Gene regulation in Bacillus subtilis by the compatible solute glycine betaine
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ABSTRACT:
ORGANISM(S): Bacillus subtilis
PROVIDER: GSE17435 | GEO | 2009/08/01
SECONDARY ACCESSION(S): PRJNA118883
REPOSITORIES: GEO
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Project description:Glycine betaine (GB) is a potent osmoprotectant for salt stressed Bacillus subtilis cells, which possess three high-affinity uptake systems for GB. OpuA is the dominant transporter for this compatible solute. Northern blot analysis, primer extension experiments and opuA-treA reporter gene fusion studies demonstrated that opuA expression is strongly induced at high osmolality from a single SigA-type promoter. Promoter mutations that improve the match of the opuA promoter to the consensus sequence substantially increase basal-level expression but reduce inducibility by high salinity. Expression of opuA is sensitively controlled by GB, which causes significant repression of opuA transcription at low and high salinity. GB influences the kinetics as well as the final level of high salinity induction of opuA in a concentration-dependent fashion. The repressing effect of GB on opuA transcription requires the intracellular presence of GB, regardless whether it is taken up via OpuA or other transporters or synthesized from choline. Genome-wide transcriptional profiling of salt-stressed B. subtilis cells demonstrated that the repressive effect of GB targets only a subset of high-salinity induced genes. This group of GB-responsive genes comprises in essence the full set of genes with demonstrated functions in either the uptake or synthesis of compatible solutes. Four different samples (untreated, GB, NaCl, and GB + NaCl treated) were analyzed and each sample was hybridized in triplicate.
2010-05-15 | E-GEOD-17435 | biostudies-arrayexpress
Project description:In order to reveal so far unknown facets of the adaptation of B. subtilis to growth under high-salinity conditions, a whole-transcriptome analysis of B. subtilis BSB (168 Trp+) was performed using strand-specific tiling arrays (tiling step of 22 nucleotides). In addition, the effects of glycine betaine (GB) were analyzed under high salinity and standard growth conditions in a chemically defined medium. Important novel findings were a sustained low-level induction of the SigB-dependent general stress response and strong repression of biofilm matrix genes under high-salinity conditions. GB influences gene expression not only under high-salinity, but also under standard growth conditions without additional salt.
2020-05-18 | GSE145124 | GEO
Project description:Analysis of root gene expression of salt-tolerant genotypes FL478, Pokkali and IR63731, and salt-sensitive genotype IR29 under control and salinity-stressed conditions during vegetative growth. Results provide insight into the genetic basis of salt tolerance in indica rice. Keywords: stress response
2009-07-16 | GSE14403 | GEO
Project description:Here, we investigated for the first time the systems-wide response of B. subtilis to different simultaneous stresses, i.e. nutrient limitation and high osmolarity. To address the anticipated complexity of the cellular response networks, we combined chemostat experiments under conditions of carbon limitation, salt stress and osmoprotection with multi-omics analyses at the transcriptome, proteome, metabolome and fluxome levels. Our results indicate that the flux through central carbon and energy metabolism is very robust under all conditions studied. The key to achieve this robustness is the adjustment of the biocatalytic machinery to compensate for solvent-induced impairment of enzymatic activities during osmotic stress. The accumulation of the exogenously provided osmoprotectant glycine betaine helps the cell to rescue enzyme activities in the presence of high salt. A major effort of the cell during osmotic stress is the production of the compatible solute proline. This is achieved by the concerted adjustment of multiple reactions around the 2-oxoglutarate node, which drives metabolism towards the proline precursor glutamate. The fine-tuning of the transcriptional and metabolic networks involves functional modules that overarch the individual pathways. We applied transcriptomic, mass spectrometry-based protein, metabolite and 13C-metabolic flux analysis techniques to B. subtilis cells grown under well-controlled conditions in a glucose-limited chemostat at a growth rate of 0.1 h-1 under i) reference conditions, ii) in the presence of 1.2 M NaCl, and iii) in the presence of 1.2 M NaCl and 1 mM GB. Microarray hybridizations were performed with RNA from three biological replicates. The individual samples were labeled with Cy5; a reference pool containing equal amounts of RNA from all 9 samples was labeled with Cy3.
2014-03-31 | E-GEOD-53333 | biostudies-arrayexpress
Project description:Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses”, “modulation of respiratory chain and related components”, and “ion homeostasis”. A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity respectively, and repressed by temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of temperature. Low salinity induced genes involved in “protein-folding-stress response”, suggesting disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by temperature. However, salt-induced cell motility was reduced at high temperature, possibly caused by an alteration of Na+ permeability by temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. In addition, compared to low salinity external iron increased hydroxyectoine accumulation by 20% at high salinity, but reduced the intracellular content of ectoines by 50% at high salinity plus high temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens
2018-08-31 | GSE69612 | GEO
Project description:Analysis of root gene expression of salt-tolerant genotypes FL478, Pokkali and IR63731, and salt-sensitive genotype IR29 under control and salinity-stressed conditions during vegetative growth. Results provide insight into the genetic basis of salt tolerance in indica rice. Experiment Overall Design: Seedlings were cultured in sand and irrigated with a nutrient solution for 22 d (salt-treated) and 30 d (control) after germination, respectively. Salinity treatment was applied by adding NaCl and CaCl2 (5:1 molar concentration) in two steps over a period of 3 days (final electrical conductivity: 7.4 dS m-1) to prevent osmotic shock. All plants were harvested on day 30.
2009-08-07 | E-GEOD-14403 | biostudies-arrayexpress
Project description:Oilseed mustard, Brassica juncea, exhibits high levels of genetic variability for salinity tolerance. To obtain the global view of transcriptome and investigate the molecular basis of salinity tolerance in a salt-tolerant variety CS52 of B. juncea, we performed transcriptome sequencing of control and salt-stressed seedlings. De novo assembly of 184 million high-quality paired-end reads yielded 42,327 unique transcripts longer than 300 bp with RPKM ≥1. When compared with non-redundant proteins, we could annotate 67% unigenes obtained in our study. Based on the mapping to expressed sequence tags (ESTs), 52.6% unigenes are novel compared to EST data available for B. juncea and constituent genomes. Differential expression analysis revealed altered expression of 1469 unigenes in response to salinity stress. Of these, 587, mainly associated with ROS detoxification, sulfur assimilation and calcium signaling pathways, are up regulated. Notable of these is RSA1 (SHORT ROOT IN SALT MEDIUM 1) INTERACTING TRANSCRIPTION FACTOR 1 (RITF1) homolog up regulated by >100 folds in response to stress. RITF1, encoding a bHLH transcription factor, is a positive regulator of SOS1 and several key genes involved in scavenging of salt stress-induced reactive oxygen species (ROS). Further, we performed comparative expression profiling of key genes implicated in ion homeostasis and sequestration (SOS1, SOS2, SOS3, ENH1, NHX1), calcium sensing pathway (RITF1) and ROS detoxification in contrasting cultivars, B. juncea and B. nigra, for salinity tolerance. The results revealed higher transcript accumulation of most of these genes in B. juncea var. CS52 compared to salt-sensitive cultivar even under normal growth conditions. Together, these findings reveal key pathways and signaling components that contribute to salinity tolerance in B. juncea var. CS52. We report transcriptome sequencing of two-weeks-old seedlings of B. juncea var. CS52 under normal growth conditions (CTRL) and in response to salinity stress (SS) using Illumina paired-end sequencing
2015-02-28 | E-GEOD-66389 | biostudies-arrayexpress
Project description:Oilseed mustard, Brassica juncea, exhibits high levels of genetic variability for salinity tolerance. To obtain the global view of transcriptome and investigate the molecular basis of salinity tolerance in a salt-tolerant variety CS52 of B. juncea, we performed transcriptome sequencing of control and salt-stressed seedlings. De novo assembly of 184 million high-quality paired-end reads yielded 42,327 unique transcripts longer than 300 bp with RPKM ≥1. When compared with non-redundant proteins, we could annotate 67% unigenes obtained in our study. Based on the mapping to expressed sequence tags (ESTs), 52.6% unigenes are novel compared to EST data available for B. juncea and constituent genomes. Differential expression analysis revealed altered expression of 1469 unigenes in response to salinity stress. Of these, 587, mainly associated with ROS detoxification, sulfur assimilation and calcium signaling pathways, are up regulated. Notable of these is RSA1 (SHORT ROOT IN SALT MEDIUM 1) INTERACTING TRANSCRIPTION FACTOR 1 (RITF1) homolog up regulated by >100 folds in response to stress. RITF1, encoding a bHLH transcription factor, is a positive regulator of SOS1 and several key genes involved in scavenging of salt stress-induced reactive oxygen species (ROS). Further, we performed comparative expression profiling of key genes implicated in ion homeostasis and sequestration (SOS1, SOS2, SOS3, ENH1, NHX1), calcium sensing pathway (RITF1) and ROS detoxification in contrasting cultivars, B. juncea and B. nigra, for salinity tolerance. The results revealed higher transcript accumulation of most of these genes in B. juncea var. CS52 compared to salt-sensitive cultivar even under normal growth conditions. Together, these findings reveal key pathways and signaling components that contribute to salinity tolerance in B. juncea var. CS52.
2015-02-28 | GSE66389 | GEO
Project description:Rice (Oryza sativa) stands among the world's most important crop species and is salt-sensitive. The undue accumulation of sodium ions (Na+) in shoots has the strongest negative correlation with rice productivity under long-term salinity. The plasma membrane Na+/H+ exchanger protein SOS1 is the only Na+ efflux transporter that has to date been genetically characterized and only in dicot plants. Here, the importance of Na+ fluxes governed by the SOS system in the salt tolerance of rice was analyzed by a reverse-genetics approach. A sos1 loss-of-function mutant displayed exceptional salt sensitivity that correlated with excessive Na+ intake and impaired Na+ loading into the xylem. Thus, SOS1 controls net Na+ uptake by roots and the long-distance transport to shoots. The acute Na+ sensitivity of sos1 plants at low NaCl concentrations allowed the inspection of the transcriptional response to sodicity stress, without interference by the osmotic challenge intrinsic to high salinity treatments. The transcriptional response to salt of the sos1 mutant roots involved the preferential down-regulation of stress-related genes compared to the wild-type despite the greater intensity of the stress imposed to the mutant, which suggested impaired stress detection or inability to mount a comprehensive response to salinity.
2019-04-16 | GSE129844 | GEO
Project description:Background The combination of high-throughput transcript profiling and next-generation sequencing technologies is a prerequisite for genome-wide comprehensive transcriptome analysis. Our recent innovation of deepSuperSAGE is based on an advanced SuperSAGE protocol and its combination with massively parallel pyrosequencing on RocheM-bM-^@M-^Ys 454 sequencing platform. As a demonstration of the power of this combination, we have chosen the salt stress transcriptomes of roots and nodules of the third most important legume crop chickpea (Cicer arietinum L.). While our report is more technology-oriented, it nevertheless addresses a major world-wide problem for crops generally: high salinity. Together with low temperatures and water stress, high salinity is responsible for crop losses of millions of tons of various legume (and other) crops. Continuously deteriorating environmental conditions will combine with salinity stress to further compromise crop yields. As a good example for such stress-exposed crop plants, we started to characterize salt stress responses of chickpeas on the transcriptome level. Results We used deepSuperSAGE to detect early global transcriptome changes in salt-stressed chickpea. The salt stress responses of 86,919 transcripts representing 17,918 unique 26bp deepSuperSAGE tags (UniTags) from roots of the salt-tolerant variety INRAT-93 two hours after treatment with 25 mM NaCl were characterized. Additionally, the expression of 57,281 transcripts representing 13,115 UniTags was monitored in nodules of the same plants. From a total of 144,200 analyzed 26bp tags in roots and nodules together, 21,401 unique transcripts were identified. Of these, only 363 and 106 specific transcripts, respectively, were commonly up- or down-regulated (>3.0-fold) under salt stress in both organs, witnessing a differential organ-specific response to stress. Profiting from recent pioneer works on massive cDNA sequencing in chickpea, more than 9,400 UniTags were able to be linked to UniProt entries. Additionally, gene ontology (GO) categories over-representation analysis enabled to filter out enriched biological processes among the differentially expressed UniTags. Subsequently, the gathered information was further cross-checked with stress-related pathways. From several filtered pathways, here we focus exemplarily on transcripts associated with the generation and scavenging of reactive oxygen species (ROS), as well as on transcripts involved in Na+ homeostasis. Although both processes are already very well characterized in other plants, the information generated in the present work is of high value. Information on expression profiles and sequence similarity for several hundreds of transcripts of potential interest is now available. Conclusions This report demonstrates, that the combination of the high-throughput transcriptome profiling technology SuperSAGE with one of the next-generation sequencing platforms allows deep insights into the first molecular reactions of a plant exposed to salinity. Cross validation with recent reports enriched the information about the salt stress dynamics of more than 9,000 chickpea ESTs, and enlarged their pool of alternative transcripts isoforms. As an example for the high resolution of the employed technology that we coin deepSuperSAGE, we demonstrate that ROS-scavenging and -generating pathways undergo strong global transcriptome changes in chickpea roots and nodules already 2 hours after onset of moderate salt stress (25mM NaCl). Additionally, a set of more than 15 candidate transcripts are proposed to be potential components of the salt overly sensitive (SOS) pathway in chickpea. Newly identified transcript isoforms are potential targets for breeding novel cultivars with high salinity tolerance. We demonstrate that these targets can be integrated into breeding schemes by micro-arrays and RT-PCR assays downstream of the generation of 26bp tags by SuperSAGE. SuperSAGE libraries from chickpea roots and nodules were constructed starting from hydro aeroponics-generated material. Control and stressed plants were grown in parallel Sequencing Instrument: First gerenration 454-Machine Place of sequencing: 454 Life Sciences, Branford, CT, USA
2011-02-01 | E-GEOD-26638 | biostudies-arrayexpress