Project description:Plant basic helix-loop-helix (bHLH) transcription factors are involved in physiological and developmental processes, and also play essential roles in abiotic stresses. However, their exact roles in abiotic stress are still need to be elucidated, and most of bHLHs have not been functionally characterized. In the present study, we characterized the functional role of AtbHLH112 in response to abiotic stresses. AtbHLH112 is a nuclear-localized protein, and its nuclear-localization is induced by salt, drought and ABA. Besides binding to E-box motif, AtbHLH112 is found to bind to a novel motif with the sequence “GG[GT]CC[GT][GA][TA]C” (GCG-box), and the binding affinity is induced by salt and ABA. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by upregulating the expression of P5CS genes and decreasing the expression of P5CDH and PRODH genes to increase proline levels, and via enhancing the expression of POD and SOD genes to improve ROS scavenging ability. All data together suggested that AtbHLH112 regulates the expression of genes through binding to GCG-box and E-box to mediate the physiological stress responses, including proline biosynthesis and ROS scavenging pathways to enhance stress tolerance.
Project description:Arabidopsis ecotypes of Sha and Ler showed differences in tolerance to salinity stress. A previous study indicated that a premature stop codon resulting in a truncated Response to ABA and Salt 1 (RAS1) protein in Sha contributes to the increased salt tolerance relative to Ler ecotype. Sha exhibited higher germination rates and longer roots on MS plate, presumably due to the decreased ABA sensitivity in Sha. More Sha plants also survived in soil after salt treatment with relatively lower electrolyte leakage when compared to Ler. Transcriptome analysis revealed that expression levels of many genes were changed between Sha and Ler ecotypes and by salt treatments. About 500 transcripts were commonly changed by at least one salinity effect and one ecotype effect, and 171 of them were co-regulated by all four comparisons. Transcripts involved in redox, secondary metabolism, auxin metabolism, photosynthesis, cell wall, and protein synthesis were mainly down-regulated by salinity effects, while transposable element genes, microRNA and antisense sequences, histone superfamily genes, and biotic stress related genes were significantly changed by Sha ecotype effects and only slightly by salinity. Several metabolic pathways such as stress, TCA, hormone/lipid/secondary metabolism, redox, development, and GO terms involved in stress, oxidation, and defense response were enriched by both salinity and ecotype effects. Ninety-five highly inducible genes were identified as candidates of RAS1 target genes and the functions involved hormone metabolism, biotic stress, RNA, DNA synthesis, protein metabolism, cell, and microRNA metabolism. All these results indicated that the Sha ecotype was possibly preconditioned to abiotic stress relative to Ler through regulation of signaling pathways and stress responsive gene expression. These comparative transcriptomic and analytical results also confirm the complexity of ABA responses and salt stress tolerance mechanisms, and they suggest additional targets for improving tolerance.
Project description:We performed that comprehensive identification of genes responsible for stress tolerance by analyzing the whole-genome expression profiles of poplar (Populus alba × P. glandulosa) leaves exposed to drought and salt stresses. Examination at the molecular level how this tree species responds to drought and salt stresses by regulating the expression of genes involved in signal transduction, transcriptional regulation, and stress responses.
Project description:this study discovered unique glycoprotein resources responsible for plant salt stress tolerance and suggested crucial roles of Nthis study discovered unique glycoprotein resources responsible for plant salt stress tolerance and suggested crucial roles of N-glycans in regulating salt responsive protein expression in Arabidopsis.-glycans in regulating salt responsive protein expression in Arabidopsis.
Project description:ZmDREB2A is a DREB2-type transcription factor cloned from maize, whose transcript was upregulated by drought, high salt, low temperature and heat stresses. The ZmDREB2A gene possesses two kinds of transcription forms by alternative splicing. Only the functional form was studied to be highly induced by stresses. Transgenic plants overexpressing ZmDREB2A (35S:ZmDREB2A) showed dwarfism and enhanced drought stress tolerance. Microarray analysis of two independent transgenic plants revealed that in addition to genes encoding LEA proteins, some genes related to heat shock and detoxification were also upregulated. Experiments on termotolerance tests of these transgenic plants showed overexpressing ZmDREB2A gene also improved plant tolerance to heat stress.
Project description:Plant basic helix-loop-helix (bHLH) transcription factors are involved in physiological and developmental processes, and also play essential roles in abiotic stresses. However, their exact roles in abiotic stress are still need to be elucidated, and most of bHLHs have not been functionally characterized. In the present study, we characterized the functional role of AtbHLH112 in response to abiotic stresses. AtbHLH112 is a nuclear-localized protein, and its nuclear-localization is induced by salt, drought and ABA. Besides binding to E-box motif, AtbHLH112 is found to bind to a novel motif with the sequence M-bM-^@M-^\GG[GT]CC[GT][GA][TA]CM-bM-^@M-^] (GCG-box), and the binding affinity is induced by salt and ABA. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by upregulating the expression of P5CS genes and decreasing the expression of P5CDH and PRODH genes to increase proline levels, and via enhancing the expression of POD and SOD genes to improve ROS scavenging ability. All data together suggested that AtbHLH112 regulates the expression of genes through binding to GCG-box and E-box to mediate the physiological stress responses, including proline biosynthesis and ROS scavenging pathways to enhance stress tolerance. Differentially expression genes of AtbHLH112-overexpression plants, mutant (SALK_033618C) plants and wild type of Columbia Arabidopsis thaliana were measured under salt stressed and normal condition for 3 hours, respectively. Three independent experiments were performed at each treatment using different plants for each experiment.
Project description:The OsCPK4 gene is a member of the complex gene family of the Calcium-dependent protein kinases (CPKs) in rice. Expression of OsCPK4 is induced by high salinity, drought and the phytohormone abscisic acid. The OsCPK4 protein localizes to the plasma membrane. Transgenic rice overexpressing OsCPK4 enhances tolerance to salt and drought stress, the transgenic plants having stronger water-holding capability than control plants. Microarray analysis of OsCPK4 rice plants revealed up-regulation of genes involved in metabolism, particularly lipid metabolism, as well as genes involved in oxidative stress and redox control. Meanwhile, OsCPK4 overexpression has no impact on the expression of the well-characterized abiotic stress-associated transcription factors (i.e. DREB and NAC), or the typical salt and drought-inducible genes (i.e. LEA genes, including Dehydrin genes). Under salt stress conditions, the OsCPK4 transgenic lines showed lesser membrane lipid peroxidation as compared to control plants, indicating that OsCPK4 rice plants have a better capacity to prevent oxidative damage in cellular membrane lipids. Collectively, our data suggest that OsCPK4-mediated processes protect the plant cell from uncontrolled redox reactions affecting membrane functions, which, in turn, results in salt and drought tolerance. OsCPK4 shows great promise for genetic improvement of tolerance to abiotic stress in rice.
Project description:Arabidopsis 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.
Project description:Arabidopsis ecotypes of Sha and Ler showed differences in tolerance to salinity stress. A previous study indicated that a premature stop codon resulting in a truncated Response to ABA and Salt 1 (RAS1) protein in Sha contributes to the increased salt tolerance relative to Ler ecotype. Sha exhibited higher germination rates and longer roots on MS plate, presumably due to the decreased ABA sensitivity in Sha. More Sha plants also survived in soil after salt treatment with relatively lower electrolyte leakage when compared to Ler. Transcriptome analysis revealed that expression levels of many genes were changed between Sha and Ler ecotypes and by salt treatments. About 500 transcripts were commonly changed by at least one salinity effect and one ecotype effect, and 171 of them were co-regulated by all four comparisons. Transcripts involved in redox, secondary metabolism, auxin metabolism, photosynthesis, cell wall, and protein synthesis were mainly down-regulated by salinity effects, while transposable element genes, microRNA and antisense sequences, histone superfamily genes, and biotic stress related genes were significantly changed by Sha ecotype effects and only slightly by salinity. Several metabolic pathways such as stress, TCA, hormone/lipid/secondary metabolism, redox, development, and GO terms involved in stress, oxidation, and defense response were enriched by both salinity and ecotype effects. Ninety-five highly inducible genes were identified as candidates of RAS1 target genes and the functions involved hormone metabolism, biotic stress, RNA, DNA synthesis, protein metabolism, cell, and microRNA metabolism. All these results indicated that the Sha ecotype was possibly preconditioned to abiotic stress relative to Ler through regulation of signaling pathways and stress responsive gene expression. These comparative transcriptomic and analytical results also confirm the complexity of ABA responses and salt stress tolerance mechanisms, and they suggest additional targets for improving tolerance. Ten days old seedlings of two Arabidopsis ecotypes, Sha and Ler, were treated with 100 mM NaCl on MS plate. Plant materials were collected for RNA extraction at 4th days after treatments.