Project description:To identify chloroplastic H2O2-responseive genes, an estrogen-inducible RNAi method was used for silencing of tAPX, a H2O2-scavenging enzyme in chloroplasts. At 48 h after treatment with estrogen, the expression of tAPX was silenced in the IS-tAPX-19-23 plants, but not in the IS-GUS-2-17 plants (negative control), resulting a large change in gene expression. These genes are candidates for chloroplastic H2O2-responseive genes. IS-GUS-2-17 vs. IS-tAPX-19-23 leaves. Biological replicates 2.
Project description:To identify chloroplastic H2O2-responseive genes, an estrogen-inducible RNAi method was used for silencing of tAPX, a H2O2-scavenging enzyme in chloroplasts. At 48 h after treatment with estrogen, the expression of tAPX was silenced in the IS-tAPX-19-23 plants, but not in the IS-GUS-2-17 plants (negative control), resulting a large change in gene expression. These genes are candidates for chloroplastic H2O2-responseive genes.
Project description:The Oscillation Zone (OZ) of unsynchronized roots was dissected and divided into an upper (OZ2) and lower (OZ1) half . Samples were ordered according to DR5:GUS expression as analyzed by real time PCR to find periodic expression patterns Seedlings were grown for 5 days. 39 individual roots were dissected for RNA extraction. These microarray samples profile a specific region of the root tip designated as the Oscillation zone. Arrangement of the samples in the following order: OZ1-1, OZ1-4, OZ1-23, OZ1-14, OZ1-17, OZ1-2, OZ1-6, OZ1-13, OZ1-15, OZ1-16, OZ1-10, OZ1-32, OZ1-3, OZ1-31, OZ1-22, OZ1-35, OZ1-19, OZ1-9, OZ1-33, OZ1-20, OZ2-4, OZ2-23, OZ2-14, OZ2-6, OZ2-13, OZ2-15, OZ2-10, OZ2-32, OZ2-22, OZ2-35, OZ2-19, OZ2-9, OZ2-20, OZ2-36, OZ2-39, OZ2-21, OZ2-40, OZ2-38, OZ2-1, was used to identify periodic expression patterns.
Project description:Oxidative stress due to endogenous hydrogen peroxide production by Lactobacillus species is a well-known issue in the food industry. In this study, the transcriptional response to oxygen of Lactobacillus johnsonii, one of the H2O2-producing strains used in the food industry, was analyzed. It was found that aerobic growth conditions led to a more than two-fold downregulation of 45 genes as compared to anaerobic growth, whereas 6 genes were more than twofold upregulated. Among the upregulated genes were two genes that displayed significant homology to NADH-dependent oxidoreductase (NOX). The postulated transcriptional regulation of the nox promoter by oxygen was studied using a GUS-reporter construct, confirming a 2.1-fold upregulated GUS-expression upon aerobic growth. Exposure to sublethal levels of hydrogen peroxide did not result in significant regulation of the nox promoter. In a previous study of hydrogen peroxide production by L. johnsonii, a NADH flavin reductase (NFR) was identified to be involved in hydrogen peroxide production. An NFR-deficient derivative was strongly impaired in H2O2 production, but regained a partial H2O2 producing capacity upon prolonged oxygen exposure. The nox-promoter appeared to be 3.6-fold upregulated under aerobic conditions in the NFR-deficient background, which may imply a role of this gene in the regained H2O2 production. Indeed, deletion of the nox-gene in the NFR-deletion background, resulted in a strain that no longer produced H2O2, also during prolonged exposure to oxygen. The double-mutant (nfr, nox) displayed strongly impaired aerobic growth and oxygenation induced rapid growth stagnation that is not caused by H2O2. We conclude that H2O2 production in L. johnsonii is primarily dependent on NFR but can also involve an oxygen-inducible NADH oxidase under aerobic conditions. Moreover, our results imply that H2O2 production plays a prominent role in oxygen tolerance of L. johnsonii.
Project description:Oxidative stress due to endogenous hydrogen peroxide production by Lactobacillus species is a well-known issue in the food industry. In this study, the transcriptional response to oxygen of Lactobacillus johnsonii, one of the H2O2-producing strains used in the food industry, was analyzed. It was found that aerobic growth conditions led to a more than two-fold downregulation of 45 genes as compared to anaerobic growth, whereas 6 genes were more than twofold upregulated. Among the upregulated genes were two genes that displayed significant homology to NADH-dependent oxidoreductase (NOX). The postulated transcriptional regulation of the nox promoter by oxygen was studied using a GUS-reporter construct, confirming a 2.1-fold upregulated GUS-expression upon aerobic growth. Exposure to sublethal levels of hydrogen peroxide did not result in significant regulation of the nox promoter. In a previous study of hydrogen peroxide production by L. johnsonii, a NADH flavin reductase (NFR) was identified to be involved in hydrogen peroxide production. An NFR-deficient derivative was strongly impaired in H2O2 production, but regained a partial H2O2 producing capacity upon prolonged oxygen exposure. The nox-promoter appeared to be 3.6-fold upregulated under aerobic conditions in the NFR-deficient background, which may imply a role of this gene in the regained H2O2 production. Indeed, deletion of the nox-gene in the NFR-deletion background, resulted in a strain that no longer produced H2O2, also during prolonged exposure to oxygen. The double-mutant (nfr, nox) displayed strongly impaired aerobic growth and oxygenation induced rapid growth stagnation that is not caused by H2O2. We conclude that H2O2 production in L. johnsonii is primarily dependent on NFR but can also involve an oxygen-inducible NADH oxidase under aerobic conditions. Moreover, our results imply that H2O2 production plays a prominent role in oxygen tolerance of L. johnsonii. loop design of the samples including two shortcuts
Project description:We produced RNA-Seq reads from messenger RNA isolated from seedling, root, and floral bud tissue for 17 MAGIC founder accessions (inbred strains) of Arabidopsis thaliana (see Gan et al. 2011. Nature, 477:419-23 for a description of the MAGIC genetic mapping resource). The resulting RNA-Seq data provide a resource to assess tissue-specific expression across different accessions of A. thaliana. Note that comparable read data for accessions Col-0 and Can-0, which are also founders of the MAGIC lines, has previously been released under GEO series GSE30795 (Gan et al. 2011. Nature, 477:419-23).
Project description:The purpose of this head-to-head study was to gain molecular insights into the MOA for IXE and GUS in PsO and to compare and contrast the gene expression profiles at early time-points for IXE targeting IL-17A and GUS targeting IL-23.
Project description:We produced RNA-Seq reads from messenger RNA isolated from root tissue for the 19 MAGIC founder accessions (inbred strains) of Arabidopsis thaliana (see Gan et al. 2011. Nature 477:419-23 for a description of the MAGIC genetic mapping resource). The read data was generated with biological replication (two replicates). The resulting RNA-Seq data provide a resource to assess root gene expression across different accessions of A. thaliana. Comparable RNA-Seq read data for the MAGIC founder accessions for aerial seedling tissue has previously been released under GEO series GSE30720 (Gan et al. 2011. Nature, 477:419-23).
Project description:Ascorbate is a major plant metabolite that plays crucial roles in various processes, from reactive oxygen scavenging to epigenetic regulation. However, to what extent and how ascorbate modulates metabolism is largely unknown. To address this, we investigated the consequences of chloroplastic and total cellular ascorbate-deficiencies by studying chloroplastic ascorbate transporter pht4;4 mutant lines, and the ascorbate-deficient vtc2-4 mutant of Arabidopsis thaliana. Under regular growth conditions, both ascorbate-deficiencies caused minor alterations in photosynthesis, with no apparent signs of oxidative damage. In contrast, metabolomics analysis revealed a global and largely overlapping metabolome rewiring in both ascorbate deficiencies, suggesting that chloroplastic ascorbate modulates plant metabolism. We observed significant alterations in amino acid metabolism, particularly in arginine metabolism, activation of nucleotide salvage pathways, and changes in secondary metabolism. In addition, proteome wide analysis of thermostability revealed that ascorbate may interact with enzymes involved in arginine metabolism, the Calvin-Benson cycle, and several photosynthetic electron transport components. Overall, our results suggest that, independently of oxidative stress, chloroplastic ascorbate interconnects and coordinates diverse metabolic pathways in vascular plants and thus acts as a regulatory hub.