Ontology highlight
ABSTRACT:
PROVIDER: PRJNA515221 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR8443470.fastq.gz | Fastqsanger.gz | |||
| SRR8443471.fastq.gz | Fastqsanger.gz | |||
| SRR8443472.fastq.gz | Fastqsanger.gz | |||
| SRR8443473.fastq.gz | Fastqsanger.gz | |||
| SRR8443474.fastq.gz | Fastqsanger.gz |
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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).
2020-06-30 | GSE85778 | GEO
Project description:We explore where transcriptional regulation of ascorbate concentration lies in plants. Is it in biosynthesis, recycling, regulation or consumption? Arabidopsis thaliana plants were grown under controlled environment at four photon flux density levels (PFD). Rosettes from plants were harvested at the four PFD levels and over a diurnal cycle and after a step change in PFD and analysed for ascorbate concentration and transcript levels measured by RNAseq. Ascorbate concentrations and expression of genes in the L-galactose ascorbate biosynthesis, recycling, consumption pathways and regulation are presented to provide a full analysis of the control of ascorbate by environmentally modulated gene expression. Ascorbate concentration responded to PFD levels but not to time of day and showed only a small response to change of PFD after 2 days. Of the L-galactose pathway genes, only GDP galactose phosphorylase (GGP) showed a significant response in to different PFDs, time of day and to change in PFD. Other genes also showed limited responses. This study compares gene expression of a range of ascorbate related genes to changes in environment in a unified way and supports the concept that GGP is the key regulatory gene in ascorbate biosynthesis and that post transcriptional regulation is also important.
2017-02-17 | GSE94995 | GEO
Project description:Ascorbate (vitamin C) is an important antioxidant in leaves with multiple functions in photosynthesis and its levels are tightly regulated by light quality. The majority of work to date has focussed on regulation of ascorbate levels via biosynthesis. However, the pathway of ascorbate degradation, which is localised in the apoplast may additionally play a significant role. The degradative pathway begins with ascorbate oxidation by the enzyme ascorbate oxidase (AO) and hence we have examined the impact of manipulation of ascorbate oxidase activity on the content of ascorbate and the acclimation of photosynthesis to changing light levels. Leaf ascorbate content was highly light dependent in Nicotiana tobaccum being double in high compared with low light conditions. In contrast ascorbate oxidase activity was not altered by changing light levels. Transgenic tobacco lines with reduced or enhanced AO activity exhibited no morphological phenotype and photosynthesis under high light was similarly impaired irrespective of the measured AO activity. However further investigation between AO activity and leaf acclimation to changing light intensity revealed a suite of metabolic and transcriptome changes indicating a role for the apoplastic ascorbate pool in chloroplast to nucleus communication. In all genotypes, transcripts associated with ascorbate synthesis and recycling were less abundant following transition from high to low light. However transcripts associated with glutathione recycling, light harvesting, reaction centre function and the Calvin cycle were all increased in abundance. Following the transition from high to low light increases in leaf threonate, an ascorbate degradation product, were proportional to AO activity. A number of chloroplast synthesised amino acids were significantly increased both during high light and following transfer back to LL for 12 h. Similarly, several primary carbohydrates and TCA intermediates were significantly enhanced following high light treatment. In addition to light effects, AO activity had a significant impact on ï¢-alanine, aspartate and threonine. Intriguingly, a large number of fatty acids were reduced in antisense AO and wild-type plants immediately after high light stress however the content of these compounds were significantly increased in overexpressing sense lines. We conclude that AO mediated turnover plays an important role in adjusting cellular ascorbate content to photosynthetic need in a fluctuating light environment and that light mediated signals rapidly adjust that the apoplastic ascorbate pool.
2017-03-01 | E-MTAB-4816 | biostudies-arrayexpress
Project description:VITAMIN C DEFECTIVE 3 (VTC3) is a distinctive protein with both kinase and phosphatase domains and is essential for ascorbate accumulation in Arabidopsis. In the vtc3 mutant, ascorbate levels are approximately 50% of those in the wild type, and light-induced increases in the ascorbate pool size are markedly suppressed. The regulation of the ascorbate pool size by light involves GDP-L-galactose phosphorylase (VTC2), a key biosynthetic enzyme. To elucidate the physiological function of VTC3, we compared the transcriptomes of vtc3, wild-type, and vtc2 plants. Contrary to expectations, the loss of VTC3 had minimal impact on the transcriptome. Among the few genes upregulated in the vtc3 mutant, several were related to pathogen responses.
2025-12-10 | GSE293768 | GEO
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.
2012-05-03 | GSE34826 | GEO
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
2014-10-06 | E-MTAB-4434 | biostudies-arrayexpress
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
2012-05-02 | E-GEOD-34826 | biostudies-arrayexpress
Project description:We focused on Arabidopsis chloroplast ascorbate peroxidases (sAPX and tAPX) and proton gradient regulation 5 (PGR5) and used pgr5 single mutant, sapx tapx double mutant, and sapx tapx pgr5 triple mutant for RNA-seq analysis.
2020-08-26 | GSE156883 | GEO
Project description:Ascorbate is the most abundant water-soluble antioxidant in plants, and it is an essential molecule for normal plant development. It is present in all green plants, with very different concentrations in different plant species. While ascorbate accumulation is a trait of nutritional, and therefore, agronomical interest, the impact of different concentrations over cellular homeostasis remains elusive. In order to shed light over this question, we leveraged Arabidopsis lines with very low ascorbate (vtc2 mutant with 20% of WT ascorbate levels), and low ascorbate concentration (vtc4 mutant with 65% of WT levels), and we generated a line that accumulates 165% of WT levels (vtc2/OE-VTC2). An 80% reduction of ascorbate increased the expression of genes implicated in defense against pathogens, but repressed genes associated with abiotic stress responses. Unexpectedly, lines with increased (165% of WT) and decreased (65% of WT) ascorbate levels shared 85% of induced transcription factors and the GO terms associated with their transcriptional programs. Among the group of genes whose expression is positively correlated with ascorbate content, we identified TAA1/WEI8, a gene encoding a tryptophan aminotransferase that catalyzes the first step of auxin biosynthesis. Using a combination of genetic and pharmacological approaches in fluorescent and histochemical reporter lines for auxin biosynthesis and signaling activity, we revealed that TAA1- and TAA1-RELATED2 (TAR2)-mediated auxin biosynthesis is necessary for plants to cope with increased ascorbate concentration in a light-dependent manner, revealing a new layer of complexity in the regulatory landscape of redox homeostasis.
2025-05-17 | GSE296827 | GEO