Comparisons between Thellungiella plants responding to stress in cabinets and in their natural habitats showed differences but also overlap between transcript and metabolite profiles. The traits in common offer potential targets for improving crops that must respond appropriately to multiple, concurrent stresses.
Wang, R., X. Li, et al. (2012) Isolation and sequence analysis of a STZ transcription factor gene in Thellungiella halophila Journal of Northwest A & F University - Natural Science Edition 40: 215-220.Objective: In the study, the coding region of ThSTZ (Thellungiella halophila STZ) was isolated and analyzed by using bioinformatics tools, which will provide a theoretical basis for further functional analysis of ThSTZ transcription factor in stress response. Method: A pair of specific primer was designed based on EST sequences of ThSTZ from GenBank database. The coding region of ThSTZ gene was isolated by 3 RACE technique. The structure, function and subcellular location of ThSTZ protein were analyzed by bioinformatics software. System evolution tree of ThSTZ gene was constructed. Result: The coding sequence of ThSTZ gene is 717 bp in length, and encodes a 238 amino acid sequence which includes two C2H2 zinc-finger domain and located in nucleus. ThSTZ belongs to the C2H2 transcription factor family. Multiple sequence alignment and system evolution analysis of ThSTZ protein revealed that ThSTZ transcription factor has highest identity with homologous protein in Arabidopsis. Conclusion: A full length of the STZ transcription factor gene in T. halophila was isolated and analyzed. This study will provide a further functional analysis of ThSTZ transcription factor in stress response.
Wang, R., X.-s. Han, et al. (2012) Preliminary Proteomic Analysis of Drought Stress-responsive Proteins in Thellungiella halophila Leaves Xibei Zhiwu Xuebao 32: 465-470.Drought is one of the most severe environmental factors that may impair growth and development of plant and decrease crop productivity. Thellungiella halophila, an Arabidopsis-related halophyte is an emerging model used for plant abiotic stress tolerance research. The proteome investigation of the response of drought stress in T. halophila leaf will advance the understanding on how plant adapt to drought stress. In this study,a proteomic study based on two-dimensional gel electrophoresis is performed in order to analyze the drought stress response of T. halophila Totally. 63 differentially displayed spots are determined, including 31 up-regulated, 14 newly-appeared,15 down-regulated and 3 disappeared protein spots. Nine differentially displayed spots,including thioredoxin,ferritin-1 and lectin are identified by mass spectrometry analysis. Function classification analysis of the nine identified proteins reveals that the drought tolerance of T. halophila is achieved, at least partly, by enhancing ROS scavenging, adjusting energy metabolism and maintaining photosynthesis function.
Vysotskii, D. A., M. B. Kostina, et al. (2012) Sequence Analysis and Expression Profiling of 14-3-3 Genes from the Extremophile Thelungiella salsuginea, Ecotype Yakutsk Russian Journal of Plant Physiology 59: 255-265. 10.1134/s1021443712020185Members of the 14-3-3 protein family are known to be important regulators of plant primary metabolism, hormonal signal transduction, and ion homeostasis. We identified nine isoforms of 14-3-3 genes of Thellungiella salsuginea, an extremophile relative of Arabidopsis thaliana. All the identified isoforms were designated according to their Arabidopsis orthologs: Chi, Omega, Psi, Phi, Upsilon, Lambda, Mu, Epsilon, and Omicron. Comparison of the deduced amino acid sequences reveals high degree of identity between the members of this protein family. Isoforms, designated as Ts14-3-3 Chi, Omicron, and Mu, display noticeable differences in their C-terminal domain as compared to their Arabidopsis homologs. Phylogenetic analysis demonstrated that the identified isoforms split into two groups, epsilon and non-epsilon, according to the common classification of the 14-3-3 family genes. The Thellungiella 14-3-3 isoforms are differentially expressed in various plant tissues, and real-time RT-PCR revealed that most of the isoforms are highly expressed even under normal growth conditions. In response to abiotic stress, low temperatures and high concentrations of salts, 14-3-3 genes exhibited different expression patterns. Our data suggest that, due to the high expression levels of the 14-3-3 genes, Thellungiella plants are likely pre-adapted to the stress conditions. Differences between the C-terminal domains of some Thellungiella 14-3-3 proteins and their Arabidopsis homologs may result in differences in target protein specificity.
Undurraga, S. F., M. P. Santos, et al. (2012) Arabidopsis sodium dependent and independent phenotypes triggered by H+-PPase up-regulation are SOS1 dependent Plant Science 183: 96-105. 10.1016/j.plantsci.2011.11.011Coordinate regulation of transporters at both the plasma membrane and vacuole contribute to plant cell's ability to adapt to a changing environment and play a key role in the maintenance of the chemiosmotic circuits required for cellular growth. The plasma membrane (PM) Na+/H+ antiporter (SOS1) is involved in salt tolerance, presumably in sodium extrusion: the vacuolar type I H+-PPaseAVP1 is involved in vacuolar sodium sequestration, but its overexpression has also been shown to alter the abundance and activity of the PM H+-ATPase. Here we investigate the relationship between these transporters utilizing loss-of-function mutants of SOS1 (sos1) and increased expression of AVP1 (AVP1OX). Heightened expression of AVP1 enhances pyrophosphate-dependent proton pump activity, salt tolerance, ion vacuolar sequestration, K+ uptake capacity, root hair development, osmotic responses, and PM ATPase hydrolytic and proton pumping activities. In sos1 lines overexpressing AVP1, these phenotypes are negatively affected demonstrating that sos1 is epistatic to AVP1. Enhanced AVP1 protein levels require SOS1 and this regulation appears to be post-translational. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
Shabala, S. and R. Munns. (2012) Salinity Stress: Physiological Constraints and Adaptive Mechanisms Plant Stress Physiology 59-93.A significant part of the world's land area is salt-affected. Most crops are not able to handle large amounts of salt without a negative impact on their growth and metabolism, so understanding the physiological mechanisms by which plants deal with salinity is essential to minimize detrimental effects and reduce the multibillion dollar penalties imposed by salt stress on crop production. This chapter summarizes our current knowledge of physiological mechanisms conferring plant adaptive responses to salinity. The classification of saline soils is given, with causes of primary and secondary types of salinity. Major physiological constraints are then summarized, and physiological and genetic diversity of plant responses to salinity are discussed. Key physiological and anatomical mechanisms conferring salinity tolerance in plants are then analysed in detail, and practical ways of ameliorating salinity stress are considered. Altogether, this chapter shows that plants have evolved numerous mechanisms to prevent accumulation of toxic Na+ levels in cell cytosol. This ability is complemented by mechanisms enabling efficient osmotic adjustment and maintenance of the cell turgor, as well as mechanisms of coping with oxidative stress imposed by salinity. A more complete physiological and genetic understanding of these processes will enable breeders to produce new salt-tolerant plants for the future.
Saadia, M., A. Jamil, et al. (2012) A Study of Proline Metabolism in Canola (Brassica napus L.) Seedlings under Salt Stress Molecules 17: 5803-5815. 10.3390/molecules17055803Expression analysis of crop plants has improved our knowledge about the veiled underlying mechanisms for salt tolerance. In order to observe the time course effects of salinity stress on gene expression for enzymes regulating proline metabolism, we comparatively analyzed the expression of specific genes for proline metabolism in root and shoot tissues of salt-tolerant (cv. Dunkled) and salt-sensitive (cv. Cyclone) canola (Brassica napus L.) cultivars through reverse-transcriptase polymerase chain reaction (RT-PCR); following the NaCl treatment for various durations. Both lines showed an increase in Delta(1)-pyrroline-5-carboxylate synthase1 (P5CS1) gene expression after induction of salt stress with enhanced expression in the root tissue of the tolerant line, while maximum expression was noted in the shoot tissues of the sensitive line. We observed a much reduced proline dehydrogenase (PDH) expression in both the root and shoot tissues of both canola lines, with more marked reduction of PDH expression in the shoot tissues than that in the root ones. To confirm the increase in P5CS1 gene expression, total proline content was also measured in the root and shoot tissues of both the canola lines. The root tissues of canola sensitive line showed a gradually increasing proline concentration pattern with regular increase in salinity treatment, while an increase in proline concentration in the tolerant line was noted at 24 h post salinity treatment after a sudden decrease at 6 h and 12 h of salt treatment. A gradually increasing concentration of free proline content was found in shoot tissues of the tolerant canola line though a remarkable increase in proline concentration was noted in the sensitive canola line at 24 h post salinity treatment, indicating the initiation of proline biosynthesis process in that tissue of sensitive canola.
Renou, J.-P. P., L. Soubigou-Taconnat, et al. (2012) E-GEOD-19740.raw.1.zip ArrayExpress ArchiveSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila - flower/leaf transcriptomic comparison in Arabidopsis and Thellungiella. adt09-01_thellungiella - thelungiella 2 dye-swap - CATMA arrays.
Renou, J.-P. P., L. Soubigou-Taconnat, et al. (2012) E-GEOD-19740.processed.1.zip ArrayExpress ArchiveSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila - flower/leaf transcriptomic comparison in Arabidopsis and Thellungiella. adt09-01_thellungiella - thelungiella 2 dye-swap - CATMA arrays.
Pei, L. M., J. M. Wang, et al. (2012) Overexpression of Thellungiella halophila H+-pyrophosphatase Gene Improves Low Phosphate Tolerance in Maize Plos One 7: e43501 10.1371/journal.pone.0043501Low phosphate availability is a major constraint on plant growth and agricultural productivity. Engineering a crop with enhanced low phosphate tolerance by transgenic technique could be one way of alleviating agricultural losses due to phosphate deficiency. In this study, we reported that transgenic maize plants that overexpressed the Thellungiella halophila vacuolar H+-pyrophosphatase gene (TsVP) were more tolerant to phosphate deficit stress than the wild type. Under phosphate sufficient conditions, transgenic plants showed more vigorous root growth than the wild type. When phosphate deficit stress was imposed, they also developed more robust root systems than the wild type, this advantage facilitated phosphate uptake, which meant that transgenic plants accumulated more phosphorus. So the growth and development in the transgenic maize plants were not damaged as much as in the wild type plants under phosphate limitation. Overexpression of TsVP increased the expression of genes involved in auxin transport, which indicated that the development of larger root systems in transgenic plants might be due in part to enhanced auxin transport which controls developmental events in plants. Moreover, transgenic plants showed less reproductive development retardation and a higher grain yield per plant than the wild type plants when grown in a low phosphate soil. The phenotypes of transgenic maize plants suggested that the overexpression of TsVP led to larger root systems that allowed transgenic maize plants to take up more phosphate, which led to less injury and better performance than the wild type under phosphate deficiency conditions. This study describes a feasible strategy for improving low phosphate tolerance in maize and reducing agricultural losses caused by phosphate deficit stress.
Pedras, M. S. C. and I. Khallaf. (2012) Molecular interactions of the phytotoxins destruxin B and sirodesmin PL with crucifers and cereals: Metabolism and elicitation of plant defenses Phytochemistry 77: 129-139. 10.1016/j.phytochem.2012.02.010Destruxin B and sirodesmin PL are phytotoxins produced by the phytopathogenic fungi Alternaria brassicae (Berk.) Sacc. and Leptosphaeria maculans (asexual stage Phoma lingam), respectively. The molecular interaction of destruxin B and sirodesmin PL with cruciferous and cereal species was investigated using HPLC-ESI-MSn. It was determined that crucifers transformed destruxin B to hydroxydestruxin B, but sirodesmin PL was not transformed. Overall, the results suggest that the five cruciferous species Arabidopsis thaliana, Thellungiella salsuginea, Erucastrum gallicum, Brassica rapa and Brassica napus are likely to produce a destruxin B detoxifying enzyme (destruxin B hydroxylase), similar to other cruciferous species reported previously. In addition, HPLC analyses and quantification of the phytoalexins elicited in each cruciferous species by these phytotoxins indicates that sirodesmin PL elicits a larger number of phytoalexins than destruxin B. Interestingly, transformation of destruxin B appears to occur also in the cereals Avena sativa and Triticum aestivum; however, the various destruxin metabolites detected in these cereals suggest that these reactions are non-specific enzymatic transformations, contrary to those observed in crucifers, where only a main transformation pathway is detectable. None of the toxins appear to elicit production of metabolites in either A. sativa or T. aestivum. (C) 2012 Elsevier Ltd. All rights reserved.
Patrick, R. M. and K. S. Browning. (2012) The eIF4F and eIFiso4F Complexes of Plants: An Evolutionary Perspective Comparative and Functional Genomics 287814 10.1155/2012/287814Translation initiation in eukaryotes requires a number of initiation factors to recruit the assembled ribosome to mRNA. The eIF4F complex plays a key role in initiation and is a common target point for regulation of protein synthesis. Most work on the translation machinery of plants to date has focused on flowering plants, which have both the eIF4F complex (eIF4E and eIF4G) as well as the plant-specific eIFiso4F complex (eIFiso4E and eIFiso4G). The increasing availability of plant genome sequence data has made it possible to trace the evolutionary history of these two complexes in plants, leading to several interesting discoveries. eIFiso4G is conserved throughout plants, while eIFiso4E only appears with the evolution of flowering plants. The eIF4G N-terminus, which has been difficult to annotate, appears to be well conserved throughout the plant lineage and contains two motifs of unknown function. Comparison of eIFiso4G and eIF4G sequence data suggests conserved features unique to eIFiso4G and eIF4G proteins. These findings have answered some questions about the evolutionary history of the two eIF4F complexes of plants, while raising new ones.
Pang, Q. Y., J. Guo, et al. (2012) Effect of salt treatment on the glucosinolate-myrosinase system in Thellungiella salsuginea Plant and Soil 355: 363-374. 10.1007/s11104-011-1108-0Glucosinolates are specialized plant metabolites derived from amino acids. Found in many important crop species (e.g., oilseed rape, broccoli and cabbage), glucosinolates and their degradation products have important roles in plant defense and interactions with the environment. The objective of this research was to study the effects of salt stress on the glucosinolate-myrosinase system in Thellungiella halophila, which has been characterized as a model organism for studying the molecular mechanisms underlying salt tolerance in plants. In this study, Thellungiella plants were transferred into 1/2 Hoagland's solution containing 200 mM, 300 mM, 400 mM, or 500 mM NaCl for salinity stress at three different growth stages: (1) the young vegetative stage, (2) the late older rosette stage prior to the initiation of bolting, and (3) the early bolting stage. We analyzed the glucosinolate-myrosinase system in different organs and developmental stages of Thellungiella salsuginea under salt stress. NaCl treatment caused a significant variation in the patterns of aliphatic, aromatic, and indole glucosinolate concentrations, resulting in varying levels of total glucosinolates in different organs at three different developmental stages. Although the major class of glucosinolates in different organs varied, increased concentrations of glucosinolates were observed under certain salt conditions. Myrosinase activity was also measured, and statistical analysis clearly indicated no synergetic effect between myrosinase activity and glucosinolate levels. The functional implications of glucosinolate metabolism under salt stress conditions are discussed. In the present study, salt stress had a significant effect on glucosinolate levels and myrosinase activity in Thellungiella at different growth stages. The findings indicate that salt-induced increases in glucosinolate content may be involved in the salt stress response of Thellungiella, but the effects of salinity on glucosinolate biosynthesis and metabolism deserve further attention.
Oh, D.-H., M. Dassanayake, et al. (2012) Life at the extreme: lessons from the genome Genome Biology 13: 241 10.1186/gb-2012-13-3-241Extremophile plants thrive in places where most plant species cannot survive. Recent developments in high-throughput technologies and comparative genomics are shedding light on the evolutionary mechanisms leading to their adaptation.
Obata, T. and A. R. Fernie. (2012) The use of metabolomics to dissect plant responses to abiotic stresses Cellular and Molecular Life Sciences 69: 3225-3243. 10.1007/s00018-012-1091-5Plant metabolism is perturbed by various abiotic stresses. As such the metabolic network of plants must be reconfigured under stress conditions in order to allow both the maintenance of metabolic homeostasis and the production of compounds that ameliorate the stress. The recent development and adoption of metabolomics and systems biology approaches enable us not only to gain a comprehensive overview, but also a detailed analysis of crucial components of the plant metabolic response to abiotic stresses. In this review we introduce the analytical methods used for plant metabolomics and describe their use in studies related to the metabolic response to water, temperature, light, nutrient limitation, ion and oxidative stresses. Both similarity and specificity of the metabolic responses against diverse abiotic stress are evaluated using data available in the literature. Classically discussed stress compounds such as proline, gamma-amino butyrate and polyamines are reviewed, and the widespread importance of branched chain amino acid metabolism under stress condition is discussed. Finally, where possible, mechanistic insights into metabolic regulatory processes are discussed.
Marr, K. L., R. J. Hebda, et al. (2012) New alpine plant records for British Columbia and a previously unrecognized biogeographical element in western North America Botany-Botanique 90: 445-455. 10.1139/b2012-009The distribution of northern British Columbia alpine plants is poorly documented. To improve our understanding of the flora of this vast, remote region, we collected more than 11 000 specimens from 65 mountains during 2002-2011. Most of these locations had not been visited by botanists. Of the more than 400 species we have collected, two are new to the province, others represent significant range extensions. Twelve species share elements of a disjunct distribution that has apparently not been previously recognized and consists of three regions: (1) northwestern North America; (2) Beartooth Plateau; and (3) northern Colorado. These 12 species appear to be absent from the extensive areas of suitable habitat that occur in the intervening areas. The most reasonable explanation for this pattern is that these species, adapted to arctic-alpine tundra conditions, migrated throughout western North America during the Pleistocene, a time when suitable habitat was much more widespread than now, and subsequently went extinct in many areas as the climate warmed during the Holocene.
Liu, R., L.-j. Zhou, et al. (2012) Studies on Expression of miRNAs in Thellungiella under Salt Stress Xibei Zhiwu Xuebao 32: 665-669.The expressions of tsa-miR172a and tsa-miR398b in roots of Thellungiella halophila (T. salsuginea),which were screened via Solexa sequencing, were studied by stern-loop RT-PCR methodology. The results showed that tsa-miR172a was up-expressing and tsa-miR398b was down-expressing under the treatment of NaCl (300 mmol.L-1, 72 h). With the stem-loop RT-PCR, tsa-miR172a and tsa-miR398b were amplified and the optical densities of electrophores were analyzed specifically. The ratios of NaCl stress to control were I. 8 and 0. 55, which were roughly consistent with the results 2. 00 and 0. 44 obtained by Solexa. Our study established an effective stem-loop RT-PCR. system: three primers, namely miRNA stem-loop primer, miRNA forward primer and miRNA universal reverse primer, were designed for each miRNA. The reactions were incubated at: 94 degrees C for 2 min, followed by 23 cycles of 94 degrees C for 15 s and 55 degrees C for 45 s. The stem-loop RT-PCR system to identify miRNAs in Thellungiella was discussed.
Liu, M., D. Li, et al. (2012) Transgenic expression of ThIPK2 gene in soybean improves stress tolerance, oleic acid content and seed size Plant Cell Tissue and Organ Culture 111: 277-289. 10.1007/s11240-012-0192-zInositol polyphosphate kinase (IPK; EC 2.7.1.151) participates in inositol metabolism, calcium signaling, stress response, gene transcription and other physiological and biochemical processes. In the present work, ThIPK2 (an inositol polyphosphate kinase from Thellungiella halophila) was transferred into soybean through an Agrobacterium tumefaciens-mediated transformation. Transgenic plants with ThIPK2 gene displayed water deficit-, salt- and oxidative-tolerance compared to non-transformed controls. Furthermore, the expression of ThIPK2 altered the ratio of fatty acid components in soybean seeds, resulting in an increase of oleic acid (C18:1). Also seed size was increased in transgenic plants. These findings might be available to improve soybean seed quality and soybean yield.
Lee, Y. P., A. Babakov, et al. (2012) Comparison of freezing tolerance, compatible solutes and polyamines in geographically diverse collections of Thellungiella sp. and Arabidopsis thaliana accessions Bmc Plant Biology 12: 131 10.1186/1471-2229-12-131Background: Thellungiella has been proposed as an extremophile alternative to Arabidopsis to investigate environmental stress tolerance. However, Arabidopsis accessions show large natural variation in their freezing tolerance and here the tolerance ranges of collections of accessions in the two species were compared. Results: Leaf freezing tolerance of 16 Thellungiella accessions was assessed with an electrolyte leakage assay before and after 14 days of cold acclimation at 4 degrees C. Soluble sugars (glucose, fructose, sucrose, raffinose) and free polyamines (putrescine, spermidine, spermine) were quantified by HPLC, proline photometrically. The ranges in nonacclimated freezing tolerance completely overlapped between Arabidopsis and Thellungiella. After cold acclimation, some Thellungiella accessions were more freezing tolerant than any Arabidopsis accessions. Acclimated freezing tolerance was correlated with sucrose levels in both species, but raffinose accumulation was lower in Thellungiella and only correlated with freezing tolerance in Arabidopsis. The reverse was true for leaf proline contents. Polyamine levels were generally similar between the species. Only spermine content was higher in nonacclimated Thellungiella plants, but decreased during acclimation and was negatively correlated with freezing tolerance. Conclusion: Thellungiella is not an extremophile with regard to freezing tolerance, but some accessions significantly expand the range present in Arabidopsis. The metabolite data indicate different metabolic adaptation strategies between the species.
Lamdan, N. L., Z. Attia, et al. (2012) The Arabidopsis-related halophyte Thellungiella halophila: boron tolerance via boron complexation with metabolites? Plant Cell and Environment 35: 735-746. 10.1111/j.1365-3040.2011.02447.xTolerance to boron (B) is still not completely understood. We tested here the hypothesis that Thellungiella halophila, an Arabidopsis thaliana-related extremophile plant, with abundance of B in its natural environment, is tolerant to B, and examined the potential mechanisms of this tolerance. With 110 mm B applied ([B]ext) to Thellungiella and Arabidopsis grown in hydroponics, the steady-state accumulated B concentration ([B]int) in the root was below [B]ext, and was similar in both, suggesting both extrude B actively. Whether grown in soil or hydroponically, the shoot [B]int was higher in Arabidopsis than in Thellungiella, suggesting more effective net B exclusion by Thellungiella root. Arabidopsis exhibited toxicity symptoms including reduced shoot fresh weight (FW), but Thellungiella was not affected, even at similar levels of shoot-accumulated [B]int (about 10 to 40 mm B in shoot water), suggesting additional B tolerance mechanism in Thellungiella shoot. At [B]ext = 5 mm, the summed shoot concentration of the potentially B-binding polyhydroxyl metabolites (malic acid, fructose, glucose, sucrose and citric acid) in Arabidopsis was below [B]int, but in Thellungiella it was over twofold higher than [B]int, and therefore likely to allow appreciable 1:2 boronmetabolite complexation in the shoot. This, we suggest, is an important component of Thellungiella B tolerance mechanism.
Kelly, L. J., A. R. Leitch, et al. (2012) Why size really matters when sequencing plant genomes Plant Ecology & Diversity 5: 415-425. 10.1080/17550874.2012.716868Genome sequencing has been restricted to species with a small genome size. With the advent of second- and third-generation sequencing technologies, the potential to sequence genomes of all sizes is becoming a reality. As the field of whole genome sequencing has developed, there has been a growing appreciation of the need to better represent the major lineages of the plant tree of life, rather than just those that contain economically important taxa. We argue that as well as accounting for phylogenetic diversity when selecting species to analyse, in order to gain a comprehensive understanding of genome evolution, large-scale sequencing projects also need to reflect the diversity of genome sizes in plants. In this article we briefly outline evidence from the literature to support this view.
Janz, D. and A. Polle. (2012) Harnessing salt for woody biomass production Tree Physiology 32: 1-3. 10.1093/treephys/tpr127Thellungiella salsuginea is an excellent organism to study abiotic stress tolerance, especially for salt stress tolerance.
Huertas, R., R. Olias, et al. (2012) Overexpression of SlSOS2 (SlCIPK24) confers salt tolerance to transgenic tomato Plant Cell and Environment 35: 1467-1482. 10.1111/j.1365-3040.2012.02504.xThe Ca2+-dependent SOS pathway has emerged as a key mechanism in the homeostasis of Na+ and K+ under saline conditions. We have identified and functionally characterized the gene encoding the calcineurin-interacting protein kinase of the SOS pathway in tomato, SlSOS2. On the basis of protein sequence similarity and complementation studies in yeast and Arabidopsis, it can be concluded that SlSOS2 is the functional tomato homolog of Arabidopsis AtSOS2 and that SlSOS2 operates in a tomato SOS signal transduction pathway. The biotechnological potential of SlSOS2 to provide salt tolerance was evaluated by gene overexpression in tomato (Solanum lycopersicum L. cv. MicroTom). The better salt tolerance of transgenic plants relative to non-transformed tomato was shown by their faster relative growth rate, earlier flowering and higher fruit production when grown with NaCl. The increased salinity tolerance of SlSOS2-overexpressing plants was associated with higher sodium content in stems and leaves and with the induction and up-regulation of the plasma membrane Na+/H+ (SlSOS1) and endosomal-vacuolar K+,Na+/H+ (LeNHX2 and LeNHX4) antiporters, responsible for Na+ extrusion out of the root, active loading of Na+ into the xylem, and Na+ and K+ compartmentalization.
Hu, M., Z. Shi, et al. (2012) Effects of exogenous glucose on seed germination and antioxidant capacity in wheat seedlings under salt stress Plant Growth Regulation 68: 177-188. 10.1007/s10725-012-9705-3Glucose (Glc) is an essential signaling molecule that controls plant development and gene expression, but little is known about its role in salt stress resistance on seed germination and plant growth. Here we report the effects of exogenous Glc on wheat seed germination and seedling growth under salt stress. The treatments used were 0 and 200 mM NaCl solutions supplemented with each of four Glc concentrations of 0, 0.1, 0.5 and 50 mM. The results showed that salt alone significantly inhibited seeds germination and reduced the growth of wheat seedlings. Addition of exogenous Glc in the salt solution attenuated the salt stress effects in a dose-dependent manner of Glc, as indicated by enhancement of the growth of celoeptile and radicle. Glc addition also showed significant reversal of salt stress in chlorophyll decay, water loss, dry weight, root length and accumulation of proline. The Glc-induced salt stress resistance was associated with enhanced K+ and K+/Na+ ratio in leaves, and activated antioxidant enzymes activities, thus decreasing thiobarbituric acid reactive substances (TBARS) and malondialdehyde (MDA) contents. As our knowledge this is the first report to show the protective effects of exogenous Glc against salt-induced oxidative damage in wheat seedlings associating with the evidences of ion homeostasis in cells and a better antioxidant system.
Guo, Y. H., D. Wang, et al. (2012) Effects of seed vernalisation and photoperiod on flowering induction in the halophyte Thellungiella halophila Australian Journal of Botany 60: 743-748. 10.1071/bt12180Salt cress, Thellungiella halophila, is a late-flowering, halophytic plant that requires a prolonged period of vernalisation to flower. This poorly defined vernalisation requirement restricts the use of T. halophila as a model plant for the study of salt-stress tolerance. To facilitate research on T. halophila, the present study quantified the effects of seed vernalisation and photoperiod on its flowering. Imbibed seeds of T. halophila responded to a cold treatment (4 degrees C), and flowering was optimal after 30 days of seed vernalisation. A longer vernalisation period shortened the time until the first flower appeared, increased the number of flowers and reduced expression of ThFLC (a repressor of flowering). Plants growing from seed that had been vernalised for 30 days did not flower when daylength was < 9 h, and daylengths > 9h promoted flowering. Therefore, like for many plants in this clade of the Brassicaceae, vernalisation requirement and long-day response are features of T. halophila. These results will facilitate the use T. halophila as a model plant for the study of abiotic stress.
Guo, Y. H., W. J. Jia, et al. (2012) Thellungilla halophila is more adaptive to salinity than Arabidopsis thaliana at stages of seed germination and seedling establishment Acta Physiologiae Plantarum 34: 1287-1294. 10.1007/s11738-012-0925-yThellungiella halophila is a salt tolerant relative of Arabidopsis thaliana with high genetic and morphological similarity. In the present study, effects of salinity on germination and seedling growth of T. halophila and A. thaliana were compared. The present results showed that the salinity inhibited seed germination in both species. Unexpectedly, percentages of seed germination in A. thaliana were higher than T. halophila in a range of 0-200 mM NaCl. Seeds of both species could not germinate when the concentration of NaCl was over 200 mM. However, when compared with A. thaliana, seeds of T. halophila did not suffer ion toxicity, as evidenced by the higher final germination rate after ungerminated seeds pretreated with NaCl were transferred to distilled water. Seedlings of T. halophila were more salt tolerant than those of A. thaliana, e.g., seedlings of T. halophila had better plant growth (root length, fresh and dry mass), higher chlorophyll content, less MDA content and higher proline content and K+/Na+ ratio under salinity. These results indicate that T. halophila is more salt tolerant than A. thaliana during both seed germination and seedling stages and explain why A. thaliana is excluded from saline locations and T. halophila can survive in saline soils.
Guevara, D. R., M. J. Champigny, et al. (2012) Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat show phenotypic plasticity Bmc Plant Biology 12: 175 10.1186/1471-2229-12-175Background: Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm. Results: To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen media suggests that Thellungiella shows metabolic plasticity in response to environmental stress and that resource availability can influence the expression of stress tolerance traits under field conditions. Conclusion: Comparisons between Thellungiella plants responding to stress in cabinets and in their natural habitats showed differences but also overlap between transcript and metabolite profiles. The traits in common offer potential targets for improving crops that must respond appropriately to multiple, concurrent stresses.
Ghars, M. A., L. Richard, et al. (2012) Phospholipases C and D Modulate Proline Accumulation in Thellungiella halophila/salsuginea Differently According to the Severity of Salt or Hyperosmotic Stress Plant and Cell Physiology 53: 183-192. 10.1093/pcp/pcr164Proline accumulation is one of the most common responses of plants to environmental constraints. Thellungiella halophila/salsuginea, a model halophyte, accumulates high levels of proline in response to abiotic stress and in the absence of stress. Recently, lipid signaling pathways have been shown to be involved in the regulation of proline metabolism in Arabidopsis thaliana. Here we investigated the relationship between lipid signaling enzymes and the level of proline in T. salsuginea. Inhibition of phospholipase C (PLC) enzymes by the specific inhibitor U73122 demonstrated that proline accumulation is negatively controlled by PLCs in the absence of stress and under moderate salt stress (200 mM NaCl). The use of 1-butanol to divert some of the phospholipase D (PLD)-derived phosphatidic acid by transphosphatidylation revealed that PLDs exert a positive control on proline accumulation under severe stress (400 mM NaCl or 400 mM mannitol) but have no effect on its accumulation in non-stress conditions. This experimental evidence shows that positive and negative lipid regulatory components are involved in the fine regulation of proline metabolism. These signaling pathways in T. salsuginea are regulated in the opposite sense to those previously described in A. thaliana, revealing that common signaling components affect the physiology of closely related glycophyte and salt-tolerant plants differently.
Gaxiola, R. A., C. A. Sanchez, et al. (2012) Genetic Manipulation of a "Vacuolar" H+-PPase: From Salt Tolerance to Yield Enhancement under Phosphorus-Deficient Soils Plant Physiology 159: 3-11. 10.1104/pp.112.195701Plant scientists face the difficult challenge of increasing food production without further degradation of the environment. In order to protect drinking water resources and prevent the proliferation of harmful algal blooms and "dead zones" in coastal marine ecosystems, it is imperative to reduce anthropogenic nutrient inputs (Conley et al., 2009). These challenges are further compounded by the goal of utilizing agriculture to provide replacement fuels such as biodiesel and alcohol for our oil-based economy. Phosphate (Pi) is an essential macronutrient required for plant growth and development (Chen et al., 2008). Plant nutrient acquisition and partitioning depend on the H+ gradients generated by the plasma membrane H+-ATPases (Palmgren, 2001; Fuglsang et al., 2011). In this update, we discuss the potential role that the type I H+-proton-pyrophosphatase (PPase) could play in optimizing Pi use efficiency in plants.
Gao, Q., G. Yue, et al. (2012) Recent Progress Using High-throughput Sequencing Technologies in Plant Molecular Breeding Journal of Integrative Plant Biology 54: 215-227. 10.1111/j.1744-7909.2012.01115.x[ Ye Yin ] High-throughput sequencing is a revolutionary technological innovation in DNA sequencing. This technology has an ultra-low cost per base of sequencing and an overwhelmingly high data output. High-throughput sequencing has brought novel research methods and solutions to the research fields of genomics and post-genomics. Furthermore, this technology is leading to a new molecular breeding revolution that has landmark significance for scientific research and enables us to launch multi-level, multi-faceted, and multi-extent studies in the fields of crop genetics, genomics, and crop breeding. In this paper, we review progress in the application of high-throughput sequencing technologies to plant molecular breeding studies.
Fang, L., F. Cheng, et al. (2012) The impact of genorne triplication on tandem gene evolution in Brassica rapa Frontiers in Plant Science 3: 261 10.3389/fpls.2012.00261Whole genome duplication (WGD) and tandem duplication (TD) are both important modes of gene expansion. However, how WGD influences tandemly duplicated genes is not well studied. We used Brassica rapa, which has undergone an additional genome triplication (MT) and shares a common ancestor with Arabidopsis thaliana, Arabidopsis lyrata, and Thellungiella parvula, to investigate the impact of genome triplication on tandem gene evolution. We identified 2,137, 1,569, 1,751, and 1,135 tandem gene arrays in B. rapa, A. thaliana, A. lyrata, and T parvula respectively. Among them, 414 conserved tandem arrays are shared by the three species without WGT, which were also considered as existing in the diploid ancestor of B. rapa. Thus, after genome triplication, B. rapa should have 1,242 tandem arrays according to the 414 conserved tandems. Here, we found 400 out of the 414 tandems had at least one syntenic ortholog in the genome of B. rapa. Furthermore, 294 out of the 400 shared syntenic orthologs maintain tandem arrays (more than one gene for each syntenic hit) in B. rapa. For the 294 tandem arrays, we obtained 426 copies of syntenic paralogous tandems in the triplicated genome of B. rapa. In this study, we demonstrated that tandem arrays in B. rapa were dramatically fractionated after WGT when compared either to non-tandem genes in the B. rapa genome or to the tandem arrays in closely related species that have not experienced a recent whole genome polyploidization event.
Dittami, S. M. and T. Tonon. (2012) Genomes of extremophile crucifers: new platforms for comparative genomics and beyond Genome Biology 13: 166. 10.1186/gb-2012-13-8-166Molecular systematics is widely used to determine organismal relationships. However, until now, systematics of angiosperms has mostly employed organellar genes, but these genes are generally inherited uniparentally, only partially reflecting the evolutionary history. In addition, chloroplast and mitochondrial genes are highly conserved, with limited numbers of phylogenetically informative characters. In contrast, nuclear genes are inherited biparentally and have relatively large numbers of informative sites, but only few nuclear genes have been utilized. In this work, sequences of five low-copy nuclear genes were obtained in 17 species from Brassicaceae and used for phylogenetic analyses with the Maximum-Parsimony, Maximum-Likelihood and Bayesian methods. Highly similar topologies were obtained using the five genes; in addition, compared with organellar genes, the nuclear genes had more phylogenetically informative sites and provided stronger supports. Specifically, the supporting values of all the nodes were 100% in MP trees using the five nuclear genes. Therefore, these five genes are excellent candidate marker genes for plant taxonomists who aim to resolve the relationships among low-level taxonomic hierarchies and might also be useful for DNA barcoding.
Dedrick, J., E. A. Weretilnyk, et al. (2012) Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat ArrayExpress ArchiveBackground: Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm. Results: To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen media suggests that Thellungiella shows metabolic plasticity in response to environmental stress and that resource availability can influence the expression of stress tolerance traits under field conditions. Conclusion: Comparisons between Thellungiella plants responding to stress in cabinets and in their natural habitats showed differences but also overlap between transcript and metabolite profiles. The traits in common offer potential targets for improving crops that must respond appropriately to multiple, concurrent stresses. A custom cDNA mcroarray was used for transcript profiling. Cauline leaves from individual plants collected at a Yukon, Canada field site were used in this study. Three samples were obtained in 2003 (Field 2003 A, B and C) and three harvested in 2005 (Field 2005 A, B and D). Cauline leaves from 12 week old chamber grown plants served as controls. For each microarray experiment a technical replicate (dye swap) was performed resulting in a total of 12 hybridizations.
Dassanayake, M., D.-H. Oh, et al. (2012) The scope of things to come: New paradigms in biotechnology Plant Biotechnology and Agriculture: Prospects for the 21st Century 19-34. 10.1016/B978-0-12-381466-1.00002-xChromosomal synteny analysis is important in genome comparison to reveal genomic evolution of related species. Shared synteny describes genomic fragments from different species that originated from an identical ancestor. Syntenic genes are orthologs located in these syntenic fragments, so they often share similar functions. Syntenic gene analysis is very important in Brassicaceae species to share gene annotations and investigate genome evolution. Here we designed and developed a direct and efficient tool, SynOrths, to identify pairwise syntenic genes between genomes of Brassicaceae species. SynOrths determines whether two genes are a conserved syntenic pair based not only on their sequence similarity, but also by the support of homologous flanking genes. Syntenic genes between Arabidopsis thaliana and Brassica rapa, Arabidopsis lyrata and B. rapa, and Thellungiella parvula and B. rapa were then identified using SynOrths. The occurrence of genome triplication in B. rapa was clearly observed, many genes that were evenly distributed in the genomes of A. thaliana, A. lyrata, and T. parvula had three syntenic copies in B. rapa. Additionally, there were many B. rapa genes that had no syntenic orthologs in A. thaliana, but some of these had syntenic orthologs in A. lyrata or T. parvula. Only 5,851 genes in B. rapa had no syntenic counterparts in any of the other three species. These 5,851 genes could have originated after B. rapa diverged from these species. A tool for syntenic gene analysis between species of Brassicaceae was developed, SynOrths, which could be used to accurately identify syntenic genes in differentiated but closely-related genomes. With this tool, we identified syntenic gene sets between B. rapa and each of A. thaliana, A. lyrata, T. parvula. Syntenic gene analysis is important for not only the gene annotation of newly sequenced Brassicaceae genomes by bridging them to model plant A. thaliana, but also the study of genome evolution in these species.
Ali, Z., H. C. Park, et al. (2012) TsHKT1;2, a HKT1 Homolog from the Extremophile Arabidopsis Relative Thellungiella salsuginea, Shows K+ Specificity in the Presence of NaCl Plant Physiology 158: 1463-1474. 10.1104/pp.111.193110Cellular Na+/K+ ratio is a crucial parameter determining plant salinity stress resistance. We tested the function of plasma membrane Na+/K+ cotransporters in the High-affinity K+ Transporter (HKT) family from the halophytic Arabidopsis (Arabidopsis thaliana) relative Thellungiella salsuginea. T. salsuginea contains at least two HKT genes. TsHKT1;1 is expressed at very low levels, while the abundant TsHKT1;2 is transcriptionally strongly up-regulated by salt stress. TsHKT-based RNA interference in T. salsuginea resulted in Na+ sensitivity and K+ deficiency. The athkt1 mutant lines overexpressing TsHKT1;2 proved less sensitive to Na+ and showed less K+ deficiency than lines overexpressing AtHKT1. TsHKT1;2 ectopically expressed in yeast mutants lacking Na+ or K+ transporters revealed strong K+ transporter activity and selectivity for K+ over Na+. Altering two amino acid residues in TsHKT1;2 to mimic the AtHKT1 sequence resulted in enhanced sodium uptake and loss of the TsHKT1;2 intrinsic K+ transporter activity. We consider the maintenance of K+ uptake through TsHKT1; 2 under salt stress an important component supporting the halophytic lifestyle of T. salsuginea.
Zhou, S., Z. Zhang, et al. (2011) Enhanced V-ATPase activity contributes to the improved salt tolerance of transgenic tobacco plants overexpressing vacuolar Na+/H+ antiporter AtNHX1 Biotechnology Letters 33: 375-380. 10.1007/s10529-010-0418-2AtNHX1, a vacuolar Na+/H+ antiporter gene from Arabidopsis thaliana, was introduced into tobacco genome via Agrobacterium tumefaciens-mediated transformation to evaluate the role of vacuolar energy providers in plants salt stress response. Compared to the wild-type plants, over-expression of AtNHX1 increased salt tolerance in the transgenic tobacco plants, allowing higher germination rates of seeds and successful seedling establishment in the presence of toxic concentrations of NaCl. More importantly, the induced Na+/H+ exchange activity in the transgenic plants was closely correlated to the enhanced activity of vacuolar H+-ATPase (V-ATPase) when exposed to 200 mM NaCl. In addition, inhibition of V-ATPase activity led to the malfunction of Na+/H+ exchange activity, placing V-ATPase as the dominant energy provider for the vacuolar Na+/H+ antiporter AtNHX1. V-ATPase and vacuolar Na+/H+ antiporter thus function in an additive or synergistic way. Simultaneous overexpression of V-ATPase and vacuolar Na+/H+ antiporter might be appropriate for producing plants with a higher salt tolerance ability.
Zhang, Y., Y.-X. Yang, et al. (2011) The continuous accumulation of Na+ in detached leaf sections is associated with over-expression of NTHK1 and salt tolerance in poplar plants Functional Plant Biology 38: 236-245. 10.1071/fp10215Detached leaf sections (2 x 2 cm(2)) from transgenic poplar line 18-1 and its wild type (WT) (Populus x euramericana 'Neva') were used to test their salt tolerance and gene expression under controlled environment conditions. The sections from line 18-1 displayed better tolerance to NaCl stress, indicated by high chlorophyll retention and K+ content but low relative electrolyte leakage (REL). Transient overexpression of NTHK1 (Nicotiana tabacum histidine kinase 1) and V-H+-PPase was found in the detached young leaves from line 18-1 after they had been stressed for a few minutes. The activities of vacuolar-type H+-ATPase and H+-PPase in line 18-1 were boosted initially and then decreased to normal level as in unstressed leaves. After sections were stressed for 10 days, the maximal Na+ concentration in line 18-1 was much higher than that in the WT. The higher capacity for Na+ accumulation in line 18-1 may be due to stable Na+ sequestration into the vacuoles. Osmotic stress imposed little effect on REL and chlorophyll content of the sections. The capacity of detached leaf sections in NaCl solution to tolerate stress and to accumulate Na+ may be useful for identifying genotypes with good salt tolerance in poplar and other plants.
Zhang, J., M. Zhang, et al. (2011). Two-dimensional Electron Gas Characteristics of Ferroelectric/GaN Heterostructure. in Proceeding of the Fourth International Conference on Surface and Interface Science and Engineering. Y. Xiong (eds). 18. Zhang, J., J. Li, et al. (2011) OVP1, a Vacuolar H -translocating inorganic pyrophosphatase (V-PPase), overexpression improved rice cold tolerance Plant Physiology and Biochemistry 49: 33-38. 10.1016/j.plaphy.2010.09.014Vacuolar H(+)-translocating inorganic pyrophosphatase (V-PPase, EC 3.6.1.1) is an electrogenic proton pump and has been studied in many plants. Here we report characterization of the OVP1 gene from rice (Oryza sativa L). Quantitative reverse transcriptase-polymerase chain reaction analysis (RT-qPCR) showed that OVP1 was induced by cold stress. OVP1 overexpression resulted in enhanced cold tolerance in transgenic rice, which was related to an increased integrity of cell membrane, decreased MDA content and accumulation of proline to higher level as compared with wild type rice seedlings. These results indicated that V-PPase was an important element in the survival strategies of plants under cold stress. (C) 2010 Elsevier Masson SAS. All rights reserved.
Yu, J., S. Chen, et al. (2011) Physiological and Proteomic Analysis of Salinity Tolerance in Puccinellia tenuiflora Journal of Proteome Research 10: 3852-3870. 10.1021/pr101102pSoil salinity poses a serious threat to agriculture productivity throughout the world. Studying mechanisms of salinity tolerance in halophytic plants will provide valuable information for engineering plants for enhanced salt tolerance. Monocotyledonous Puecinellia tenuiflora is a halophytic species that widely distributed in the saline-alkali soil of the Songnen plain in northeastern China. Here we investigate the molecular mechanisms underlying moderate salt tolerance of P. tenuiflora using a combined physiological and proteomic approach. The changes in biomass, inorganic ion content, osmolytes, photosynthesis, defense-related enzyme activities, and metabolites in the course of salt treatment were analyzed in the leaves. Comparative proteomic analysis revealed 107 identities (representing 93 unique proteins) differentially expressed in P. tenuiflora leaves under saline conditions. These proteins were mainly involved in photosynthesis, stress and defense, carbohydrate and energy metabolism, protein metabolism, signaling, membrane, and transport. Our results showed that reduction of photosynthesis under salt treatment was attributed to the down-regulation of the light-harvesting complex (LHC) and Calvin cycle enzymes. Selective uptake of inorganic ions, high K+/Na+ ratio, Ca2+ concentration changes, and an accumulation of osmolytes contributed to ion balance and osmotic adjustment in leaf cells. Importantly, P. tenuiflora plants developed diverse reactive oxygen species (ROS) scavenging mechanisms in their leaves to cope with moderate salinity, including enhancement of the photorespiration pathway and thermal dissipation, synthesis of the low-molecular-weight antioxidant alpha-tocopherol, and an accumulation of compatible solutes. This study provides important information toward improving salt tolerance of cereals.
Yang, G., R. Zhou, et al. (2011) Gene Expression Profiles in Response to Salt Stress in Hibiscus Tiliaceus Plant Molecular Biology Reporter 29: 609-617. 10.1007/s11105-010-0267-0Hibiscus tiliaceus, a mangrove associate, is an ideal plant for studying salt tolerance and adaptation since it can inhabit both inland and littoral habitats. In this study, we explored the expression profiles of H. tiliaceus under salt stress using a full-length cDNA microarray. Four hundred eighty-six salt-responsive unigenes were identified in H. tiliaceus; 224 of which had high sequence similarity to Arabidopsis. Many genes identified are known to be salt-stress responsive. Furthermore we examined the physiological performance of H. tiliaceus under salt stress. Physiological analysis displayed decrease in ratio of K+/Na+ and negative influence on photosynthesis of H. tiliaceus. Our study indicated that to survive under high salinine intertidal environments, H. tiliaceus evolved its own mechanisms to re-gain both ionic and osmotic homeostasis through coordinated engagement of genes associated with gene transcription, signaling, and down-stream cell transport and detoxification pathways.
Wei, A., C. He, et al. (2011) The pyramid of transgenes TsVP and BetA effectively enhances the drought tolerance of maize plants Plant Biotechnology Journal 9: 216-229. 10.1111/j.1467-7652.2010.00548.xP>Stress resistance has repeatedly been enhanced in plants by the transfer of a single gene using genetic engineering. However, further enhancement of resistance to abiotic stress is still necessary. In our research, maize plants that were transgenic for both betA (encoding choline dehydrogenase from Escherichia coli) and TsVP (encoding V-H+-PPase from Thellungiella halophila) were produced by cross-pollination. The existence of the transgenes in the pyramided plants was demonstrated by PCR and Southern blotting. The stable expression of transgenes was confirmed by real-time RT-PCR (reverse transcription polymerase chain reaction) analysis. An examination of the drought resistance characteristics demonstrated that the pyramided transgenic plants had higher glycinebetaine contents and H+-PPase activity compared with the parental lines, which had either betA or TsVP, and contained higher relative water content (RWC), greater solute accumulation and lower cell damage under drought stress treatment. The pyramided plants grew more vigorously with less growth retardation, shorter anthesis-silking interval and higher yields than their parental lines and the wild-type. We concluded that co-expression of the two genes involved in different metabolism pathways in pyramided transgenic maize helped to improve the drought resistance over their parental lines that contained either single transgene. Our study suggests that the co-expression of multiple, effective genes in transgenic plants could effectively enhance the resistance to abiotic stress and provide a feasible approach for obtaining maize plants with improved drought resistance.
Wang, X., H. Wang, et al. (2011) Thermal denaturation produced degenerative proteins and interfered with MS for proteins dissolved in lysis buffer in proteomic analysis Electrophoresis 32: 348-356. 10.1002/elps.201000496In 1-DE, proteins were traditionally mixed with the standard Laemmli buffer and boiled for several minutes. Recently, proteins dissolved in lysis buffer were used to produce better-resolved 2-DE gels, but thermal denaturation procedure still remained in some proteomic analysis. To determine the detailed effects of thermal denaturation on SDS-PAGE and MS, both 1-DE and 2-DE were performed using proteins heated at 100 degrees C for different periods of time, and 17 protein bands/spots were positively identified by MALDI TOF/TOF MS/MS. Protein profiles on both 1-DE and 2-DE gels changed obviously and more polydisperse bands/spots were observed with increased heating time for over-heated samples. Based on these observations, an alternative protein marker-producing method was designed by directly dissolving protein standards without BSA into lysis buffer. This new kind of protein marker could be stored at room temperature for a long time, thus was more convenient for using and shipping. The identification of 17 proteins via MS and comparison of their identities revealed MASCOT-searched scores, number of both matched peptides, total searched peptides and sequence coverage became progressively lower with increasing denaturation intensity, probably due to the interference of thermal denaturation on trypsin cleavage efficiency and produced redundant modified peptides. Therefore, it was concluded that thermal denaturation not only changed the protein profiles and produced more polydisperse protein bands/spots, but also heavily interfered with the subsequent MS analysis, hence not recommended in future proteomic analysis for proteins dissolved in lysis buffer.
Wang, J., X. R. Li, et al. (2011) MEK/ERK inhibitor U0126 enhanced salt stress-induced programmed cell death in Thellungiella halophila suspension-cultured cells Plant Growth Regulation 63: 207-216. 10.1007/s10725-010-9517-2Programmed cell death (PCD) is an active cellular suicide that occurs both in animals and plants throughout development and in response to abiotic or biotic stress. In contrast to plant hypersensitive response-like cell death, little is known about the molecular machinery that regulates the halophyte plant PCD under high salinity stress. Since mitogen-activated protein kinases (MAPKs) are involved in plant response/tolerance to salt stress, and plant MAPK genes belong to the extracellular signal-regulated kinase (ERK) subfamily, we have investigated the role of ERK-like enzymes in high salinity stress-induced cell death in Thellungiella halophila. The data showed that ERK-like enzymes were early (10 min) and transiently activated under 300 mM NaCl stress. Pretreatment with 10 mu M U0126, a special MEK/ERK inhibitor, resulted in a small but statistically significant increase of the percentage of terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL)-positive nuclei in contrast to salt alone. The effects of U0126 on H(2)O(2) production and cytochrome c (cyt c) release were also investigated. We found that the pretreatment with U0126 accelerated H(2)O(2) production as well as cyt c release, and eventually enhanced cell death. The results suggest that ERK-like enzymes in Thellungiella halophila may act as a positive regulator of salt tolerance, as illustrated by pretreatment with U0126 which enhanced cell death under high salinity stress.
University of, I. (2011) Eutrema parvulum Genome sequencing European Nucleotide ArchiveGenomic DNA from seedlings was used for sequencing. The inbred line for sequencing originated from a salt flat in Central Anatolia, Turkey. Sequencing was done using whole genome shotgun methodology.
Szabados, L., H. Kovacs, et al. (2011). Plants in Extreme Environments: Importance of Protective Compounds in Stress Tolerance. in Plant Responses to Drought and Salinity Stress: Developments in a Post-Genomic Era. I. Turkan (eds). 57: 105-150. Shabala, S. and A. Mackay (2011). Ion Transport in Halophytes. in Plant Responses to Drought and Salinity Stress: Developments in a Post-Genomic Era. I. Turkan (eds). 57: 151-199. Rahman, L. N., G. S. T. Smith, et al. (2011) Phosphorylation of Thellungiella salsuginea Dehydrins TsDHN-1 and TsDHN-2 Facilitates Cation-Induced Conformational Changes and Actin Assembly Biochemistry 50: 9587-9604. 10.1021/bi201205mGroup 2 late embryogenesis abundant (LEA) proteins, also known as dehydrins, are intrinsically disordered proteins that are expressed in plants experiencing extreme environmental conditions such as drought or low temperatures. These proteins are characterized by the presence of at least one conserved, lysine-rich K-segment and sometimes by one or more serine-rich S-segments that are phosphorylated. Dehydrins may stabilize proteins and membrane structures during environmental stress and can sequester and scavenge metal ions. Here, we investigate how the conformations of two dehydrins from Thellungiella salsuginea, denoted as TsDHN-1 (acidic) and TsDHN-2 (basic), are affected by pH, interactions with cations and membranes, and phosphorylation. Both TsDHN-1 and TsDHN-2 were expressed as SUMO fusion proteins for in vitro phosphorylation by casein kinase H (CKII), and structural analysis by circular dichroism and attenuated total reflection-Fourier transform infrared spectroscopy. We show that the polyproline II conformation can be induced in the dehydrins by their environmental conditions, including changes in the concentration of divalent cations such as Ca(2+). The assembly of actin by these dehydrins was assessed by sedimentation assays and viewed by transmission electron and atomic force microscopy. Phosphorylation allowed both dehydrins to polymerize actin filaments. These results support the hypothesis that dehydrins stabilize the cytoskeleton under stress conditions and further that phosphorylation may be an important feature of this stabilization.
Rahman, L. N., V. V. Bamm, et al. (2011) Zinc induces disorder-to-order transitions in free and membrane-associated Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2: a solution CD and solid-state ATR-FTIR study Amino Acids 40: 1485-1502. 10.1007/s00726-010-0759-0Dehydrins are intrinsically unstructured proteins that are expressed in plants experiencing extreme environmental conditions such as drought or low temperature. Although their role is not completely understood, it has been suggested that they stabilize proteins and membrane structures during environmental stress and also sequester metals such as zinc. Here, we investigate two dehydrins (denoted as TsDHN-1 and TsDHN-2) from Thellungiella salsuginea. This plant is a crucifer that thrives in the Canadian sub-Arctic (Yukon Territory) where it grows on saline-rich soils and experiences periods of both extreme cold and drought. We show using circular dichroism and attenuated total reflection-Fourier transform infrared spectroscopy that ordered secondary structure is induced and stabilized in these proteins, both in free and vesicle-bound form, by association with zinc. In membrane-associated form, both proteins have an increased proportion of beta-strand conformation induced by the cation, in addition to the amphipathic alpha-helices formed by their constituent K-segments. These results support the hypothesis that dehydrins stabilize plant plasma and organellar membranes in conditions of stress, and further that zinc may be an important co-factor in stabilization. Whereas dehydrins in the cytosol of a plant cell undergoing dehydration or temperature stress form bulk hydrogels and remain primarily disordered, dehydrins with specific membrane- or protein-associations will have induced ordered secondary structures.
Radyukina, N. L., Y. V. Ivanov, et al. (2011) Regulation of Gene Expression Governing Proline Metabolism in Thellungiella salsuginea by NaCl and Paraquat Russian Journal of Plant Physiology 58: 643-652. 10.1134/s102144371104011xDifferential expression of the proline metabolism genes in Thellungiella salsuginea (Pall) E. Schulz was investigated under salinity (100 and 300 mM NaCl), upon the effect of paraquat (0.1 mu M), and at their joint action. It was shown that, depending on the intensity of stress factor, expression of the P5CS1 gene was induced in the leaves (at 100 mM NaCl) or roots (at 300 mM NaCl). When the plants on control medium were treated with paraquat, the proline content changed only in the leaves. Time course of proline content in the leaves complied with the dynamic of P5CS1 gene expression, while expression of PDH gene essentially did not change. When the plants, which experienced salt stress, were treated with paraquat, the content of proline and the P5CS1 mRNA level increased even more. The obtained results suggest a complicated nature of signaling between the organs of the halophyte Th. salsuginea causing expression of the proline biosynthesis genes in the leaves and roots under the effect of salinity, paraquat, or upon their joint action. The proline catabolism in these plants was maintained essentially unchanged, which is probably related to the participation of proline and/or the products of its degradation in the pathways of other metabolite biosynthesis. We suggested that proline took part in ROS scavenging process and proline level was under strong control in Th. salsuginea.
Perez-Alfocea, F., M. Edmond Ghanem, et al. (2011) Omics of Root-to-Shoot Signaling Under Salt Stress and Water Deficit Omics-a Journal of Integrative Biology 15: 893-901. 10.1089/omi.2011.0092Maximizing crop yield depends on the leaves receiving an optimal supply of water, mineral nutrients, small organic molecules, proteins, and hormones from the root system via the xylem. Soil drying and salinization alter these xylem fluxes, and modern omics techniques offer unparalleled opportunities to understand the complexity of these responses. Although absolute xylem concentrations of any constituent depend on the genotype and xylem sap sampling methodology, analysis of the relative changes in concentrations has revealed some conserved behavior. Typically, these stresses increase xylem concentrations of the plant hormone abscisic acid (ABA) that limits crop water loss, but decrease the concentrations of certain cytokinins that stimulate expansive growth and prevent premature leaf senescence. Further understanding of the ionic and biophysical alterations in the rhizosphere environment that cause increased xylem concentrations of the ethylene precursor (ACC) is needed. Interactions of these plant hormones with plant nutrient status and xylem nutrient delivery may be important in tuning plant responses to their environment. Xylem proteomics is an emerging area that will help understand mechanisms of plant stress adaptation. Using omics techniques to underpin rootstock-mediate plant improvement is likely to improve crop yields in dry or saline soil.
Pedras, M. S. C. (2011). Fungal Attack and Cruciferous Defenses: Tricking Plant Pathogens. in Biological Activity of Phytochemicals. D. R. Gang (eds). 41: 127-139. Pashkovskiy, P. P. and N. L. Raduykina. (2011) MicroRNA and regulation of gene expression of Cu/Zn-SOD in Thellungiella salsuginea plants under effect of the different concentrations of copper Tomsk State University Journal of Biology 147-151.One of the important element of posttranscriptional regulation of gene activity is a mechanism for silencing genes, due to RNA interference, which is associated with expression of small RNAs. In Arabidopsis thaliana L. plants found two major classes of small RNAs in size 21-23 base pair involved in the suppression of gene expression: siRNA (small interfering) and miRNA (microRNA). There is increasing evidence that under stress conditions changes as the expression of miRNA and expression of they targets genes and the activity of miRNA-protein complexes. The purpose of present study was to examine the role of microRNAs in posttranscriptional regulation of genes Cu/Zn-SOD and CCS gene in a plant Thellungiella salsuginea under the influence of different concentrations of copper, given that copper is a trace element essential for plant nutrition and is a member of the cofactors of plastocyanin, Cu/Zn- SOD, cytochrome c and laccase. Object of research is plants Thellungiella salsuginea, Pallas were grown in water culture in a medium of Johnson. At the age of 6 weeks the plants were divided into groups and subjected to treatment CuSO4 (0,1 and 100 muM). Experiments were performed in three biological and three analytical replications. Isolation of total RNA was performed TRIzol® reagent. Level of expression of miRNAs was assessed by Northern blot hybridization. Evaluation of protein content CSD1 and CCS1 performed using Western blot analysis by standard methods Laemmli (1970). The level of expression of genes other studied was performed by RT-PCR with gene-specific primers. Several studies have shown that in the conditions of a copper lack decrease content of the protein Cu/Zn-SOD and its enzymatic activity. It was also shown that in A. thaliana and other higher plants, various concentrations of copper regulate expression of mRNA CCS1, encoding a chaperone copper, delivering Cu to apoprotein different isoenzymes of Cu/Zn-SOD. As have shown Nozern-blot hybridization of total RNA Th. salsuginea, at entering 100 muM CuSO4 in a nutrient medium occurred almost full inhibition of an expression miR398. In experiments with absence of copper in a nutrient medium observed increase expression of miR398. The study of CSD1 expression showed that after 24 hours absence of copper in the growth medium caused a decrease expression of this gene. When the copper concentration was 100 muM in all parts of the plant Th. salsuginea observed increase in mRNA CSD1. However, western blot analysis with specific forms for the cytosolic Cu/Zn- SOD antibody revealed that this protein was determined only in the leaves of plants at all studied concentrations of copper in the medium. This give evidence that the synthesis of the protein may be exercised only in the leaves. At high concentrations of copper (100 muM) in the leaves was shown enhance of CSD1 expression, however, increase of the protein content CSD1 didn`t happened. On the other hand, the study of gene expression CCS1 copper chaperone for SOD in leaves and roots showed that the amount of mRNA of this gene increased in the leaves at a concentration of CuSO4 1 and 100 muM, in the absence of copper as expression of this gene significantly decreased in the leaves and roots. CCS1 protein found only in the leaves in the control plants (0,25 muM CuSO4), as well as 1 muM CuSO4 in the nutrient medium. In terms of different concentrations of copper in the growth medium of plants observed reciprocal relationship between the expression of miR398 and genes expression CSD1 and CCS1. We can assume that under conditions of different concentrations of copper in the growth medium, there is a miR398-mediated regulation of genes CSD1 and CCS1. It is likely that the increase due to miR398 regulation of mRNA CCS1 in the absence of copper in the growth medium reduces the number of copper delivered to the protein CSD1 and, consequently, reduced its contents in the leaves. Probably, in the absence of copper in the nutrient medium may be coming redistribution of copper ions between Cu/Zn-SOD and copper-containing proteins other important, for example, such as plastocyanin. регуляции генов Cu/Zn-СОД и гена CCS в растении Thellungiella salsuginea при действии различных концентраций меди. Объектом исследований являлись растения Thellungiella salsuginea. Оценку содержания белка CSD1 и CCS1 проводили с помощью вестерн-блот анализа, уровень экспрессии других генов проводили методом ОТ-ПЦР с ген-специфичными праймерами. Показано, что в зависимости от концентрации меди в питательной среде в растениях прослеживается реципрокный характер взаимоотношений между экспрессией miR398 и экспрессией генов CSD1 CCS1. Сделано предположение, что повышенное содержание меди в питательной среде ингибирует процессинг белка Cu/Zn-СОД за счет нарушения структуры активного центра ионами меди.
Pasapula, V., G. Shen, et al. (2011) Expression of an Arabidopsis vacuolar H+-pyrophosphatase gene (AVP1) in cotton improves drought- and salt tolerance and increases fibre yield in the field conditions Plant Biotechnology Journal 9: 88-99. 10.1111/j.1467-7652.2010.00535.xThe Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump on the vacuolar membrane. Overexpression of AVP1 in Arabidopsis, tomato and rice enhances plant performance under salt and drought stress conditions, because up-regulation of the type I H+-PPase from Arabidopsis may result in a higher proton electrochemical gradient, which facilitates enhanced sequestering of ions and sugars into the vacuole, reducing water potential and resulting in increased drought-and salt tolerance when compared to wild-type plants. Furthermore, over-expression of AVP1 stimulates auxin transport in the root system and leads to larger root systems, which helps transgenic plants absorb water more efficiently under drought conditions. Using the same approach, AVP1-expressing cotton plants were created and tested for their performance under high-salt and reduced irrigation conditions. The AVP1-expressing cotton plants showed more vigorous growth than wild-type plants in the presence of 200 mM NaCl under hydroponic growth conditions. The soil-grown AVP1-expressing cotton plants also displayed significantly improved tolerance to both drought and salt stresses in greenhouse conditions. Furthermore, the fibre yield of AVP1-expressing cotton plants is at least 20% higher than that of wild-type plants under dry-land conditions in the field. This research indicates that AVP1 has the potential to be used for improving crop's drought- and salt tolerance in areas where water and salinity are limiting factors for agricultural productivity.
Nazar, R., N. Iqbal, et al. (2011) Understanding the significance of sulfur in improving salinity tolerance in plants Environmental and Experimental Botany 70: 80-87. 10.1016/j.envexpbot.2010.09.011Salinity is a major abiotic stress factor affecting plant growth and productivity worldwide. The salinity-induced reduction in photosynthesis, growth and development of plants is associated with ionic/osmotic effects, nutritional imbalance or oxidative stress. Plants develop several mechanisms to induce tolerance to overcome salinity effects. Of the several possible mechanisms to reduce the effects of salinity stress, management of mineral nutrients status of plants can be the efficient defense system. Sulfur (S) is an important plant nutrient involved in plant growth and development. It is considered fourth in importance after nitrogen, phosphorus, and potassium. It is an integral part of several important compounds, such as vitamins, co-enzymes, phytohormones and reduced sulfur compounds that decipher growth and vigor of plants under optimal and stress conditions. The present review focuses on improving our understanding on the salinity effects on physiology and metabolism of plants and the importance of sulfur in salinity tolerance. (C) 2010 Elsevier B.V. All rights reserved.
Morales, A. J., P. Bajgain, et al. (2011) Physiological responses of Chenopodium quinoa to salt stress International Journal of Plant Physiology and Biochemistry 3: 219-232.Physiological responses to salt stress were measured in Chenopodium quinoa, a regionally important halophytic staple crop of Andean South America. In a greenhouse experiment, salt (NaCl) was applied to quinoa varieties, Chipaya and KU-2, and to the model halophyte Thellungiella halophila to assess their relative responses to salt stress. Height and weight data from a seven-week time course demonstrated that both C. quinoa cultivars exhibited greater tolerance to salt stress than the model plant T. halophila in these specific conditions. In a separate growth chamber experiment, two quinoa cultivars (chipaya and ollague) adapted to saline soils and one quinoa cultivar (CICA-17) adapted to a lower elevation were grown hydroponically and evaluated for physiological responses to four salt stress treatments. Tissues collected from the growth chamber experiments were used to obtain leaf water content, tissue ion concentrations, compatible solute concentrations, and RNA for real-time PCR. High levels of trigonelline, a known osmoprotectant, were found to accumulate in the high salt treatment suggesting a key role in salt tolerance of quinoa. The expression profiles of genes involved in salt stress, showed constitutive expression in leaf tissue and up-regulation in root tissue in response to salt stress. These data suggest that quinoa tolerates salt through a combination of salt exclusion and accumulation mechanisms.
Liu, L., Y. Wang, et al. (2011) Cloning of a Vacuolar H+-pyrophosphatase Gene from the Halophyte Suaeda corniculata whose Heterologous Overexpression Improves Salt, Saline-alkali and Drought Tolerance in Arabidopsis Journal of Integrative Plant Biology 53: 731-742. 10.1111/j.1744-7909.2011.01066.xSalt, saline-alkali conditions, and drought are major environmental factors limiting plant growth and productivity. The vacuolar H+-translocating inorganic pyrophosphatase (V-H+-PPase) is an electrogenic proton pump that translocates protons into vacuoles in plant cells. Expression of V-H+-PPase increases in plants under a number of abiotic stresses, and is thought to have an important role in adaptation to abiotic stress. In this work, we report the isolation and characterization of the gene, ScVP, encoding a vacuolar inorganic pyrophosphatase (V-H+-PPase) from the halophyte, Suaeda corniculata. Semi-quantitative reverse transcription-polymerase chain reaction analysis showed that ScVP was induced in roots, stems and leaves under treatment with salt, saline-alkali and drought. Compared with wild-type (WT) Arabidopsis, transgenic plants overexpressing ScVP accumulated more Na+ in leaves and roots, and showed increased tolerance to high salinity, saline-alkali and drought stresses. The germination percentage of transgenic Arabidopsis seeds was higher than that of WT seeds under the abiotic stresses. The root length of transgenic plants under salt stress was longer than that of WT plants. Furthermore, the rate of water loss during drought stress was higher in WT than in transgenic plants. Collectively, these results indicate that ScVP plays an important role in plant tolerance to salt, saline-alkali and drought stress.
Kushwaha, H. R., G. Kumar, et al. (2011) Analysis of a salinity induced BjSOS3 protein from Brassica indicate it to be structurally and functionally related to its ortholog from Arabidopsis Plant Physiology and Biochemistry 49: 996-1004. 10.1016/j.plaphy.2011.03.013Arabidopsis has been a favorite model system for plant biologist. It is anticipated that comparative analysis of this plant with other members of Brassicaceae may aid in identification of orthologs playing role as key genetic determinants for salinity response. In this endeavor, we have recently identified SOS family members from Brassica juncea in our laboratory and reported their salinity responsive transcriptional induction in seedlings of various diploid and amphidiploids species. In the present study, we have carried out detailed time kinetics for BjSOS3 expression in a salinity tolerant B. juncea var. CS52. Transcript analysis at the sensitive growth stages of plants viz, seedling and reproductive stage indicated clear differential transcriptional regulation of BjSOS3 under non-induced as well as salinity induced conditions in a time and organ specific manner, mirroring their respective tolerance physiology. Similar to its ortholog from Arabidopsis thaliana, the modeled BjSOS3 protein show typical features of a Ca(2+) binding protein with four conserved EF-hands. We have also attempted to study the binding of SOS3 protein with the modeled SOS2 protein. It has been established that SOS3 protein senses Ca(2+) though the binding is very weak: we show the down regulation of BjSOS3 mRNA in presence of calcium chelator - EGTA under the various stress conditions including ABA. In situ localization of BjSOS3-GFP fusion protein in onion peel has shown its presence strongly in plasma membrane as well as cytosol. The leads presented in the paper will assist in understanding and establishing the SOS signaling machinery in B. juncea. (C) 2011 Elsevier Masson SAS. All rights reserved.
Kosova, K., P. Vitamvas, et al. (2011) Plant proteome changes under abiotic stress - Contribution of proteomics studies to understanding plant stress response Journal of Proteomics 74: 1301-1322. 10.1016/j.jprot.2011.02.006Plant acclimation to stress is associated with profound changes in proteome composition. Since proteins are directly involved in plant stress response, proteomics studies can significantly contribute to unravel the possible relationships between protein abundance and plant stress acclimation. In this review, proteomics studies dealing with plant response to a broad range of abiotic stress factors-cold, heat, drought, waterlogging, salinity, ozone treatment, hypoxia and anoxia, herbicide treatments, inadequate or excessive light conditions, disbalances in mineral nutrition, enhanced concentrations of heavy metals, radioactivity and mechanical wounding are discussed. Most studies have been carried out on model plants Arabidopsis thaliana and rice due to large protein sequence databases available; however, the variety of plant species used for proteomics analyses is rapidly increasing. Protein response pathways shared by different plant species under various stress conditions (glycolytic pathway, enzymes of ascorbate-glutathione cycle, accumulation of LEA proteins) as well as pathways unique to a given stress are discussed. Results from proteomics studies are interpreted with respect to physiological factors determining plant stress response. In conclusion, examples of application of proteornics studies in search for protein markers underlying phenotypic variation in physiological parameters associated with plant stress tolerance are given. (C) 2011 Elsevier B.V. All rights reserved.
Khedr, A. H. A., M. S. Serag, et al. (2011) A DREB gene from the xero-halophyte Atriplex halimus is induced by osmotic but not ionic stress and shows distinct differences from glycophytic homologues Plant Cell Tissue and Organ Culture 106: 191-206. 10.1007/s11240-010-9906-2Studying the regulation of stress inducible genes can lead to understanding of the mechanisms by which halophytes maintain growth and thrive under abiotic stress. Verifying whether ionic or osmotic components of salt stress control the regulation of Dehydration Responsive Element- binding transcription factor (DREB) was investigated in the present study. DREB belongs to AP2/EREB group that is induced under abiotic stress and regulates many stress inducible genes that contain DRE binding sites in their promoters. DREB in Atriplex halimus was regulated by the osmotic component but not by the ionic one of salt stress. It seemed that DREB was not involved in the regulation of sodium manipulating genes like NHX1, SOS1 or H (+)-PPase. Moreover, DREB could be involved directly of indirectly in CMO regulation because of timing of induction. Also, DREB was the most upregulated gene under salt (fivefold) and drought (twofold) conditions, which reinforced the importance of this gene in A. halimus tolerance to stress. Moreover, its constitutive expression under normal conditions also indicated its involvement in other growth and developmental programs. The tolerance of A. halimus and of halophytes, in general, could be attributed to the constitutive expression of its genes and differences in protein structures between halophytes and glycophytes.
Guan, B., Y. Hu, et al. (2011) Molecular characterization and functional analysis of a vacuolar Na+/H+ antiporter gene (HcNHX1) from Halostachys caspica Molecular Biology Reports 38: 1889-1899. 10.1007/s11033-010-0307-8According to sequences of several vacuolar Na+/H+ antiporter genes from Xinjiang halophytic plants, a new vacuolar Na+/H+ antiporter gene (HcNHX1) from the halophyte Halostachys caspica was obtained by RACE and RT-PCR using primers corresponding to conserved regions of the coding sequences. The obtained HcNHX1 cDNA was 1,983 bp and contained a 1,656 bp open reading frame encoding a deduced protein of 551 amino acid residues. The deduced amino acid sequence showed high identity with other NHX1 we have cloned previously from halophyte in Xinjiang desert area. The phylogenetic analysis showed that HcNHX1 formed a clade with NHX homologs of Chenopodiaceae. Expression profiles under salt treatment and ABA induction were investigated, and the results revealed that expression of HcNHX1 was induced by NaCl and ABA. To compare the degree of salt tolerance, we over-expressed HcNHX1 in Arabidopsis. Two transgenic lines grew more vigorously than the wild type (WT) under salt stress. The analysis of ion contents indicated that under salt stress, the transgenic plants compartmentalized more Na+ in the leaves compared with wild-type plants. Together, these results suggest that the products of the novel gene HcNHX1 from halophyte Halostachys caspica is a functional tonoplast Na+/H+ antiporter.
Golldack, D., I. Lueking, et al. (2011) Plant tolerance to drought and salinity: stress regulating transcription factors and their functional significance in the cellular transcriptional network Plant Cell Reports 30: 1383-1391. 10.1007/s00299-011-1068-0Understanding the responses of plants to the major environmental stressors drought and salt is an important topic for the biotechnological application of functional mechanisms of stress adaptation. Here, we review recent discoveries on regulatory systems that link sensing and signaling of these environmental cues focusing on the integrative function of transcription activators. Key components that control and modulate stress adaptive pathways include transcription factors (TFs) ranging from bZIP, AP2/ERF, and MYB proteins to general TFs. Recent studies indicate that molecular dynamics as specific homodimerizations and heterodimerizations as well as modular flexibility and posttranslational modifications determine the functional specificity of TFs in environmental adaptation. Function of central regulators as NAC, WRKY, and zinc finger proteins may be modulated by mechanisms as small RNA (miRNA)-mediated posttranscriptional silencing and reactive oxygen species signaling. In addition to the key function of hub factors of stress tolerance within hierarchical regulatory networks, epigenetic processes as DNA methylation and posttranslational modifications of histones highly influence the efficiency of stress-induced gene expression. Comprehensive elucidation of dynamic coordination of drought and salt responsive TFs in interacting pathways and their specific integration in the cellular network of stress adaptation will provide new opportunities for the engineering of plant tolerance to these environmental stressors.
German, D. A. and P. V. Veselova. (2011) Type specimens of Brassicaceae (Cruciferae) taxa deposited in the Herbarium of Institute of Botany and Phytointroduction of Kazakhstan (AA) Botanicheskii Zhurnal 96: 1378-1388.The data on the type collection of Cruciferae deposited in the Herbarium AA are reported. The type material includes 94 specimens (12 holotypes, 4 lectotypes, 8 isotypes, 25 isolectotypes, 23 syntypes, 16 paratypes, 1 isoparatype, as well as 6 authentic specimens not cited in protologues; in two cases two names are based on the same specimen) representing 51 Cruciferae taxa (39 species, 9 varieties, and 3 forms); 30 of them are firstly reported to be represented by any original material in AA. Lectotypes of 3 names are designated (Eutrema pseudocordifolium and Parrya michaelis - AA, P. subsiliquosa - LE).
Genga, A., M. Mattana, et al. (2011) Plant Metabolomics: A Characterisation of Plant Responses to Abiotic Stresses Abiotic Stress in Plants - Mechanisms and Adaptations 309-350.Early changes in physiological and oxidative status induced by salt stress were monitored in two Brassicaceae plants differing in their tolerance to salinity, Cakile maritima (halophyte) and Arabidopsis thaliana (glycophyte). Growth response and antioxidant defense of C. maritima under 400 mM NaCl were compared with those of A. thaliana exposed to 100 mM NaCl. Salinity induced early growth reduction that is less pronounced in C. maritima than in A. thaliana. Maximum hydrogen peroxide (H2O2) level occurred in the leaves of both species 4 h after the onset of salt treatment. A rapid decline in H2O2 concentration was observed thereafter in C. maritima, whereas it remained high in A. thaliana. Correlatively, superoxide dismutase, catalase and peroxidase activities increased at 4 h of treatment in C. maritima and decreased thereafter. However, the activity of these enzymes remained higher in treated plants than that in controls, regardless of the duration of treatment, in A. thaliana. The concentrations of malondialdehyde (MDA) reached maximum values at 24 h of salt stress in both species. Again, MDA levels decreased later in C. maritima, but remained high in A. thaliana. The contents of alpha-tocopherol remained constant during salt stress in C. maritima and decreased during the first 24 h of salt stress and then remained low in A. thaliana. The results clearly showed that C. maritima, in contrast to A. thaliana, can rapidly evolve physiological and antioxidant mechanisms to adapt to salt and manage the oxidative stress. This may explain, at least partially, the difference in salt tolerance between halophytes and glycophytes.
Dong, Q.-L., D.-D. Liu, et al. (2011) MdVHP1 encodes an apple vacuolar H+-PPase and enhances stress tolerance in transgenic apple callus and tomato Journal of Plant Physiology 168: 2124-2133. 10.1016/j.jplph.2011.07.001Vacuolar H+-translocating inorganic pyrophosphatase (VHP, EC 3.6.1.1) is an electrogenic proton pump, which is related to growth as well as abiotic stress tolerance in plants. In this study, a VHP gene MdVHP1 was isolated from apple. The alignment of nucleotide and amino acid sequences showed that it encoded a type I VHP protein. It expressed in vegetative and reproductive organs, and its expression was induced by salt, PEG-mediated osmotic stress, cold and heat in apple in vitro shoot cultures. MdVHP1 expression showed a similar pattern in different apple tissues, but different change dynamics in response to abiotic stresses, compared with MdVHP2 (another MdVHP gene in apple). MdVHP1 overexpression enhanced tolerance to salt, PEG-mimic drought, cold and heat in transgenic apple calluses, which was related to an increased accumulation of proline and decreased MDA content compared with control calluses. In addition, MdVHP1 overexpression confers improved tolerance to salt and drought in transgenic tomato, along with an increased ion accumulation, high RWC and low solute potential compared with wild type. These results indicate that MdVHP1 is an important regulator for plant tolerance to abiotic stresses by modulating internal stores of ions and solutes. (C) 2011 Elsevier GmbH. All rights reserved.
Dassanayake, M., D. H. Oh, et al. (2011) The genome of the extremophile crucifer Thellungiella parvula Nature Genetics 43: 913-U137. 10.1038/ng.889Thellungiella parvula(1) is related to Arabidopsis thaliana and is endemic to saline, resource-poor habitats(2), making it a model for the evolution of plant adaptation to extreme environments. Here we present the draft genome for this extremophile species. Exclusively by next generation sequencing, we obtained the de novo assembled genome in 1,496 gap-free contigs, closely approximating the estimated genome size of 140 Mb. We anchored these contigs to seven pseudo chromosomes without the use of maps. We show that short reads can be assembled to a near-complete chromosome level for a eukaryotic species lacking prior genetic information. The sequence identifies a number of tandem duplications that, by the nature of the duplicated genes, suggest a possible basis for T. parvula's extremophile lifestyle. Our results provide essential background for developing genomically influenced testable hypotheses for the evolution of environmental stress tolerance.
Chang, L.-l., B. Han, et al. (2011) Advance in Molecular Responsive Mechanisms of Thellungiella halophila under Salt Stress Xibei Zhiwu Xuebao 31: 2565-2571.Soil salinity is considered as one of the major abiotic stress in nature. Soil containing high concentrations of sodium ions will restrict plant growth and development seriously. For clarifying the salt tolerance mechanism in plant and breeding salt tolerance crops, it is crucial to illuminate the physiological and molecular mechanism of plant response to salt stress. Thellungiella halophila as a close relative of Arabidopsis can survive in extreme salinity condition and thus has been developed into a new model system for studying plant salt tolerance mechanism. This review summarized the current research progress and the prospects on the molecular mechanism of T. halophila response to salt stress, including the ion homeostasis (containing Na+ absorption, efflux and compartmentalization into cell vacuole), osmotic homeostasis and detoxification.
Beritognolo, I., A. Harfouche, et al. (2011) Comparative study of transcriptional and physiological responses to salinity stress in two contrasting Populus alba L. genotypes Tree Physiology 31: 1335-1355. 10.1093/treephys/tpr083Soil salinity is an important limiting factor to tree growth and productivity. Populus alba L. is a moderately salt-tolerant species and its natural populations are adapted to contrasting environments, thus providing genetic resources to identify key genes for tolerance to abiotic stress, such as salinity. To elucidate the molecular and genetic basis of variation for salinity tolerance in P. alba, we analyzed the short-term ecophysiological and transcriptome response to salinity. Two contrasting genotypes, 6K3, salt sensitive, and 14P11, salt tolerant, originating from North and South Italy, respectively, were challenged with salt stress (200 mM NaCl). Sodium accumulated in the leaves of salt-treated plants and its concentration increased with time. The net photosynthesis was strongly reduced by salinity in both genotypes, with 6K3 being significantly more affected than 14P11. The transcriptional changes in leaves were analyzed using cDNA microarrays containing about 7000 stress-related poplar expressed sequence tags (EST). A microarray experiment based on RNA pooling showed a number of salinity--regulated transcripts that markedly increased from 3 h to 3 days of salinity treatment. Thus, a detailed analysis was performed on replicated plants collected at 3 days, when similar to 20% of transcripts showed significant change induced by salinity. In 6K3, there were more genes with decreased expression than genes with increased expression, whereas such a difference was not found in 14P11. Most transcripts with decreased expression were shared between the two genotypes, whereas transcripts with increased expression were mostly regulated in a genotype-specific manner. The commonly decreased transcripts (71 genes) were functionally related to carbohydrate metabolism, energy metabolism and photosynthesis. These biological processes were consistent with the strong inhibition of photosynthesis, caused by salinity. The commonly increased transcripts (13 genes) were functionally related to primary metabolism and biosynthesis of proteins and macromolecules. The salinity-increased transcripts discriminated the molecular response of the two genotypes. In 14P11, the 21 genes specifically salinity-induced were related to stress response, cell development, cell death and catabolism. In 6K3, the 15 genes with salinity-increased expression were involved in protein biosynthesis, metabolism of macromolecules and cell organization and biogenesis. The difference in transcriptome response between the two genotypes could address the molecular basis of intra-specific variation of salinity tolerance in P. alba.
Atares, A., E. Moyano, et al. (2011) An insertional mutagenesis programme with an enhancer trap for the identification and tagging of genes involved in abiotic stress tolerance in the tomato wild-related species Solanum pennellii Plant Cell Reports 30: 1865-1879. 10.1007/s00299-011-1094-ySalinity and drought have a huge impact on agriculture since there are few areas free of these abiotic stresses and the problem continues to increase. In tomato, the most important horticultural crop worldwide, there are accessions of wild-related species with a high degree of tolerance to salinity and drought. Thus, the finding of insertional mutants with other tolerance levels could lead to the identification and tagging of key genes responsible for abiotic stress tolerance. To this end, we are performing an insertional mutagenesis programme with an enhancer trap in the tomato wild-related species Solanum pennellii. First, we developed an efficient transformation method which has allowed us to generate more than 2,000 T-DNA lines. Next, the collection of S. pennelli T(0) lines has been screened in saline or drought conditions and several presumptive mutants have been selected for their salt and drought sensitivity. Moreover, T-DNA lines with expression of the reporter uidA gene in specific organs, such as vascular bundles, trichomes and stomata, which may play key roles in processes related to abiotic stress tolerance, have been identified. Finally, the growth of T-DNA lines in control conditions allowed us the identification of different development mutants. Taking into account that progenies from the lines are being obtained and that the collection of T-DNA lines is going to enlarge progressively due to the high transformation efficiency achieved, there are great possibilities for identifying key genes involved in different tolerance mechanisms to salinity and drought.
Aleman, F., M. Nieves-Cordones, et al. (2011) Root K+ Acquisition in Plants: The Arabidopsis thaliana Model Plant and Cell Physiology 52: 1603-1612. 10.1093/pcp/pcr096K+ is an essential macronutrient required by plants to complete their life cycle. It fulfills important functions and it is widely used as a fertilizer to increase crop production. Thus, the identification of the systems involved in K+ acquisition by plants has always been a research goal as it may eventually produce molecular tools to enhance crop productivity further. This review is focused on the recent findings on the systems involved in K+ acquisition. From Epstein's pioneering work > 40 years ago, K+ uptake was considered to consist of a high- and a low-affinity component. The subsequent molecular approaches identified genes encoding K+ transport systems which could be involved in the first step of K+ uptake at the plant root. Insights into the regulation of these genes and the proteins that they encode have also been gained in recent studies. A demonstration of the role of the two main K+ uptake systems at the root, AtHKA5 and AKT1, has been possible with the study of Arabidopsis thaliana T-DNA insertion lines that knock out these genes. AtHAK5 was revealed as the only uptake system at external concentrations < 10 mu M. Between 10 and 200 mu M both AtHAK5 and AKT1 contribute to K+ acquisition. At external concentrations > 500 mu M, AtHAK5 is not relevant and AKT1's contribution to K+ uptake becomes more important. At 10 mM K+, unidentified systems may provide sufficient K+ uptake for plant growth.
Abraham, E., I. P. Salamo, et al. (2011) Identification of Arabidopsis and Thellungiella genes involved in salt tolerance by novel genetic system Acta Biologica Szegediensis 55: 53-57.High salinity is a major constraint to plant growth and development. Plants respond to environmental stresses by altering gene expression pattern via a complex signaling network. We developed a novel genetic system based on conditional cDNA overexpression to isolate genes involved in plant salt tolerance. Transformation-ready Arabidopsis and Thellungiella cDNA libraries cloned in a plant expression vector under control of an inducible promoter were used to transfer into Arabidopsis, where activation of the inserted cDNA can lead to conditional phenotypes. Transgenic lines were tested in different screens (germination assay, growth-survival test). Our genetic system was suitable to identify not only well-known genes coding for proteins involved in stress tolerance, but several novel regulatory genes were discovered. Line N33 shows estradiol-dependent salt tolerant germination. It has a single T-DNA insertion; the full length cDNA encodes an unknown protein. This gene was designated as Novel Salt Tolerance (NSTO). The Thellungiella library allowed large scale random interspecific gene transfer and subsequent identification of novel regulatory genes which control stress tolerance in halophyte species. Our data illustrate that application of inducible cDNA expression libraries provides an efficient tool for genetic identification and functional analysis of novel positive or negative regulators of plant salt tolerance. Acta Biol Szeged 55(1):53-57 (2011).
Zhou, Y. J., F. Gao, et al. (2010) Alterations in phosphoproteome under salt stress in Thellungiella roots Chinese Science Bulletin 55: 3673-3679. 10.1007/s11434-010-4116-1High salinity stress is a major environmental factor that limits plant's distribution and productivity. An Arabiclopsis-related halophyte, Thellungiella halophila, is an emerging model system used for plant abiotic stress tolerance research. Previous studies have suggested that protein phosphorylation has a crucial role in the high salinity response in plants. However, the phosphoproteome differential expression under high salinity stress in halophytes has not been well studied. In this report, phosphoproteome differential expression was analyzed under high salinity stress in Thellungiella roots. Twenty-six putative phosphoproteins were found to have changed expression pattern at the post-translational level. Twenty of these were identified by mass spectrometric analysis, including 18 upregulated and two downregulated phosphoproteins. These proteins were involved in a variety of cellular processes, such as signal transduction, ROS detoxification, energy pathway, protein synthesis and protein folding. While most of these salt-responsive putative phosphoproteins are known salt-stress-related proteins, some of them have not been previously reported. Our results provide not only new insights into salt stress responses in Thellungiella but also a good foundation for further investigation of these high salinity-regulated phosphoproteins.
Zhang, S., N. Li, et al. (2010) Over-expression of TsCBF1 gene confers improved drought tolerance in transgenic maize Molecular Breeding 26: 455-465. 10.1007/s11032-009-9385-5The DREB/CBF transcription factors play important roles during low temperature, drought, and high-salt stress in higher plants. In this paper, we transferred TsCBF1 gene from a dicotyledonous halophyte Thellungiella halophila into the monocotyledonous crop maize (Zea mays L.). PCR, Southern blot, and RT-PCR analysis indicated that the TsCBF1 gene had been integrated into the genome of transgenic plants and was expressed in their progeny. After 14 days of drought stress treatments, transgenic plants showed improved drought tolerance with higher Relative Water Content (RWC), higher solute accumulation, and less cell damage compared with wild-type (WT) plants. Most importantly, they showed shorter anthesis-silking interval (ASI) and produced much higher grain yield than WT under drought stress. The results indicate that the TsCBF1 gene conferred enhanced drought tolerance to maize plants and may have utility for improving tolerance to other abiotic stresses as well.
Zhang, J.-L., T. J. Flowers, et al. (2010) Mechanisms of sodium uptake by roots of higher plants Plant and Soil 326: 45-60. 10.1007/s11104-009-0076-0The negative impact of soil salinity on agricultural yields is significant. For agricultural plants, sensitivity to salinity is commonly (but not exclusively) due to the abundance of Na(+) in the soil as excess Na(+) is toxic to plants. We consider reducing Na(+) uptake to be the key, as well as the most efficient approach, to control Na(+) accumulation in crop plants and hence to improve their salt resistance. Understanding the mechanism of Na(+) uptake by the roots of higher plants is crucial for manipulating salt resistance. Hence, the aim of this review is to highlight and discuss recent advances in our understanding of the mechanisms of Na(+) uptake by plant roots at both physiological and molecular levels. We conclude that continued efforts to investigate the mechanisms of root Na(+) uptake in higher plants are necessary, especially that of low-affinity Na(+) uptake, as it is the means by which sodium enters into plants growing in saline soils.
Wang, Y.-q., X.-l. Wang, et al. (2010) Membrane-Potential Alteration During K+ Uptake of Different Salt-Tolerant Wheat Varieties Agricultural Sciences in China 9: 974-979. 10.1016/s1671-2927(09)60179-6K+ is the most abundant cation in plant cells and plays an important role in many ways. K+ uptake of plant has respect to its salt resistant capacity. There are two categories of channel transportation for plants to uptake K+, one is through K+ channels and the other is through nonselective cation channels (NSCCs). The transmembrane localization of K+ may change membrane potential (MP). In this paper, three wheat varieties with different salt tolerance were selected and the MP was measured by microelectrode during K+ uptake. The results showed that the effects of K+ uptake on MP through K+ channels or NSCCs were distinct. K+ influx through K+ channels led to MP hyperpolarization, while K+ influx through NSCCs resulted in depolarization. Diverse MP alteration of wheat varieties with different salt tolerance was mainly due to NSCCs-mediated K+ uptake. Compared with the salt-tolerant wheat, the MP hyperpolarization during K+ uptake of salt-sensitive wheat was much more evident, probably because of the cation outflux through NSCCs during this process.
Wang, W. Q., Y. R. Wu, et al. (2010) A large insert Thellungiella halophila BIBAC library for genomics and identification of stress tolerance genes Plant Molecular Biology 72: 91-99. 10.1007/s11103-009-9553-3Salt cress (Thellungiella halophila), a salt-tolerant relative of Arabidopsis, has turned to be an important model plant for studying abiotic stress tolerance. One binary bacterial artificial chromosome (BIBAC) library was constructed which represents the first plant-transformation-competent large-insert DNA library generated for Thellungiella halophila. The BIBAC library was constructed in BamHI site of binary vector pBIBAC2 by ligation of partial digested nuclear DNA of Thellungiella halophila. This library consists of 23,040 clones with an average insert size of 75 kb, and covers 4x Thellungiella halophila haploid genomes. BIBAC clones which contain inserts over 50 kb were selected and transformed into Arabidopsis for salt tolerant plant screening. One transgenic line was found to be more salt tolerant than wild type plants from the screen of 200 lines. It was demonstrated that the library contains candidates of stress tolerance genes and the approach is suitable for the transformation of stress susceptible plants for genetic improvement.
Wang, J., X. R. Li, et al. (2010) Salt stress induces programmed cell death in Thellungiella halophila suspension-cultured cells Journal of Plant Physiology 167: 1145-1151. 10.1016/j.jplph.2010.03.008Thellungiella halophila (T. halophila) suspension-cultured cells were used to gain knowledge of the pathway of programmed cell death (PCD) in halophytes under salt stress. Several apoptotic-like features occurred in T. halophila cells after exposure to 300 mM NaCl, including the retraction of the plasma membrane from the cell wall, nuclear condensation, DNA laddering and the release of cytochrome c accompanying the increase of caspase 3-like protease activity. This process resulted in ultrastructural changes of mitochondria and Golgi bodies, and autophagy was also induced by high salinity stress. DNA laddering and caspase 3-like activity were inhibited prior to the inhibition of cell death by a specific caspase 3 inhibitor, Ac-DEVD-CHO. The results indicate that 300 mM NaCl stress-induced PCD in T. halophila is similar to animal apoptosis, and this process occurs partly through a caspase 3-like dependent kpathway. (C) 2010 Elsevier GmbH. All rights reserved.
Vinocur, B., E. Drori, et al. (2010) Plant Tolerance to Salinity Stress is Regulated by the Metabolome and by SUMOylation of SP1, a Novel Stress-associated Protein In Vitro Cellular & Developmental Biology-Animal 46: S4-S4.Salinity and waterlogging interact to reduce growth for most crop and pasture species. The combination of these stresses often cause a large increase in the rate of Na+ and Cl- transport to shoots; however, the mechanisms responsible for this are largely unknown. To identify mechanisms contributing to the adverse interaction between salinity and waterlogging, we compared two Lotus species with contrasting tolerances when grown under saline (200 mM NaCl) and O-2-deficient (stagnant) treatments. Measurements of radial O-2 loss (ROL) under stagnant conditions indicated that more O-2 reaches root tips of Lotus tenuis, compared with Lotus corniculatus. Better internal aeration would contribute to maintaining Na+ and Cl- transport processes in roots of L. tenuis exposed to stagnant-plus-NaCl treatments. L. tenuis root Na+ concentrations after stagnant-plus-NaCl treatment (200 mM) were 17% higher than L. corniculatus, with 55% of the total plant Na+ being accumulated in roots, compared with only 39% for L. corniculatus. L. tenuis accumulated more Na+ in roots, presumably in vacuoles, thereby reducing transport to the shoot (25% lower than L. corniculatus). A candidate gene for vacuole Na+ accumulation, an NHX1-like gene, was cloned from L. tenuis and identity established via sequencing and yeast complementation. Transcript levels of NHX1 in L. tenuis roots under stagnant-plus-NaCl treatment were the same as for aerated NaCl, whereas L. corniculatus roots had reduced transcript levels. Enhanced O-2 transport to roots enables regulation of Na+ transport processes in L. tenuis roots, contributing to tolerance to combined salinity and waterlogging stresses.
Taranov, V. V., M. V. Berdnikova, et al. (2010) Cold shock domain proteins in the extremophyte Thellungiella salsuginea (salt cress): gene structure and differential response to cold Molekuliarnaia biologiia 44: 889-897.Four genes encoding cold shock domain (CSD) proteins have been identified in salt cress [Thellungiella salsuginea (halophila), an extremophyte currently recognized as a promising model for studying stress tolerance]. The deduced proteins prove highly homologous to those of Arabidopsis thaliana (up to 95% identity) and are accordingly enumerated TsCSDP1-TsCSDP4; after the N-proximal conserved CSD, they have respectively 6, 2, 7, and 2 zinc finger motifs evenly spaced by Gly-rich stretches. Much lower similarity (approximately 45%) is observed in the regions upstream of TATA-box promoters of TsCSDP1 vs. AtCSP1, with numerous distinctions in the sets of identifiable cis-regulatory elements. Plasmid expression of sCSDP1 rescues a cold-sensitive cup-lacking mutant of Escherichia coli, confirming that the protein is functional. In leaves of salt cress plants under normal conditions, the mRNA levels for the four TsCSDPs relate as 10: 27: 1: 31. Chilling to 4 degrees C markedly alters the gene expression; the 4-day dynamics are different for all four genes and quite dissimilar from those reported for their Arabidopsis homologues under comparable conditions. Thus, the much greater cold hardiness of Thellungiella vs. Arabidopsis cannot be explained by structural distinctions of its CSDPs, but rather may be due to expedient regulation of their expression at low temperature.
Taranov, V. V., M. V. Berdnikova, et al. (2010) Cold shock domain proteins in the extremophyte Thellungiella salsuginea (salt cress): Gene structure and differential response to cold Molecular Biology 44: 787-794. 10.1134/s0026893310050158Four genes encoding cold shock domain (CSD) proteins have been identified in salt cress Thellungiella salsuginea (halophila), an extremophyte currently recognized as a promising model for studying stress tolerance]. The deduced proteins prove highly homologous to those of Arabidopsis thaliana (up to 95% identity) and are accordingly enumerated TsCSDP1-TsCSDP4; after the N-proximal conserved CSD, they have respectively 6, 2, 7, and 2 zinc finger motifs evenly spaced by Gly-rich stretches. Much lower similarity (similar to 45%) is observed in the regions upstream of TATA-box promoters of TsCSDP1 vs. AtCSP1, with numerous distinctions in the sets of identifiable cis-regulatory elements. Plasmid expression of TsCSDP1 (like AtCSP1/3) rescues a cold-sensitive csp-lacking mutant of Escherichia coli, confirming that the protein is functional. In leaves of salt cress plants under normal conditions, the mRNA levels for the four TsCSDPs relate as 10: 27: 1: 31. Chilling to 4A degrees C markedly alters the gene expression; the 4-day dynamics are different for all four genes and quite dissimilar from those reported for their Arabidopsis homologous under comparable conditions. Thus, the much greater cold hardiness of Thellungiella vs. Arabidopsis cannot be explained by structural distinctions of its CSDPs, but rather may be due to expedient regulation of their expression at low temperature.
Taji, T., K. Komatsu, et al. (2010) Comparative genomic analysis of 1047 completely sequenced cDNAs from an Arabidopsis-related model halophyte, Thellungiella halophila Bmc Plant Biology 10: 261 10.1186/1471-2229-10-261Background: Thellungiella halophila (also known as T. salsuginea) is a model halophyte with a small size, short life cycle, and small genome. Thellungiella genes exhibit a high degree of sequence identity with Arabidopsis genes (90% at the cDNA level). We previously generated a full-length enriched cDNA library of T. halophila from various tissues and from whole plants treated with salinity, chilling, freezing stress, or ABA. We determined the DNA sequences of 20 000 cDNAs at both the 5'- and 3' ends, and identified 9569 distinct genes. Results: Here, we completely sequenced 1047 Thellungiella full-length cDNAs representing abiotic-stress-related genes, transcription factor genes, and protein phosphatase 2C genes. The predicted coding sequences, 5'-UTRs, and 3'-UTRs were compared with those of orthologous genes from Arabidopsis for length, sequence similarity, and structure. The 5'-UTR sequences of Thellungiella and Arabidopsis orthologs shared a significant level of similarity, although the motifs were rearranged. While examining the stress-related Thellungiella coding sequences, we found a short splicing variant of T. halophila salt overly sensitive 1 (ThSOS1), designated ThSOS1S. ThSOS1S contains the transmembrane domain of ThSOS1 but lacks the C-terminal hydrophilic region. The expression level of ThSOS1S under normal growth conditions was higher than that of ThSOS1. We also compared the expression levels of Na (+)-transport-system genes between Thellungiella and Arabidopsis by using full-length cDNAs from each species as probes. Several genes that play essential roles in Na(+) excretion, compartmentation, and diffusion (SOS1, SOS2, NHX1, and HKT1) were expressed at higher levels in Thellungiella than in Arabidopsis. Conclusions: The full-length cDNA sequences obtained in this study will be essential for the ongoing annotation of the Thellungiella genome, especially for further improvement of gene prediction. Moreover, they will enable us to find splicing variants such as ThSOS1S (AB562331).
Sun, Q. H., F. Gao, et al. (2010) Identification of a new 130 bp cis-acting element in the TsVP1 promoter involved in the salt stress response from Thellungiella halophila Bmc Plant Biology 10: 90 10.1186/1471-2229-10-90Background: Salt stress is one of the major abiotic stresses affecting plant growth and productivity. Vacuolar H(+)-pyrophosphatase (H(+)-PPase) genes play an important role in salt stress tolerance in multiple species. Results: In this study, the promoter from the vacuolar H(+)-pyrophosphatase from Thellungiella halophila (TsVP1) was cloned and compared with the AVP1 promoter from Arabidopsis thaliana. Sequence analysis indicated that these two promoters had seven similar motifs at similar positions. To determine which tissues the two promoters are active in, transgenic plants were produced with expression of the GUS reporter gene under the control of one of the promoters. In transgenic Arabidopsis with the TsVP1 promoter, the GUS reporter gene had strong activity in almost all tissues except the seeds and the activity was induced in both shoots and roots, especially in the root tips, when treated with salt stress. Such induction was not found in transgenic Arabidopsis with the AVP1 promoter. By analyzing different 5' deletion mutants of the TsVP1 promoter, an 856 bp region (-2200 to -1344) was found to contain enhancer elements that increased gene expression levels. Two AAATGA motifs, which may be the key elements for the anther specific expression profile, in the deleted TsVP1 promoters (PT2 to PT6) were also identified. A 130 bp region (-667 to -538) was finally identified as the key sequence for the salt stress response by analyzing the different mutants both with and without salt stress. GUS transient assay in tobacco leaves suggested the 130 bp region was sufficient for the salt stress response. Bioinformatic analysis also revealed that there may be novel motifs in this region that are the key elements for the salt stress responsive activity of the TsVP1 promoter. Conclusions: The TsVP1 promoter had strong activity in almost all tissues except the seeds. In addition, its activity was induced by salt stress in leaves and roots, especially in root tips. A 130 bp region (-667 to -538) was identified as the key region for responding to salt stress.
Song, L., W. Ye, et al. (2010) Isolation and analysis of salt tolerance related gene (GhVP) from Gossypium hirsutum Cotton Science 22: 285-288.Vacuolar proton-translocating inorganic pyrophosphatase can acidify the vacuoles and power the vacuolar secondary active transport systems in plants. A gene, named GhVP, was isolated firstly by rapid amplification of cDNA end (RACE) from the EST sequences of the SSH (suppression subtractive hybridization) library of Gossypium hirsutum. Bioinformatics analysis showed that the gene contains an uninterrupted open reading frame of 2301 bp, encoding for a polypeptide of 766 amino acids. Homology alignment revealed that the protein has higher homologies (90 and 93%) with that from Arabidopsis thaliana and Nicotiana tabacum. The result of RT-PCR showed that the expression of GhVP tended to increase with prolonged time under 0.4% salt stress, and reached highest at 6 h after salt treatment, which were similar with that of Thellungiella halophila.
Shabala, S. and I. I. Pottosin (2010). Potassium and Potassium-Permeable Channels in Plant Salt Tolerance. in Ion Channels and Plant Stress Responses. V. Demidchik and F. Maathuis (eds): 87-110. Rupyshev, Y. A., T. G. Boikov, et al. (2010) ON NEW AND RARE VASCULAR PLANTS OF BURYAT REPUBLIC Byulleten' Moskovskogo Obshchestva Ispytatelei Prirody Otdel Biologicheskii 115: 81-81.Suitability of CATMA for the analysis of the transcriptome of Thellungiella halophila - flower/leaf transcriptomic comparison in Arabidopsis and Thellungiella. adt09-01_thellungiella - thelungiella 2 dye-swap - CATMA arrays.
Reinbach, H. C., T. Martinussen, et al. (2010) Effects of hot spices on energy intake, appetite and sensory specific desires in humans Food Quality and Preference 21: 655-661. 10.1016/j.foodqual.2010.04.003This study investigated the effect of hot spices on energy intake and appetite. Forty participants received five meals of fixed portion sizes, served with or without five hot spices followed by a buffet. Spices were used in doses perceived as moderately hot, ensuring that the meals were palatable. Food intake (kJ), appetite and liking (before, during, after the meal and after the buffet), mood (before, after the meal and after the buffet) and desire to eat sweet, sour, fatty, salty, bitter and hot foods (after the meal and after the buffet) were measured on 9-point scales. Hot spices did not affect energy intake (p > 0.05). Desire for sweet foods was increased by chili (0.6 point, p < 0.05) whereas desire to eat salty foods was decreased by mustard (1 point, p < 0.01), suggesting that hot spices can induce changes in sensory specific desires. Liking of the meals tended to increase during the buffet when compared to the relatively constant liking of the fixed starter meals, suggesting that traditional sensory specific satiety does not play a large role in determining eating behaviour with complex meals. (C) 2010 Elsevier Ltd. All rights reserved.
Rahman, L. N., L. Chen, et al. (2010) Interactions of intrinsically disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 with membranes - synergistic effects of lipid composition and temperature on secondary structure Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire 88: 791-807. 10.1139/o10-026Dehydrins are intrinsically disordered (unstructured) proteins that are expressed in plants experiencing stressful conditions such as drought or low temperature. Dehydrins are typically found in the cytosol and nucleus, but also associate with chloroplasts, mitochondria, and the plasma membrane. Although their role is not completely understood, it has been suggested that they stabilize proteins or membrane structures during environmental stress, the latter association mediated by formation of amphipathic a-helices by conserved regions called the K-segments. Thellungiella salsuginea is a crucifer that thrives in the Canadian sub-Arctic (Yukon Territory) where it grows on saline-rich soils and experiences periods of both extreme cold and drought. We have cloned and expressed in Escherichia coli two dehydrins from this plant, denoted TsDHN-1 (acidic) and TsDHN-2 (basic). Here, we show using transmission-Fourier transform infrared (FTIR) spectroscopy that ordered secondary structure is induced and stabilized in these proteins by association with large unilamellar vesicles emulating the lipid compositions of plant plasma and organellar membranes. Moreover, this induced folding is enhanced at low temperatures, lending credence to the hypothesis that dehydrins stabilize plant outer and organellar membranes in conditions of cold.
Pedras, M. S. C. and Q. A. Zheng. (2010) Metabolic responses of Thellungiella halophila/salsuginea to biotic and abiotic stresses: Metabolite profiles and quantitative analyses Phytochemistry 71: 581-589. 10.1016/j.phytochem.2009.12.008The metabolite profiles of the model crucifer Thellungiella salsuginea (salt cress) ecotype Shandong subjected to various biotic and abiotic stresses were analyzed using HPLC-DAD-ESI-MS. Two different cruciferous microbial pathogens, Albugo candida, a biotrophic oomycete, and Leptosphaeria maculans, a necrotrophic fungus, elicited formation of the phytoalexins wasalexins A and B without causing visual damage on inoculated leaves. Analyses of non-polar and polar metabolites led to elucidation of the chemical structures of five metabolites: 4'-O-(E)-sinapoyl-7-methoxyisovitexin-2 ''-O-beta-D-glucopyranoside, 4'-O-(E)-sinapoylisovitexin-2 ''-O-beta-D-glucopyranoside, 4-O-beta-D-glucopyranosyl-7-hydroxymatairesinol, 5'-O-beta-D-glucopyranosyldihydroneoascorbigen and 3-O-beta-D-glucopyranosylthiane. 3-O-beta-D-glucopyrano-sylthiane, an unique metabolite for which we suggest the name glucosalsuginin, is proposed to derive from the glucosinolate glucoberteroin. In addition, the identification of a broad range of polar metabolites identical to those of other crucifers was carried out. Quantification of several metabolites over a period of eight days showed that concentrations of the polar phytoanticipin 4-methoxyglucobrassicin increased substantially in leaves irradiated with UV light (lambda(max) 254 nm) relative to control leaves, but not in leaves subjected to other stresses. (C) 2009 Elsevier Ltd. All rights reserved.
Pedras, M. S. C., E. E. Yaya, et al. (2010) Unveiling the phytoalexin biosynthetic puzzle in salt cress: unprecedented incorporation of glucobrassicin into wasalexins A and B Organic & Biomolecular Chemistry 8: 5150-5158. 10.1039/c0ob00265hSalt cress (Thellungiella salsuginea also known as T. halophila) is a wild cruciferous extremophile highly resistant to salt, drought, and cold. The recent discovery that salt cress produces the phytoalexins wasalexins A and B, and the phytoanticipins 1-methoxyglucobrassicin and 4-methoxyglucobrassicin in relatively higher amounts than other cruciferous species, prompted investigation of their biosynthetic relationships. Toward this end, perdeuterated 1-methoxybrassinin, L-Trp, glucobrassicin, 1-methoxyindolyl-3-acetaldoxime, brassinin, and methionine, as well as the corresponding natural abundance compounds, were administered to salt cress plants previously irradiated with UV-light (lambda(max) 254 nm). Remarkably, administration of hexadeuterated glucobrassicin led to incorporation of several deuterium atoms into wasalexins A and B, 1-methoxyglucobrassicin and 4-methoxyglucobrassicin. This unprecedented discovery suggests that glucobrassicin is a biosynthetic precursor of wasalexins and methoxylated glucosinolates in salt cress.
Pedras, M. S. C. and E. E. Yaya. (2010) Phytoalexins from Brassicaceae: News from the front Phytochemistry 71: 1191-1197. 10.1016/j.phytochem.2010.03.020The chemical structures, syntheses, metabolism and biological activities of the cruciferous phytoalexins discovered to date, with particular focus on the latest results dealing with their biosynthesis and detoxification are reviewed. (C) 2010 Elsevier Ltd. All rights reserved.
Pashkovskii, P. P., S. S. Ryazanskii, et al. (2010) MIR398 and expression regulation of the cytoplasmic Cu/Zn-superoxide dismutase gene in Thellungiella halophila plants under stress conditions Russian Journal of Plant Physiology 57: 707-714. 10.1134/s1021443710050146In the salt-tolerant plant Thellungiella halophila, expression of microRNA from MIR398 family, which regulated expression of superoxide dismutase (Cu/Zn-SOD) in Arabidopsis thaliana at posttranscriptional level, was revealed. The effects of various salinity levels, illumination intensity, and UV-B radiation on MIR398 expression was demonstrated by Northern-blot hybridization. These stressors changed the level of MIR398 expression in roots and leaves in opposite directions, which indicates a possible stress-dependent transport of MIR398 over the plant. Under salinity stress and UV-B irradiation, a negative correlation was observed between expression of MIR398 and its target, mRNA of Cu/Zn-SOD, one of the key enzymes of plant antioxidant defense. Thus, MIR398-dependent expression of CSD1 gene is characteristic of not only glycophytes but also halophytes, being organ-unspecific and independent of abiotic stressors affecting the plant.
Pang, Q. Y., S. X. Chen, et al. (2010) Comparative Proteomics of Salt Tolerance in Arabidopsis thaliana and Thellungiella halophila Journal of Proteome Research 9: 2584-2599. 10.1021/pr100034fSalinity is a major abiotic stress affecting plant cultivation and productivity. Thellungiella halophila is a halophyte and has been used as a model for studying plant salt tolerance. Understanding the molecular mechanisms of salinity tolerance will facilitate the generation of salt tolerant crops. Here we report comparative leaf proteomics of Arabidopsis, a glycophyte, and its close relative Thellungiella, a halophyte, under different salt stress conditions. Proteins from control and NaCl treated Arabidopsis and Thellungiella leaf samples were extracted and separated by two-dimensional gel electrophoresis. A total of 88 protein spots from Arabidopsis gels and 37 protein spots from Thellungiella gels showed significant changes. Out of these spots, a total of 79 and 32 proteins were identified by mass spectrometry in Arabidopsis and Thellungiella, respectively. Most of the identified proteins were involved in photosynthesis, energy metabolism, and stress response in Arabidopsis and Thellungiella. As a complementary approach, isobaric tag for relative and absolute quantification (iTRAQ) LC-MS was used to identify crude microsomal proteins. A total of 31 and 32 differentially expressed proteins were identified in Arabidopsis and Thellungiella under salt treatment, respectively. Overall, there were more proteins changed in abundance in Arabidopsis than in Thellungiella. Distinct patterns of protein changes in the two species were observed. Collectively, this work represents the most extensive proteomic description of salinity responses of Arabidopsis and Thellungiella and has improved our knowledge of salt tolerance in glycophytes and halophytes.
Orsini, F., M. P. D'Urzo, et al. (2010) A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana Journal of Experimental Botany 61: 3787-3798. 10.1093/jxb/erq188Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research.
Oh, D. H., M. Dassanayake, et al. (2010) Genome Structures and Halophyte-Specific Gene Expression of the Extremophile Thellungiella parvula in Comparison with Thellungiella salsuginea (Thellungiella halophila) and Arabidopsis Plant Physiology 154: 1040-1052. 10.1104/pp.110.163923The genome of Thellungiella parvula, a halophytic relative of Arabidopsis (Arabidopsis thaliana), is being assembled using Roche-454 sequencing. Analyses of a 10-Mb scaffold revealed synteny with Arabidopsis, with recombination and inversion and an uneven distribution of repeat sequences. T. parvula genome structure and DNA sequences were compared with orthologous regions from Arabidopsis and publicly available bacterial artificial chromosome sequences from Thellungiella salsuginea (previously Thellungiella halophila). The three-way comparison of sequences, from one abiotic stress-sensitive species and two tolerant species, revealed extensive sequence conservation and microcolinearity, but grouping Thellungiella species separately from Arabidopsis. However, the T. parvula segments are distinguished from their T. salsuginea counterparts by a pronounced paucity of repeat sequences, resulting in a 30% shorter DNA segment with essentially the same gene content in T. parvula. Among the genes is SALT OVERLY SENSITIVE1 (SOS1), a sodium/proton antiporter, which represents an essential component of plant salinity stress tolerance. Although the SOS1 coding region is highly conserved among all three species, the promoter regions show conservation only between the two Thellungiella species. Comparative transcript analyses revealed higher levels of basal as well as salt-induced SOS1 expression in both Thellungiella species as compared with Arabidopsis. The Thellungiella species and other halophytes share conserved pyrimidine-rich 5' untranslated region proximal regions of SOS1 that are missing in Arabidopsis. Completion of the genome structure of T. parvula is expected to highlight distinctive genetic elements underlying the extremophile lifestyle of this species.
Oh, D.-H., S. Y. Lee, et al. (2010) Intracellular consequences of SOS1 deficiency during salt stress Journal of Experimental Botany 61: 1205-1213. 10.1093/jxb/erp391A mutation of AtSOS1 (Salt Overly Sensitive 1), a plasma membrane Na(+)/H(+)-antiporter in Arabidopsis thaliana, leads to a salt-sensitive phenotype accompanied by the death of root cells under salt stress. Intracellular events and changes in gene expression were compared during a non-lethal salt stress between the wild type and a representative SOS1 mutant, atsos1-1, by confocal microscopy using ion-specific fluorophores and by quantitative RT-PCR. In addition to the higher accumulation of sodium ions, atsos1-1 showed inhibition of endocytosis, abnormalities in vacuolar shape and function, and changes in intracellular pH compared to the wild type in root tip cells under stress. Quantitative RT-PCR revealed a dramatically faster and higher induction of root-specific Ca(2+) transporters, including several CAXs and CNGCs, and the drastic down-regulation of genes involved in pH-homeostasis and membrane potential maintenance. Differential regulation of genes for functions in intracellular protein trafficking in atsos1-1 was also observed. The results suggested roles of the SOS1 protein, in addition to its function as a Na(+)/H(+) antiporter, whose disruption affected membrane traffic and vacuolar functions possibly by controlling pH homeostasis in root cells.
Nieves-Cordones, M., F. Aleman, et al. (2010) The Arabidopsis thaliana HAK5 K+ Transporter Is Required for Plant Growth and K+ Acquisition from Low K+ Solutions under Saline Conditions Molecular Plant 3: 326-333. 10.1093/mp/ssp102K+ uptake in the high-affinity range of concentrations and its components have been widely studied. In Arabidposis thaliana, the AtHAK5 transporter and the AtAKT1 channel have been shown to be the main transport proteins involved in this process. Here, we study the role of these two systems under two important stress conditions: low K+ supply or the presence of salinity. T-DNA insertion lines disrupting AtHAK5 and AtAKT1 are employed for long-term experiments that allow physiological characterization of the mutant lines. We found that AtHAK5 is required for K+ absorption necessary to sustain plant growth at low K+ in the absence as well as in the presence of salinity. Salinity greatly reduced AtHAK5 transcript levels and promoted AtAKT1-mediated K+ efflux, resulting in an important impairment of K+ nutrition. Although having a limited capacity, AtHAK5 plays a major role for K+ acquisition from low K+ concentrations in the presence of salinity.
Lugan, R., M. F. Niogret, et al. (2010) Metabolome and water homeostasis analysis of Thellungiella salsuginea suggests that dehydration tolerance is a key response to osmotic stress in this halophyte Plant Journal 64: 215-229. 10.1111/j.1365-313X.2010.04323.xP>Thellungiella salsuginea, a Brassicaceae species closely related to Arabidopsis thaliana, is tolerant to high salinity. The two species were compared under conditions of osmotic stress to assess the relationships between stress tolerance, the metabolome, water homeostasis and growth performance. A broad range of metabolites were analysed by metabolic fingerprinting and profiling, and the results showed that, despite a few notable differences in raffinose and secondary metabolites, the same metabolic pathways were regulated by salt stress in both species. The main difference was quantitative: Thellungiella had much higher levels of most metabolites than Arabidopsis whatever the treatment. Comprehensive quantification of organic and mineral solutes showed a relative stability of the total solute content regardless of the species or treatment, meaning that little or no osmotic adjustment occurred under stress. The reduction in osmotic potential observed in plants under stress was found to result from a passive loss of water. Thellungiella shoots contain less water than Arabidopsis shoots, and have the ability to lose more water, which could contribute to maintain a water potential gradient between soil and plant. Significant differences between Thellungiella and Arabidopsis were also observed in terms of the physicochemical properties of their metabolomes, such as water solubility and polarity. On the whole, the Thellungiella metabolome appears to be more compatible with dehydration. Osmotic stress was also found to impact the metabolome properties in both species, increasing the overall polarity. Together, the results suggest that Thellungiella copes with osmotic stress by tolerating dehydration, with its metabolic configuration lending itself to osmoprotective strategies rather than osmo-adjustment.
Ludivine, S.-T., F. Bitton, et al. (2010) GSM492995: 13852113 - Leaf Arabidopsis vs Flower Arabidopsis Gene Expression OmnibusSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila.
Ludivine, S.-T., F. Bitton, et al. (2010) GSM492996: 13832877 - Flower Arabidopsis vs Leaf Arabidopsis Gene Expression OmnibusSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila.
Ludivine, S.-T., F. Bitton, et al. (2010) GSM492998: 13832882 - Flower Thellungiella vs Leaf Thellungiella Gene Expression OmnibusSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila.
Ludivine, S.-T., F. Bitton, et al. (2010) GSM492997: 13832879 - Leaf Thellungiella vs Flower Thellungiella Gene Expression OmnibusSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila.
Ludivine, S.-T., F. Bitton, et al. (2010) GSE19740: Osmotic stress tolerance in Thellungiella halophila Gene Expression OmnibusSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila - flower/leaf transcriptomic comparison in Arabidopsis and Thellungiella.
adt09-01_thellungiella - thelungiella.
The Arabidopsis vacuolar H+-pyrophosphatase (AVP1), when over-expressed in transgenic (TG) plants, regulates root and shoot development via facilitation of auxin flux, and enhances plant resistance to salt and drought stresses. Here, we report that TG perennial creeping bentgrass plants over-expressing AVP1 exhibited improved resistance to salinity than wild-type (WT) controls. Compared to WT plants, TGs grew well in the presence of 100 mM NaCl, and exhibited higher tolerance and faster recovery from damages from exposure to 200 and 300 mM NaCl. The improved performance of the TG plants was associated with higher relative water content (RWC), higher Na+ uptake and lower solute leakage in leaf tissues, and with higher concentrations of Na+, K+, Cl- and total phosphorus in root tissues. Under salt stress, proline content was increased in both WT and TG plants, but more significantly in TGs. Moreover, TG plants exhibited greater biomass production than WT controls under both normal and elevated salinity conditions. When subjected to salt stress, fresh (FW) and dry weights (DW) of both leaves and roots decreased more significantly in WT than in TG plants. Our results demonstrated the great potential of genetic manipulation of vacuolar H+-pyrophosphatase expression in TG perennial species for improvement of plant abiotic stress resistance.
Jha, D., N. Shirley, et al. (2010) Variation in salinity tolerance and shoot sodium accumulation in Arabidopsis ecotypes linked to differences in the natural expression levels of transporters involved in sodium transport Plant Cell and Environment 33: 793-804. 10.1111/j.1365-3040.2009.02105.xSalinity tolerance can be attributed to three different mechanisms: Na+ exclusion from the shoot, Na+ tissue tolerance and osmotic tolerance. Although several key ion channels and transporters involved in these processes are known, the variation in expression profiles and the effects of these proteins on Na+ transport in different accessions of the same species are unknown. Here, expression profiles of the genes AtHKT1;1, AtSOS1, AtNHX1 and AtAVP1 are determined in four ecotypes of Arabidopsis thaliana. Not only are these genes differentially regulated between ecotypes, the expression levels of the genes can be linked to the concentration of Na+ in the plant. An inverse relationship was found between AtSOS1 expression in the root and total plant Na+ accumulation, supporting a role for AtSOS1 in Na+ efflux from the plant. Similarly, ecotypes with high expression levels of AtHKT1;1 in the root had lower shoot Na+ concentrations, due to the hypothesized role of AtHKT1;1 in retrieval of Na+ from the transpiration stream. The inverse relationship between shoot Na+ concentration and salinity tolerance typical of most cereal crop plants was not demonstrated, but a positive relationship was found between salt tolerance and levels of AtAVP1 expression, which may be related to tissue tolerance.
Han, J.-M., B. Xu, et al. (2010). Cloning and Expression Analysis of A Partial bcDREB2 Relative Gene in Non-heading Chinese Cabbage (Brassica campestris ssp chinensis Makino). in Icms2010: Proceedings of the Third International Conference on Modelling and Simulation, Vol 4: Modelling and Simulation in Biology, Ecology & Environment (Y. Jiang and H. Bao eds.) Guan, B., G.-q. Jiang, et al. (2010) Identification of differentially expressed transcripts involved in the salt-stress response of Salsola ferganica by suppression subtractive hybridization Plant Cell Tissue and Organ Culture 103: 343-352. 10.1007/s11240-010-9787-4To understand the molecular and cellular mechanisms underlying the salt response and to isolate differentially expressed genes, we constructed a forward subtractive cDNA library from Salsola ferganica treated with 600 mM NaCl for different lengths of time (0, 4, 8, 12, 16, 24, 36 h) using the suppression subtractive hybridization (SSH) technique. This SSH library contained approximately 2,200 positive clones, with the insert size ranging from 250 to 700 bp. Eighty clones were selected for further study based on results from reverse Northern blotting and sequencing and, these cDNAs are the first reported expressed sequence tags (ESTs) of Salsola ferganica listed in GenBank. Among these 80 differentially expressed genes, 32 are genes with known function that display a high homology (between 68 and 100% identity) to known sequences, 47 have an unknown function, showing no homology with known sequences, and one is a novel gene that does not match any previously reported genes. Five cDNA fragments, sf3d8, sf6d8, sf4a8, sf8d6, and sf6c7, were randomly chosen from the 80 differentially expressed genes for reverse transcription-PCR analysis. The expression of sf8d6 was entirely induced by salt stress and that of sf3d8, sf6d8, sf4a8, and sf6c7 was increased from a relatively lower level. The isolated ESTs reported here may enable us to find new genes involved in salt tolerance in Salsola ferganica.
Grene, R., P. Li, et al. (2010). Elevated CO2 and Ozone: Their Effects on Photosynthesis. in Chloroplast: Basics and Applications. C. A. Rebeiz, C. Benning, H. J. Bohnertet al (eds). 31: 323-346. German, D. A. and I. A. Al-Shehbaz. (2010) Nomenclatural novelties in miscellaneous Asian Brassicaceae (Cruciferae) Nordic Journal of Botany 28: 646-651. 10.1111/j.1756-1051.2010.00983.xThe new tribe Crucihimalayeae and three new genera Schrenkiella, Leiocarpaea and Ladakiella are described, and their diagnostic characters are discussed. Spirorhynchus is reduced to synonymy of Goldbachia, Ptilotrichum and Berteroella are merged with Stevenia, and Phaeonychium and Eurycarpus are merged with Solms-laubachia. Thirteen new combinations are proposed: Goldbachia sabulosa (Kar. & Kir.) D. German & Al-Shehbaz, Ladakiella klimesii (Al-Shehbaz) D. German & Al-Shehbaz, Leiocarpaea cochlearioides (Murr.) D. German & Al-Shehbaz, Schrenkiella parvula (Schrenk) D. German & Al-Shehbaz, Stevenia dahurica (Peschkova) D. German & Al-Shehbaz, Stevenia maximowiczii (Palib.) D. German & Al-Shehbaz, Solms-laubachia albiflora (T. Anderson) D. German & Al-Shehbaz, Solms-laubachia kashgarica (Botsch.) D. German & Al-Shehbaz, Solms-laubachia lanuginosa (Hook. f. & Thomson) D. German & Al-Shehbaz, Solms-laubachia marinellii (Pamp.) D. German & Al-Shehbaz, Solms-laubachia parryoides (Kurz ex Hook. f. & T. Anderson) D. German & Al-Shehbaz, Solms-laubachia surculosa (N. Busch) D. German & Al-Shehbaz, and Solms-laubachia villosa (Maxim.) D. German & Al-Shehbaz.
Chen, Z.-q. and W.-l. Chen (2010). Effects of NaCl on photosynthesis in Arabidopsis and Thellungiella leaves based on the fluorescence spectra, the fast Chlorophyll Fluorescence Induction Dynamics Analysis and the delayed fluorescence technique. in Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues Viii. D. L. Farkas, D. V. Nicolau and R. C. Leif (eds). 7568. Ardie, S. W., S. Liu, et al. (2010) Expression of the AKT1-type K+ channel gene from Puccinellia tenuiflora, PutAKT1, enhances salt tolerance in Arabidopsis Plant Cell Reports 29: 865-874. 10.1007/s00299-010-0872-2Potassium channels are important for many physiological functions in plants, one of which is to regulate plant adaptation to stress conditions. In this study, a K+ channel PutAKT1 cDNA was isolated from the salt-tolerant plant Puccinellia tenuiflora. A phylogenetic analysis showed that PutAKT1 belongs to the AKT1-subfamily in the Shaker K+ channel family. PutAKT1 was localized in the plasma membrane and it was preferentially expressed in the roots. The expression of PutAKT1 was induced by K+-starvation stress in the roots and was not down-regulated by the presence of excess Na+. Arabidopsis plants over-expressing PutAKT1 showed enhanced salt tolerance compared to wild-type plants as shown by their shoot phenotype and dry weight. Expression of PutAKT1 increased the K+ content of Arabidopsis under normal, K+-starvation, and NaCl-stress conditions. Arabidopsis expressing PutAKT1 also showed a decrease in Na+ accumulation both in the shoot and in the root. These results suggest that PutAKT1 is involved in mediating K+ uptake (i) both in low- and in high-affinity K+ uptake range, and (ii) unlike its homologs in rice, even under salt-stress condition.
Arbona, V., R. Argamasilla, et al. (2010) Common and divergent physiological, hormonal and metabolic responses of Arabidopsis thaliana and Thellungiella halophila to water and salt stress Journal of Plant Physiology 167: 1342-1350. 10.1016/j.jplph.2010.05.012To explain the higher tolerance of Thellungiella to abiotic stress in comparison to Arabidopsis several studies have focused on differences in ion absorption and gene expression However little is known about hormone regulation and metabolic responses In this work plants of both species were subjected to desiccation and salt stress to compare common and divergent responses In control conditions the number of significantly upregulated mass features as well as proline levels was higher in Tellungiella than in Arabidopsis When subjected to desiccation both species exhibited similar rates of water loss but proline over accumulation only occurred in Thellungiella both species accumulated ABA and JA with a similar trend although Arabidopsis showed higher concentrations of both hormones which indicated a stronger impact of desiccation on Arabidopsis However Arabidopsis showed a higher number of significantly altered mass features than Thellungiella Under salt stress Thellungiella plants accumulated lower amounts of Cl(-) ions than Arabidopsis but exhibited a similar proline response Under these conditions ABA and JA levels increased in Arabidopsis whereas minimal changes in both hormone concentrations were recorded in Thellungiella Contrastingly the impact of salt stress on metabolite profiles was higher in Thellungiella than in Arabidopsis Overall data indicated that physiological responses in Arabidopsis are induced after stress imposition through hormonal regulation whereas Thellungiella has a basal metabolic configuration better prepared to endure environmental cues (C) 2010 Elsevier GmbH All rights reserved.
Amtmann, A. and R. Leigh (2010). Ion Homeostasis. in Abiotic Stress Adaptation in Plants: Physiological, Molecular and Genomic Foundation (A. Pareek, S. K. Sopory, H. J. Bohnert and X. Govindjee eds.) Amtmann, A. and M. J. Beilby (2010). The Role of Ion Channels in Plant Salt Tolerance. in Ion Channels and Plant Stress Responses. V. Demidchik and F. Maathuis (eds): 23-46. Adt. (2010) Osmotic stress tolerance in Thellungiella halophila European Nucleotide ArchiveSuitability of CATMA for the analysis of the transcriptome of Thellungiella halophila - flower/leaf transcriptomic comparison in Arabidopsis and Thellungiella. adt09-01_thellungiella - thelungiella Overall design: 2 dye-swap - CATMA arrays.
Abraham, E., C. Hourton-Cabassa, et al. (2010). Methods for Determination of Proline in Plants. in Plant Stress Tolerance: Methods and Protocols. R. Sunkar (eds). 639: 317-331. Zhu, J. Q., J. T. Zhang, et al. (2009) Molecular characterization of ThIPK2, an inositol polyphosphate kinase gene homolog from Thellungiella halophila, and its heterologous expression to improve abiotic stress tolerance in Brassica napus Physiologia Plantarum 136: 407-425. 10.1111/j.1399-3054.2009.01235.xInositol polyphosphate kinases play important roles in diverse cellular processes. In this study, the function of an inositol polyphosphate kinase gene homolog named ThIPK2 from a dicotyledonous halophyte Thellungiella halophila was investigated. The deduced translation product (ThIPK2) shares 85% identity with the Arabidopsis inositol polyphosphate kinase AtIPK2 beta. Transient expression of ThIPK2-YFP fusion protein in tobacco (Nicotiana tabacum) protoplasts indicates that the protein is localized to the nucleus and plasma membrane, with a minor localization to the cytosol. Heterologous expression of ThIPK2 in ipk2 delta (also known as arg82 delta), a yeast mutant strain that lacks inositol polyphosphate multikinase (Ipk2) activity, rescued the mutant's salt-, osmotic- and temperature-sensitive growth defects. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) revealed ubiquitous expression of ThIPK2 in various tissues, including roots, rosette leaves, cauline leaves, stem, flowers and siliques, and shoot ThIPK2 transcript was strongly induced by NaCl or mannitol in T. halophila as exhibited by real-time PCR analysis. Transgenic expression of ThIPK2 in Brassica napus led to significantly improved salt-, dehydration- and oxidative stress resistance. Furthermore, the transcripts of various stress responsive marker genes increased in ThIPK2 transgenic plants under salt stress condition. These results suggest that ThIPK2 is involved in plant stress responses, and for the first time demonstrate that ThIPK2 could be a useful candidate gene for improving drought and salt tolerance in important crop plants by genetic transformation.
Zhou, L., J. Zhu, et al. (2009) Cloning and sequence analysis of a Na+/H+ antiporter gene in halophyte Limonium gmelinii Acta Horticulturae Sinica 36: 1353-1358.A plasma membrane Na+/H+ antiporter gene (LgSOS1, GenBank accession No. EU780458) has been separated from halophyte Limonium gmelinii by RT-PCR and RACE. The LgSOS1 cDNA is 3 910 bp long including 5′ untranslated region of 79 bp, 3′ untranslated region of 376 bp with Poly A, and an open reading frame of 3 455 bp encoding a protein of 1 151 amino acids with a predicted molecular mass of 126 kD. By multiple sequence alignment analysis of amino acids, it has been shown that the identities in amino acids to plasma membrane Na+/H+ antiporters gene of LgSOS1 is 69.02%, and 64.42%, 61.96%, 60.12%, and 59.62% of Mesembryanthemum crystallinum, Populus euphratica, Lycopersicon esculentum, Thellungiella halophila and Arabidopsis thaliana, respectively. TMpred prediction showed LgSOS1 has 12 transmembrane domains. Phylogenetic analysis indicates that LgSOS1 is more related to plasma membrane-type Na+/H+ antiporter, compared with vacuolar-type Na+/H+ antiporter, to which it is less related.
Zhao, X., H. J. Tan, et al. (2009) Effect of salt stress on growth and osmotic regulation in Thellungiella and Arabidopsis callus Plant Cell Tissue and Organ Culture 98: 97-103. 10.1007/s11240-009-9542-xThe response of Thellungiella (Thellungiella holophila) and Arabidopsis (Arabidopsis thaliana) callus to salt stress was investigated. The relative growth rate of Arabidopsis calli decreased with increased levels of NaCl. However, the relative growth rate of Thellungiella calli increased with higher levels of NaCl, reaching maximal growth at 100 mM NaCl, but then subsequently declined. A similar pattern of accumulation of proline, glycine betaine, and total flavonoid was observed; whereas, accumulation of treholase continued to increase with increasing NaCl levels in both Thellungiella and Arabidopsis calli. Overall, with increasing NaCl levels, accumulation of glycine betaine, total flavonoid, and treholase was higher in Thellungiella than in Arabidopsis calli; while, proline and sucrose contents were higher in Arabidopsis than in Thellungiella calli. These results indicated that compatible solutes were involved in the response of plant calli to salt stress, and that the halophyte Thellungiella and glycophyte Arabidopsis selected different compatible solutes to adapt to salt stress environments.
Zhao, X., H.-j. Tan, et al. (2009) Changes of PM and TP ATPase Activities in Thellungiella Seedlings under Salt Stress Xibei Zhiwu Xuebao 29: 717-723.The effect of salt stress on the modification of plasma membrane (PM) and tonoplast (TP) H+-ATPase activities in Thellungiella (Thellungiella halophila) and Arabidopsis seedlings were studied. Under 100 similar to 400 mmol center dot L-1 NaCl stress, the H+-ATPase, Ca2+-ATPase and K+-ATPase activities in Thellungiella roots and leaves increased about 41%similar to 212%, 35%similar to 53% in PM and 281%similar to 373%, 4%similar to 38% in TP than the untreated plant. Under the same NaCl concentration stress,the H+-ATPase, Ca2+-ATPase and K+-ATPase activities in Thellungiella leaves were 4 similar to 8 times than those in its roots. The TP H+-ATPase beta subunit Western blotting results showed the same increased level as the H+-ATPase activity in roots,and PM Na/H antiporter Western blotting results showed significant difference with the different Na+ contents in its leaves and roots. Ca2+-ATPase and K+-ATPase activities were highly correlated with Ca2+ and K+ concentration in Thellungiella roots treated by NaCl. It suggested that Ca2+ was the second signal transduction in Thellungiella root and involved in feedback regulation of PM H+-ATPase. These results indicated that Thellungiella enhanced the salt resistant characteristic through increasing the roots and leaves H+-ATPase, Ca2+-ATPase and K+-ATPase activities.
Yamanaka, T., M. Miyama, et al. (2009) Transcriptome Profiling of the Mangrove Plant Bruguiera gymnorhiza and Identification of Salt Tolerance Genes by Agrobacterium Functional Screening Bioscience Biotechnology and Biochemistry 73: 304-310. 10.1271/bbb.80513To identify key genes in the regulation of salt tolerance in the mangrove plant Bruguiera gymnorhiza, transcriptome profiling in the lateral and main roots under conditions of salt stress was performed. Statistical analysis revealed that 175 and 40 3 of 11,997 genes shoewd significantly increased high expression in the lateral and main roots respectively. One hundred and sixty genes were up-regulated in both types of roots in the early time period, 1 to 12h after salt treatment. Expression vectors for 28 selected salt responsive genes were constructed and transformed in Agrobacterium tumefaciens, and then screened for salt tolerance. A. tumefaciens transformed with genes for lipid transfer, zinc finger, and ankyrin repeat proteins showed enhanced salt tolerance. Transgenic Arabidopsis plants expressing these three genes also exhibited increased tolerance to NaCl. These results indicate that Agrobacterium functional screening is an effective supplemental method of pre-screening genes involved in abiotic stress tolerance.
Xu, X. J., Y. J. Zhou, et al. (2009) Molecular cloning and expression of a Cu/Zn-Containing superoxide dismutase from Thellungiella halophila Molecules and Cells 27: 423-428. 10.1007/s10059-009-0060-9Superoxide dismutases (SODs) constitute the first line of cellular defense against oxidative stress in plants. SODs generally occur in three different forms with Cu/Zn, Fe, or Mn as prosthetic metals. We cloned the full-length cDNA of the Thellungiella halophila Cu/Zn-SOD gene ThCSD using degenerate RT-PCR and rapid amplification of cDNA ends (RACE). Sequence analysis indicated that the ThCSD gene (GenBank accession number EF405867) had an open reading frame of 456 bp. The deduced 152-amino acid polypeptide had a predicted molecular weight of 15.1 kDa, an estimated pI of 5.4, and a putative Cu/Zn-binding site. Recombinant ThCSD protein was expressed in Escherichia coli and assayed for SOD enzymatic activity in a native polyacrylamide gel. The SOD activity of ThCSD was inactivated by potassium cyanide and hydrogen peroxide but not by sodium azide, confirming that ThCSD is a Cu/Zn-SOD. Northern blotting demonstrated that ThCSD is expressed in roots, stems, and leaves. ThCSD mRNA levels increased by about 30-fold when plants were treated with sodium chloride (NaCl), abscisic acid (ABA), and indole-acetic acid (IAA) and by about 50-fold when treated with UVB light. These results indicate that ThCSD is involved in physiological pathways activated by a variety of environmental conditions.
Wu, C., X. Gao, et al. (2009) Molecular Cloning and Functional Analysis of a Na(+)/H(+) Antiporter Gene ThNHX1 from a Halophytic Plant Thellungiella halophila Plant Molecular Biology Reporter 27: 1-12. 10.1007/s11105-008-0048-1Na(+)/H(+) exchanger catalyzes the countertransport of Na(+) and H(+) across membranes. Using the rapid amplification of cDNA ends method, a Na(+)/H(+) antiporter gene (ThNHX1) was isolated from a halophytic plant, salt cress (Thellungiella halophila). The deduced amino acid sequence contained 545 amino acid residues with a conserved amiloride-binding domain ((87)LFFIYLLPPI(96)) and shared more than 94% identity with that of AtNHX1 from Arabidopsis thaliana. The ThNHX1 mRNA level was upregulated by salt and other stresses (abscisic acid, polyethylene glycol, and high temperature). This gene partially complemented the Na(+)/Li(+)-sensitive phenotype of a yeast mutant that was deficient in the endosomal-vacuolar Na(+)/H(+) antiporter ScNHX1. Overexpression of ThNHX1 in Arabidopsis increased salt tolerance of transgenic plants compared with the wild-type plants. In addition, the silencing of ThNHX1 gene in T. halophila caused the transgenic plants to be more salt and osmotic sensitive than wild-type plant. Together, these results suggest that ThNHX1 may function as a tonoplast Na(+)/H(+) antiporter and play an important role in salt tolerance of T. halophila.
Wang, C.-M., J.-L. Zhang, et al. (2009) Puccinellia tenuiflora maintains a low Na+ level under salinity by limiting unidirectional Na+ influx resulting in a high selectivity for K+ over Na+ Plant Cell and Environment 32: 486-496. 10.1111/j.1365-3040.2009.01942.xPuccinellia tenuiflora is a useful monocotyledonous halophyte that might be used for improving salt tolerance of cereals. This current work has shown that P. tenuiflora has stronger selectivity for K+ over Na+ allowing it to maintain significantly lower tissue Na+ and higher K+ concentration than that of wheat under short- or long-term NaCl treatments. To assess the relative contribution of Na+ efflux and influx to net Na+ accumulation, unidirectional Na-22(+) fluxes in roots were carried out. It was firstly found that unidirectional Na-22(+) influx into root of P. tenuiflora was significantly lower (by 31-37%) than in wheat under 100 and 150 mm NaCl. P. tenuiflora had lower unidirectional Na+ efflux than wheat; the ratio of efflux to influx was similar between the two species. Leaf secretion of P. tenuiflora was also estimated, and found the loss of Na+ content from leaves to account for only 0.0006% of the whole plant Na+ content over 33 d of NaCl treatments. Therefore, it is proposed that neither unidirectional Na+ efflux of roots nor salt secretion by leaves, but restricting unidirectional Na+ influx into roots with a strong selectivity for K+ over Na+ seems likely to contribute to the salt tolerance of P. tenuiflora.
Walia, H., C. Wilson, et al. (2009) Comparing genomic expression patterns across plant species reveals highly diverged transcriptional dynamics in response to salt stress Bmc Genomics 10: 398 10.1186/1471-2164-10-398Background: Rice and barley are both members of Poaceae (grass family) but have a marked difference in salt tolerance. The molecular mechanism underlying this difference was previously unexplored. This study employs a comparative genomics approach to identify analogous and contrasting gene expression patterns between rice and barley. Results: A hierarchical clustering approach identified several interesting expression trajectories among rice and barley genotypes. There were no major conserved expression patterns between the two species in response to salt stress. A wheat salt-stress dataset was queried for comparison with rice and barley. Roughly one-third of the salt-stress responses of barley were conserved with wheat while overlap between wheat and rice was minimal. These results demonstrate that, at transcriptome level, rice is strikingly different compared to the more closely related barley and wheat. This apparent lack of analogous transcriptional programs in response to salt stress is further highlighted through close examination of genes associated with root growth and development. Conclusion: The analysis provides support for the hypothesis that conservation of transcriptional signatures in response to environmental cues depends on the genetic similarity among the genotypes within a species, and on the phylogenetic distance between the species.
Taji, T., H. Ono, et al. (2009) Identification of stress tolerance related genes via FOX hunting system of Thellungiella halophila full-length cDNA library Plant Biology (Rockville) 2009: 155-155.To identify key proteins in the regulation of salt tolerance in the mangrove plant Bruguiera gymnorhiza, proteome analysis of samples grown under conditions of salt stress was performed. Comparative two-dimensional electrophoresis revealed that two, three and one protein were differentially expressed in the main root, lateral root and leaf, respectively, in response to salt stress. Among these, three proteins were identified by internal peptide sequence analysis: fructose-1,6-bisphosphate (FBP) aldolase and a novel protein in the main root, and osmotin in the lateral root. These results suggest that FBP aldolase and osmotin play roles in salt tolerance mechanisms common to both glycophytes and mangrove plants. Osmotin was abundant at early time points following salt treatment and seems to play a role in initial osmotic adaptation in lateral roots of B. gymnorhiza under salt stress, but does not contribute towards adaptation to prolonged or continuous exposure to salt stress. The amounts of these proteins were not correlated with those of the respective mRNAs, as determined by microarray analysis. A novel salt-responsive protein, not previously detected by expressed sequence tag analysis or transcriptome analysis, was also identified in this proteomic approach, and may provide insight into the salt tolerance mechanism of the mangrove plant. This is the first report of proteome analysis with detailed analysis of main and lateral roots of mangrove plants under salt stress conditions.
Sun, W. Y., J. F. Li, et al. (2009) A FACILE PROCEDURE FOR EFFICIENT PLANTLET REGENERATION AND FRUITING WITHOUT VERNALIZATION IN THELLUNGIELLA SALSUGINEA Pakistan Journal of Botany 41: 843-848.A facile and rapid system for efficient shoot regeneration and callus keeping was developed for Thellungiella salsuginea (Pall.) O. E. Schulz. Three kinds of explants including basal leaves, stems and anthers of vernalized plants were adopted here. Calli were formed from all these explants on MS medium supplemented with various plant hormone treatments. The highest callus inducing ratio for anther explants were observed on MS medium supplemented with 2.0 mg/l 2,4-D and 1.0 mg/l ZT zeatin, while for both stem and leaf explants 1.0 mg/l 2,4-D, 1.0 mg/l IBA and 0.1 mg/l ZT were used. The highest shoot regeneration ratios of anther and leaf calli were observed on MS medium with 0.1 mg/l IBA and 2.0 mg/l ZT and for stem calli it was 0.1 mg/l IBA and 1.0 mg/l ZT. Anther calli could keep vigorous growth on MS medium with 1.0 mg/l 2,4-D and 0.1 mg/l ZT. Even after three times subculture, shoots regenerated from anther calli could also develop flowers without vernalization while shoots regenerated from stem and leaf calli couldn't. Without vernalization almost 100% of seedling regenerated from anther blossomed whereas only 7.3% and 3.0% of seedling from stem and leaf did respectively, which provided us not only a facile, rapid regeneration system but also an activator for research work of vernalization mechanism.
Stepien, P. and G. N. Johnson. (2009) Contrasting Responses of Photosynthesis to Salt Stress in the Glycophyte Arabidopsis and the Halophyte Thellungiella: Role of the Plastid Terminal Oxidase as an Alternative Electron Sink Plant Physiology 149: 1154-1165. 10.1104/pp.108.132407The effects of short-term salt stress on gas exchange and the regulation of photosynthetic electron transport were examined in Arabidopsis (Arabidopsis thaliana) and its salt-tolerant close relative Thellungiella (Thellungiella halophila). Plants cultivated on soil were challenged for 2 weeks with NaCl. Arabidopsis showed a much higher sensitivity to salt than Thellungiella; while Arabidopsis plants were unable to survive exposure to greater than 150 mM salt, Thellugiella could tolerate concentrations as high as 500 mM with only minimal effects on gas exchange. Exposure of Arabidopsis to sublethal salt concentrations resulted in stomatal closure and inhibition of CO(2) fixation. This lead to an inhibition of electron transport though photosystem II (PSII), an increase in cyclic electron flow involving only PSI, and increased nonphotochemical quenching of chlorophyll fluorescence. In contrast, in Thellungiella, although gas exchange was marginally inhibited by high salt and PSI was unaffected, there was a large increase in electron flow involving PSII. This additional electron transport activity is oxygen dependent and sensitive to the alternative oxidase inhibitor n-propyl gallate. PSII electron transport in Thellungiella showed a reduced sensitivity to 2'-iodo-6-isopropyl-3-methyl-2',4,4'-trinitrodiphenylether, an inhibitor of the cytochrome b(6)f complex. At the same time, we observed a substantial up-regulation of a protein reacting with antibodies raised against the plastid terminal oxidase. No such up-regulation was seen in Arabidopsis. We conclude that in salt-stressed Thellungiella, plastid terminal oxidase acts as an alternative electron sink, accounting for up to 30% of total PSII electron flow.
Sengupta, S. and A. L. Majumder. (2009) Insight into the salt tolerance factors of a wild halophytic rice, Porteresia coarctata: a physiological and proteomic approach Planta 229: 911-929. 10.1007/s00425-008-0878-ySalinity poses a serious threat to yield performance of cultivated rice in South Asian countries. To understand the mechanism of salt-tolerance of the wild halophytic rice, Porteresia coarctata in contrast to the salt-sensitive domesticated rice Oryza sativa, we have compared P. coarctata with the domesticated O. sativa rice varieties under salinity stress with respect to several physiological parameters and changes in leaf protein expression. P. coarctata showed a better growth performance and biomass under salinity stress. Relative water content was conserved in Porteresia during stress and sodium ion accumulation in leaves was comparatively lesser. Scanning electron microscopy revealed presence of two types of salt hairs on two leaf surfaces, each showing a different behaviour under stress. High salt stress for prolonged period also revealed accumulation of extruded NaCl crystals on leaf surface. Changes induced in leaf proteins were studied by two-dimensional gel electrophoresis and subsequent quantitative image analysis. Out of more than 700 protein spots reproducibly detected and analyzed, 60% spots showed significant changes under salinity. Many proteins showed steady patterns of up- or downregulation in response to salinity stress. Twenty protein spots were analyzed by MALDI-TOF, leading to identification of 16 proteins involved in osmolyte synthesis, photosystem functioning, RubisCO activation, cell wall synthesis and chaperone functions. We hypothesize that some of these proteins confer a physiological advantage on Porteresia under salinity, and suggest a pattern of salt tolerance strategies operative in salt-marsh grasses. In addition, such proteins may turn out to be potential targets for recombinant cloning and introgression in salt-sensitive plants.
Rubio, F., F. Aleman, et al. (2009) Differential regulation of the genes encoding the high-affinity K(+) transporters HAK5 of Thellungiella halophila and Arabidopsis thaliana in response to salinity Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology 153A: S188-S188. 10.1016/j.cbpa.2009.04.415The production of phytoalexins in Thellungiella halophila exposed to UV-radiation and NaCl was investigated over a period of 8 days. UV-radiation induced substantially larger quantities of wasalexins A and B than NaCl irrigation or CuCl(2) spray. Isolation of two metabolites and their chemical structure determination using X-ray diffraction analysis provided the phytoalexins biswasalexins A1 and A2, that resulted from head-to-tail photodimerization of wasalexin A. The production of biswasalexins A1 and A2 in stressed T. halophila, as well as their chemical synthesis and antifungal activity are reported. Biswasalexins A1 and A2 (60 nmol/g and 15 nmol/g fresh wt, respectively, 2 days after UV elicitation) are cruciferous phytoalexins whose formation in planta appears to result from a photochemical reaction, which might protect the plant from fungal attack and UV-radiation. (C) 2009 Elsevier Ltd. All rights reserved.
Pang, Q. Y., S. X. Chen, et al. (2009) Characterization of glucosinolate-myrosinase system in developing salt cress Thellungiella halophila Physiologia Plantarum 136: 1-9. 10.1111/j.1399-3054.2009.01211.xGlucosinolates are specialized plant metabolites derived from amino acids. They can be hydrolyzed by myrosinases into different degradation products, which have a variety of biological activities. In this study, the compositions and contents of glucosinolates in salt cress (Thellungiella halophila) at different developmental stages were analyzed by high performance liquid chromatography and mass spectrometry (HPLC-MS). Myrosinase activities were also measured. Seven glucosinolates were identified in T. halophila throughout its life cycle. The glucosinolate profiles varied significantly among different tissues. The roots at stage 4 contained the highest concentrations of total, aromatic and indole glucosinolates among all tissues. Whereas roots, flowers and siliques contained all seven glucosinolates, seeds contained only four aliphatic glucosinolates. During development, the concentrations also displayed significant changes. From seeds to cotyledons and from stage 4 roots to stage 5 roots, there were dramatic declines of glucosinolates, which correlated well with changes in myrosinase activities. In other tissues, myrosinase activity alone could not explain the glucosinolate concentration changes. Certain tissues of T. halophila contained Arabidopsis myrosinase TGG1 and TGG2 orthologs. The molecular basis and functional significance of our findings are discussed here.
Oh, D.-H., A. Zahir, et al. (2009) SOS1 and halophytism Plant signaling & behavior 4: 1081-1083.Much is already known about the function and functioning of the three genes that make up the SOS (Salt-Overly-Sensitive) pathway in plants, but recent studies indicate that the linkage between external increases in salinity and stress protection provided by genes SOS1, SOS2 and SOS3 is more complex than previously appreciated. It has recently been shown that the engineered reduced expression of the sodium/proton antiporter SOS1 affected several pathways indicating a role for SOS1 that exceeds its known function as an antiporter. Interference with expression of SOS1, characterized as a sodium/proton antiporter in the halophyte Thellungiella salsuginea converted Thellungiella into an essentially glycophytic species.
Oh, D.-H., E. Leidi, et al. (2009) Loss of Halophytism by Interference with SOS1 Expression Plant Physiology 151: 210-222. 10.1104/pp.109.137802The contribution of SOS1 (for Salt Overly Sensitive 1), encoding a sodium/proton antiporter, to plant salinity tolerance was analyzed in wild-type and RNA interference (RNAi) lines of the halophytic Arabidopsis (Arabidopsis thaliana)-relative Thellungiella salsuginea. Under all conditions, SOS1 mRNA abundance was higher in Thellungiella than in Arabidopsis. Ectopic expression of the Thellungiella homolog ThSOS1 suppressed the salt-sensitive phenotype of a Saccharomyces cerevisiae strain lacking sodium ion (Na(+)) efflux transporters and increased salt tolerance of wild-type Arabidopsis. thsos1-RNAi lines of Thellungiella were highly salt sensitive. A representative line, thsos1-4, showed faster Na(+) accumulation, more severe water loss in shoots under salt stress, and slower removal of Na(+) from the root after removal of stress compared with the wild type. thsos1-4 showed drastically higher sodium-specific fluorescence visualized by CoroNa-Green, a sodium-specific fluorophore, than the wild type, inhibition of endocytosis in root tip cells, and cell death in the adjacent elongation zone. After prolonged stress, Na(+) accumulated inside the pericycle in thsos1-4, while sodium was confined in vacuoles of epidermis and cortex cells in the wild type. RNAi-based interference of SOS1 caused cell death in the root elongation zone, accompanied by fragmentation of vacuoles, inhibition of endocytosis, and apoplastic sodium influx into the stele and hence the shoot. Reduction in SOS1 expression changed Thellungiella that normally can grow in seawater-strength sodium chloride solutions into a plant as sensitive to Na(+) as Arabidopsis.
Nah, G., C. L. Pagliarulo, et al. (2009) Comparative sequence analysis of the SALT OVERLY SENSITIVE1 orthologous region in Thellungiella halophila and Arabidopsis thaliana Genomics 94: 196-203. 10.1016/j.ygeno.2009.05.007To provide a framework for studies to understand the contribution of SALT OVERLY SENSITIVE1 (SOS1) to salt tolerance in Thellungiella halophila, we sequenced and annotated a 193-kb T halophila BAC containing a putative SOS1 locus (ThSOS1) and compared the sequence to the orthologous 146-kb region of the genome of its salt-sensitive relative, Arabidopsis thaliana. Overall, the two sequences were colinear, but three major expansion/contraction regions in T halophila were found to contain five Long Terminal Repeat retro-transposons, MuDR DNA transposons and intergenic sequences that contribute to the 47.8-kb size variation in this region of the genome. Twenty-seven genes were annotated in the T halophila BAC including the putative ThSOS1 locus. ThSOS1 shares gene structure and sequence with A. thaliana SOS1 including 11 predicted transmembrane domains and a cyclic nucleotide-binding domain; however, different patterns of Simple Sequence Repeats were found within a 540-bp region upstream of SOS1 in the two species. (c) 2009 Elsevier Inc. All rights reserved.
Lv, S. L., L. J. Lian, et al. (2009) Overexpression of Thellungiella halophila H(+)-PPase (TsVP) in cotton enhances drought stress resistance of plants Planta 229: 899-910. 10.1007/s00425-008-0880-4An H(+)-PPase gene, TsVP from Thellungiella halophila, was transferred into two cotton (Gossypium hirsutum) varieties (Lumianyan19 and Lumianyan 21) and southern and northern blotting analysis showed the foreign gene was integrated into the cotton genome and expressed. The measurement of isolated vacuolar membrane vesicles demonstrated that the transgenic plants had higher V-H(+)-PPase activity compared with wild-type plants (WT). Overexpressing TsVP in cotton improved shoot and root growth, and transgenic plants were much more resistant to osmotic/drought stress than the WT. Under drought stress conditions, transgenic plants had higher chlorophyll content, improved photosynthesis, higher relative water content of leaves and less cell membrane damage than WT. We ascribe these properties to improved root development and the lower solute potential resulting from higher solute content such as soluble sugars and free amino acids in the transgenic plants. In this study, the average seed cotton yields of transgenic plants from Lumianyan 19 and Lumianyan 21 were significantly increased compared with those of WT after exposing to drought stress for 21 days at flowering stage. The average seed cotton yields were 51 and 40% higher than in their WT counterparts, respectively. This study benefits efforts to improve cotton yields in arid and semiarid regions.
Leonova, T., V. Ovchinnykova, et al. (2009) Isolated Thellungiella shoots do not require roots to survive NaCl and Na2SO4 salt stresses Plant signaling & behavior 4: 1059-1062.Shoots of Thellungiella derived by micropropagation were used to estimate the plants' salt tolerance and ability to regulate Na+ uptake. Two species with differing salt tolerances were studied: Thellungiella salsuginea (halophilla), which is less tolerant, and Thellungiella botschantzevii, which is more tolerant. Although the shoots of neither ecotype survived at 700 mM NaCl or 200 mM Na2SO4, micropropagated shoots of T. botschantzevii were more tolerant to Na2SO4 (10-100 mM) and NaCl (100-300 mM). In the absence of roots, Na2SO4 salinity reduced shoot growth more dramatically than NaCl salinity. Plantlets of both species were able to adapt to salt stress even when they did not form roots. First, there was no significant correlation between Na+ accumulation in shoots and Na+ concentration in the growth media. Second, K+ concentrations in the shoots exposed to different salt concentrations were maintained at equivalent levels to control plants grown in medium without NaCl or Na2SO4. These results suggest that isolated shoots of Thellungiella possess their own mechanisms for enabling salt tolerance, which contribute to salt tolerance in intact plants.
Kumari, S., P. Singh, et al. (2009) Heterologous Expression of a Salinity and Developmentally Regulated Rice Cyclophilin Gene (OsCyp2) in E-coli and S-cerevisiae Confers Tolerance Towards Multiple Abiotic Stresses Molecular Biotechnology 42: 195-204. 10.1007/s12033-009-9153-0Cyclophilin 2 (OsCyp2) is a cytosolic member of immunophilin family from rice. We have isolated its full length cDNA (1,056 bp) with an open reading frame of 519 bp encoding a polypeptide of 172 amino acids and an estimated pI of 8.61. Peptidyl prolyl cis-trans isomerase activity of the protein was determined using N-succinyl-ala-ala-pro-phe-p-nitroanilidine as peptide substrate. It has a catalytic efficiency (K (cat)/K (m)) of 4.5 x 10(6)/(mol/l)/s, which is comparable to known cyclophilins from plants. Its activity is specifically inhibited by cyclosporin A, a macrolide drug inhibitor of cyclophilins. Transcript analysis showed it to be a developmentally and differentially regulated gene; showing changes in abundance at seedling, tillering and heading stage under non-stress and salinity stress conditions. Expression of OsCyp2 enhances the ability of Escherichia coli to survive under diverse abiotic stresses viz. salinity, high temperature, osmotic stress (mannitol) and oxidative stress (H(2)O(2)). OsCyp2 was able to complement the yeast mutant lacking native Cyp2 and also improved the growth of wild type yeast under above-mentioned stress conditions. Based on these results, we propose that OsCyp2 may serve as a 'suitable candidate' for raising transgenic plants for enhanced multiple abiotic stress tolerance.
Kosyk, O. I., A. A. Okanenko, et al. (2009) Plant sulfolipid. III. Role in adaptation Biopolimery i Kletka 25: 85-94.The quality and/or relative content of plant sulfoquinovosyl diacylglycerol (SQDG,) change in response to a stress action. Various types of stress action induce two types of response - more general to the oxidative stress and specific - to a concrete stress factor. Besides, two types of reaction take place in photosynthesizing and non-photosynthesizing tissues. SQDG molecules take part in the adaptation reaction being cytochrome oxidase, CF1, F-1, ATPase regulators, protectors and stabilizing agents for D-1/D-2 dimers and LHC II. This compound in non-photosynthesising tissues could be connected with negative charge domination required for lipoprotein complex stabilisation. SQDG quantitative changes and acyl composition shifts take place at both abiotic and biotic factors impact.
Kidachi, Y., T. Noshita, et al. (2009) The Augmenting Activity of 6-(Methylsulfinyl)hexyl Isothiocyanate on Cellular Glutathione Levels Is Less Sensitive to Thiol Compounds Than Its Cytotoxic Activity Bioscience Biotechnology and Biochemistry 73: 1419-1421. 10.1271/bbb.80791We analyzed the effects of thiol compounds on the biological activities of 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC). Thiol compounds abolished the cytotoxic activity of 6-MITC, but did not abolish its activity augmenting cellular total glutathione levels and gamma-glutamylcysteine ligase gene expression. Thiol compounds might play an important role in the augmentation of several significant biological activities by overcoming the inherent limitations of 6-MITC.
Jha, B., P. K. Agarwal, et al. (2009) Identification of salt-induced genes from Salicornia brachiata, an extreme halophyte through expressed sequence tags analysis Genes & Genetic Systems 84: 111-120.Salinity severely affects plant growth and development causing crop loss worldwide. We have isolated a large number of salt-induced genes as well as unknown and hypothetical genes from Salicornia brachiata Roxb. (Amaranthaceae). This is the first description of identification of genes in response to salinity stress in this extreme halophyte plant. Salicornia accumulates salt in its pith and survives even at 2 M NaCl under field conditions. For isolating salt responsive genes, cDNA subtractive hybridization was performed between control and 500 mM NaCl treated plants. Out of the 1200 recombinant clones, 930 sequences were submitted to the NCBI database (GenBank accession: EB484528 to EB485289 and EC906125 to EC906292). 789 ESTs showed matching with different genes in NCBI database. 4.8% ESTs belonged to stress-tolerant gene category and approximately 29% ESTs showed no homology with known functional gene sequences, thus classified as unknown or hypothetical. The detection of a large number of ESTs with unknown putative function in this species makes it an interesting contribution. The 90 unknown and hypothetical genes were selected to study their differential regulation by reverse Northern analysis for identifying their role in salinity tolerance. Interestingly, both up and down regulation at 500 mM NaCl were observed (21 and 10 genes, respectively). Northern analysis of two important salt tolerant genes, ASR1 (Abscisic acid stress ripening gene) and plasma membrane H(+)ATPase, showed the basal level of transcripts in control condition and an increase with NaCl treatment. ASR1 gene is made full length using 5' RACE and its potential role in imparting salt tolerance is being studied.
Gho, C., S. Luo, et al. (2009) Cloning of buckthorn salt-tolerance HrNHX1 gene and sequence analysis of 3′ UTR Xinjiang Agricultural Sciences 46: 1031-1035.Total RNA was isolated from buckthorn's leaf with the improved SDS method, and was translated to the first cDNA strand as the template of PCR. A pair degenerated primers were designed according to the homologous cDNA segments cloned before. The middle segment of HrNHX1 gene was cloned, then the HrNHX1 3′ cDNA sequence also was obtained with the method of 3′ RACE. The total length of this sequence (Genbank accession number: EU718492) was 1 373 bp which was made up by 1 094 bp coding region encoding 364 amino acids and 239 bp 3′ UTR, and whose largest sequence homology was 80% with known NHX1 sequences. 3′ UTR sequence analysis showed that the buckthorn's 3′ UTR sequence homology of upland cotton, grapefruit and Thellungiella halophila were 43.97%, 45.63% and 40.64%, respectively, which was obviously lower than that of coding region s. The result indicated that the coding region of NHX1 gene was very conserved, but the 3′ UTR sequence had lower homology, which showed that the untranslated region was very important in environmental adaptation and offered us a significant reference in researching the molecular mechanisms of fitting environment in plant.
German, D. A. and W.-L. Chen. (2009) Notes on the family Brassicaceae in China Journal of Systematics and Evolution 47: 202-219. 10.1111/j.1759-6831.2009.00022.xA critical revision of the collections of Brassicaceae in some Chinese (PE, XJA, XJBI, XJFA, XJNM, XJU) and foreign (LE, P) herbaria is made. One genus, Neurotropis (DC.) E K. Mey., and I I species, Alyssum szarabiacum Nyar., Barbarea stricta Andrz., Erysimum czernjajevii N. Busch, Erysimum kotuchovii D. German, Erysimum mongolicum D. German, Lepidium karelinianum Al-Shehbaz, Matthiola superba Conti, Neurotropis platycarpa (Fisch. & Mey.) E K. Mey., Ptilotrichum dahuricum Peschkova, Sisymbrium subspinescens Bunge, and Smelowskia micrantha (Botsch. & Vved.) Al-Shehbaz & S. I. Warwick, are reported from China for the first time. Six species, Aphragmus involucratus (Bunge) O. E. Schulz, Dontostemon perennis C. A. Mey, Goldbachia torulosa DC., Lepidium amplexicaule Willd., Neotorularia brevipes (Kar. & Kir.) Hedge & J. Leonard, and Parrya stenocarpa Kar. & Kir., are confirmed to occurr in China. Five species, Dontostemon integrifolius (L.) C. A. Mey, Draba zangbeiensis L. L. Lou, Lepidium alashanicum H. L. Yang, Sinapis arvensis L., and Strigosella brevipes (Bunge) Botsch., are reported as novelties for some provinces in China, and Strigosella hispida (Litv.) Botsch. occurs in Xinjiang, China. However, the occurrence of one genus, Pseudoarabidopsis Al-Shehbaz, O'Kane & Price, and four species, Draba huetii Boiss., Eutrema halophilum (C. A. Mey.) Al-Shehbaz & S. I. Warwick, Galitzkya spathulata (Steph. ex Willd.) V Bocz., and Pseudoarabidopsis toxophylla (Bieb.) Al-Shehbaz, O'Kane & Price, could not be confirmed in China. The occurrence of six species, Aphragmus bouffordii Al-Shehbaz, Barbarea orthoceras Ledeb., Lepidium latifolium L., Ptilotrichum canescens (DC.) C. A. Mey., Strigosella hispida (Litv.) Botsch., and Strigosella scorpioides (Bunge) Botsch., is not confirmed in certain provinces of China. All names follow the latest taxonomic treatment for relevant groups; detailed morphological descriptions of the newly recorded taxa are provided; and distinguishing characters from related species already known in China are discussed. Other comments are provided where needed.
Gao, Q., F. Gao, et al. (2009) Molecular Cloning, Expression, and Polyclonal Antibody Production of a Novel Flavin-Containing Monooxygenase from Thellungiella halophila Plant Molecular Biology Reporter 27: 94-101. 10.1007/s11105-008-0059-yA novel flavin-containing monooxygenase (FMO)-like gene, designated as TsFMO, was cloned from Thellungiella halophila by reverse-transcriptase polymerase chain reaction (RT-PCR) coupled with rapid amplification of cDNA ends approach. The cDNA sequence of TsFMO had a complete open reading frame encoding a putative protein of 461 amino acids, which contained the conserved domains of FMOs. Sequence analysis showed that it had highest similarity with Arabidopsis FMO(GS-OX1). RT-PCR analysis revealed that TsFMO was constitutively expressed in all examined tissues including the roots and rosette leaves of the seedlings and mature plants, bolts, and open flowers. Real-time PCR suggested that the gene was quickly and significantly upregulated in the leaves exposed to NaCl stress, which showed that TsFMO might be regulated with the redox state of plant cell. TsFMO was found to complement and rescue the retardant growth to dithiothreitol of yeast fmo mutant strain. In addition, TsFMO was expressed in Escherichia coli and the recombinant protein was purified to produce polyclonal antibody. Western blot with T. halophila extracts showed that the polyclonal antibody was effective and specific.
Gao, F., Y. J. Zhou, et al. (2009) Proteomic analysis of cold stress-responsive proteins in Thellungiella rosette leaves Planta 230: 1033-1046. 10.1007/s00425-009-1003-6Low temperature is one of the most severe environmental factors that impair plant growth and agricultural production. To investigate how Thellungiella halophila, an Arabidopsis-like extremophile, adapts to cold stress, a comparative proteomic approach based on two-dimensional electrophoresis was adopted to identify proteins that changed in abundance in Thellungiella rosette leaves during short term (6 h, 2 and 5 days) and long term (24 days) exposure to cold stress. Sixty-six protein spots exhibited significant change at least at one time point and maximal cold stress induced-proteome change was found in long-term cold stress group while the minimal change was found in 6-h cold treatment group. Fifty protein spots were identified by mass spectrometry analysis. The identified proteins mainly participate in photosynthesis, RNA metabolism, defense response, energy pathway, protein synthesis, folding and degradation, cell wall and cytoskeleton and signal transduction. These proteins might work cooperatively to establish a new homeostasis under cold stress. Nearly half of the identified cold-responsive proteins were associated with various aspects of chloroplast physiology suggesting that the cold stress tolerance of T. halophila is achieved, at least partly, by regulation of chloroplast function. All protein spots involved in RNA metabolism, defense response, protein synthesis, folding and degradation were found to be upregulated markedly by cold treatment, indicating enhanced RNA metabolism, defense and protein metabolism may play crucial roles in cold tolerance mechanism in T. halophila.
Deng, Z. Y., Y. Li, et al. (2009) Structural analysis of 83-kb genomic DNA from Thellungiella halophila: Sequence features and microcolinearity between salt cress and Arabidopsis thaliana Genomics 94: 324-332. 10.1016/j.ygeno.2009.07.006Salt cress (Thellungiella halophila) has become a desirable plant model for molecular analysis of the mechanisms of salt tolerance. Analysis of its physiological action and expressed EST has resulted in better understanding. However, less is known about its genomic features. Here we determined a continuous sequence approximately 83 kb from a salt cress BAC clone, providing the first insight into the genomic feature for this species. The gene density is approximately one gene per 3.6 kb in this sequence. Many types of repetitive sequences are present in this salt cress sequence, including LTR retroelements, DNA transposons and a number of simple sequence repeats. Comparison of sequence similarity indicated that salt cress shares a close relationship with Arabidopsis. Extensive conservation and high-level microcolinearity were uncovered for both genomes. Our study also indicated that genomic DNA alternations (involving chromosome inversion, sequence loss and gene translocation) contributed to the genomic discrepancies between salt cress and Arabidopsis. (c) 2009 Elsevier Inc. All rights reserved.
Deng, Z., Y. Li, et al. (2009) Structural analysis of 83-kb genomic DNA from Thellungiella halophila: sequence features and microcolinearity between salt cress and Arabidopsis thaliana Genomics (San Diego) 94: 324-332. 10.1016/j.ygeno.2009.07.006Salt cress (Thellungiella halophila) has become a desirable plant model for molecular analysis of the mechanisms of salt tolerance. Analysis of its physiological action and expressed EST has resulted in better understanding. However, less is known about its genomic features. Here we determined a continuous sequence approximately 83 kb from a salt cress BAC clone, providing the first insight into the genomic feature for this species. The gene density is approximately one gene per 3.6 kb in this sequence. Many types of repetitive sequences are present in this salt cress sequence, including LTR retroelements, DNA transposons and a number of simple sequence repeats. Comparison of sequence similarity indicated that salt cress shares a close relationship with Arabidopsis. Extensive conservation and high-level microcolinearity were uncovered for both genomes. Our study also indicated that genomic DNA alternations (involving chromosome inversion, sequence loss and gene translocation) contributed to the genomic discrepancies between salt cress and Arabidopsis.
Amtmann, A. (2009) Learning from Evolution: Thellungiella Generates New Knowledge on Essential and Critical Components of Abiotic Stress Tolerance in Plants Molecular Plant 2: 3-12. 10.1093/mp/ssn094Thellungiella salsuginea (halophila) is a close relative of Arabidopsis thaliana but, unlike A. thaliana, it grows well in extreme conditions of cold, salt, and drought as well as nitrogen limitation. Over the last decade, many laboratories have started to use Thellungiella to investigate the physiological, metabolic, and molecular mechanisms of abiotic stress tolerance in plants, and new knowledge has been gained in particular with respect to ion transport and gene expression. The advantage of Thellungiella over other extremophile model plants is that it can be directly compared with Arabidopsis, and therefore generate information on both essential and critical components of stress tolerance. Thellungiella research is supported by a growing body of technical resources comprising physiological and molecular protocols, ecotype collections, expressed sequence tags, cDNA-libraries, microarrays, and a pending genome sequence. This review summarizes the current state of knowledge on Thellungiella and re-evaluates its usefulness as a model for research into plant stress tolerance.
Aleman, F., M. Nieves-Cordones, et al. (2009) Differential regulation of the HAK5 genes encoding the high-affinity K(+) transporters of Thellungiella halophila and Arabidopsis thaliana Environmental and Experimental Botany 65: 263-269. 10.1016/j.envexpbot.2008.09.011A Thellungiella halophila cDNA, ThHAK5, encoding a transporter of the KT/HAK/KUP family has been isolated. According to a phylogenetic study, ThHAK5 is located within group I of the family. Expression in yeast demonstrates that it mediates high-affinity K(+) uptake with similar characteristics to K(+)-starved plants, which show high levels of ThHAK5 transcripts. These results show that, as in glycophytes, HAK1-type transporters are major contributors to high-affinity K(+) uptake. However, the regulation ofthis type of gene may differ between glycophytes and halophytes grown under salinity. Whereas ThHAK5 transcripts are detected in K(+)-starved plants grown with NaCl, transcripts of the Arabidopsis thaliana homologue AtHAK5 are absent. As a result, high-affinity K(+) uptake is reduced to a lesser extent in T halophila than in A. thaliana when plants are grown with NaCl. The results presented here indicate that plants which differ in salt tolerance show differential regulation of the expression of genes encoding K(+) transporters. (C) 2008 Elsevier B.V. All rights reserved.
Aleman, F., M. Nieves-Cordones, et al. (2009) Potassium/sodium steady-state homeostasis in Thellungiella halophila and Arabidopsis thaliana under long-term salinity conditions Plant Science 176: 768-774. 10.1016/j.plantsci.2009.02.020Salinity is one of the most important abiotic stresses that challenges plant growth and development. Crops are glycophytes and salinity causes important losses in agriculture. One of the approaches to reduce salinity impact is to increase crop salt tolerance by transferring genetic determinants important for salt tolerance from halophytes to crop species. These determinants may be identified by comparative studies in model species that differ in their salt tolerance. Thus, some recent studies have been focused on the comparison of Arabidopsis thaliana and Thellungiella halophila. To further gain insights into mechanisms important for salt tolerance we present here a comparative study of salt tolerance in these two species. This study is performed in plants growing hydroponically with salinity under steady-state conditions, allowing a characterization of K(+)/Na(+) homeostasis under conditions that are closer to those that the plants face in the field. The results show that T. halophila shows a higher root/shoot ratio under non-salt conditions than A. thaliana and that this difference is exacerbated under salinity conditions. The presence of NaCl produced higher reductions of tissue K(+) concentrations as well as of K(+)-specific absorption rates in A. thaliana than in T halophila. On the other hand, A. thaliana showed higher rates of Na(+) absorption and transport to the shoot. As a result T. halophila shows an overall K(+)/Na(+) selectivity that may contribute to its higher salt tolerance. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
Zhou, S., X. Chen, et al. (2008) Improved salt tolerance in tobacco plants by co-transformation of a betaine synthesis gene BADH and a vacuolar Na+/H+ antiporter gene SeNHX1 Biotechnology Letters 30: 369-376. 10.1007/s10529-007-9548-6Three types of transgenic tobacco plants were acquired by separate transformation or co-transformation of a vacuolar Na+/H+ antiporter gene, SeNHX1, and a betaine synthesis gene, BADH. When exposed to 200 mM NaCl, the dual gene-transformed plants displayed greater accumulation of betaine and Na+ than their wild-type counterparts. Photosynthetic rate and photosystem II activity in the transgenic plants were less affected by salt stress than wild-type plants. Transgenic plants exhibited a greater increase in osmotic pressure than wild-type plants when exposed to NaCl. More importantly, the dual gene transformed plants accumulated higher biomass than either of the single transgenic plants under salt stress. Taken together, these findings indicate that simultaneous transformation of BADH and SeNHX1 genes into tobacco plants can enable plants to accumulate betaine and Na+, thus conferring them more tolerance to salinity than either of the single gene transformed plants or wild-type tobacco plants.
Zhao, X., F. Sheng, et al. (2008) Effects of salt stress on chemical composition and protein conformation changes in Thellungiella and Arabidopsis seedlings Chinese Journal of Applied and Environmental Biology 14: 371-377.A technique based on Fourier transform infrared (FTIR) spectrometry was used to detect the corresponding changes in chemical composition which associated with the rapid changes in sodium with 200 mmol/L NaCl stressed halophyte Thellungiella halophila. The changes in glycophyte Arabidopsis thaliana stressed with 50 mmol/L NaCl were also examined for comparison. The results showed that within 48 h of mild salt stress, the absorption band intensities in the fingerprint region decreased continuously in both the plants, suggesting that the carbon assimilation was affected at the early stage of stress. The intensities of ester and amide 1 absorption bands decreased slightly in A. thaliana, but increased in T. halophila, suggesting that the cell expansion and protein synthesis ceased in A. thaliana but continued in T. halophila. In the two plants, the analysis of the ratio between 1 668 and 1 638 cm(-1) in amide I absorption bands revealed that T. halophila was able to maintain a higher-ordered form of proteins under the stress. Furthermore, the changes in protein conformation showed a positive correlation with the sodium contents in T. halophila leaves. Fig 6, Tab 1, Ref 29.
Zhang, Y. Y., J. B. Lai, et al. (2008) Comparison analysis of transcripts from the halophyte Thellungiella halophila Journal of Integrative Plant Biology 50: 1327-1335. 10.1111/j.1744-7909.2008.00740.xThe Brassicaceae family halophyte Thellungiella halophila has a high salinity tolerance and serves as a valuable halophytic genetic model plant with experimental convenience similar to Arabidopsis thaliana. A cDNA library of Thellungiella was generated from salt-treated seedlings including rosettes and roots. More than 1 000 randomly selected clones were sequenced and 946 expressed sequence tags (ESTs) were generated. The accession numbers of our EST data are available online in the GenBank database from EC598928 to EC599965. In total 679 unique clusters were assembled, and 632 (93%) had BLASTX hits in the nr databases and 7% are Thellungiella unique. According to the Gene Ontology (GO) hierarchy, 385 of 679 unigenes were categorized. Compared with public Arabidopsis microarray data, our results provide more potential salt tolerance genes in Thellungiella. These results will provide a broader coverage into Thellungiella transcriptome and benefit the discovery of salt tolerance related genes.
Xie, Q. and Z. Gong. (2008) Understanding abiotic stresses and the solution Journal of Integrative Plant Biology 50: 1185-1186. 10.1111/j.1744-7909.2008.00774.xThe calcineurin B-like (CBL) proteins, comprising a large subfamily of calcium sensors in plant cells, play an important role inmany stress responses. We cloned a gene from the halophyte Thellungiella halophila that is homologous to AtCBL9 in Arabidopsisthaliana. The 1008-bp ThCBL9 contains an ORF of 639 bp and encodes 213 amino acids, with a 5'-untranslated regionof 193 Ib I) and a 3'-untranslated region of 176 bp. Its amino acid sequence shares high homology with AtCBLs. ThCBL9 is upregulate(t by ABA, NaCI, and PEG in Theilungiella leaves. Using molecular biological methods, we over-expressed ThCBL9 inA. thaliana andl found that this enhanced tolerances to both high salt and osmotic stress in transgenic Arabidopsis.
Taji, T., T. Sakurai, et al. (2008) Large-scale collection and annotation of full-length enriched cDNAs from a model halophyte, Thellungiella halophila Bmc Plant Biology 8: 115 10.1186/1471-2229-8-115Background: Thellungiella halophila ( also known as Thellungiella salsuginea) is a model halophyte with a small plant size, short life cycle, and small genome. It easily undergoes genetic transformation by the floral dipping method used with its close relative, Arabidopsis thaliana. Thellungiella genes exhibit high sequence identity ( approximately 90% at the cDNA level) with Arabidopsis genes. Furthermore, Thellungiella not only shows tolerance to extreme salinity stress, but also to chilling, freezing, and ozone stress, supporting the use of Thellungiella as a good genomic resource in studies of abiotic stress tolerance. Results: We constructed a full-length enriched Thellungiella (Shan Dong ecotype) cDNA library from various tissues and whole plants subjected to environmental stresses, including high salinity, chilling, freezing, and abscisic acid treatment. We randomly selected about 20 000 clones and sequenced them from both ends to obtain a total of 35 171 sequences. CAP3 software was used to assemble the sequences and cluster them into 9569 nonredundant cDNA groups. We named these cDNAs "RTFL" (RIKEN Thellungiella Full-Length) cDNAs. Information on functional domains and Gene Ontology ( GO) terms for the RTFL cDNAs were obtained using InterPro. The 8289 genes assigned to InterPro IDs were classified according to the GO terms using Plant GO Slim. Categorical comparison between the whole Arabidopsis genome and Thellungiella genes showing low identity to Arabidopsis genes revealed that the population of Thellungiella transport genes is approximately 1.5 times the size of the corresponding Arabidopsis genes. This suggests that these genes regulate a unique ion transportation system in Thellungiella. Conclusion: As the number of Thellungiella halophila ( Thellungiella salsuginea) expressed sequence tags ( ESTs) was 9388 in July 2008, the number of ESTs has increased to approximately four times the original value as a result of this effort. Our sequences will thus contribute to correct future annotation of the Thellungiella genome sequence. The full-length enriched cDNA clones will enable the construction of overexpressing mutant plants by introduction of the cDNAs driven by a constitutive promoter, the complementation of Thellungiella mutants, and the determination of promoter regions in the Thellungiella genome.
Sun, Z. B., X. Y. Qi, et al. (2008) Overexpression of a Thellungiella halophila CBL9 homolog, ThCBL9, confers salt and osmotic tolerances in transgenic Arabidopsis thaliana Journal of Plant Biology 51: 25-34.The calcineurin B-like (CBL) proteins, comprising a large subfamily of calcium sensors in plant cells, play an important role in many stress responses. We cloned a gene from the halophyte Thellungiella halophila that is homologous to AtCHL9 in Arabidopsis thaliana. The 1008-bp ThCBL9 contains an ORF of 639 bp and encodes 213 amino acids, with a 5'-untranslated region of 193 bp and a 3'-untranslated region of 176 bp. Its amino acid sequence shares high homology with AtCBLs. ThCBL9 is upregulated by ABA, NaCl, and PEG in Thellungiella leaves. Using molecular biological methods, we over-expressed ThCBL9 in A. thaliana and found that this enhanced tolerances to both high salt and osmotic stress in transgenic Arabidopsis.
Stepien, P. (2008) Contrasting response of photosynthesis to salt stress in the glycophyte Arabidopsis thaliana and the halophyte Thellungiella hatophila Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology 150: S191-S191. 10.1016/j.cbpa.2008.04.519New metabolic profiling technologies provide data on a wider range of metabolites than traditional targeted approaches. Metabolomic technologies currently facilitate acquisition of multivariate metabolic data using diverse, mostly hyphenated, chromatographic detection systems, such as GC-MS or liquid chromatography coupled to mass spectrometry, Fourier-transformed infrared spectroscopy or NMR-based methods. Analysis of the resulting data can be performed through a combination of non-supervised and supervised statistical methods, such as independent component analysis and analysis of variance, respectively. These methods reduce the complex data sets to information, which is relevant for the discovery of metabolic markers or for hypothesis-driven, pathway-based analysis. Plant responses to salinity involve changes in the activity of genes and proteins, which invariably lead to changes in plant metabolism. Here, we highlight a selection of recent publications in the salt stress field, and use gas chromatography time-of-flight mass spectrometry profiles of polar fractions from the plant models, Arabidopsis thaliana, Lotus japonicus and Oryza sativa to demonstrate the power of metabolite profiling. We present evidence for conserved and divergent metabolic responses among these three species and conclude that a change in the balance between amino acids and organic acids may be a conserved metabolic response of plants to salt stress.
Roelofs, D., M. G. M. Aarts, et al. (2008) Functional ecological genomics to demonstrate general and specific responses to abiotic stress Functional Ecology 22: 8-18. 10.1111/j.1365-2435.2007.01312.xStress is a major component of natural selection in soil ecosystems. The most prominent abiotic stress factors in the field are temperature extremes (heat, cold), dehydration (drought), high salinity and specific toxic compounds such as heavy metals. Organisms are able to deal with these stresses to a certain extent, which determines the limits of their ecological amplitudes. Functional genomic tools are now becoming available to study stress in ecologically relevant soil organisms. Here we give an overview of transcriptomic studies aiming to elucidate how plants and soil invertebrates respond and adapt to a stressful environment. The picture emerging from signalling pathways and transcription factors identified in transcription profiling studies suggests that there is a large overlap of genomic responses to drought, salinity and cold; however, heat and heavy metals trigger different stress response pathways. The heat shock response and the oxidative stress response seem to represent universal components of the environmental stress response (ESR). Furthermore, the commonality across plants and animals seems to be higher in effector genes than in transcriptional regulators. Finally, adaptation to stress factors in soil seems to evolve through enhanced constitutive transcription of otherwise stress responsive genes both in plants and animals.
Quan, X. Q., Z. L. Wang, et al. (2008) Cloning and characterization of TsMT3, a type 3 metallothionein gene from salt cress (Thellungiella salsuginea) Mitochondrial DNA 19: 340-346. 10.1080/10425170701606201A full-length type 3 plant metallothionein cDNA was isolated from 200 mM NaCl stressed shoots of the salt cress (Thellungiella salsuginea). The 447 bp TsMT3 cDNA sequence has a 207 bp open reading frame (ORF) and encodes a deduced 69 residue peptide of molecular weight 7.52 kDa. Southern blot analysis indicates that, there is only one copy of TsMT3 in the T. salsuginea genome. The accumulation of TsMT3 mRNA is enhanced by the stress imposed by PEG6000, 200 mM NaCl, 50 mM ABA, 4 degrees C, 40 mu M CuSO4 or 25 mu M CdCl2. The expression vector pET28-TsMT3 was heterologously expressed in Escherichia coli to define the contribution of TsMT3 to heavy metal tolerance. In the presence of 2 mM CuSO4, 0.3 mM Pb(NO3)(2) or 0.4 mM CdCl2, TsMT3 expressing cells exhibited enhanced metal tolerance and accumulated more metal than the controls. We believe that TsMT3 is probably involved in the processes of metal homeostasis, tolerance, and reactive oxygen species (ROS) scavenging.
Quan, X. Q., Z. L. Wang, et al. (2008) Cloning and charecterization of TsMT3, a type 3 metallothionein gene from salt cress (Thellungiella salsuginea) DNA Sequence 19: 340-346. 10.1080/10425170701606201A full-length type 3 plant metallothionein cDNA was isolated from 200 mM NaCl stressed shoots of the salt cress (Thellungiella salsuginea). The 447 bp TsMT3 cDNA sequence has a 207 bp open reading frame (ORF) and encodes a deduced 69 residue peptide of molecular weight 7.52 kDa. Southern blot analysis indicates that, there is only one copy of TsMT3 in the T salsuginea genome. The accumulation of TsMT3 mRNA is enhanced by the stress imposed by PEG6000, 200 mM NaCl, 50 mu M ABA, 4 degrees C, 40 mu M CuSO(4) or 25 mu M CdCl(2). The expression vector pET28-TsMT3 was heterologously expressed in Escherichia coli to define the contribution of TsMT3 to heavy metal tolerance. In the presence of 2 mM CuSO(4), 0.3 mM Pb(NO(3))(2) or 0.4 mM CdCl(2), TsMT3 expressing cells exhibited enhanced metal tolerance and accumulated more metal than the controls. We believe that TsMT3 is probably involved in the processes of metal homeostasis, tolerance, and reactive oxygen species (ROS) scavenging.
Pedras, M. S. C. and A. M. Adio. (2008) Phytoalexins and phytoanticipins from the wild crucifers Thellungiella halophila and Arabidopsis thaliana: Rapalexin A, wasalexins and camalexin Phytochemistry 69: 889-893. 10.1016/j.phytochem.2007.10.032investigation of phytoalexin production using abiotic elicitation showed that the phytoalexin rapalexin A was produced by both Thellungiella halophila and Arabidopsis thaliana, but while A. thaliana produced camalexin, T halophila produced wasalexins A and B and methoxybrassenin B. Considering that the genome of T halophila is being sequenced currently and that the wasalexin pathway present in T halophila is expected to involve a number of genes also present in Brassica species, our discovery should facilitate the isolation of genes involved in biosynthetic pathways of phytoalexins of the most economically important crucifer species. (C) 2007 Elsevier Ltd. All rights reserved.
Pareek, A., S. L. Singla-Pareek, et al. (2008). Analysis of salt stress-related transcriptome fingerprints from diverse plant species. in Springer Series on Biofilms. N. Balaban (eds). 2: 267-287. Mapelli, S., I. M. Brambilla, et al. (2008) Free and bound polyamines changes in different plants as a consequence of UV-B light irradiation General and Applied Plant Physiology 34: 55-66.All abiotic and biotic stresses induce or involve oxidative stress to some degree, and the plant ability to control oxidant levels is highly correlated with stress tolerance. Polyamines (PAs) have antioxidant properties and their induction in response to stress is well known. Mesembryanthemum crystallinum L., Thellungiella halophila Mey., Plantago major L. and Geum urbanum L. plants were grown for six weeks in water culture with modified Winter nutrient medium, 14 h at 350 mol/m2 s1, 23°C-16°C. Six-week-old plants were exposed to the range of 3 to 9 kJ m-2 d-1 UV-B irradiation. Starting from the following day, leaves and roots were used for analyses of PA. Free, soluble bound and insoluble conjugated fractions were extracted and determined. After UV-B irradiation the plants with different adaptation strategy showed different dynamics of PAs content. M. crystallinum, T. halophila, P. major are known to have a more effective antioxidant system than G. urbanum. The data provided evidence that the UV-B stress caused PA divergent responses and fractionations in halophyte (M. crystallinum and T. halophila) and glycophyte (P. major and G. urbamum) plants. The changes in the levels and fractions of putrescine (Put), spermidine (Spd) and spermine (Spm), in roots and leaves, correlated with higher tolerance of M. crystallinum, and T. halophila. The effect of UV-B irradiation depended on the exposition intensity, and the strong effect on PAs was evident after 9 kJ m-2 d-1 application. The lighter was the UV-B irradiation, the higher and faster was the capacity in the higher tolerant plant to go back to the PAs level in the control plants.
Mandakova, T. and M. A. Lysak. (2008) Chromosomal Phylogeny and Karyotype Evolution in x=7 Crucifer Species (Brassicaceae) Plant Cell 20: 2559-2570. 10.1105/tpc.108.062166Karyotype evolution in species with identical chromosome number but belonging to distinct phylogenetic clades is a long-standing question of plant biology, intractable by conventional cytogenetic techniques. Here, we apply comparative chromosome painting (CCP) to reconstruct karyotype evolution in eight species with x=7 (2n= 14, 28) chromosomes from six Brassicaceae tribes. CCP data allowed us to reconstruct an ancestral Proto-Calepineae Karyotype (PCK; n=7) shared by all x=7 species analyzed. The PCK has been preserved in the tribes Calepineae, Conringieae, and Noccaeeae, whereas karyotypes of Eutremeae, Isatideae, and Sisymbrieae are characterized by an additional translocation. The inferred chromosomal phylogeny provided compelling evidence for a monophyletic origin of the x=7 tribes. Moreover, chromosomal data along with previously published gene phylogenies strongly suggest the PCK to represent an ancestral karyotype of the tribe Brassiceae prior to its tribe-specific whole-genome triplication. As the PCK shares five chromosomes and conserved associations of genomic blocks with the putative Ancestral Crucifer Karyotype (n=8) of crucifer Lineage I, we propose that both karyotypes descended from a common ancestor. A tentative origin of the PCK via chromosome number reduction from n=8 to n=7 is outlined. Comparative chromosome maps of two important model species, Noccaea caerulescens and Thellungiella halophila, and complete karyotypes of two purported autotetraploid Calepineae species (2n=4x=28) were reconstructed by CCP.
Malagoli, P., D. T. Britto, et al. (2008) Futile Na+ cycling at the root plasma membrane in rice (Oryza sativa L.): kinetics, energetics, and relationship to salinity tolerance Journal of Experimental Botany 59: 4109-4117. 10.1093/jxb/ern249Globally, over one-third of irrigated land is affected by salinity, including much of the land under lowland rice cultivation in the tropics, seriously compromising yields of this most important of crop species. However, there remains an insufficient understanding of the cellular basis of salt tolerance in rice. Here, three methods of Na-24(+) tracer analysis were used to investigate primary Na+ transport at the root plasma membrane in a salt-tolerant rice cultivar (Pokkali) and a salt-sensitive cultivar (IR29). Futile cycling of Na+ at the plasma membrane of intact roots occurred at both low and elevated levels of steady-state Na+ supply ([Na+](ext)=1 mM and 25 mM) in both cultivars. At 25 mM [Na+](ext), a toxic condition for IR29, unidirectional influx and efflux of Na+ in this cultivar, but not in Pokkali, became very high [> 100 mu mol g (root FW)(-1) h(-1)], demonstrating an inability to restrict sodium fluxes. Current models of sodium transport energetics across the plasma membrane in root cells predict that, if the sodium efflux were mediated by Na+/H+ antiport, this toxic scenario would impose a substantial respiratory cost in IR29. This cost is calculated here, and compared with root respiration, which, however, comprised only similar to 50% of what would be required to sustain efflux by the antiporter. This suggests that either the conventional 'leak-pump' model of Na+ transport or the energetic model of proton-linked Na+ transport may require some revision. In addition, the lack of suppression of Na+ influx by both K+ and Ca2+, and by the application of the channel inhibitors Cs+, TEA(+), and Ba2+, questions the participation of potassium channels and non-selective cation channels in the observed Na+ fluxes.
Lv, S., K. W. Zhang, et al. (2008) Overexpression of an H(+)-PPase gene from Thellungiella halophila in cotton enhances salt tolerance and improves growth and photosynthetic performance Plant and Cell Physiology 49: 1150-1164. 10.1093/pcp/pcn090Salinity is one of the major environmental factors limiting plant growth and productivity. An H(+)-PPase gene, TsVP from Thellungiella halophila, was transferred into cotton (Gossypium hirsutum) in sense and antisense orientations under control of the cauliflower mosaic virus (CaMV) 35S promoter. Southern and Northern blotting analysis showed that the sense or antisense TsVP were integrated into the cotton genome and expressed. Transgenic plants overexpressing the vacuolar H(+)-PPase were much more resistant to 150 and 250 mM NaCl than the isogenic wild-type plants. In contrast, the plants from the antisense line (L2), with lower H(+)-PPase activity, were more sensitive to salinity than the wild-type plants. Overexpressing TsVP in cotton improved shoot and root growth and photosynthetic performance. These transgenic plants accumulated more Na(+), K(+), Ca(2+), Cl(-) and soluble sugars in their root and leaf tissues under salinity conditions compared with the wild-type plants. The lower membrane ion leakage and malondialdehyde (MDA) level in these transgenic plants suggest that overexpression of H(+)-PPase causes the accumulation of Na(+) and Cl(-) in vacuoles instead of in the cytoplasm, thus reducing their toxic effects. On the other hand, the increased accumulation of ions and sugars decreases the solute potential in cells, and facilitates water uptake under salinity, which is an important mechanism for the increased salt tolerance in TsVP-overexpressing cotton.
Li, B., A. Wei, et al. (2008) Heterologous expression of the TsVP gene improves the drought resistance of maize Plant Biotechnology Journal 6: 146-159. 10.1111/j.1467-7652.2007.00301.xIn this study, it was shown that the TsVP gene [vacuolar H+-pyrophosphatase (V-H+-PPase) gene from a dicotyledonous halophyte Thellungiella halophila] could be transferred into the monocotyledonous crop maize (Zea mays L.), and that the heterologous expression of the transgene improved the drought resistance of transgenic plants. Polymerase chain reaction amplification and Southern blotting confirmed the existence of the foreign gene in transformed plants and their progeny. Expression differences of the TsVP gene in different transgenic lines were monitored by reverse transcriptase-polymerase chain reaction. The measurement of isolated vacuolar membrane vesicles from the TsVP transgenic and wild-type (WT) plants demonstrated that the transgenic plants had higher V-H+-PPase activity, and the performance of maize-expressed TsVP in response to osmotic/drought stress was better in lines with higher V-H+-PPase activity. Transgenic plants showed a higher percentage of seed germination, better developed root systems and greater biomass, greater solute accumulation and less cell membrane damage relative to WT plants under osmotic stress. After drought stress treatment, transgenic plants showed less growth retardation and shorter anthesis-silking interval, and produced much larger grain yields, than WT plants. It was concluded that the high V-H+-PPase activity of transgenic maize improved the drought resistance of plants. This report provides a feasible approach to increase monocotyledonous crop yields under conditions of soil water deficit by the heterologous expression of TsVP.
Kartashov, A. V., N. L. Radyukina, et al. (2008) Role of antioxidant systems in wild plant adaptation to salt stress Russian Journal of Plant Physiology 55: 463-468. 10.1134/s1021443708040055Wild plants differing in the strategies of adaptation to salinity were grown for six weeks in the phytotron and then subjected to salt stress (100 mM NaCl, 24 h). The activities of principal antioxidant enzymes and the accumulation of sodium ions and proline were studied. Independently of the level of constitutive salt tolerance, plants of all species tested accumulated sodium ions under salinity conditions but differed in their capability of stress-dependent proline accumulation and superoxide dismutase (SOD) and guaiacol-dependent peroxidase activities. Proline-accumulating species were found among both halophytes (Artemisia lerchiana and Thellungiella halophila) and glycophytes (Plantago major and Mycelis muralis). The high activities of ionically-bound and covalently bound peroxidases were characteristic of Th. halophila plants. High constitutive and stress-induced SOD activities were, as a rule, characteristic of glycophytes with the low constitutive proline level: Geum urbanum and Thalictrum aquilegifolium. Thus, a negative correlation was found between proline content and SOD activity in wild species tested; it was especially bright in the halophyte Th. halophila and glycophyte G. urbanum. An extremely high constitutive and stress-induced levels of proline and peroxidase activity in Th. halophila maybe compensate SOD low activity in this plant, and this contributed substantially into its salt resistance. Thus, monitoring of stress-dependent activities of some antioxidant enzymes and proline accumulation in wild plant species allowed a supposition of reciprocal interrelations between SOD activity and proline accumulation. It was also established that the high SOD activity is not obligatory trait of species salt tolerance. Moreover, plants with the high activity of peroxidase and active proline accumulation could acclimate to salts stress (100 mM NaCl, 24 h) independently of SOD activity.
Kant, S., Y. M. Bi, et al. (2008) The Arabidopsis halophytic relative Thellungiella halophila tolerates nitrogen-limiting conditions by maintaining growth, nitrogen uptake, and assimilation Plant Physiology 147: 1168-1180. 10.1104/pp.108.118125A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mM nitrate) and severe (0.4 mM nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mM nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low (NO3-)-N-15 supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance.
Kabala, K. and G. Klobus. (2008) Modification of vacuolar proton pumps in cucumber roots under salt stress Journal of Plant Physiology 165: 1830-1837. 10.1016/j.jplph.2008.01.003The time-dependent effect of 50 mM NaCl on the activities of two tonoplast proton pumps was investigated in Cucumis sativus L. var. Krak root cells. Distinct activity profiles for vacuolar proton transporting ATPase (V-ATPase) (EC 3.6.3.14) and vacuolar proton transporting pyrophosphatase (V-PPase) (EC 3.6.1.1) under salinity are presented. ATP-dependent proton transport and ATP hydrolysis increased after 24 h of NaCl exposure, and then decreased in roots stressed with NaCl for 4 and 8d. Both PPi-driven H+ transport and PPi hydrolysis were clearly inhibited by NaCl at all. times examined. It was demonstrated that changes in enzyme activities were not due to the salt action on the expression of encoding genes. The levels of specific transcripts for subunit A of V-ATPase (CsVHA-A), subunit c of V-ATPase (CsVHA-c) and V-PPase (CsVP) were similar in cucumber roots untreated (control) and treated with salt. Such results suggest that alterations of proton pump activities under salinity are rather due to the post-translational alterations induced by NaCl. (C) 2008 Elsevier GrnbH. All rights reserved.
Ghars, M. A., E. Parre, et al. (2008). Opposite lipid signaling pathways tightly control proline accumulation in Arabidopsis thaliana and Thellungiella halophila. in Biosaline Agriculture and High Salinity Tolerance (C. Abdelly, M. Ozturk, M. Ashraf and C. Grignon eds.) Ghars, M. A., E. Parre, et al. (2008) Comparative salt tolerance analysis between Arabidopsis thaliana and Thellungiella halophila, with special emphasis on K+/Na+ selectivity and proline accumulation Journal of Plant Physiology 165: 588-599. 10.1016/j.jplph.2007.05.014The eco-physiology of salt tolerance, with an emphasis on K+ nutrition and proline accumulation, was investigated in the halophyte Thellungiella halophila and in both wild type and eskimo-1 mutant of the glycophyte Arabidopsis thaliana, which differ in their proline accumulation capacity. Plants cultivated in inert sand were challenged for 3 weeks with up to 500 mM NaCl. Low salinity significantly decreased A. thaliana growth, whereas growth restriction was significant only at salt concentrations equal. to or exceeding 300mM NaCl. in T halophila. Na+ content generally increased with the amount of salt added in the culture medium in both species, but T halophila showed an ability to control Na+ accumulation in shoots. The analysis of the relationship between water and Na+ contents suggested an apoplastic sodium accumulation in both species; this trait was more pronounced in A. thaliana than in T halophila. The better NaCl tolerance in the tatter was associated with a better K+ supply, resulting in higher K+/Na+ ratios. It was also noteworthy that, despite highly accumulating proline, the A. thaliana eskimo-1 mutant was the most salt-sensitive species. Taken together, our findings indicate that salt tolerance may be partly linked to the plants' ability to control Na+ influx and to ensure appropriate K+ nutrition, but is not linked to proline accumulation. (C) 2007 Elsevier GmbH. All rights reserved.
German, D. A. (2008) The genus Thellungiella (Cruciferae) in Europe Botanicheskii Zhurnal 93: 1273-1280.Thellungiella bolschantzevii D. German known so far from North Kazakhstan and South-West Siberia is reported for Europe for the first time. Previous reports of Asian-American T. salsuginea (Pall.) O. E. Schulz from Europe belong to T. botschantzevii. General distribution of T. botschantzevii is characterized and mapped; western limit of distribution of T. salsuginea is outlined.
Gao, F., Y. J. Zhou, et al. (2008) Proteomic analysis of long-term salinity stress-responsive proteins in Thellungiella halophila leaves Chinese Science Bulletin 53: 3530-3537. 10.1007/s11434-008-0455-6Salinity is one of the most severe environmental factors that may impair crop productivity. A proteomic study based on two-dimensional gel electrophoresis is performed in order to analyze the long-term salinity stress response of Thellungiella halophila, an Arabidopsis-related halophyte. Four-week-old seedlings are exposed to long-term salinity treatment. The total crude proteins are extracted from leaf blades, separated by 2-DE, stained with Coomassie Brilliant Blue, and differentially displayed spots are identified by MALDI-TOF MS or QTOF MS/MS. Among 900 protein spots reproducibly detected on each gel, 30 spots exhibit significant change and some of them are identified. The identified proteins include not only some previously characterized stress-responsive proteins such as TIR-NBS-LRR class disease resistance protein, ferritin-1, and pathogenesis-related protein 5, but also some proteins related to energy pathway, metabolism, RNA processing and protein degradation, as well as proteins with unknown functions. The possible functions of these proteins in salinity tolerance of T. halophila are discussed and it is suggested that the long-term salinity tolerance of T. halophila is achieved, at least partly, by enhancing defense system, adjusting energy and metabolic pathway and maintaining RNA structure.
Gao, D. H., Q. Wang, et al. (2008) Microsatellite DNA loci from the typical halophyte Thellungiella salsuginea (Brassicaceae) Conservation Genetics 9: 953-955. 10.1007/s10592-007-9403-2Tamarix hispida, a woody halophyte, thrives in saline and saline-alkali soil. To better understand the gene expression profiles that manifest in response to saline-alkali stress, three cDNA libraries were constructed from leaf tissue of T. hispida plants that were well watered and exposed to NaHCO3 for 24 and 52 h. A total of 9,447 high quality expressed sequence tags (ESTs) were obtained from the three libraries. These ESTs represent 3,945 unigenes, including 986 contigs and 2,959 singlets. The numbers of unigenes obtained from the three libraries were 1,752, 1,558 and 1,675, respectively. The EST analysis was performed to compare gene expression in the three cDNA libraries; the transcripts responsive to NaHCO3 were identified. The differentially expressed transcripts were identified. The up-regulation genes were involved in a variety function areas, such as stress-related proteins, hormone signaling transduction, antioxidative response, transcriptional regulators, protein synthesis and destination, ion homeostasis, photosynthesis and metabolism. The results indicated that the response to NaHCO3 in T. hispida is a complex one, involving multiple physiological and metabolic pathways. Nine gene expression patterns were compared in response to NaHCO3 and NaCl using real time reverse transcription-polymerase chain reaction (RT-PCR). Gene expression trends were similar after a 24-h exposure to either NaCl or NaHCO3, however, great variability was found after a 52-h exposure, indicating that short-term responses to either salt may not be obviously different.
Flowers, T. J. and T. D. Colmer. (2008) Salinity tolerance in halophytes New Phytologist 179: 945-963. 10.1111/j.1469-8137.2008.02531.xHalophytes, plants that survive to reproduce in environments where the salt concentration is around 200 mM NaCl or more, constitute about 1% of the world's flora. Some halophytes show optimal growth in saline conditions; others grow optimally in the absence of salt. However, the tolerance of all halophytes to salinity relies on controlled uptake and compartmentalization of Na(+), K(+) and Cl(-) and the synthesis of organic 'compatible' solutes, even where salt glands are operative. Although there is evidence that different species may utilize different transporters in their accumulation of Na(+), in general little is known of the proteins and regulatory networks involved. Consequently, it is not yet possible to assign molecular mechanisms to apparent differences in rates of Na(+) and Cl(-) uptake, in root-to-shoot transport (xylem loading and retrieval), or in net selectivity for K(+) over Na(+). At the cellular level, H(+)-ATPases in the plasma membrane and tonoplast, as well as the tonoplast H(+)-PP(i)ase, provide the trans-membrane proton motive force used by various secondary transporters. The widespread occurrence, taxonomically, of halophytes and the general paucity of information on the molecular regulation of tolerance mechanisms persuade us that research should be concentrated on a number of 'model' species that are representative of the various mechanisms that might be involved in tolerance.
Fang, Q. Y., J. Liu, et al. (2008) Cloning and characterization of a flowering time gene from Thellungiella halophila Acta Biochimica Et Biophysica Sinica 40: 747-753. 10.1111/j.1745-7270.2008.00446.xThellungiella halophila (T. halophila) (salt cress) is a close relative of Arabidopsis and a model plant for salt tolerance research. However, the nature of its later flowering causes some difficulties in genetic analysis. The FRIGIDA (FRT) gene plays a key role in the Arabidopsis vernalization flowering pathway, whose homolog in T. halophila may also be a key factor in controlling flowering time. In order to study the molecular mechanism of vernalization responses in T. halophila, a full length cDNA named ThFRI (Thellungiella halophila FRIGIDA) was isolated from the young seedlings of T. halophila by RT-PCR and RACE. The ThFRI cDNA was 2017 bp in length and contained an open reading frame encoding a putative protein of 605 ami no acids. The ThFRI showed significant homology to AtFRI (74.5% at the nucleotide level and 63.9% at the ami no acid level). To study its function, ThFRI cDNA was transformed into Arabidopsis thaliana, driven by CaMV 35S promoter. Transgenic plants expressing ThFRI exhibited late-flowering phenotype, which suggests that ThFRI is the funtional FRI homolog in T. halophila. The cloning and funtional characterization of the FRI homolog of T. halophila will faciliate further study of flowering time control in T. halophila.
Du, J., Y.-P. Huang, et al. (2008) Functional gene-mining for salt-tolerance genes with the power of Arabidopsis Plant Journal 56: 653-664. 10.1111/j.1365-313X.2008.03602.xHere we report on a functional gene-mining method developed to isolate stress tolerance genes without any prior knowledge of the genome or genetic mapping of the source germplasms. The feasibility of this approach was demonstrated by isolating novel salt stress tolerance genes from salt cress (Thellungiella halophila), an extremophile that is adapted to a harsh saline environment and a close relative of the model plant Arabidopsis thaliana. This gene-mining method is based on the expression of salt cress cDNA libraries in Arabidopsis. A cDNA expression library of the source germplasm, salt cress, was constructed and used to transform Arabidopsis via Agrobacterium-mediated gene transfer. A transgenic seed library consisting of > 125 000 independent lines was generated and screened for salt-tolerant lines via a high-throughput genetic screen. A number of salt-tolerant lines were isolated, and the salt cress cDNAs were identified by PCR amplification and sequencing. Among the genes isolated, several novel small protein-encoding genes were discovered. The homologs of these genes in Arabidopsis have not been experimentally analyzed, and their functions remain unknown. The function of two genes isolated by this method, ST6-66 and ST225, and their Arabidopsis homologs, were investigated in Arabidopsis using gain- and loss-of-function analyses, and their importance in salt tolerance was demonstrated. Thus, our functional gene-mining method was validated by these results. Our method should be applicable for the functional mining of stress tolerance genes from various germplasms. Future improvements of the method are also discussed.
Byrt, C. S. and R. Munns. (2008) Living with salinity New Phytologist 179: 903-905. 10.1111/j.1469-8137.2008.02596.xThe ability of T. halophila to selectively absorb K+ and Na+ can represent its salt tolerance. We stressed T. halophila and A. thaliana seedlings with 0-300 mmol NaCl/l solution for 48 h, and the K+ and Na+ contents in roots and leaves of T. halophila and A. thaliana were determined. When the NaCl concentration was increased from 0 to 300 mmol/l, the Na+ percentage in A. thaliana leaves increased while the K+ percentage decreased sharply and the value of K+/Na+ decreased gradually. T. halophila was completely different and with the increased NaCl concentration, the Na+ percentage did not change. At first the K+ percentage increased but then dropped off so the value of K+/Na+ increased initially and then decreased gradually. At 100 and 200 mmol NaCl/l, the K+/Na+ value in T. halophila was 2- and 5-fold higher, respectively, than those in A. thaliana. In roots, the increased Na+ content and decreased K+ gave similar results in both T. halophila and A. thaliana. Compared with A. thaliana, T. halophila selectively absorbed the K+ but resisted the Na+. An analysis of these results showed that the positive correlations of Na+ and K+ content in A. thaliana were significant, but they were not correlated in T. halophila. Thus, the Na+ and K+ channels in A. thaliana were linked together, but there was no correlation between Na+ and K+ contents in T. halophila, indicating that the Na+ and K+ channels or carriers were different.
Zhang, G., Z. Wang, et al. (2007) Molecular cloning and bioinformatics analysis of a vacuolar Na+/H+ antiporter gene in Elytrigia intermedia Yichuan 29: 1263-1270. 10.1360/yc-007-1263TiNHX1, homologous with the TaNHX1 gene encoding a vacuole Na+/H(+)antiporter was cloned from Elytrigia intermedia by RT-PCR, with primers designed according to the sequence of TaNHX1. The largest open reading frame of TiNHX1 gene has 164 1 bp in length and encoded a protein of 546 amino acid residues. The estimated molecular weight and isoelectric points of the putative protein was 59.8 kDa and 8.0, respectively. Components of amino acids encoded by TiNHX1 contained 38 basic amino acids, 36 acidic amino acid, 256 hydrophobic amino acids and 129 polar amino acids. The predicted secondary structure composition for the protein has about 44% alpha helixes, 21% extended strand, 4% beta turn and 29% random coil. Hydrophobic analysis indicated that the TiNHX1 contained 10 potential transmembrane segments. Blast result and the phylogenetic analysis showed that TiNHX1, AtNHX1, OsNHX1, GmNHX1, TaNHX1 share a cluster.
Zhan, X., R. A. Bressan, et al. (2007) Pyruvate kinase-like HGCs control stress responsive seed germination Plant Biology (Rockville) 2007: 40-40.Medicago intertexta and Melilotus indicus, two wild leguminous herbs with different tolerance to salinity were investigated for NaCl-incluced changes in the expression level of some Na+ transporters. M. indicus plants grew well at NaCl concentration from 0 to 400 mM, whereas growth of M. intertexta plants was severely inhibited at NaCl concentrations higher than 100 mM. In M. intertexta, increasing NaCl in the growth media caused a strong increase in Na+ content concomitant with a decrease in K+ content in leaves and, above all, roots. in comparison, M. indicus plants cultivated in the presence of NaCl accumulated much less Na+ in leaves and roots and no differences in K+ content among plants grown in nutrient solution containing 100-400 mM NaCl were detected. The expression levels of four genes coding for NHX-type Na+/H+ antiporters in the above two wild legumes were studied in plants cultivated under the different NaCl concentrations. Expression levels of the genes were higher in M. intertexta as compared with M. indicus plants. In M. intertexta, salt treatments increased MtNHX1, MtNHX3 and MtNHX4 transcript levels in leaves and roots. However, in M. indicus NaCl treatments only induced the expression of MtNHX1 in roots. Our data suggest that two different mechanisms, Na+ avoidance or accumulation into cellular compartments, are developed by the two wild legumes to cope with salt stress, and that expression of NHX antiporters is linked to the accumulator phenotype.
Yang, P., X. Cai, et al. (2007) Cloning and sequence analysis of ThNHX1 gene from Thellungiella halophila Jiangsu Journal of Agricultural Sciences 23: 556-563.To study the salt tolerance mechanism of halophytes, a full-length cDNA fragment was amplified from T. halophila with primers designed based on the Arabidopsis thaliana AtNHX1 gene sequence using RT-PCR and 5′-and 3′-RACE methods. The cDNA sequence was 245 bp in length, including an open reading frame of 1638 bp, encoding a predicted polypeptide of 545 amino acids. Detailed sequence analysis showed that the gene shared the highest homology with AtNHX1. The cDNA encoded a putative Na+/H+ antiporter gene (ThNHX1). ThNHX1 had similar intron and exon structures as AtHNX1. The phylogenetic analysis of various Na+/H+ antiporters indicated that ThNHX1 was grouped with tonoplast Na+/H+ antiporters, and distinguished from plasma membrane Na+/H+ antiporters.
Xu, S. M., X. C. Wang, et al. (2007) Zinc finger protein 1 (ThZF1) from salt cress (Thellungiella halophila) is a Cys-2/His-2-type transcription factor involved in drought and salt stress Plant Cell Reports 26: 497-506. 10.1007/s00299-006-0248-9Zinc finger proteins (ZFPs) play important roles in growth and development in both animals and plants. Recently, some Arabidopsis genes encoding distinct ZFPs have been identified. However, the physiological role of their homologues with putative zinc finger motif remains unclear. In the present study, a novel gene, ThZF1, was characterized from salt stressed cress (Thellungiella halophila, Shan Dong), encoding a functional transcription factor. ThZF1 contains two conserved C2H2 regions and shares conserved domains, including DNA-binding motif, with Arabidopsis thaliana ZFP family members. The transcript of the ThZF1 gene was induced by salinity and drought. Transient expression analysis of ThZF1-GFP fusion protein revealed that ThZF1 was localized preferentially in nucleus. A gel-shift assay showed that ThZF1 specially bind to the wild-type (WT) EP2 element, a cis-element present in the promoter regions of several target genes regulated by ZFPs. Furthermore, a functional analysis demonstrated that ThZF1 was able to activate HIS marker gene in yeast. Finally, ectopic expression of ThZF1 in Arabidopsis mutant azJ2 suggested that ThZF1 may have similar roles as Arabidopsis AZF2 in plant development as well as regulation of downstream gene.
Wang, Y., C. Yang, et al. (2007) Microarray and suppression subtractive hybridization analyses of gene expression in Puccinellia tenuiflora after exposure to NaHCO3 Plant Science 173: 309-320. 10.1016/j.plantsci.2007.06.011To investigate genes expression in Puccinellia tenuiflora exposed to saline-alkali, NaHC03-induced stress, four suppression subtractive hybridization (SSH) libraries were constructed. Non-treated P. tenuiflora cDNA was used as the driver, and cDNAs from P. tenuiflora exposed to 0.4 mol/I NaHCO3 for 6, 12, 24 and 48 h were used as the respective testers. Randomly selected clones from each SSH library were sequenced, and 1850 expressed sequence tags (ESTs) were obtained and analyzed. Approximately 400 ESTs from each library were randomly selected for placement on the cDNA microarray. In total, 158 differentially expressed genes were identified, and 93, 56, 21 and 71 genes were differentially expressed with NaHCO3 stress for 6, 12, 24 and 48 h, respectively. These differentially expressed genes were categorized as putative novel (31.6%). photosynthesis (15.8%), unknown (15.2%), metabolism (12.7%) and defense genes (8.9%). The other differentially expressed genes were involved in a variety of functional areas, such as transport, transcriptional regulation, and protein synthesis. These results demonstrate that the response to NaHCO3 stress in P. tenuiflora is a complex network involving multiple physiological and metabolic pathways. The differentially expressed genes were grouped using hierarchical cluster analysis, and six different clusters were defined. Approximately 80% of grouped genes belonged to two independent expression patterns, indicating that these two expression patterns may represent two important stress tolerance pathways or networks in P. tenuiflora. (c) 2007 Elsevier Ireland Ltd. All rights reserved.
Taji, T., T. Sakurai, et al. (2007) Construction and functional annotation of a full-length cDNA library of Thellungiella halophila, a model halophyte Plant and Cell Physiology 48: S139-S139.Systematics relationship of Arabidopsis, Thellungiella and related genera (Brassicaceae) from China were studied using leaf epidermal features and sequence analysis of the chloroplast DNA (cpDNA) trnL intron and traL-F spacer. The results of this study indicate that Thellungiella is far away from Arabidopsis and should be put in Sisymbrieae. Within Sisymbrieae, it is closely related to Eutrema. However, Arabidopsis should be in Arabideae rather than Sisymbrieae.
Sun, Z.-y. and F.-z. Li. (2007) Molecular systematics of partial genera and species in tribe Lepidieae (Brassicaceae) from China Xibei Zhiwu Xuebao 27: 1674-1678.Systematics studies of partial genera and related genera of Lepidieae (Brassicaceae) from China were studied using sequence analysis of the chloroplast DNA (cpDNA) trnL intron and trnL-F spacer. The results show that Lepidieae is a polyphyletic group. In the molecular tree,the partial genera of Lepidieae from China are divided into three different parallel lineages. Among them,Capsella and Camelina form into lineage I with three genera of Arabideae,it suggests that Capsella and Camelina should be moved out from Lepidieae and Sisymbrieae respectively, and moved into Arabideae. Thlaspi and Isatis form into lineage II with three genera of Sisymbrieae,it supports the opinion that Isatis and Thlaspi should not be in Lepidieae, but in Sisymbrieae. Lepidium, Coronopus and Cardaria have closer relationships, and composed lineage III, Coronopus didymus is among the species of Lepidium, so it supports the conclution that Coronopus should be merged into Lepidium.
Radyukina, N. L., A. V. Kartashov, et al. (2007) Functioning of defense systems in halophytes and glycophytes under progressing salinity Russian Journal of Plant Physiology 54: 806-815. 10.1134/s1021443707060131Six-week-old Plantago major L. and Thellungiella halophila Mey. plants were subjected to progressing salinity by a daily increase in the NaCl concentration by 100 mM until the final concentration of 400 mM. A dynamics of stress-dependent accumulation of Na+ and Cl- ions, proline, and free polyamines and also activities of antioxidant enzymes, superoxide oxidase (SOD) and free, ion-bound, and covalently bound guaiacol-dependent peroxidases was studied. We also examined the intensity of gene expression encoding enzymes of proline metabolism and polyamine biosynthesis. It was shown that the high salt-resistance of the halophyte T. halophila was determined by plant capability of ion accumulation and stress-dependent proline accumulation. An important role in the maintenance of this plant homeostasis under salinity plays a high constitutive levels of activities of three types of peroxidases tested and also of proline manifesting a polyfunctional protective action. In contrast, P. major plants characterized by a lower tolerance to salt excess did not display a high constitutive level of proline or the activity of guaiacol-dependent peroxidases; they also were not capable Of stress-induced accumulation of compatible osmolytes and did not accumulate the salt. However, this glycophyte contained relatively much spermidine and active SOD, which provided for a decrease in the damaging effects of reactive oxygen species under salt shock. In both plant species, it was established that salinity changed the intracellular content of polyamines, which was not dependent on the activity of gene transcription encoding the enzymes of their biosynthesis. The results obtained support a hypothesis that halophytes and glycophytes have some common mechanisms of tolerance to salinity, but the control of these mechanisms differs substantially.
Oh, D. H., Q. Q. Gong, et al. (2007) Sodium stress in the halophyte Thellungiella halophila and transcriptional changes in a thsos1-RNA interference line Journal of Integrative Plant Biology 49: 1484-1496. 10.1111/j.1672-9072.2007.00548.xThe plasma membrane Na+/H+-antiporter salt overly sensitivel (SOS1) from the halophytic Arabidopsis-relative Thel-lungiella halophila (ThSOS1) shows conserved sequence and domain structure with the orthologous genes from Arabidopsis thaliana and other plants. When expression of ThSOS1 was reduced by RNA interference (RNAi), pronounced characteristics of salt-sensitivity were observed. We were interested in monitoring altered transcriptional responses between Thellungiella wild type and thsos1-4, a representative RNAi line with particular emphasis on root responses to salt stress at 350 mmol/L NaCl, a concentration that is only moderately stressful for mature wild type plants. Transcript profiling revealed several functional categories of genes that were differently affected in wild-type and RNAi plants, Down-regulation of SOS1 resulted in different gene expression even in the absence of stress. The pattern of gene induction in the RNAi plant under salt stress was similar to that of glycophytic Arabidopsis rather than that of wild type Thellungiella. The RNAi plants failed to down-regulate functions that are normally reduced in wild type Thellungiella upon stress and did not up-regulate functions that characterize the Thellungiella salt stress response. Metabolite changes observed in wild type Thellungiella after salt stress were less pronounced or absent in RNAi plants. Transcript and metabolite behavior suggested SOS1 functions including but also extending its established function as a sodium transporter. The down-regulation of ThSOS1 converted the halophyte Thellungiella into a salt-sensitive plant.
Ni, W. S., Z. Y. Lei, et al. (2007) Construction of a plant transformation-ready expression cDNA library for Thellungiella halophila using recombination cloning Journal of Integrative Plant Biology 49: 1313-1319. 10.1111/j.1672-9072.2007.00483.xSalt cress (Thellungielia halophila), a close relative of the model plant Arabidopsis thaliana L., is an extremophile that is adapted to harsh saline environments. To mine salt-tolerance genes from this species, we constructed an entry cDNA library from the salt cress plant treated with salt-stress by using a modified cDNA synthesis and an improved recombination-assisted cDNA library construction method that is completely free of manipulations involving restriction enzymes and DNA ligase. This cDNA library construction procedure is significantly simplified and the quality of the cDNA library is improved. This entry cDNA library was subsequently shuttled into the destination binary vector pCB406 designed for plant transformation and expression via recombination-assisted cloning. The library is plant transformation ready and is used to transform Arabidopsis on a large scale in order to create a large collection of transgenic lines for functional gene mining.
Moller, I. S. and M. Tester. (2007) Salinity tolerance of Arabidopsis: a good model for cereals? Trends in Plant Science 12: 534-540. 10.1016/j.tplants.2007.09.009Arabidopsis is a glycophyte species that is sensitive to moderate levels of NaCl. Arabidopsis offers unique benefits to genetic and molecular research and has provided much information about both Na+ transport processes and Na+ tolerance. A compilation of data available on Na+ accumulation and Na+ tolerance in Arabidopsis is presented, and comparisons are made with several crop plant species. The relationship between Na+ tolerance and Na+ accumulation is different in Arabidopsis and cereals, with an inverse relationship often found within cereal species that is not as evident in Arabidopsis ecotypes. Results on salinity tolerance obtained in Arabidopsis should therefore be extrapolated to cereals with caution. Arabidopsis remains a useful model to study and discover plant Na+ transport processes.
Mohamed, S. A., T. M. Mohamed, et al. (2007) Preparation of Japanese horseradish peroxidase and its applications Bulletin of the National Research Centre (Cairo) 32: 53-65.JAPANESE horseradish peroxidase, which could be used for commercial applications such as diagnostic glucose kits, was prepared by a simple reproducible method consisting of extraction, ammonium sulphate precipitation, filtration through non binding protein filter and lyophilization. The purification method as developed provided 33 mg of enzyme from I Kg of horseradish roots. One mg of enzyme contained 900 units of peroxidase. This value is similar to that produced by Sigma (50-1000 unit mg(-1) powder). The final preparation is a salt free reddish brown powder with a free ammonia content of less than 0.01 mu g/unit. The purity number (RZ value A400/A280) of the enzyme was 2.6, which is a good criterion of purity and heme content. The Iyophilized enzyme was stable at -20 degrees C for at least one year. The solubilized form of the enzyme was stable up to 25 days at 4 degrees C, but it lost most of its activity at room temperature in the same period. The values of apparent Kin for H2O2 and guaiacol were 5.2 mM (at 40 mM guaiacol) and 11.6 mM(at 8 mM H2O2), respectively. The enzyme had a broad pH optimum ranged from 4.5 to 5.5 and a temperature optimum at 40 degrees C with activation energy of 12 kcal mol(-1) and temperature stability up to 30 degrees C. All metal ions inhibited the enzyme except Ca2+ which had no effect. The prepared enzyme was used to determine serum glucose. The analysis of glucose in human sera gave results using the kit containing the prepared peroxidase similar to those obtained with a commercial glucose kit (Diamond).
Mandakova, T. and M. A. Lysak. (2007) Karyotype evolution in n=7 species from different tribes of the mustard family (Brassicaceae) Chromosome Research 15: 39-39.Thellungiella halophila and Arabidopsis thaliana were irrigated with medium containing NaCl at various concentrations. The salt treatment resulted in a restriction of rosette biomass deposition in both species. In A. thaliana leaves, this inhibition was stronger than for T halophila and was associated with strong inhibition of both leaf initiation and leaf expansion. At highest medium salinity, A. thaliana accumulated Na+ and Cl- at higher levels than T halophila, but similar leaf dehydration was observed in the two species. Proline accumulation, which increased with NaCl concentration, did not differentiate the two species. The magnitude of the electrolyte leakage and the level of lipid peroxidation (assessed through hydroxy fatty acid content) were modest in T halophila and quite marked in A. thaliana. The detrimental effects of the salt on photosynthetic activity and stomatal. conductance of A. thaliana leaves were much more important than in T halophila leaves. The abundance of the CDSP32 thioredoxin, a critical component of the defence system against oxidative damage and lipid peroxidation, was found to be higher in T halophila than in A. thaliana under control conditions and salt treatment. These results suggest that the rosette leaves of T halophila exhibit more efficient protective mechanisms against Na+ metabolic toxicity than those of A. thaliana. (c) 2006 Elsevier GmbH. All rights reserved.
Liu, N., A. P. Chen, et al. (2007) Functional screening of salt stress-related genes from Thellungiella halophila using fission yeast system Physiologia Plantarum 129: 671-678. 10.1111/j.1399-3054.2007.00857.xSalinity stress is one of the most serious factors limiting plant growth and threatening global food security. Identification of salt tolerance relevant genes from halophytes can provide more insights into the determinants of salt stress tolerance in plants. In this study, functional screening of genes for the salinity tolerance in Thellungiella halophila (salt cress) was carried out using fission yeast as a host organism. A cDNA library of the salt cress, constructed in the yeast vector under the control of the inducible promoter nmt1, was transformed into the fission yeast Schizosaccharomyces pombe. Transgenic yeast cells that showed enhanced salt tolerance were selected. A total of 69 such clones were identified from 10(6) of yeast transformants by one-time screening. Functional assignment indicates that a large percentage (81%) of these cDNAs encode for homologues of proteins that are known to have roles in plant salt tolerance, while the other portion (19%) codes for unknown proteins. Among the proteins encoded by the known functional genes, the regulatory proteins account for a relatively higher proportion. Northern blot analysis showed that the expression of some isolated genes was salt stress inducible, whereas that of the others was constitutive. These results indicate that fission yeast is a simple and efficient system for functional and large-scale identification of salt tolerance-related genes from other organisms.
Li, H. Q., J. Xu, et al. (2007) Establishment of an efficient Agrobacterium tumefaciens-mediated leaf disc transformation of Thellungiella halophila Plant Cell Reports 26: 1785-1789. 10.1007/s00299-007-0391-yThellungiella halophila is a salt-tolerant close relative of Arabidopsis, which is adopted as a halophytic model for stress tolerance research. We established an Agrobacterium tumefaciens-mediated transformation procedure for T. halophila. Leaf explants of T. halophila were incubated with A. tumefaciens strain EHA105 containing a binary vector pCAMBIA1301 with the hpt gene as a selectable marker for hygromycin resistance and an intron-containing beta-glucuronidase gene as a reporter gene. Following co-cultivation, leaf explants were cultured on selective medium containing 10 mg l(-1) hygromycin and 500 mg l(-1) cefotaxime. Hygromycin-resistant calluses were induced from the leaf explants after 3 weeks. Shoot regeneration was achieved after transferring the calluses onto fresh medium of the same composition. Finally, the shoots were rooted on half strength MS basal medium supplemented with 10 mg l(-1) hygromycin. Incorporation and expression of the transgenes were confirmed by PCR, Southern blot analysis and GUS histochemical assay. Using this protocol, transgenic T. halophila plants can be obtained in approximately 2 months with a high transformation frequency of 26%.
Kawasaki, Y., T. Taji, et al. (2007) A functional analysis of a Na+ transporter in a model halophyte, Thellungiella halophila Plant and Cell Physiology 48: S139-S139.The TFIII A-type zinc finger protein belongs to C2H2-type zinc finger protein family with the finger structure of CX2-4CX3FX5LX2HX3-5H. Recent studies have shown that TFIIIA zinc finger protein family also play important roles in stress responses. It is being believed that TFIIIA zinc finger protein genes will become another target for engineering the biotech crops with enhanced tolerance to abiotic stress.
Griffith, M., M. Timonin, et al. (2007) Thellungiella: an Arabidopsis-related model plant adapted to cold temperatures Plant Cell and Environment 30: 529-538. 10.1111/j.1365-3040.2007.01653.xThellungiella salsuginea, a wild crucifer that grows in subarctic Canada and is closely related to Arabidopsis thaliana, was examined for its suitability as a model plant for studies of tolerance to cold and freezing temperatures. Thellungiella completed its life cycle at 5 degrees C, demonstrating that temperature-sensitive processes such as seed germination and the production of pollen and seeds were resistant to cold temperatures. Moreover, the plant exhibited dramatically different vegetative and flowering phenotypes in response to growth at cold temperature and shifts to cold temperature. Northern analyses showed that genes induced by cold in Arabidopsis, including CBF1, the transcriptional activator for the cold-regulated (COR) genes COR15a and COR47, were also expressed in Thellungiella. Freezing tolerance, assayed by the regrowth of intact plants, increased from -13.0 to -18.5 degrees C after cold treatment. The plants lacked endogenous ice nucleation or anti-freeze activity, indicating a potential for supercooling. As a close relative to Arabidopsis, Thellungiella exhibits extreme cold tolerance and should be an important model system in the elucidation of stress tolerance mechanisms.
Ehlting, B., P. Dluzniewska, et al. (2007) Interaction of nitrogen nutrition and salinity in Grey poplar (Populus tremula x alba) Plant Cell and Environment 30: 796-811. 10.1111/j.1365-3040.2007.01668.xSalinity represents an increasing environmental problem in managed ecosystems. Populus spp. is widely used for wood production by short-rotation forestry in fertilized plantations and can be grown on saline soil. Because N fertilization plays an important role in salt tolerance, we analysed Grey poplar (Populus tremula x alba, syn. Populus canescens) grown with either 1 mM nitrate or ammonium subjected to moderate 75 mM NaCl. The impact of N nutrition on amelioration of salt tolerance was analysed on different levels of N metabolism such as N uptake, assimilation and N (total N, proteins and amino compounds) accumulation. Na concentration increased in all tissues over time of salt exposure. The N nutrition-dependent effects of salt exposure were more intensive in roots than in leaves. Application of salt reduced root increment as well as stem height increase and, at the same time, increased the concentration of total amino compounds more intensively in roots of ammonium-fed plants. In leaves, salt treatment increased concentrations of total N more intensively in nitrate-fed plants and concentrations of amino compounds independently of N nutrition. The major changes in N metabolism of Grey poplar exposed to moderate salt concentrations were detected in the significant increase of amino acid concentrations. The present results indicate that N metabolism of Grey poplar exposed to salt performed better when the plants were fed with nitrate instead of ammonium as sole N source. Therefore, nitrate fertilization of poplar plantations grown on saline soil should be preferred.
Duan, X.-G., A.-F. Yang, et al. (2007) Heterologous expression of vacuolar H+-PPase enhances the electrochemical gradient across the vacuolar membrane and improves tobacco cell salt tolerance Protoplasma 232: 87-95. 10.1007/s00709-007-0268-5The vacuolar H+-translocating inorganic pyrophosphatase (H+-PPase) uses pyrophosphate as substrate to generate the proton electrochemical gradient across the vacuolar membrane to acidify vacuoles in plant cells. The heterologous expression of H+-PPase genes (TsVP from Thellungiella halophila and AVP1 from Arabidopsis thaliana) improved the salt tolerance of tobacco plants. Under salt stress, the transgenic seedlings showed much better growth and greater fresh weight than wild-type plants, and their protoplasts had a normal appearance and greater vigor. The cytoplasmic and vacuolar pH in transgenic and wild-type cells were measured with a pH-sensitive fluorescence indicator. The results showed that heterologous expression of H+-PPase produced an enhanced proton electrochemical gradient across the vacuolar membrane, which accelerated the sequestration of sodium ions into the vacuole. More Na+ accumulated in the vacuoles of transgenic cells under salt (NaCl) stress, revealed by staining with the fluorescent indicator Sodium Green. It was concluded that the tonoplast-resident H+-PPase plays important roles in the maintenance of the proton gradient across the vacuolar membrane and the compartmentation of Na+ within vacuoles, and heterologous expression of this protein enhanced the electrochemical gradient across the vacuolar membrane, thereby improving the salt tolerance of tobacco cells.
Chen, Z., I. I. Pottosin, et al. (2007) Root plasma membrane transporters controlling K+/Na+ homeostasis in salt-stressed barley Plant Physiology 145: 1714-1725. 10.1104/pp.107.110262Plant salinity tolerance is a polygenic trait with contributions from genetic, developmental, and physiological interactions, in addition to interactions between the plant and its environment. In this study, we show that in salt- tolerant genotypes of barley (Hordeum vulgare), multiple mechanisms are well combined to withstand saline conditions. These mechanisms include: (1) better control of membrane voltage so retaining a more negative membrane potential; (2) intrinsically higher H+ pump activity; (3) better ability of root cells to pump Na+ from the cytosol to the external medium; and (4) higher sensitivity to supplemental Ca2+. At the same time, no significant difference was found between contrasting cultivars in their unidirectional Na-22(+) influx or in the density and voltage dependence of depolarization-activated outward-rectifying K+ channels. Overall, our results are consistent with the idea of the cytosolic K+-to-Na+ ratio being a key determinant of plant salinity tolerance, and suggest multiple pathways of controlling that important feature in salt-tolerant plants.
Chen, A. P., G. L. Wang, et al. (2007) Ectopic expression of ThCYP1, a stress-responsive cyclophilin gene from Thellungiella halophila, confers salt tolerance in fission yeast and tobacco cells Plant Cell Reports 26: 237-245. 10.1007/s00299-006-0238-yThe halophyte Thellungiella halophila (salt cress) is an ideal model system for studying the molecular mechanisms of salinity tolerance in plants. Herein, we report the identification of a stress-responsive cyclophilin gene (ThCYP1) from T. halophila, using fission yeast as a functional system. The expression of ThCYP1 is highly inducible by salt, abscisic acid (ABA), H2O2 and heat shock. Ectopic overexpression of the ThCYP1 gene enhance the salt tolerance capacity of fission yeast and tobacco (Nicotiana tabacum L.) cv. Bright Yellow 2 (BY-2) cells significantly. ThCYP1 is expressed constitutively in roots, stems, leaves and flowers, with higher expression occurring in the roots and flowers. The ThCYP1 proteins are distributed widely within the cell, but are enriched significantly in the nucleus. The present results suggest that ThCYP1 may participate in response to stresses in the salt cress, perhaps by regulating appropriate folding of certain stress-related proteins, or in the signal transduction processes.
Campanoni, P., J. U. Sutter, et al. (2007) A generalized method for transfecting root epidermis uncovers endosomal dynamics in Arabidopsis root hairs Plant Journal 51: 322-330. 10.1111/j.1365-313X.2007.03139.xProgress in analysing the cellular functions of many structural proteins has accelerated through the use of confocal microscopy together with transient gene expression. Several methods for transient expression have been developed in the past few years, but their application has seen limited success beyond a few tractable species and tissues. We have developed a simple and efficient method to visualize fluorescent proteins in Arabidopsis root epidermis using co-cultivation of seedlings with Agrobacterium rhizogenes. The method is equally suitable for transient gene expression in other species, including Thellungiella, and can be combined with supporting molecular and biochemical analyses. The method promises significant advantages for study of membrane dynamics, cellular development and polar growth in root hairs without interference in the development of the plant. Since the method targets specifically the root epidermis, it also offers a powerful tool to approach issues of root-rhizosphere interactions, such as ion transport and nutrient acquisition. As a proof of principle, we carried out transfections with fluorescent markers for the plasma membrane (NpPMA2-GFP, Nicotiana plumbaginifolia L. Plasma Membrane H+-ATPase 2), the endoplasmic reticulum (YFP-HDEL), and the Golgi apparatus (sialyl transferase-GFP) to trace their distribution in growing Arabidopsis root hairs and epidermis. The results demonstrate that, in Arabidopsis root hairs, movement of the Golgi is faster than previously reported for tobacco leaf epidermal cells, consistent with the high secretory dynamics of the tip growing cell; they show a pattern to the endoplasmic reticulum within the cytoplasm that is more diffuse than found in tobacco leaf epidermis, and they confirm previous findings of a polarized distribution of the endoplasmic reticulum at the tip of growing root hairs.
Bressan, R. A. and P. M. Hasegawa (2007). SOS1 gene from halophila that confers salt tolerance, Purdue Research Foundation. Barkla, B. J., R. Vera-Estrella, et al. (2007) Enhanced separation of membranes during free flow zonal electrophoresis in plants Analytical Chemistry (Washington) 79: 5181-5187. 10.1021/ac070159vFree flow zonal electrophoresis (FFZE) is a versatile technique that allows for the separation of cells, organelles, membranes, and proteins based on net surface charge during laminar flow through a thin aqueous layer. We have been optimizing the FFZE technique to enhance separation of plant vacuolar membranes (tonoplast) from other endomembranes to pursue a directed proteomics approach to identify novel tonoplast transporters. Addition of ATP to a mixture of endomembranes selectively enhanced electrophoretic mobility of acidic vesicular compartments during FFZE toward the positive electrode. This has been attributed to activation of the V-ATPase generating a more negative membrane potential outside the vesicles, resulting in enhanced migration of acidic vesicles, including tonoplast, to the anode (Morre, D. J.; Lawrence, J.; Safranski, K.; Hammond, T.; Morre, D. M. J. Chromatogr., A 1994, 668, 201-213). We confirm that ATP does induce a redistribution of membranes during FFZE of microsomal membranes isolated from several plant species, including Arabidopsis thaliana, Thellungiella halophila, Mesembryanthemum crystallinum, and Ananas comosus. However, we demonstrate, using V-ATPase-specific inhibitors, nonhydrolyzable ATP analogs, and ionophores to dissipate membrane potential, that the ATP-dependent migrational shift of membranes under FFZE is not due to activation of the V-ATPase. Addition of EDTA to chelate Mg2+, leading to the production of the tetravalent anionic form of ATP, resulted in a further enhancement of membrane migration toward the anode, and manipulation of cell surface charge by addition of polycations also influenced the ATP-dependent migration of membranes. We propose that ATP enhances the mobility of endomembranes by screening positive surface charges on the membrane surface.
Barkla, B. J., R. Vera-Estrella, et al. (2007) Enhanced separation of membranes during free flow zonal electrophoresis in plants Analytical Chemistry 79: 5181-5187. 10.1021/ac070159vFree flow zonal electrophoresis (FFZE) is a versatile technique that allows for the separation of cells, organelles, membranes, and proteins based on net surface charge during laminar flow through a thin aqueous layer. We have been optimizing the FFZE technique to enhance separation of plant vacuolar membranes (tonoplast) from other endomembranes to pursue a directed proteomics approach to identify novel tonoplast transporters. Addition of ATP to a mixture of endomembranes selectively enhanced electrophoretic mobility of acidic vesicular compartments during FFZE toward the positive electrode. This has been attributed to activation of the V-ATPase generating a more negative membrane potential outside the vesicles, resulting in enhanced migration of acidic vesicles, including tonoplast, to the anode (Morre, D. J.; Lawrence, J.; Safranski, K.; Hammond, T.; Morre, D. M. J. Chromatogr., A 1994, 668, 201-213). We confirm that ATP does induce a redistribution of membranes during FFZE of microsomal membranes isolated from several plant species, including Arabidopsis thaliana, Thellungiella halophila, Mesembryanthemum crystallinum, and Ananas comosus. However, we demonstrate, using V-ATPase-specific inhibitors, nonhydrolyzable ATP analogs, and ionophores to dissipate membrane potential, that the ATP-dependent migrational shift of membranes under FFZE is not due to activation of the V-ATPase. Addition of EDTA to chelate Mg2+, leading to the production of the tetravalent anionic form of ATP, resulted in a further enhancement of membrane migration toward the anode, and manipulation of cell surface charge by addition of polycations also influenced the ATP-dependent migration of membranes. We propose that ATP enhances the mobility of endomembranes by screening positive surface charges on the membrane surface.
Audet, B., G. Gauthier, et al. (2007) Feeding ecology of greater snow goose goslings in mesic tundra on Bylot Island, Nunavut, Canada Condor 109: 361-376. 10.1650/0010-5422(2007)109[361:feogsg]2.0.co;2Although mesic tundra is a habitat commonly used by arctic-nesting geese, their feeding ecology in this habitat is little known compared to wetlands. Our objectives were to determine the diet and food selection of Greater Snow Goose (Chen caerulescens atlantica) goslings in relation to the nutritional quality of plants growing in mesic tundra habitats on Bylot Island, Nunavut, Canada. We used two different but complementary approaches: examination of esophageal contents of sacrificed wild goslings, and direct observation of the feeding activity of captive, human-imprinted goslings. The latter method was innovative and provided a reliable description of the diet, with results comparable to those obtained from wild goslings. Although mesic habitats have a more diverse floristic composition than wetlands and sparse graminoid cover, Gramineae were preferentially selected and dominated the diet (similar to 50%). The rest of the diet consisted mainly of members of the Juncaceae, Polygonaceae, and Leguminosae families. The diet of very young goslings was diverse, but as they aged and gained efficiency, they concentrated on a few taxa. Goslings ate mostly leaves (similar to 80%), but flowers (similar to 20%) were also important. Food selection was influenced by nitrogen and total phenolic compounds content of plants, but the ratio of phenolic compounds to nitrogen in plant organs was most determinative of food choice. Neutral detergent fiber content of plants did not influence plant selection. Both plant nutritional quality and availability determined gosling diet across different mesic habitats and growing goslings appeared to maximize their intake of metabolizable proteins.
Apse, M. P. and E. Blumwald. (2007) Na+ transport in plants Febs Letters 581: 2247-2254. 10.1016/j.febslet.2007.04.014The ability of plants to grow in high NaCl concentrations is associated with the ability of the plants to transport, compartmentalize, extrude, and mobilize Na+ ions. While the influx and efflux at the roots establish the steady state rate of entry of Na+ into the plant, the compartmentation of Na+ into the cell vacuoles and the radial transport of Na+ to the stele and its loading into the xylem establish the homeostatic control of Na+ in the cytosol of the root cells. Removal of Na+ from the transpirational stream, its distribution within the plant and its progressive accumulation in the leaf vacuoles, will determine the ability to deal with the toxic effects of Na+. The aim of this review is to highlight and discuss the recent progress in understanding of Na+ transport in plants. (c) 2007 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Alb, T. and A. Serrano. (2007) Identification of genes and characterization of proteins involved in polyphosphate metabolism in photosynthetic organisms Photosynthesis Research 91: 248-249.Eutrema bouffordii and Draba yueii are described as new from Sichuan Province, China. The relationships and distinguishing characters from their nearest relatives, E. fontana and D. winterbottomii are discussed.
Zhu, J.-H., H.-L. Li, et al. (2006) Cloning and molecular characterization of a RING zinc-finger gene of Hevea brasiliensis Zhiwu Shengli yu Fenzi Shengwuxue Xuebao 32: 627-633.Using the information about the sequence from a differentially expressed clone (designated as HbSSH10) encodes a protein specifying a cysteine-rich sequence containing a putative "RING finger" or "C3HC4" consensus motif that was cloned recently by the subtractive hybridization between latex and leaves from rubber tree (Hevea brasiliensis). A full-length cDNA encoding C3HC4 type zinc-finger protein was isolated and characterized from rubber tree. Sequence analysis revealed that the ORFs of HbRZF encode 156 amino acid residues with a total predicted molecular mass of 17.2 kD, HbRZF protein having a putative "RING finger" segment (amino acid residues 100-144). The deduced amino acid sequences of HbRZF showed high identities of 48%, 52% and 50% to those of the ring zinc protein from Poncirus trifoliata, Arabidopsis thaliana, Thellungiella halophila. The result of Northern blot analysis indicated that the transcripts of the HbRZF were expressed more in the latex than in the leaves, whereas little expression was detected in roots and flowers. The transcription of HbRZF was induced by jasmonic acid, whereas ethylene had little effect.
Zhu, J.-H., H.-L. Li, et al. (2006) Cloning and molecular characterization of a RING zinc-finger gene of Hevea brasiliensis Zhi wu sheng li yu fen zi sheng wu xue xue bao = Journal of plant physiology and molecular biology 32: 627-633.Using the information about the sequence from a differentially expressed clone (designated as HbSSH10) encodes a protein specifying a cysteine-rich sequence containing a putative "RING finger" or "C3HC4" consensus motif that was cloned recently by the subtractive hybridization between latex and leaves from rubber tree (Hevea brasiliensis). A full-length cDNA encoding C3HC4 type zinc-finger protein was isolated and characterized from rubber tree. Sequence analysis revealed that the ORFs of HbRZF encode 156 amino acid residues with a total predicted molecular mass of 17.2 kD, HbRZF protein having a putative "RING finger" segment (amino acid residues 100-144). The deduced amino acid sequences of HbRZF showed high identities of 48%, 52% and 50% to those of the ring zinc protein from Poncirus trifoliata, Arabidopsis thaliana, Thellungiella halophila. The result of Northern blot analysis indicated that the transcripts of the HbRZF were expressed more in the latex than in the leaves, whereas little expression was detected in roots and flowers. The transcription of HbRZF was induced by jasmonic acid, whereas ethylene had little effect.
Wong, C. E., Y. Li, et al. (2006) Transcriptional profiling implicates novel interactions between abiotic stress and hormonal responses in Thellungiella, a close relative of Arabidopsis Plant Physiology 140: 1437-1450. 10.1104/pp.105.070508Thellungiella, an Arabidopsis (Arabidopsis thaliana)-related halophyte, is an emerging model species for studies designed to elucidate molecular mechanisms of abiotic stress tolerance. Using a cDNA microarray containing 3,628 unique sequences derived from previously described libraries of stress-induced cDNAs of the Yukon ecotype of Thellungiella salsuginea, we obtained transcript profiles of its response to cold, salinity, simulated drought, and rewatering after simulated drought. A total of 154 transcripts were differentially regulated under the conditions studied. Only six of these genes responded to all three stresses of drought, cold, and salinity, indicating a divergence among the end responses triggered by each of these stresses. Unlike in Arabidopsis, there were relatively few transcript changes in response to high salinity in this halophyte. Furthermore, the gene products represented among drought-responsive transcripts in Thellungiella associate a down-regulation of defense-related transcripts with exposure to water deficits. This antagonistic interaction between drought and biotic stress response may demonstrate Thellungiella's ability to respond precisely to environmental stresses, thereby conserving energy and resources and maximizing its survival potential. Intriguingly, changes of transcript abundance in response to cold implicate the involvement of jasmonic acid. While transcripts associated with photosynthetic processes were repressed by cold, physiological responses in plants developed at low temperature suggest a novel mechanism for photosynthetic acclimation. Taken together, our results provide useful starting points for more in-depth analyses of Thellungiella's extreme stress tolerance.
Warwick, S. I., I. A. Al-Shehbaz, et al. (2006) Phylogenetic position of Arabis arenicola and generic limits of Aphragmus and Eutrema (Brassicaceae) based on sequences of nuclear ribosomal DNA Canadian Journal of Botany-Revue Canadienne De Botanique 84: 269-281. 10.1139/b05-161Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) region of 45 taxa were used to determine the phylogenetic relationship of Arabis arenicola to Arabis, Arabidopsis, Braya, and Eutrema, and that of Eutrema to the purportedly related genera Aphragmus, Lignariella, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. Arabis arenicola was originally described as Eutrema in 1830, transferred to Arabis in 1898, and has remained in Arabis to the present, even though it is morphologically more similar to Arabidopsis, Braya, and Eutrema. Sequence data were obtained from representative taxa of Arabis, Arabidopsis, and related Boechera and Catolobus, Brava and Neotorularia, and Eutrema, Aphragmus, Lignariella, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. The five Arabis arenicola accessions examined had ITS sequences that were identical to each other and to four Arabidopsis lyrata accessions. In both maximum parsimony and maximum likelihood analyses, Arabis arenicola fell within the Arabidopsis clade and was closely aligned with Arabidopsis lyrata. Two of six purportedly related genera were not closely related to Eutrema. Both analyses placed Lignariella within a separate well-supported clade with Aphragmus, while the other four genera, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella, fell within a well-supported clade with Eutrema. Morphology and molecular data strongly suggest transferring Arabis arenicola to Arabidopsis, expanding Aphragmus to include Lignariella, and expanding Eutrema to include Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. New combinations in Arabidopsis and Aphragmus are proposed.
Warwick, S. I., I. Al-Shehbaz, et al. (2006) Phylogenetic position of Arabis arenicola and generic limits of Eutrema and Aphragmus (Brassicaceae) based on sequences of nuclear ribosomal DNA TreeBASESequence data from the nuclear ITS region of 45 taxa were used to determine the phylogenetic relationship of Arabis arenicola to Arabis, Arabidopsis, Braya, and Eutrema and that of Eutrema to purported related genera Aphragmus, Lignariella, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. Arabis arenicola was originally described as Eutrema in 1830, transferred to Arabis in 1898 and has remained in Arabis to the present, even though it is morphologically more similar to Arabidopsis, Braya and Eutrema. Sequence data were obtained from representative taxa of Arabis, Arabidopsis and related Boechera and Catolobus, Braya and Neotorularia, and Eutrema, Aphragmus, Lignariella, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. The five Arabis arenicola accessions examined had identical ITS sequences to each other and to four Arabidopsis lyrata accessions. In both maximum parsimony and maximum likelihood analyses Arabis arenicola fell within the Arabidopsis clade and was closely aligned with Arabidopsis lyrata. Two of six purported related genera were not closely related to Eutrema. Both analyses placed Lignariella within a separate well-supported clade with Aphragmus, while the other four genera Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella fell within a well-supported clade with Eutrema. Morphology and molecular data strongly suggest transferring Arabis arenicola to Arabidopsis, expanding Aphragmus to include Lignariella, and expanding Eutrema to include Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella. New combinations in Arabidopsis and Aphragmus are proposed.
Wang, B., R. J. Davenport, et al. (2006) Low unidirectional sodium influx into root cells restricts net sodium accumulation in Thellungiella halophila, a salt-tolerant relative of Arabidopsis thaliana Journal of Experimental Botany 57: 1161-1170. 10.1093/jxb/erj116Thellungiella halophila is a useful model species for research into plant salt tolerance. It is closely related to Arabidopsis thaliana, but shows considerably higher salt tolerance. Comparative analysis of ion homeostasis in the two species allows the identification of ion transport pathways that are critical for salt tolerance and provides the basis for future studies into their molecular features. Previous studies indicated that salt tolerance in T. halophila is accompanied by low accumulation of Na in the leaves. Kinetic analysis of net ion uptake over three days confirmed lower Na uptake and K loss in T. halophila compared with A. thaliana. Differential net Na uptake rates were still apparent after 6 weeks of salt treatment. To assess the contribution of unidirectional Na fluxes to net Na uptake, kinetic studies of Na-22 fluxes were carried out in both species. The results show that unidirectional root Na influx is significantly lower in salt-grown T. halophila plants than in A. thaliana exposed to the same level of salinity (100 mM). Quantitative comparison of unidirectional influx and net Na accumulation suggests that both species operate efficient Na efflux, which partly compensates for Na influx. Kinetic analysis of Na-22 efflux indicated higher root Na efflux in A. thaliana than in T. halophila. Thus A. thaliana appears to spend more energy on Na export while nevertheless accumulating more Na than T. halophila. It is proposed that limitation of Na influx is the main mechanism by which T. halophila secures low net Na accumulation in saline conditions. This strategy provides the basis for a positive balance between growth and net Na uptake rates, which is essential for survival in high salt.
Volkov, V. and A. Amtmann. (2006) Thellungiella halophila, a salt-tolerant relative of Arabidopsis thaliana, has specific root ion-channel features supporting K+/Na+ homeostasis under salinity stress Plant Journal 48: 342-353. 10.1111/j.1365-313X.2006.02876.xThellungiella halophila is a salt-tolerant relative of Arabidopsis thaliana with high genetic and morphological similarity. In a saline environment, T. halophila accumulates less sodium and retains more potassium than A. thaliana. Detailed electrophysiological comparison of ion currents in roots of both species showed that, unlike A. thaliana, T. halophila exhibits high potassium/sodium selectivity of the instantaneous current. This current differs in its pharmacological profile from the current through inward- and outward-rectifying K+ channels insofar as it is insensitive to Cs+ and TEA(+), but resembles voltage-independent channels of glycophytes as it is inhibited by external Ca2+. Addition of Cs+ and TEA(+) to the growth medium confirmed the key role of the instantaneous current in whole-plant sodium accumulation. A negative shift in the reversal potential of the instantaneous current under high-salt conditions was essential for decreasing sodium influx to twofold lower than the corresponding value in A. thaliana. The lower overall sodium permeability of the T. halophila root plasma membrane resulted in a smaller membrane depolarization during salt exposure, thus allowing the cells to maintain their driving force for potassium uptake. Our data provide quantitative evidence that specific features of ion channels lead to superior sodium/potassium homeostasis in a halophyte compared with a closely related glycophyte.
Tang, G.-y., Z.-y. Sun, et al. (2006) Pollen morphologies of Sisymbrieae(Brassicaceae) in China Xibei Zhiwu Xuebao 26: 1540-1547.Pollen morphologies of 14 species of ten genera in Sisymbrieae(Brassicaceae) in China were observed by light microscopy and scanning electron microscopy. It was shown that the pollens of the tribe could be divided into four groups, (1) 3-colpate perprolate pollen grains with reticulate ornamentation and two-layered exine;(2)3-colpate perprolate pollen grains with finely reticulate ornamentation and one layered exine;(3)3-colpate(4-colpate on rare occasions) prolate pollen grains with reticulate ornamentation and two layered exine; (4) 6-colpate prolate pollen grains with reticulate ornamentation and two layered exine. Therefore, Sisymbrieae(Brassicaceae) in China has a higher diversity in pollen morphology and this indicates that it is a polyphly goup rather than a natural group and this result agrees with the results in previous research. The study reported Beteroelleae F. Z. Li,G. Y. Tang & Z. Y. Sun had 6-colpate pollen grains for the first time and the author of paper defined it as a new tribe, tribe Berteroelleae F. Z. Li, G. Y. Tang Z. Y. Sun because of the uniqueness of the 6-colpate pollen grains in Brassicaceae.
Taji, T., M. Takeda, et al. (2006) Metabolome analysis of Thellungiella halophila, model halophyte Plant and Cell Physiology 47: S229-S229.In this review we summarize recent advances in our understanding of phylogenetics, polyploidization and comparative genomics in the family Brassicaceae. These findings pave the way for a unified comparative genomic framework. We integrate several of these findings into a simple system of 24 conserved chromosomal blocks (labeled A-X). The naming, order, orientation and color-coding of these blocks are based on their positions in a proposed ancestral karyotype (n = 8), rather than by their position in the reduced genome of Arabidopsis thaliana (n = 5). We show how these crucifer building blocks can be rearranged to model the genome structures of A. thaliana, Arabidopsis lyrata, Capsella rubella and Brassica rapa. A framework for comparison between species is timely because several crucifer genome-sequencing projects are underway.
Moffatt, B., C. E. Wong, et al. (2006) GSE2981: Transcriptional Profiling Implicates Novel Interactions between Abiotic Stress and Hormonal Responses in Thellungiella Gene Expression OmnibusThellungiella, an Arabidopsis-related halophyte, is an emerging model species for studies designed to elucidate molecular mechanisms of abiotic stress tolerance. Using a cDNA microarray containing 3628 unique sequences derived from previously reported libraries of stress-induced cDNAs of the Yukon ecotype of Thellungiella, we obtained transcript profiles of its response to drought, cold, high salinity and re-watering after drought. A total of 153 transcripts were found to be significantly differentially regulated under the conditions studied. Only six of these genes responded to all three stresses of drought, cold and salinity. Unlike in Arabidopsis, there were relatively few transcript changes in response to high salinity in this halophyte. Furthermore, drought responsive-transcripts in Thellungiella provided a link between the down-regulation of defense-related transcripts and the increase of endogenous abscisic acid during drought. This antagonistic interaction between drought and biotic stress response may potentially be beneficial for survival under drought stress. Intriguingly, changes of transcript abundance in response to cold implicate the involvement of jasmonic acid in the cold acclimation of Thellungiella. Taken together, our results provide useful starting points for more in depth analysis of Thellungiellas extreme stress tolerance.
M'Rah, S., Z. Ouerghi, et al. (2006) Effects of NaCl on the growth, ion accumulation and photosynthetic parameters of Thellungiella halophila Journal of Plant Physiology 163: 1022-1031. 10.1016/j.jplph.2005.07.015Thellungiella halophila seedlings grown on a solid substrate for 25 days on standard medium were challenged with NaCl. Growth, tissue hydration, ion accumulation, photosynthesis, tipid peroxidation and antioxidant enzymatic activities were studied on rosette leaves. Three accessions of Arabidopsis thaliana were cultivated under the same conditions. During the first two weeks of salt treatment, the growth of T hatophila leaves was restricted by NaCl. No significant difference appeared between T hatophila and A. thaliana concerning biomass deposition, or hydric and ionic parameters. However, all A. thaliana plants displayed foliar damage, and died during the third week of salt (50 mM NaCl) treatment. Almost all (94%) T halophila plants remained alive, but did not display any sign of altered physiological condition. Tissue hydration, chlorophyll content, stomatal conductance, photosynthetic quantum yield, and photosynthetic rate were very similar to those of control plants. Lipid peroxidation, estimated from thermoluminescence, was very low and insensitive to salt treatment. Only slight changes occurred in antioxidant enzymatic activities (SOD, several peroxidases, and catalase). From the absence of physiological disorder symptoms, we infer that salt was efficiently compartmentalized in leaf vacuoles. In salt-treated A. thaliana, the photosynthetic quantum yield was diminished, and lipid peroxidation was augmented. These observations reinforce the conclusion that T halophila could accumulate salt in its leaves without damage, in contrast to A. thaliana. (c) 2005 Elsevier GmbH All rights reserved.
Li, P. H., S. P. Mane, et al. (2006) Effects of chronic ozone exposure on gene expression in Arabidopsis thaliana ecotypes and in Thellungielia halophila Plant Cell and Environment 29: 854-868. 10.1111/j.1365-3040.2005.01465.xArabidopsis thaliana (At) ecotypes Columbia-0 (Col-0), Wassilewskija (WS), Cape Verde Islands (Cvi-0) and a relative, Thellungiella halophila (Th), were exposed to 20-25% over ambient ozone [O-3] in a free air concentration enrichment (FACE) experiment (http://www.soyFACE. uiuc.edu), mirroring increases expected in the near future. Col-0 and WS accelerated development and developed lesions within 10 d under increased ozone, while Cvi-O and Th grew slowly. RNAs were used in microarray hybridizations (Col-0-based 26000 elements, 70-mer oligonucleofides). A two-step analysis of variance (ANOVA) model, including comparison with values obtained under [O-3], was used for analyses. WS showed the greatest number of changes in gene expression in response to ozone. Th showed the least changes, suggesting that its expression state at [O-3] was sufficient for resistance at increased ozone. Patterns observed in ambient air controls for Cvi-O and Col-0 were most similar, while Th showed the greatest number of differences compared with the other controls. Compared with Col-0, however, Cvi-O showed higher levels of expression of chaperones, receptor kinase-like and photosynthesis-related genes in ambient air. Cvi-O exhibited ozone-mediated changes in a pathway involving AtSR, a homologue of the mammalian NFKB family of redox-sensitive transcription factors, changes in chaperones, WRKY and C2H2 proteins and antioxidants. WS displayed ozone-mediated decreases in the expression of two AtSR/NFKB family members, C2-domain proteins and genes associated with cell wall growth and changes in the expression of marker genes for programmed cell death (PCD), among them RCD1, a key regulator in this pathway. Microarray data were verified by reverse transcriptase (RT)-PCR. We relate O-3-response diversity across the four lines to different responses among signaling and transcriptional response networks and differences in gene expression at [O-3] levels.
Kuznetsov, V. V., V. Y. Rakitin, et al. (2006) Stress-accelerated spermine production in leaves of Thellungiella halophila is not controlled at the level of expression of SPDS gene Plant Biology (Rockville) 2006: 135-135.In this review, we consider recent advances in the study of the multifaceted biological role of polyamines, primarily under stress conditions, discuss molecular mechanisms controlling their anabolism, catabolism, and transport, and also the regulation of gene expression for key enzymes of their biosynthesis and degradation. To understand the place and role of polyamines in plant adaptation, we focus the data concerning gene expression obtained by modern physicochemical methods on mutant and transgenic plants and also on natural stress-tolerant species manifesting a high tolerance to salinity, drought, and other abiotic factors.
Kant, S., P. Kant, et al. (2006) Evidence that differential gene expression between the halophyte, Thellungiella halophila, and Arabidopsis thaliana is responsible for higher levels of the compatible osmolyte proline and tight control of Na(+) uptake in T-halophila Plant Cell and Environment 29: 1220-1234. 10.1111/j.1365-3040.2006.01502.xSalt-sensitive glycophytes and salt-tolerant halophytes employ common mechanisms to cope with salinity, and it is hypothesized that differences in salt tolerance arise because of changes in the regulation of a basic set of salt tolerance genes. We explored the expression of genes involved in two key salt tolerance mechanisms in Arabidopsis thaliana and the halophytic A. thaliana relative model system (ARMS), Thellungiella halophila. Salt overly sensitive 1 (SOS1) is a plasma membrane Na(+)/H(+) antiporter that retrieves and loads Na(+) ions from and into the xylem. Shoot SOS1 transcript was more strongly induced by salt in T. halophila while root SOS1 was constitutively higher in unstressed T. halophila. This is consistent with a lower salt-induced rise in T. halophila xylem sap Na(+) concentration than in A. thaliana. Thellungiella halophila contained higher unstressed levels of the compatible osmolyte proline than A. thaliana, while under salt stress, T. halophila accumulated more proline mainly in shoots. Expression of the A. thaliana ortholog of proline dehydrogenase (PDH), involved in proline catabolism, was undetectable in T. halophila shoots. The PDH enzyme activity was lower and T. halophila seedlings were hypersensitive to exogenous proline, indicating repression of proline catabolism in T. halophila. Our results suggest that differential gene expression between glycophytes and halophytes contributes to the salt tolerance of halophytes.
Gao, F., Q. Gao, et al. (2006) Cloning of an H+-PPase gene from Thellungiella halophila and its heterologous expression to improve tobacco salt tolerance Journal of Experimental Botany 57: 3259-3270. 10.1093/jxb/erl090An H+-pyrophosphatase (PPase) gene named TsVP involved in basic biochemical and physiological mechanisms was cloned from Thellungiella halophila. The deduced translation product has similar characteristics to H+-PPases from other species, such as Arabidopsis and rice, in terms of bioinformation. The heterologous expression of TsVP in the yeast mutant ena1 suppressed Na+ hypersensitivity and demonstrated the function of TsVP as an H+-PPase. Transgenic tobacco overexpressing TsVP had 60% greater dry weight than wild-type tobacco at 300 mM NaCl and higher viability of mesophyll protoplasts under salt shock stress conditions. TsVP and AVP1, another H+-PPase from Arabidopsis, were heterologously expressed separately in both the yeast mutant ena1 and tobacco. The salt tolerance of TsVP or AVP1 yeast transformants and transgenic tobacco were improved to almost the same level. The TsVP transgenic tobacco lines TL3 and TL5 with the highest H+-PPase hydrolytic activity were studied further. These transgenic tobacco plants accumulated 25% more solutes than wild-type plants without NaCl stress and 20-32% more Na+ under salt stress conditions. Although transgenic tobacco lines TL3 and TL5 accumulated more Na+ in leaf tissues, the malondialdehyde content and cell membrane damage were less than those of the wild type under salt stress conditions. Presumably, compartmentalization of Na+ in vacuoles reduces its toxic effects on plant cells. This result supports the hypothesis that overexpression of H+-PPase causes the accumulation of Na+ in vacuoles instead of in the cytoplasm and avoids the toxicity of excessive Na+ in plant cells.
Flowers, T. (2006) Plants and Salinity - Preface Journal of Experimental Botany 57: IV-IV. 10.1093/jxb/erj119The halophyte Thellungiella halophila is used as a model for the study of salt tolerance in plants. However, it flowers late and requires vernalization to promote flowering. In Arabidopsis thaliana, a close relative of T. halophila, FLC is the key gene controling the vernalization response pathway. Here, we report the cloning and functional characterization of T. halophila FLC gene (ThFLC). ThFLC showed significant homology to AtFLC and was negatively regulated upon vernalization treatment. Ectopic expression of ThFLC in Arabidopsis functionally complemented FLC-Ler and caused a late-flowering phenotype. An RNAi construct, developed from a 309 by fragment of ThFLC cDNA, was used for gene specific silencing of endogenous ThFLC in T. halophila. In transgenic T. halophila plants the endogenous ThFLC transcript was eliminated, producing an early flowering phenotype while retaining the same salt tolerance as wildtype. This engineered T. halophila provides a better research model for plant salt tolerance studies than wild-type T. halophila. (c) 2006 Elsevier Inc. All rights reserved.
Dong, M.-f., Z.-d. Wang, et al. (2006) Microsporogenesis and male gametophyte development in Thellungiella halophila Xibei Zhiwu Xuebao 26: 964-969.This study microscopically examined the microsporogenesis and male gametophyte development, as well as their correlations at their different stages with flower in Thellungiella halophila. It revealed that T. halophila has tetradynamous stamen each of which has four pollen sacs, the meiosis in the microspore mother cells belongs to a simultaneous type and the microspores are arranged in a tetrahedron shape in the tetrads. The mature pollen grains belong to a 3-cell type and have three germination appertures. The pollen-sac wall belongs to a dicotyledonous type and consists of four layers of cells-epidermis, endothecium, middle layer and tapetum. The tapetum is glandular one. When the flower buds can be seen with naked eyes, the male sporogonia begin to differentiate. The flower buds expose its white parts, i.e. reach 1.1 similar to 1.7 mm long,they have formed mature male gametophytes, the three-cell pollen grains.
Dong, M.-f., Z.-d. Wang, et al. (2006) Anatomic study of Thellungiella halophila fertilization and embryo development Xibei Zhiwu Xuebao 26: 2142-2145.The fertilization and embryo development of Thellungiella hallophila (C. A. Mey.)O. E. Schulz were observed by light microscopy and paraffin sectioning. The results showed that the karyomixis in fertilization occurred around the full blooming stage and two polar nuclei fuse into secondary nuclei before the fertilization took place; the fertilization fell into the category of premitotic syngamy, the endersperm development belonged to karyotype, the embryo development was onagrad types and the cotyledons rested their back on the radicles,and the mature seeds hadn't endersperm.
Biology, U. o. W. (2006) Transcriptional Profiling Implicates Novel Interactions between Abiotic Stress and Hormonal Responses in Thellungiella European Nucleotide ArchiveThellungiella, an Arabidopsis-related halophyte, is an emerging model species for studies designed to elucidate molecular mechanisms of abiotic stress tolerance. Using a cDNA microarray containing 3628 unique sequences derived from previously reported libraries of stress-induced cDNAs of the Yukon ecotype of Thellungiella, we obtained transcript profiles of its response to drought, cold, high salinity and re-watering after drought. A total of 153 transcripts were found to be significantly differentially regulated under the conditions studied. Only six of these genes responded to all three stresses of drought, cold and salinity. Unlike in Arabidopsis, there were relatively few transcript changes in response to high salinity in this halophyte. Furthermore, drought responsive-transcripts in Thellungiella provided a link between the down-regulation of defense-related transcripts and the increase of endogenous abscisic acid during drought. This antagonistic interaction between drought and biotic stress response may potentially be beneficial for survival under drought stress. Intriguingly, changes of transcript abundance in response to cold implicate the involvement of jasmonic acid in the cold acclimation of Thellungiella. Taken together, our results provide useful starting points for more in depth analysis of Thellungiellaas extreme stress tolerance. Keywords: Abiotic stress response Overall design: We used a custom cDNA microarray to perform an initial analysis of the molecular response of the Yukon ecotype of Thellungiella subjected to cold, drought, or drought followed by re-watering or salinity treatments. The 4 different sets of microarray exp are : 1) Control versus Cold 2) Control versus Drought 3) Drought versus Rewatering 4) Control versus Salinity In each set of microarray exp, we have performed 3 biological replicates (A, B, C) and technical replicate (dye swap) resulting in a total of 24 hybridizations.
Anetai, M. (2006) Food poisoning by toxic plants in Hokkaido Journal of the Food Hygienic Society of Japan 47: J178-J184.Thellungiella salsuginea (also known as T. halophila) is a close relative of Arabidopsis that is very tolerant of drought, freezing, and salinity and may be an appropriate model to identify the molecular mechanisms underlying abiotic stress tolerance in plants. We produced 6578 ESTs, which represented 3628 unique genes (unigenes), from cDNA libraries of cold-, drought-, and salinity-stressed plants from the Yukon ecotype of Thellungiella. Among the unigenes, 94.1% encoded products that were most similar in amino acid sequence to Arabidopsis and 1.5% had no match with a member of the family Brassicaceae. Unigenes from the cold library were more similar to Arabidopsis sequences than either drought- or salinity-induced sequences, indicating that latter responses may be more divergent between Thellungiella and Arabidopsis. Analysis of gene ontology using the best matched Arabidopsis locus showed that the Thellungiella unigenes represented all biological processes and all cellular components, with the highest number of sequences attributed to the chloroplast and mitochondria. Only 140 of the unigenes were found in all three abiotic stress cDNA libraries. Of these common unigenes, 70% have no known function, which demonstrates that Thellungiella can be a rich resource of genetic information about environmental responses. Some of the ESTs in this collection have low sequence similarity with those in Genbank suggesting that they may encode functions that may contribute to Thellungiella's high degree of stress tolerance when compared with Arabidopsis. Moreover, Thellungiella is a closer relative of agriculturally important Brassica spp. than Arabidopsis, which may prove valuable in transferring information to crop improvement programs.
Vinocur, B. and A. Altman. (2005) Recent advances in engineering plant tolerance to abiotic stress: achievements and limitations Current Opinion in Biotechnology 16: 123-132. 10.1016/j.copbio.2005.02.001Abiotic stresses, especially salinity and drought, are the primary causes of crop loss worldwide. Plant adaptation to environmental stresses is dependent upon the activation of cascades of molecular networks involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Consequently, engineering genes that protect and maintain the function and structure of cellular components can enhance tolerance to stress. Our limited knowledge of stress-associated metabolism remains a major gap in our understanding; therefore, comprehensive profiling of stress-associated metabolites is most relevant to the successful molecular breeding of stress-tolerant crop plants. Unraveling additional stress-associated gene resources, from both crop plants and highly salt- and drought-tolerant model plants, will enable future molecular dissection of salt-tolerance mechanisms in important crop plants.
Vera-Estrella, R., B. J. Barkla, et al. (2005) Salt stress in Thellungiella halophila activates Na+ transport mechanisms required for salinity tolerance Plant Physiology 139: 1507-1517. 10.1104/pp.105.067850Salinity is considered one of the major limiting factors for plant growth and agricultural productivity. We are using salt cress (Thellungiella halophila) to identify biochemical mechanisms that enable plants to grow in saline conditions. Under salt stress, the major site of Na+ accumulation occurred in old leaves, followed by young leaves and taproots, with the least accumulation occurring in lateral roots. Salt treatment increased both the H+ transport and hydrolytic activity of salt cress tonoplast (TP) and plasma membrane (PM) H+ -ATPases from leaves and roots. TPNa+/H+ exchange was greatly stimulated by growth of the plants in NaCl, both in leaves and roots. Expression of the PM H+ -ATPase isoform AHA3, the Na+ transporter HKT1, and the Na+/H+ exchanger SOS1 were examined in PMs isolated from control and salt-treated salt cress roots and leaves. An increased expression of SOS1, but no changes in levels of AHA3 and HKT1, was observed. NHX1 was only detected in PM fractions of roots, and a salt-induced increase in protein expression was observed. Analysis of the levels of expression of vacuolar H+ -translocating ATPase subunits showed no major changes in protein expression of subunits VHA-A or VHA-B with salt treatment; however, VHA-E showed an increased expression in leaf tissue, but not in roots, when the plants were treated with NaCl. Salt cress plants were able to distribute and store Na+ by a very strict control of ion movement across both the TP and PM.
Vera-Estrella, R., B. Barkla, et al. (2005) Salt stress in Thellungiella halophila activates transport mechanisms that are required for salinity tolerance Plant Biology (Rockville) 2005: 122-122.Thellungiella halophila was treated with different concentrations of NaCl (0, 50, 100, 200, 300 and 400 mmol/L). Water content, osmotic potential, various organic and inorganic osmotica contents in the leaves and roots were determined and the calculated osmotic potential (COP) of osmotica in the osmotic adjustment was calculated (Figs. 1-10 and Table 1). The result showed that water content, osmotic potential decreased with the increase of salinity; Na+ and Cl- were the accumulated inorganic osmotica in roots and leaves; soluble sugar, organic acid and free amino acid were the accumulated organic osmotica in roots; and proline was the accumulated organic osmotica in both root and leaf. Na+ X-ray microanalysis indicated that vacuole in the cell was the main organelle of accumulation toxic ions (Table 2).
Liu, A.-R. and K.-F. Zhao. (2005) Effects of salt stress on the growth and the nitrate reductase activity in the Thellungiella halophila Zhiwu Shengli yu Fenzi Shengwuxue Xuebao 31: 469-476.The results showed that when Thellungiella halophila was treated with NaCl, the fresh and dry weight, the water content, the succulency of whole plant and the root/shoot ratio were decreased (Figs.2-4,7); the organic matter content in roots was increased and the inorganic matter content in roots was decreased, while those in shoots changed in the opposite direction (Fig.6); osmotic adjustment ability, the Na+ content, the root activity were increased (Figs.5, 7, 8); the nitrate reductase activity increased significantly; the O-2(-) content decreased at about NaCl 50 nimol/L but increased at about NaCl 100-400 mmol/L (Fig. 10). The micrographs of T. halophila leaf surface by scanning electron microscope (SEM) indicate that there is no salt gland or bladder on the surface of T. halophila (Fig. 1), so it is not a salt-secreting halophyte. The determination of growth parameters, the Na(+)content and Na+ X-ray (Table 1) microanalysis, of T. halophila indicate that T. halophila is not a salt-exclusing halophyte but it probability is a salt-dilution halophyte.
Li, P., A. Ulanov, et al. (2005) Gene expression patterns in three Arabidopsis ecotypes and Thellungiella halophila grown under open-air elevation of CO2 Plant Biology (Rockville) 2005: 148-148.In stark contrast to Arabidopsis, a related species, Thellungiella halophila ( Thellungiella salsuginea; salt cress), displays extreme tolerance to high salinity, low humidity and freezing. High nucleotide sequence identity permits the use of tools developed for Arabidopsis for Thellungiella transcript profiling, for which a microarray platform with > 25 000 DNA elements (70- mer oligonucleotides) was used. Microarray transcript profiling and intensity analysis, quantitative RT-PCR, and metabolite profiles define genes and pathways that showed shared and divergent responses to salinity stress in the two species. Shared responses are exemplified by 40% of the regulated genes functioning in confining ribosomal functions, photosynthesis and cell growth, as well as activating osmolyte production, transport activities and abscisic acid-dependent pathways. An additional 60% of regulated genes distinguished Thellungiella from Arabidopsis. Analysis of the differences showed that Arabidopsis exhibited a global defense strategy that required bulk protein synthesis, while Thellungiella induced genes functioning in protein folding, post-translational modification and protein redistribution. At 150 mM NaCl, Thellungiella maintained unimpeded growth. Transcript intensity analyses and metabolite profiles supported the microarray results, pointing towards a stress-anticipatory preparedness in Thellungiella.
Gong, Q., P. Li, et al. (2005) Distinctive features of thellungiella and Arabidopsis salt stress transcriptomes Plant Biology (Rockville) 2005: 121-121.Paraffin sectioning was adopted to study anatomic structures of vegetative organs of Thellungiella halophila,a halophyte. The primary structure of its roots showed a layer of big and highly vacuolated cells and a small number of root hair. Its cortex consisted of only two layers of big and closely aligning cells, exodermis and endodermis. The secondary vascular tissues of its roots appeared well developed. The primary structure of its stem contained 8-10 vascular bundles of outer phloem that varied in size and aligned in a cycle as well as well-developed pith and pith rays. The secondary structure of its stem contained well-developed vascular tissues. These characteristics of its roots and stems made the plant have high capcities to take up and transport water,and that the specificities of its root in anatomic structue and conducting system could restrict saline substances inside the roots, thereby adapting to osmotic and drought stresses resulting from brackish environment. Thellungiella halophila had small leaves whose upper and lower epidermises consisted of one layer of big and highly vacuolated cells,and poorly differentiated palisade and spongy tissues,but it had a great number of large-size chloroplasis,a large intercellular space, a good air permeability, and a high photosynthetic rate. These characteristics played an important role in its adapting to the evvironments characterized by drought and salinity. Thellungiella halophila extremely differed in its above-mentioned characteristics from typical halophytes and xerophils. Its vegetative organs did not contain such salt-secreting structures as salt glands, bursas and vesicles. Accordingly, Thellungiella halophila tended to be a pseudo-halophyte in a large measure.
Bohnert, H. J., I. Rupassar, et al. (2005) Metabolite profiles under abiotic stress Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology 141: S342-S342.Agricultural productivity worldwide is subject to increasing environmental constraints, particularly to drought and salinity due to their high magnitude of impact and wide distribution. Traditional breeding programs trying to improve abiotic stress tolerance have had some success, but are limited by the multigenic nature of the trait. Tolerant plants such as Craterostigma plantagenium, Mesembryanthemum crystallinum, Thellungiella halophila and other hardy plants could be valuable tools to dissect the extreme tolerance nature. In the last decade, Arabidopsis thaliana, a genetic model plant, has been extensively used for unravelling the molecular basis of stress tolerance. Arabidopsis also proved to be extremely important for assessing functions for individual stress-associated genes due to the availability of knock-out mutants and its amenability for genetic transformation. In this review, the responses of plants to salt and water stress are described, the regulatory circuits which allow plants to cope with stress are presented, and how the present knowledge can be applied to obtain tolerant plants is discussed.
Amtmann, A., B. Wang, et al. (2005) Comparative analysis of ion transport in Arabidopsis related species differing in salt tolerance Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology 141: S339-S339.As determined by extensive molecular studies and critical evaluation of morphology, the genera Eutrema, Neomartinella, Platycraspedum, Taphrospermum, and Thellungiella form a monophyletic assemblage treated here as one genus under the oldest name, Eutrema. The present synopsis of Eutrema includes a listing of all 26 species presently assigned to the genus, including 14 new combinations (E. altaicum, E. botschantzevii, E. fontanum, E. fontanum subsp. microspermum, E. grandiflorum, E. halophilum, E. lowndesii, E. parvulum, E. platypetalum, E. salsugineum, E. verticillatum, E. violifolium, E. wuchengyii, and E. yungshunensis) and 3 new names (E. hookeri. E. schulzii, and E. sherriffii). It also includes a detailed description of the combined genus, distributions, and a key to all species.
Zhang, X., S. L. Guo, et al. (2004) Molecular cloning and identification of a heat shock cognate protein 70 gene, Thhsc70, in Thellungiella halophila Acta Botanica Sinica 46: 1212-1219.Heat shock cognate proteins 70 (hsp70s) act as molecular chaperones. Some hsp70s are also expressed in unstressed plants, known as hsc70. To gain further knowledge about the hsc70, the Thellungiella halophila hsc70 (Thhsc70) gene that encoded the cytosolic hsc70 in salt cress ( T halophila (C. A. Mey.) O. E. Schulz) was identified. In unstressed plants the expression of Thhsc70 was shown to be tissue-specific. The Thhsc70 gene was induced by heat and cold stresses, but almost not by salt and drought stresses. Overexpression of Thhsc70 could increase thermotolerance and chilling tolerance in transgenic Arabidopsis plants.
Wang, Z. I., P. H. Li, et al. (2004) Expressed sequence tags from Thellungiella halophila, a new model to study plant salt-tolerance Plant Science 166: 609-616. 10.1016/j.plantsci.2003.10.030Accumulation and analysis of expressed sequence tags (ESTs) data front halophytic plant is a relatively rapid and cheap way for discovering new genes related to salinity tolerance. We constructed a NaCl-treated cDNA library of Thellunigiella halophila and sequenced more than 1500 randomly selected clones. By sequence analysis, 8 13 unique clones were identified: 549 showed homology to previously identified genes. 264 matched uncharacterized genes. All our EST data are available oil the Internet. The identity between T. halophila and Arabidopsis thaliana cDNA sequences ill Our EST collection are 95.76% in total ESTs and 95.36% in non-redundant clones. At least eight classes of genes were related to the salt-tolerance, which accounted for about 18.89% Of total seqenced ESTs. T halophila that has many features similar to Arabidopsis call be adopted as a halophytic model for stress-tolerance research. (C) 2003 Elsevier Ireland Ltd. All rights reserved.
Volkov, V., B. Wang, et al. (2004) Thellungiella halophila, a salt-tolerant relative of Arabidopsis thaliana, possesses effective mechanisms to discriminate between potassium and sodium Plant, Cell and Environment 27: 1-14. 10.1046/j.0016-8025.2003.01116.xThellungiella halophila is a salt-tolerant close relative of Arabidopsis thaliana. Significant mRNA similarity was confirmed by hybridization of T. halophila mRNA with the A. thaliana GeneChip ATH1. To establish a platform for future molecular comparison of the two species several physiological mechanisms, which may confer high salt tolerance to T. halophila, were investigated. Determination of ion content in shoots and roots of A. thaliana and T. halophila indicated different strategies of ion uptake and translocation from root to shoot in the two species. During salt stress T. halophila accumulated less sodium than A. thaliana. Tissue concentrations of sodium and potassium showed negative correlation in A. thaliana but not in T. halophila. Electrophysiological experiments proved high potassium/sodium selectivity of root plasma membrane channels in T. halophila. In particular, voltage-independent currents were more selective for potassium in T. halophila than in A. thaliana. Single cell sampling of T. halophila leaves during salt exposure revealed increased concentrations of sodium and decreased concentrations of potassium in epidermal cells suggesting that this cell type could function to ensure storage of sodium and exchange of potassium with the rest of leaf. Application of salt resulted in a sharp drop of transpiration in A. thaliana. By contrast, transpiration in T. halophila responded more slowly and was only slightly inhibited by salt treatment, thus maintaining high water uptake and ion transport.
Verma, P. K., S. Kant, et al. (2004) THELLUNGIELLA HALOPHILA (SALT STRESS), A HALOPHYTIC RELATIVE OF ARABIDOPSIS: COMPARATIVE MOLECULAR AND PHYSIOLOGICAL STUDY OF SALT TOLERANCE Acta Physiologiae Plantarum 26: 204-204.Salt cress (Thellungiella halophila), a halophyte, is a genetic model system with a small plant size, short life cycle, copious seed production, small genome size, and an efficient transformation. Its genes have a high sequence identity (90%-95% at cDNA level) to genes of its close relative, Arabidopsis. These qualities are advantageous not only in genetics but also in genomics, such as gene expression profiling using Arabidopsis cDNA microarrays. Although salt cress plants are salt tolerant and can grow in 500 mm NaCl medium, they do not have salt glands or other morphological alterations either before or after salt adaptation. This suggests that the salt tolerance in salt cress results from mechanisms that are similar to those operating in glycophytes. To elucidate the differences in the regulation of salt tolerance between salt cress and Arabidopsis, we analyzed the gene expression profiles in salt cress by using a full-length Arabidopsis cDNA microarray. In salt cress, only a few genes were induced by 250 mm NaCl stress in contrast to Arabidopsis. Notably a large number of known abiotic- and biotic-stress inducible genes, including Fe-SOD, P5CS, PDF1.2, AtNCED, P-protein, beta-glucosidase, and SOS1, were expressed in salt cress at high levels even in the absence of stress. Under normal growing conditions, salt cress accumulated Pro at much higher levels than did Arabidopsis, and this corresponded to a higher expression of AtP5CS in salt cress, a key enzyme of Pro biosynthesis. Furthermore, salt cress was more tolerant to oxidative stress than Arabidopsis. Stress tolerance of salt cress may be due to constitutive overexpression of many genes that function in stress tolerance and that are stress inducible in Arabidopsis.
Taji, T., M. Seki, et al. (2004) Functional Genomics in Arabidopsis-related halophyte, Thellungiella halophila using Arabidopsis microarray Plant and Cell Physiology 45: S57-S57.The Resonance Light Scattering (RLS) spectra of atrazine with yeast ribonucleic acid (yRNA) had been studied. At pH 1.50, the enhanced RLS of atrazine-yRNA system is characterized by the maximum scattering peaks at 320 run and the RLS intensity is proportional to the concentration of yRNA. Under optima conditions, the linear ranges of the calibration were 0.6-5.0 mug mL(-1), the linear regression equation was I = 25.88 + 140.0 c (yRNA, mug(.)mL(-1)), r = 0.9975, with the limit of detection 20.7 ng(.)mL(-1) (3delta). The method was applied to the determination of yRNA in synthetic samples and RNA in salt cress (Thellungiella Halophila) sample satisfactorily. Mechanism studies show that there are two interaction modes between atrazine and RNA: electrostatic mode and intercalative mode.
Ren, L.-p., S.-r. Jiang, et al. (2004) Study on the resonance scattering light spectra of atrazine-RNA and its analytical application Guang pu xue yu guang pu fen xi = Guang pu 24: 1213-1216.The Resonance Light Scattering (RLS) spectra of atrazine with yeast ribonucleic acid (yRNA) had been studied. At pH 1.50, the enhanced RLS of atrazine-yRNA system is characterized by the maximum scattering peaks at 320 nm and the RLS intensity is proportional to the concentration of yRNA. Under optimal conditions, the linear ranges of the calibration were 0.6-5.0 microg x mL(-1), the linear regression equation was I = 25.88 + 140.0 c(yRNA, microg x mL(-1)), r = 0.9975, with the limit of detection 20.7 ng x mL(-1) (3delta). The method was applied to the determination of yRNA in synthetic samples and RNA in salt cress (Thellungiella halophila) sample satisfactorily. Mechanism studies show that there are two interaction modes between atrazine and RNA: electrostatic mode and intercalative mode.
Inan, G., Q. Zhang, et al. (2004) Salt cress. A halophyte and cryophyte Arabidopsis relative model system and its applicability to molecular genetic analyses of growth and development of extremophiles Plant Physiology 135: 1718-1737. 10.1104/pp.104.041723Salt cress (Thellungiella halophila) is a small winter annual crucifer with a short life cycle. It has a small genome (about 2 x Arabidopsis) with high sequence identity (average 92%) with Arabidopsis, and can be genetically transformed by the simple floral dip procedure. It is capable of copious seed production. Salt cress is an extremophile native to harsh environments and can reproduce after exposure to extreme salinity (500 mm NaCl) or cold to -15degreesC. It is a typical halophyte that accumulates NaCl at controlled rates and also dramatic levels of Pro (>150 mm) during exposure to high salinity. Stomata of salt cress are distributed on the leaf surface at higher density, but are less open than the stomata of Arabidopsis and respond to salt stress by closing more tightly. Leaves of salt cress are more succulent-like, have a second layer of palisade mesophyll cells, and are frequently shed during extreme salt stress. Roots of salt cress develop both an extra endodermis and cortex cell layer compared to Arabidopsis. Salt cress, although salt and cold tolerant, is not exceptionally tolerant of soil desiccation. We have isolated several ethyl methanesulfonate mutants of salt cress that have reduced salinity tolerance, which provide evidence that salt tolerance in this halophyte can be significantly affected by individual genetic loci. Analysis of salt cress expressed sequence tags provides evidence for the presence of paralogs, missing in the Arabidopsis genome, and for genes with abiotic stress-relevant functions. Hybridizations of salt cress RNA targets to an Arabidopsis whole-genome oligonucleotide array indicate that commonly stress-associated transcripts are expressed at a noticeably higher level in unstressed salt cress plants and are induced rapidly under stress. Efficient transformation of salt cress allows for simple gene exchange between Arabidopsis and salt cress. In addition, the generation of T-DNA-tagged mutant collections of salt cress, already in progress, will open the door to a new era of forward and reverse genetic studies of extremophile plant biology.
Holmgren, N. H. (2004) Nevada: A new genus for Smelowskia holmgrenii (Brassicaceae) Brittonia 56: 238-244. 10.1663/0007-196x(2004)056[0238:nangfs]2.0.co;2Holmgren, N. H. (The New York Botanical Garden, Bronx, NY 10458-5126, U.S.A.; e-mail: nholmgren@nybg.org). Nevada: A new genus for Smelowskia holmgrenii (Brassicaceae). Brittonia 56: 238-244. 2004.-Nevada holmgrenii was originally described by Rollins as a Smelowskia, but based on phenetic similarities it appears to be more closely related to the arctic/alpine genera Braya and Eutrema. It is, however, sufficiently distinct from these genera to be placed in a mono-typic genus, Nevada.
Yonekura, K. (2003) The Northernmost habitat of Eutrema okinosimense taken. (Brassicaceae) Journal of Japanese Botany 78: 356-358.The effect of naturally occurring allyl and phenyl isothiocyanates in the inhibition of B16F-10 melanoma cells-induced metastasis has been studied in C57BL/6 mice. The two compounds were administered by three different modalities. Simultaneous administration of the compounds with tumour induction was found to produce significant reduction in the lung tumour nodule formation; of the two compounds studied, allyl isothiocyanate have shown to be more effective and it produced 93% inhibition of tumour nodules while phenyl isothiocyanate has an inhibition of 77.3%. Prophylactic administration also produces considerable effect but no effect was observed by their administration after the tumour development. Lung collagen hydroxyproline, lung uronic acid, lung hexosamine content, serum sialic acid and serum GGT levels were also estimated and the enhanced levels of these parameters in the control animals were found to be reduced by the simultaneous administration of these isothiocyanates; these data were also correlated with the inhibition of lung tumour nodules produced and the increase in life span of the animals. (C) 2003 Elsevier Science B.V. All rights reserved.
Akhani, H. (2003) Notes on the flora of Iran: 4. Two new records and synopsis of the new data on Iranian Cruciferae since Flora Iranica Candollea 58: 369-385.Cakile maritima and Raphanus raphanistrum are recorded for the first time from Iran, i.e. the sandy coastal parts of the South Caspian sea. Notes on the sandy flora of the S Caspian coastal dunes are added. A synopsis of all new taxa, new records, taxonomic or nomenclatural changes, and a bibliography of 79 published works on, or related to Iranian Cruciferae after the publication of Flora franica in 1968 are provided. According to these data 8 new taxa, 39 new records, 35 nomenclatural or status changes and 8 reductions to synonymy were proposed during the last 35 years. Accordingly, the total number of known Iranian Cruciferae increased from 104 to 120 genera, and from 3 19 to 358 species, respectively. There have been remarkable changes or additions in the genera Alyssum, Malcolmia and Thlaspi. The following genera are added, described as new or because of taxonomic or nomenclatural reasons: Boreava, Cithareloma, Coronopus, Crucihimalaya, Fedtschenkova [= Malcolmia], Hornungia, Iberis, Irania [= Fibigia], Kotschyella, Microthlaspi, Neotorularia, Neurotropis, Noccaea, Olimarabidopsis, Petiniotia, Thellungiella and Vania.
Xiong, L. and J. K. Zhu. (2002) Molecular and genetic aspects of plant responses to osmotic stress Plant Cell and Environment 25: 131-139. 10.1046/j.1365-3040.2002.00782.xDrought, high salinity and freezing impose osmotic stress on Plants. Plants respond to the stress in part by modulating gene expression, which eventually leads to the restoration of cellular homeostasis, detoxification of toxins and recovery of growth. The signal transduction pathways mediating these adaptations can be dissected by combining forward and reverse genetic approaches with molecular, biochemical and physiological studies. Arabidopsis is a useful genetic model system for this purpose and its relatives including the halophyte Thellungiella halophila, can serve as valuable complementary genetic model systems.
Teusink, R. S., M. Rahman, et al. (2002) Cuticular waxes on Arabidopsis thaliana close relatives Thellungiella halophila and Thellungiella parvula International Journal of Plant Sciences 163: 309-315. 10.1086/338825Thellungiella halophila and Thellungiella parvula have been recently reported to be close halophytic relatives of Arabidopsis thaliana. Crystallization patterns and chemical composition of stem and leaf cuticular waxes on T. halophila, T. parvula, and A. thaliana ecotype C24 were examined. Whereas the heavy glaucousness, total wax amounts, wax crystal structures, and wax chemical constituents on inflorescence stems of these species were similar, their leaf waxes differed significantly. Arabidopsis thaliana leaf surfaces were glossy, whereas T. parvula leaf surfaces were glaucous throughout development. By comparison, T. halophila leaf surfaces were glossy before flower initiation but glaucous after. Glaucousness resulted from the presence of densely distributed epicuticular wax crystals visible with electron microscopy. Glaucous leaves of both T. halophila and T. parvula produced 12.7- and 24.1-fold more total wax, respectively, than leaves of A. thaliana. Waxes on glossy leaves of T. halophila were greatly enriched in free acids relative to waxes on glossy leaves of A. thaliana. Glaucous leaves of T. halophila and T. parvula had similar wax composition and wax crystallization patterns as their respective stems, except total wax quantity was lower on leaves. As did glaucous stems, glaucous leaves produced relatively large amounts of secondary alcohols and ketones, constituents barely detectable on glossy leaves. Our results indicate that T. halophila and T. parvula may provide, via the application of genomics approaches recently developed for A. thaliana, valuable model systems for isolating genes involved in leaf wax synthesis and the regulation of leaf and stem wax specificity.
Zhu, J. K. (2001) Plant salt tolerance Trends in Plant Science 6: 66-71. 10.1016/s1360-1385(00)01838-0Soil salinity is a major abiotic stress in plant agriculture worldwide. This has led to research into salt tolerance with the aim of improving crop plants. However, salt tolerance might have much wider implications because transgenic salt-tolerant plants often also tolerate other stresses including chilling, freezing, heat end drought. Unfortunately, suitable genetic model systems have been hard to find. A recently discovered halophytic plant species, Thellungiella halophila. now promises to help in the detection of new tolerance determinants and operating pathways in a model system that is not limited to Arabidopsis traits or ecotype variations.
Bressan, R. A., C. Q. Zhang, et al. (2001) Learning from the Arabidopsis experience. The next gene search paradigm Plant Physiology 127: 1354-1360. 10.1104/pp.010752The sphingoid base composition of monoglucosyolceramide was examined in leaves and roots of six species of the family Brassicaceae. The major components of the nine sphingoid bases we detected were 4-hydroxy-8-sphingenine [i.e. t18:1(8E) and (8Z)] and 8-sphingenine, in both leaves and roots. The composition was unique because the relative proportions of 8-E/Z isomers in 4-hydroxy-8-sphingenine and in 8-sphingenine were different. So far, only chilling-resistant plants have been found to contain more t18:I (8Z) components than t18:1(8E) [Imai et at. (1997) Biosci Biotechnol Biochem 61:351-353], Species of the family Brassicaceae can now be added to this list.
Al-Shehbaz, I. A. (2000) The Chinese endemic Neomartinella (Brassicaceae) Novon 10: 337-339. 10.2307/3392979The previously monotypic Neomartinella is expanded to include two additional species. Neomartinella grandiflora is described as new, and the new combination N. yungshunensis is proposed. Neomartinella is revised, and its relationship to Eutrema is discussed.
Holm, L. and K. Holm. (1996) Four northern Mycosphaerellae Acta Universitatis Upsaliensis Symbolae Botanicae Upsalienses 31: 285-295.Four mainly northern taxa of Mycosphaerellae are dealt with. 1. Mycosphaerella confinis on the cruciferous hosts Braya purpurascens, Cardamine bellidifolia, C. pratensis, Draba spp., and Eutrema edwardsii. A lectotype has been selected. 2. Mycosphaerella densa apparently restricted to Arenaria spp. 3. Mycosphaerella maculiformis var. herbaceae n. var. on leaves of Salix herbacea, earlier misidentified as "Mycosphaerella salicicola". 4. Mycosphaerella spetsbergensis n. sp. on leaves of Salix polaris. The possibility that the form of Mycosphaerella confinis parasitic upon C. bellidifolia is a distinct taxon is discussed together with the persistent confusion of Mycosphaerella confinis with Mycosphaerella densa.
Kuc, M. and E. Dubiel. (1995) The vascular plants of the Hornsund area (SW Spitsbergen) Fragmenta Floristica et Geobotanica 40: 797-824.The vascular plant flora of the Hornsund area at present is relatively well studied, mainly by Polish botanists being active there for nearly 40 years. On the relatively small area of Hornsund were hitherto reported 92 species, and 2 hybrids, that is nearly 55% of the flora of Svalbard. The most interesting taxa, both locally and on Svalbard, are: Cystopteris fragilis (L.) Bernh. subsp. dickieana (Sim.) Hyl, Huperzia selago (L.) Bemh. ex Schrank and Mart., Sagina Schlecht., R. spitsbergensis (Nath.) Hadac, R. nivalis L., Eutrema edwardsii R. Br., Saxifraga svalbardensis Ovstedal., Potentilla crantzii (Cr.) Beck., P. hyparctica Matte, Dryas octopetala L., arcuata (Wahlenb.) Sw., Carex nardina Fr., Arctagrostis latifolia (R. Br.) Griseb. and Festuca hyperborea Holmen. Taxa geobotanically limited to the S part of Spitsbergen are: Salix herbacea L., S. herbacea L. times S. polaris Wg., Cerastium alpinum L. subsp. lanatum (Lam.) Asch. and Grebn. and Ranunculus glacialis L.
Al-Shehbaz, I. A. and S. L. O'Kane, Jr. (1995) Placement of Arabidopsis parvula in Thellungiella (Brassicaceae) Novon 5: 309-310. 10.2307/3391953The genus Thellungiella is recognized, and the characters separating its two species from Arabidopsis are given. Arabidopsis parvula (Schrenk) 0. E. Schulz is recognized in Thellungiella.
Takagi, H. and Y. Tomitaka (1994). Vegetables peculiar to Japan. in Horticulture in Japan (K. Konishi eds.) Grant, J. R. (1994) Typification of six Robert Brown Brassicaceae names from Arctic North America Novon 4: 250-253. 10.2307/3391650Typifications are made for six taxa in the Brassicaceae described by Robert Brown from plants collected in arctic North America. The taxa were published in his 1823 preprint Chloris Melvilliana, which in 1824 appeared as the botanical appendix to William E. Parry's Supplement to the Appendix of Parry's First Voyage. Lectotypes are selected for Eutrema edwardsii R. Brown, Parrya arctica R. Brown, Parrya macrocarpa R. Brown, Platypetalum R. Brown, and Platypetalum purpurascens R. Brown, and a neotype is selected for Platypetalum dubium R. Brown.
Price, R. A. and J. D. Palmer. (1993) Tribal and generic relationships of the genus Arabidopsis (Brassicaceae) from comparisons of chloroplast DNA American Journal of Botany 80: 171-172.On the basis of the Flora Coreana and other Korean sources as well as on the results of the authors' own expeditions, a check list of 316 species and several infraspecific taxa cultivated in the Korea Democratic People's Republic is presented. For each species synonymy, distribution, use and vernacular name are given. Eutrema koreana and Fallopia ciliinervis are proposed as new combinations. The list is thought useful for work on plant genetic resources.
Weber, W. A. (1985) NEW NAMES AND COMBINATIONS PRINCIPALLY IN THE ROCKY MOUNTAIN USA FLORA V Phytologia 58: 382-384.D. stenopetala is a new species for the flora of the peninsula. It is considered similar to species of the sect. Aizopsis and closely related to D. paysonii Macbride. D. densifolia Nutt. was erroneously proposed as a synonym. E. edwardsii and S. sinensis have been found previously in this region.
Iwanami, Y. (1981) INHIBITING EFFECTS OF VOLATILE CONSTITUENTS OF PLANTS ON POLLEN GROWTH Experientia 37: 1280-1281. 10.1007/bf01948360Twenty-six species (or forms) of fossil pollen and spores from 24 genera were extracted from crude oil samples collected from the Yumen oil-bearing region in West Gansu. The fossil pollen and spores from the Tertiary petroleum in this region may be divided into 2 groups. One group of spores and pollen in a higher fossilized state mainly consisted of Schizaeoisporites zizyphinus, Gibotiumspora paradoxa, Monosulcites minimus and Bennettiteaepollenites sp. The other group included Pinus, Picea, Ephedra, Potamogeton, Lilium, Ulmus, Chenopodium, Nymphaea, Eutrema, Lens, Nitraria, Tamarix, Achillea, Artemisia, Solidago, Bidens, Graminidites and Cypheraceaepollis. The petroleum sporo-pollen assemblage of the Tertiary oil reservoir rock is a gathering of fossil pollen and spores brought from the Lower Cretaceous deposits and the Tertiary deposits, respectively. The appearance of the Early Cretaceous pollen and spores borne in the black shales of the Lower Xinminbu Formation in the Tertiary petroleum may be a result of petroleum migration. The fossil pollen and spores extracted from the Early Cretaceous petroleum in this region include Schizaeoisporites zizyphinus, Monosulcites minimus, Bennettiteaepollenites sp. and Psophosphaera. The Tertiary pollen and spores are completely absent there. Both the oil source rock and the oil reservoir rock apparently belong to the fossil-bearing Lower Xinminbu Formation. The pollen and spores found in the crude oil, the oil source rock of this oil-bearing region evidently is the black shales of the Lower Xinminbu Formation referred to as Early Cretaceous.
Ohsaki, N. (1979) COMPARATIVE POPULATION STUDIES OF 3 PIERIS BUTTERFLIES, PIERIS-RAPAE, PIERIS-MELETE AND P-NAPI, LIVING IN THE SAME AREA .1. ECOLOGICAL REQUIREMENTS FOR HABITAT RESOURCES IN THE ADULTS Researches on Population Ecology 20: 278-296. 10.1007/bf02512633New areas of distribution of T. kamtschaticum and E. edwardsii in the Kamchatka Oblast [Russian SFSR, USSR] were presented. A series of 29 taiga, tundra and arctic-alpine species, having distribution characteristics analogous to E. edwardsii in the Kamchatka Oblast, were presented.
Hara, H. (1977) COMMENTS ON THE EAST ASIATIC PLANTS PART 4 Journal of Japanese Botany 52: 257-262.Synonyms and distributional notes were given for: Persicaria praetermissa, Cerastium fontanum ssp. triviale var. angustifolium comb. et stat. nov. (C. vulgatum angustifolium Franch), Cinnamomum tenuifolium f. nervosum comb. et stat. nov. (C. pedunculatum nervosum Meisn.), Eutrema japonica var. sachalinensis, Artemisia scoparia and Habenaria flagellifera var. yosiei var. nov. A description was also given for the new variety.
Berkutenko, A. N. (1976) EUTREMA-EDWARDSII AND THLASPI-KAMTSCHATICUM CRUCIFERAE OF THE SOVIET FAR-EAST Botanicheskii Zhurnal (St. Petersburg) 61: 1754-1757.Distribution of the 2 spp. was corrected and clarified. E. edwardsii was found in southern Madagan oblast [Russian SFSR, USSR] and T. kamtschaticum in Magadan territory and Kamchatka oblast [Russian SFSR, USSR].
Hara, H. (1973) NEW OR NOTEWORTHY FLOWERING PLANTS FROM EASTERN HIMALAYA PART 12 Journal of Japanese Botany 48: 97-103.Chromosome numbers are given for 69 collections of 24 species of Cruciferae in the genera. Alyssum, Arabidopsis, Arabis, Barbarea, Cakile, Eutrema, Falimolobos, Nasturtium, Rorippa, Thellungiella, and Turritis. The following chromo-some numbers are reported for the first time Alyssum desertorum, n = 16; Arabis canadensis, 2n = 14; A. divaricarpa, 2n = 13 + 2B, 14, 20 + 2B, 21, 28; A. drummondii, 2n = 20; A. holboellii, 2n = 13 + 2B, 20 + 2B; A. lemmonii, 2n = 14; A. lyallii, 2n = 21; A. lyrata, 2n = 32; A. pendulo-carpa, 2n = 14; Barbarea orthoceras, 2n =16; Cakile edentula, 2n = 18; Rorippa curvisiliqua, 2n = 16; Thellungiella salsuginea, 2n = 14. It is concluded that species of Arabis native to North America and western Greenland have the base number x = 7 and many of them are apomictic wheras Eurasiatic species of this genus have an x = 8 base number and are sexual. || ABSTRACT AUTHORS: Author.
Weber, W. A. (1955) Additions to the flora of Colorado. II Univ Colorado Stud Ser Biol 3: 65-108.Descriptions and critical notes on 51 spp. of vascular plants new to Colorado since publication of Harrington, H.D., Manual of the plants of Colorado (1953). Notable boreal additions are: Adiantum pedatum, Deschampsia, caespitosa ssp. beringensis, Carex arctogena, C. incurviformis, Eriophorum scheuchzeri, Juncus biglumis, Koenigia islandica, Draba ventosa, Parnassia kotzebuei Saxifraga foliolosa S. rivularis Primula egaliksensis Erigeron humilis E. lanatus. Genera new to the Colorado flora are: Koenigia, Gypsophila, Braya, Eutrema, Sanguisorb, Colutea, Bergia, and Hespero-chiron. One new variety is described: Senecio hallii var. discoidea. || ABSTRACT AUTHORS: W. Weber.
Rollins, R. C. (1950) Studies on some North American Cruciferae Contr Gray Herb 171: 42-53.Descr. of Lesquerella carinata, Idaho; L. gaysonii Wyo.; L_. mcyaughiana, Texas; Physaria cordiformis, Nevada; Smelowskia holmgrenii, Nevada; and Eutrema penlandii, Colorado, with discussion of generic relationships and related spp.
Cheo, T.-Y. (1948) The Cruciferae of eastern China Bot Bull Acad Sinica 2: 178-194.The Cruciferae of E. China are represented by 16 genera, 27 spp. and one var. It is certain that more spp. will be found to occur in this region by more intensive future explorations. Tentative keys to the genera and spp. are given in this preliminary report. The genera studied are: Raphanus, Brassica, Orychophragmus, Isatis, Coronopus,Lepidium, Thlaspi, Capsella, Draba, Cardamine, Roripa, Cheir-anthus, Eutrema, Dontostemon, Arabidopsis and Descurainia, Roripa sublyrata n. comb. (Cardamine s. Miq.) is proposed. || ABSTRACT AUTHORS: C. F. Reed.
Cheo, T.-Y. (1948) A new species of Eutrema Bot Bull Acad Sinica 2: 23-24.E. reflexa n. sp. from Chekiang, China, based on a collection by H. Migo in 1936 that was first identified as E. yunnanense. || ABSTRACT AUTHORS: E. H. Walker.
Cheo and T. Y. Choc. (1948) The Cruciferae of Eastern China Botanical Bulletin of Academia Sinica, Taipei 2: 178-194.Botanical descriptions are given of species of the following genera: Raphanus, Brassica, Orychophragmus, Isatis, Coronopus, Lepidium, Thlaspi, Capsella, Draba, Cardamine, Roripa, Cherianthus, Eutrema, Contostemon, Arabidopsis and Desciirainia. Vernacular names are included.
Koidzumi, G. (1930). Florae Symbolae Orientali-Asiaticae. in Florae Symbolae Orientali-Asiaticae eds.)