Characterization of AceA regulons in Bradyrhizobium japonicum under desiccation stress
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ABSTRACT:
ORGANISM(S): Bradyrhizobium diazoefficiens USDA 110 Bradyrhizobium japonicum
PROVIDER: GSE69999 | GEO | 2015/07/21
SECONDARY ACCESSION(S): PRJNA287441
REPOSITORIES: GEO
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Project description:The growth and persistence of rhizobia and bradyrhizobia in soils are negatively impacted by drought conditions. In this study, we used genome-wide transcriptional analyses to obtain a comprehensive understanding of the response of Bradyrhizobium japonicum to drought. Desiccation of cells resulted in the differential expression of 15 to 20% of the 8,480 B. japonicum open reading frames, with considerable differentiation between early (after 4 h) and late (after 24 and 72 h) expressed genes. While 225 genes were universally up-regulated at all three incubation times in response to desiccation, an additional 43 and 403 up-regulated genes were common to the 4/24- and 24/72-h incubation times, respectively. Desiccating conditions resulted in the significant induction (>2.0-fold) of the trehalose-6-phosphate synthetase (otsA), trehalose-6-phosphate phosphatase (otsB), and trehalose synthase (treS) genes, which encode two of the three trehalose synthesis pathways found in B. japonicum. Gene induction was correlated with an elevated intracellular concentration of trehalose and increased activity of trehalose-6-phosphate synthetase, collectively supporting the hypothesis that this disaccharide plays a prominent and important role in promoting desiccation tolerance in B. japonicum. Microarray data also indicated that sigma(54)- and sigma(24)-associated transcriptional regulators and genes encoding isocitrate lyase, oxidative stress responses, the synthesis and transport of exopolysaccharides, heat shock response proteins, enzymes for the modification and repair of nucleic acids, and the synthesis of pili and flagella are also involved in the response of B. japonicum to desiccation. Polyethylene glycol-generated osmotic stress induced significantly fewer genes than those transcriptionally activated by desiccation. However, 67 genes were commonly induced under both conditions. Taken together, these results suggest that B. japonicum directly responds to desiccation by adapting to changes imparted by reduced water activity, such as the synthesis of trehalose and polysaccharides and, secondarily, by the induction of a wide variety of proteins involved in protection of the cell membrane, repair of DNA damage, stability and integrity of proteins, and oxidative stress responses. Keywords: stress response; time course
2007-09-25 | GSE9125 | GEO
Project description:Characterization of AceA regulons in Bradyrhizobium japonicum under desiccation stress
| PRJNA287441 | ENA
Project description:Expression data from B. japonicum stress response; aerobic treatment of B. japoncium culture under different stress conditons; pH stress (8 and 4; 4 h); salt stress (80 mM NaCl; 4 h); heat shock (43 °C; 15 min) and temperature stress (35.2 °C; 48 h); as reference wildtype without treatment (AG media; pH 6.9; without NaCl; 28 °C) was used heat shock data were verified by using rpoH-mutant strains B. japonicum 5009; B. japonicum 5032 and B. japonicum 09-32 as described in Narberhaus et al. 1997
2019-12-23 | GSE22388 | GEO
Project description:The Bradyrhizobium japonicum NtrC regulatory protein influences gene expression in response to changes in intracellular nitrogen status. Under conditions of low nitrogen, phosphorylation of NtrC results in up-regulation of a number of genes involved in nitrogen metabolism and nitrogen acquisition. To better define the exact nature of NtrC’s influence on gene expression, a ntrC mutation was created in B. japonicum and transcriptional profiling was performed by DNA microarray analysis of both the mutant and wild type strains.
2012-07-01 | GSE23870 | GEO
Project description:The Bradyrhizobium japonicum NtrC regulatory protein influences gene expression in response to changes in intracellular nitrogen status. Under conditions of low nitrogen, phosphorylation of NtrC results in up-regulation of a number of genes involved in nitrogen metabolism and nitrogen acquisition. To better define the exact nature of NtrC’s influence on gene expression, a ntrC mutation was created in B. japonicum and transcriptional profiling was performed by DNA microarray analysis of both the mutant and wild type strains.
2015-06-25 | GSE66091 | GEO
Project description:Genome-wide transcription profiling of B. japonicum fixJ, fixK2, and fixK1 mutant strains which were grown in free-living microoxic condition, and in the case of the fixK1 mutant also in anoxic condition. Transcriptomes of nodules from soybean plants infected with the fixJ or fixK2 mutant strains were investigated, too. This study includes also the expression data of a nifA mutant grown in free-living anoxic condition. Samples from GSM210242 to GSM210286 in GEO record number GSE8478 need to be considered for the analyses. Keywords: gene regulation, genetic modification, growth conditions, symbiosis Comparison analysis of the B. japonicum fixJ, fixK2 and fixK1 mutants and the wild type grown under different oxygen conditions in culture and during symbiosis with soybean.
2010-05-23 | E-GEOD-12491 | biostudies-arrayexpress
Project description:The Bradyrhizobium japonicum NtrC regulatory protein influences gene expression in response to changes in intracellular nitrogen status. Under conditions of low nitrogen, phosphorylation of NtrC results in up-regulation of a number of genes involved in nitrogen metabolism and nitrogen acquisition. To better define the exact nature of NtrC’s influence on gene expression, a ntrC mutation was created in B. japonicum and transcriptional profiling was performed by DNA microarray analysis of both the mutant and wild type strains. Bradyrhizobium japonicum USDA 110 and a ntrC mutant in the USDA 110 background were cultured in minimal medium supplemented with either 10mM glutamate (low nitrogen) or 10mM ammonium and 10mM glutamate (high nitrogen) as nitrogen sources. Four comparisons were performed: wild type high nitrogen vs. mutant high nitrogen, wild type low nitrogen vs. wild type high nitrogen, wild type low nitrogen vs. mutant low nitrogen, and mutant low nitrogen vs. mutant high nitrogen. For each of the four comparisons, three biological replicates were prepared for each strain and dye swap replications were performed for each hybridization producing a total of six arrays per comparison and 24 arrays in total.
2015-06-25 | E-GEOD-66091 | biostudies-arrayexpress
Project description:Genome-wide transcription profiling of B. japonicum fixJ, fixK2, and fixK1 mutant strains which were grown in free-living microoxic condition, and in the case of the fixK1 mutant also in anoxic condition. Transcriptomes of nodules from soybean plants infected with the fixJ or fixK2 mutant strains were investigated, too. This study includes also the expression data of a nifA mutant grown in free-living anoxic condition. Samples from GSM210242 to GSM210286 in GEO record number GSE8478 need to be considered for the analyses. Keywords: gene regulation, genetic modification, growth conditions, symbiosis
2008-08-21 | GSE12491 | GEO
Project description:PhyR is an unusual type of response regulator consisting of a receiver domain and an extracytoplasmic function (ECF) sigma factor-like domain. It was recently described as a master regulator of general stress response in Methylobacterium extorquens. Orthologues of this regulator are present in essentially all free-living Alphaproteobacteria. In most of them, phyR is genetically closely linked to a gene encoding an ECF sigma factor. Here, we investigate the role of these two regulators in the soybean symbiont Bradyrhizobium japonicum USDA110. Using deletion mutants and phenotypic assays, we showed that PhyR and the ECF sigma factor sigma(EcfG) are involved in heat shock and desiccation resistance upon carbon starvation. Both mutants had symbiotic defects on the plant hosts Glycine max (soybean) and Vigna radiata (mungbean). They induced fewer nodules than the wild type and these nodules were smaller, less pigmented, and their specific nitrogenase activity was drastically reduced 2 or 3 weeks after inoculation. Four weeks after infection, soybean nodule development caught up to a large extent whereas most mungbean nodules remained defective even 5 weeks after infection. Remarkably, both mutants triggered aberrant nodules on the different host plants with ectopically emerging roots. Microarray analysis revealed that PhyR and sigma(EcfG) control congruent regulons suggesting both regulators are part of the same signalling cascade. This finding was further substantiated by in vitro protein-protein interaction studies which are in line with a partner-switching mechanism controlling gene regulation triggered by phosphorylation of PhyR. The large number of genes of unknown function present in the PhyR/sigma(EcfG) regulon and the conspicuous symbiotic phenotype suggest that these regulators are involved in the Bradyrhizobium-legume interaction via yet undisclosed mechanisms. Comparative analysis of the B. japonicum phyR mutant 8402, ecfG mutant 8404 mutant and the wild type during exponential growth in rich medium (PSY) and after 24 hours starvation in carbon source-free minimal medium
2010-05-16 | E-GEOD-15910 | biostudies-arrayexpress
Project description:Bradyrhizobium japonicum is a nitrogen-fixing symbiont of soybean. In previous studies, transcriptomic profiling of B. japonicum USDA110, grown under various environmental conditions, revealed the highly induced gene aceA, encoding isocitrate lyase (ICL). The ICL catalyzes the conversion of isocitrate to succinate and glyoxylate in the glyoxylate bypass of the TCA cycle. Here, we evaluated the functional role of B. japonicum ICL under desiccation-induced stress conditions. We purified AceA (molecular mass = 65 kDa) from B. japonicum USDA110, using a His-tag and Ni-NTA column approach, and confirmed its ICL enzyme activity. The aceA mutant showed higher sensitivity to desiccation stress (27% relative humidity (RH)), compared to the wild type. ICL activity of the wild type strain increased approximately 2.5-fold upon exposure to 27% RH for 24 h. The aceA mutant also showed an increased susceptibility to salt stress. Gene expression analysis of aceA using qRT-PCR revealed a 148-fold induction by desiccation, while other genes involved in the glyoxylate pathway were not differentially expressed in this condition. Transcriptome analyses revealed that stress-related genes, such as chaperones, were upregulated in the wild-type under desiccating conditions, even though fold induction was not dramatic (ca. 1.5-2.5-fold).
| S-EPMC4519974 | biostudies-literature