Project description:miRNA profile of wild type Arabidopsis plants was compared to miRNA profiles in three different lines with altered levels of ascorbate (vtc2-1), glutathione (pad2-1) or salicylate (nahG).
Project description:To comprehensively investigate the effects of glutathione on the gene expression, the microarray analysis was performed in the glutathione-fed wild-type Arabidopsis thaliana. Wild-type Arabidopsis (ecotype Columbia-0) were fed with 1 mM oxidized glutathione (GSSG) and 2 mM reduced glutathione (GSH) for comparison at equal nitrogen equivalents. To examine the effects of glutathione other than nitrogen at equal nitrogen equivalents, plants were fed with 3 mM NH4NO3. Plants grown by water were used as a control.
Project description:Brassinosteroids (BRs) are a class of class of phytohormones with important roles in regulating physiological and developmental processes. Small RNAs, including small interfering RNAs and microRNAs (miRNAs), are non-protein coding RNAs that regulate gene expression at the transcriptional and post-transcriptional levels. However, the roles of small RNAs in BR response have not been studied well. In this study, we aimed to identify BR-responsive small RNA clusters and miRNAs in Arabidopsis. In addition, the effect of BR-responsive small RNAs on their transcripts and target genes were examined. Small RNA libraries were constructed from control and epibrassinolide-treated seedlings. After sequencing the small RNA libraries, differentially expressed small RNA clusters were identified by examining the expression levels of small RNAs in 100-nt bins of Arabidopsis genome. To identify the BR-responsive miRNAs, the expression levels of all the annotated mature miRNAs, registered in miRBase, were analyzed. Previously published RNA-seq data were utilized to monitor the BR-responsive expression patterns of differentially expressed small RNA clusters and miRNA target genes. In results, 38 BR-responsive small RNA clusters, including 30 down-regulated and eight up-regulated clusters, were identified. These differentially expressed small RNA clusters were from miRNA loci, transposons, protein-coding genes, pseudo genes and others. Of these, a transgene, BRI1, accumulates small RNAs, which are not found in the wild type. Small RNAs in this transgene are up-regulated by BRs while BRI1 mRNA is down-regulated by BRs. By analyzing the expression patterns of mature miRNAs, we have identified BR-repressed miR398a-5p and BR-induced miR156g. Although miR398a-5p is down-regulated by BRs, its predicted targets were not responsive to BRs. However, SPL3, a target of BR-inducible miR156g, is down-regulated by BRs. BR-responsive small RNAs and miRNAs identified in this study will provide an insight into the role of small RNAs in BR responses in plants. Especially, we suggest that miR156g/SPL3 module might play a role in BR-mediated growth and development in Arabidopsis.
Project description:In the dry state, orthodox seeds have little antioxidant capacity, relying on reduced glutathione and tocochromanols for antioxidant defences rather than ascorbate or ascorbate peroxidase (APX). Ascorbate is synthesised de novo within a few hours of imbibition resulting in rapid increases in the ascorbate pool in the developing embryo. The knock-on effects of enhanced oxidation on embryo development before and after imbibition remain poorly characterised. A T-DNA insertional mutant line (SAIL_769_H05) line was used in these studies together with vtc2-1 mutants that were originally identified in an ethyl-methanesulfonate (EMS) mutagenesis screen. Expression levels of dry seeds and imbibed seeds of the genotypes Col0, vtc2 (EMS) and vtc2.5 (SAIL_769_H05) were quantified using Illumina RNA-seq technology
Project description:CuZn-superoxide dismutase (CuZn-SOD) and ascorbate peroxidase (APX) constitute first line of defence against oxidative stress. In the present study, PaSOD and RaAPX genes from Potentilla atrosanguinea and Rheum australe, respectively were overexpressed individually as well as in combination in Arabidopsis thaliana. We performed RNA-seq analysis of wild type and transgenic Arabidopsis thaliana overexpressing CuZn-SOD, APX and CuZn-SOD + APX under control and salt stress
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:MicroRNAs (miRNAs) are 21-24 nucleotide (nt) small non-coding RNAs that regulate a wide variety of biological processes at the posttranscriptional level. MiRNA expression often exhibits spatial and temporal specificity. However, genome-wide miRNA expression patterns in different Arabidopsis organs during plant development have not yet been fully investigated. In this study, we sequenced 59 small RNA libraries generated from different tissue types at different developmental stages of Arabidopsis. We then re-annotated Arabidopsis miRNAs based on the most recent criteria. Global analysis of miRNA expression patterns showed that most miRNAs are ubiquitously expressed in different organs or tissues. But a small set of miRNAs, either previously annotated or newly identified, show highly specific expression patterns. In addition, the expression of some miRNA members belonging to the same family is strictly regulated spatially and temporally. Unexpectedly, we found that quite a few miRNAs are produced from different arms of their hairpin precursors at different developmental stages, suggesting that arm switching could be a general and important mechanism in developmental regulation.
Project description:The l-galactose (Smirnoff-Wheeler) pathway represents the major route to l-ascorbic acid (vitamin C) biosynthesis in plants. Arabidopsis thaliana VTC2 and its paralogue VTC5 function as GDP-l-galactose phosphorylases converting GDP-l-galactose to l-galactose-1-P, thus catalyzing the first committed step in the biosynthesis of l-ascorbate. Here we report that the l-galactose pathway of ascorbate biosynthesis described in higher plants is conserved in green algae. The Chlamydomonas reinhardtii genome encodes all the enzymes required for vitamin C biosynthesis via the Smirnoff-Wheeler pathway. We have characterized recombinant C. reinhardtii VTC2 as an active GDP-l-galactose phosphorylase. C. reinhardtii cells exposed to oxidative stress show increased VTC2 mRNA and l-ascorbate levels. We have also shown that enzymatic components of the ascorbate-glutathione system (e.g. ascorbate peroxidase, Mn superoxide dismutase, dehydroascorbate reductase) are up-regulated in response to increased oxidative stress. These results indicate that C. reinhardtii VTC2, like its plant homologs, is a key enzyme in ascorbate biosynthesis in green algae and together with components of the ascorbate recycling system represents the major route in providing protective levels of ascorbate in oxidatively stressed algal cells. Our results suggest that C. reinhardtii cells exposed to oxidative stress conditions produce more ascorbate both by de novo synthesis (Smirnoff-Wheeler pathway) and by recycling via the ascorbate-glutathione cycle. Sampling of Chlamydomonas 2137 exposed to hydrogen peroxide