Project description:Post-translational modifications of proteins by Small Ubiquitin-like Modifiers (SUMOs) regulate protein degradation and localization, protein-protein interaction, and transcriptional activity. SUMO E3 ligase functions are executed by SIZ1/SIZ2 in yeast and PIAS family members in human. The Arabidopsis genome contains only one gene, SIZ1, that is orthologous to yeast SIZ1/SIZ2. Here, we show that the Arabidopsis SIZ1 interacts with SUM1 and SCE1a, the SUMO E2 conjugating enzyme. Compared to WT, the null mutant siz-1-3 is smaller in statue because of reduced expression of gene involved in brassinosteroid biosynthesis and signalling. Drought stress induces the accumulation of SUMO-protein conjugates, which is in part dependent on SIZ1 but not on ABA. Mutant plants of siz1-3 have significant lower tolerance to drought stress. Genome wide expression analysis identified about 2,000 Arabidopsis genes that are responsive to drought, and SIZ1 mediates the induction of 600 of these genes by a pathway independent of DREB2A and ABA. SIZ1-dependent, drought-responsive genes include those encoding enzymes of the anthocyanin synthesis pathway and jasmonate response. From these results, we conclude that SIZ1 regulates Arabidopsis development and plays a role in drought stress response probably through the control of gene expression. Keywords: stress response
Project description:Post-translational modifications of proteins by Small Ubiquitin-like Modifiers (SUMOs) regulate protein degradation and localization, protein-protein interaction, and transcriptional activity. SUMO E3 ligase functions are executed by SIZ1/SIZ2 in yeast and PIAS family members in human. The Arabidopsis genome contains only one gene, SIZ1, that is orthologous to yeast SIZ1/SIZ2. Here, we show that the Arabidopsis SIZ1 interacts with SUM1 and SCE1a, the SUMO E2 conjugating enzyme. Compared to WT, the null mutant siz-1-3 is smaller in statue because of reduced expression of gene involved in brassinosteroid biosynthesis and signalling. Drought stress induces the accumulation of SUMO-protein conjugates, which is in part dependent on SIZ1 but not on ABA. Mutant plants of siz1-3 have significant lower tolerance to drought stress. Genome wide expression analysis identified about 2,000 Arabidopsis genes that are responsive to drought, and SIZ1 mediates the induction of 600 of these genes by a pathway independent of DREB2A and ABA. SIZ1-dependent, drought-responsive genes include those encoding enzymes of the anthocyanin synthesis pathway and jasmonate response. From these results, we conclude that SIZ1 regulates Arabidopsis development and plays a role in drought stress response probably through the control of gene expression. Experiment Overall Design: 12 samples that includes 3 replicates of Col 0 under control conditions, 3 replicates of Col 0 expossed to 2 hr of dehydration, 3 replicates of siz1-3 under control conditions and 3 replicates of siz1-3 expossed to 2 hr of dehydration.
Project description:Plants engineered for abiotic stress tolerance may soon be commercialized. The engineering of these plants typically involves the manipulation of complex multigene networks and may therefore have a greater potential to introduce pleiotropic effects than the simple monogenic traits that currently dominate the plant biotechnology market. Drought- tolerant Arabidopsis thaliana were engineered through overexpression of the transcription factor ABF3 in order to investigate unintended pleiotropic effects. In order to eliminate position effects, the Cre/lox recombination system was used to create control plant lines that contain identical T-DNA insertion sites but with the ABF3 transgene excised. This additionally allowed us to determine if Cre recombinase can cause unintended effects that impact the transcriptome. Microarray analysis of control plant lines that underwent Cre-mediated excision of the ABF3 transgene revealed only two genes that were differentially expressed in more than one plant line, suggesting that the impact of Cre recombinase on the transcriptome was minimal. In the absence of drought stress, overexpression of ABF3 had no effect on the transcriptome, but following drought stress, differences were observed in the gene expression patterns of plants overexpressing ABF3 relative to control plants. Examination of the functional distribution of the differentially expressed genes revealed strong similarity indicating that unintended pathways were not activated. In response to drought stress, overexpression of ABF3 results in a reprogramming of the drought response, which is characterized by changes in the timing or strength of expression of some drought response genes, without activating any unexpected gene networks. These results illustrate that important gene networks are highly regulated in Arabidopsis and that engineering stress tolerance may not necessarily cause extensive changes to the transcriptome.
Project description:Plants acclimate to environmental fluctuations by transitory reconfigurations the homeostatic network. Primary studies suggested that transcriptome responses to deal with fluctuations in light intensity and temperature tend to reversibility after stress removal in the model plant Arabidopsis thaliana. To gain more insight into this pattern in the context of acclimation, RNA-Seq analysis were conducted in Arabidopsis thaliana after different abiotic stress treatments consisting in high light (HL), high humidity, drought, heat, cold and combinations among factors or after recovery periods. Our transcriptome study is in line of a general pattern wherby transcriptome changes in response to adverse environments are prone to return to the basal state during the de-acclimation phase.
Project description:Transcriptional profiling of Arabidopsis thaliana cotyledons comparing ecotype Col-0 (Control) with lea13 T-DNA line to elucidate the response mechanism to drought stress conditions that rely on LEA protein function.
Project description:cea10-03_cyclocitral - analysis of arabidopsis transcriptome in response to b-cyclocitral treatment - Is beta--cyclocitral a bioactive molecule involved in stress response? - Analysis of Arabidopsis transcriptome in response to b-cyclocitral treatment.
Project description:Proteomic Analysis of the total proteome from Arabidopsis thaliana SUMO E3 Ligase mutants siz1-2 and mms21-1 and wild-type (Col-0) 8-day old seedlings
Project description:With frequent fluctuations in global climate, plants often experience co-occurring dry-wet cycles and pathogen infection and this combination adversely affects plant survival. In the past, some studies indicated that morpho-physiological responses of plants to the combined stress are different from the individual stressed plants. However, interaction of drought stressed or drought recovered plants with pathogen has not been widely studied at molecular level. Such studies are important to understand the defense pathways that operate as part of combined stress tolerance mechanism. In this study, Arabidopsis plants were exposed to individual drought stress (soil drying at 40% FC, D), Pseudomonas syringae pv tomato DC3000 (PStDC3000), infection and their combination. Plants recovered from drought stress were also exposed to PStDC3000. Beside we have also infiltrated P. syringae pv tabaci (PSta, non-host pathogen) individually or in combination with drought stress. Using Affymetrix WT gene 1.0 ST array, global transcriptome profiling of plants leaves under individual drought stress and pathogen infection was compared with their combination. Results implicate that plants exposed to combined drought and pathogen stress experience a new state of stress where each combination of stressor and their timing defines the plant responses and thus should be studied explicitly. Global transcriptional analysis in Arabidopsis leaves exposed to individual and combined drought and pathogen stress.