The GacA transcriptome of Pseudomonas protegens Pf-5 growing on pea seed surfaces
Ontology highlight
ABSTRACT:
ORGANISM(S): Pseudomonas protegens
SUBMITTER: Joyce Loper
PROVIDER: E-GEOD-38630 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Transcriptomic profiling of an rpoS mutant of Pseudomonas protegens Pf-5 in comparison to the wild-type Pf-5 strain grown in nutrient broth supplemented with 1% glycerol to OD600=2.0-2.4 (early stationary phase). Two-condition experiment, the rpoS mutant compared to wild-type Pf-5 grown in nutrient broth supplemented with 1% glycerol to early stationary phase. There are three biological replicates and two flip-dye replicates for a total of six slides analyzed. Each slide contains three replicate spots per gene.
2012-12-31 | E-GEOD-38632 | biostudies-arrayexpress
Project description:Transcriptomic profiling of an rpoS mutant of Pseudomonas protegens Pf-5 in comparison to the wild-type Pf-5 strain grown on pea seed surfaces for 24h. Two-condition experiment, the rpoS mutant compared to wild-type Pf-5 grown on pea seed surfaces for 24 h. There are three biological replicates and two flip-dye replicates for a total of six slides analyzed. Each slide contains four replicate spots per gene.
2012-12-31 | E-GEOD-38631 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2012-12-31 | E-GEOD-38633 | biostudies-arrayexpress
Project description:The genome of the marine Synechococcus sp. WH8102 displays a minimal regulatory network yet physiological and molecular responses of this organism are tuned to episodic limitation for nitrogen and phosphorus. Microarray analyses have demonstrated a key role for the two-component regulatory system, PhoBR, in the regulation of P transport and metabolism in this strain. However, there is some evidence that another regulator, SYNW1019 (designated as ptrA), probably under the control of PhoB, is involved in the wider response to P-depletion. PtrA is one of only two genome encoded DNA binding proteins of the CRP family in Synechococcus sp. WH8102, and a potential transcriptional regulator with homology to NtcA, the global nitrogen regulator in cyanobacteria. To define the precise role of this regulator we constructed a mutant by insertional inactivation and compared the physiology of wild-type Synechcococcus sp. WH8102 with the ptrA mutant under P-replete and P-deplete growth conditions. During P-depletion the ptrA mutant failed to up-regulate phosphatase activity. Microarrays and quantitative RT-PCR indicate that a subset of the Pho regulon is directly controlled by PtrA, including two phosphatase genes (SYNW0196, SYNW2390), a predicted phytase (SYNW0762) and a gene of unknown function (SYNW0165) all of which are highly up regulated during P-limitation. This result was confirmed by electrophoretic mobility shift assays which demonstrated binding of over expressed PtrA to promoter sequences upstream of the induced phosphatases (SYNW0165, SYNW0196 and SYNW2390). This work suggests a two-tiered response to P-depletion in this strain, the first being PhoB-dependent induction of high affinity PO4 transporters, and the second the PtrA-dependent induction of phosphatases for scavenging organic P. The levels of numerous other transcripts are also directly or indirectly controlled by PtrA, including those involved in cell surface modification, metal uptake, photosynthesis, stress responses and other metabolic process, which may indicate a wider role for PtrA in cellular organisation. In an environmental context ptrA is found in a number of picocyanobateria isolated from a range of oceanic provinces, including strains that lack a functional phoBR..These results give broader insight into the regulation of physiological responses that may dictate niche adaptation in genetically diverse lineages of marine Synechococcus, and suggest that signalling networks and coordinated responses to nutrient availability are important, even in oligotrophic ocean environments. In this series gene expression of a ptrA mutant has been analyzed under phosphorus deplete conditions just after the onset of induction of phosphatase activity in wild type. There are six duel-channel slides upon which both ptrA mutant and wild type samples were hybridized. There are three technical replicates for each of two biological replicates including one flip-dye comparison. Each slide contains six replicate spots per gene.
2010-04-08 | E-GEOD-18511 | biostudies-arrayexpress
Project description:The GacS/GacA signal transduction system is a central regulator in Pseudomonas spp., including the biological control strain P. fluorescens Pf-5, in which GacS/GacA controls the production of secondary metabolites and exoenzymes that suppress plant pathogens. A whole genome oligonucleotide microarray was developed for Pf-5 and used to assess the global transcriptomic consequences of a gacA mutation in P. fluorescens Pf-5. In cultures at the transition from exponential to stationary growth phase, GacA significantly influenced transcript levels of 632 genes, representing more than 10% of the 6147 annotated genes in the Pf-5 genome. Transcripts of genes involved in the production of hydrogen cyanide, the antibiotic pyoluteorin, and the extracellular protease AprA were at a low level in the gacA mutant, whereas those functioning in siderophore production and other aspects of iron homeostasis were significantly higher in the gacA mutant than in wild-type Pf-5. Notable effects of gacA inactivation were also observed in the transcription of genes encoding components of a type VI secretion system and cytochrome C oxidase subunits. Two novel gene clusters expressed under the control of gacA were identified from transcriptome analysis, and we propose global-regulator-based genome mining as an approach to decipher the secondary metabolome of Pseudomonas spp. In this series two conditions have been analyzed. A gacA mutant of Pseudomonas fluorescens Pf-5 was harvested at early (OD 0.5) and late (OD 2.4) time points and compared to wild-type Pf-5 harvested in parallel. For each slide, an experimental RNA sample from a gacA mutant was labeled with Cy3 or Cy5 and was hybridized with a reference RNA sample from wild-type Pf-5 labeled with the other Cy dye. There are six slides per condition. Each condition is represented by three biological replicates. There are two flip-dye replicates for each biological replicate. Each slide contains three replicate spots per gene.
2010-03-03 | E-GEOD-16898 | biostudies-arrayexpress
Project description:Primary productivity of open ocean environments, such as those inhabited by marine picocyanobacteria Synechococcus sp.WH8102, are often limited by low inorganic phosphate (P). To observe how this organism copes with P starvation, we constructed a full genome microarray and examined differences in gene expression under P-limited and P-replete growth conditions. To determine the temporal nature of the responses, comparisons were made for cells newly entered into P-stress (at a time point corresponding to the induction of extracellular alkaline phosphatase activity) and a later time point (late log phase). In almost all instances the P starvation response was transitory, with 36 genes showing significant upregulation (>log2 fold) while 23 genes were highly downregulated at the early time point; however, these changes in expression were maintained for only five of the upregulated genes. Knockout mutants were constructed for genes SYNW0947 or SYNW0948, comprising a two component regulator hypothesized to play a key role in regulating the response to P-limitation. A high degree of overlap in the sets of genes affected by P-limited conditions and in the knockout mutants supports this hypothesis; however there is some indication that other regulators may play a role in this response in Synechococcus sp. WH8102. Consistent with what has been observed in many other cyanobacteria, the Pho regulon of this strain is comprised largely of genes for alkaline phosphatases, P transport or P metabolism. Interestingly, however, the exact composition and arrangement of the Pho regulon appears highly variable in marine cyanobacteria. In this series four conditions have been analyzed. These are low phosphate stress during early log phase, low phosphate stress during late log phase, SYNW0947 mutation, and SYNW0948 mutation. There are six slides per condition, each with two biological replicates. There are three technical replicates for each biological replicate including one flip-dye comparison. The exception is the low phosphate stress during late log phase experiment which has a total of five slides, two biological replicates with three and two technical replicates, respectively, and one flip-dye comparison for each biological replicate. Each slide contains six replicate spots per gene.
2010-05-18 | E-GEOD-13170 | biostudies-arrayexpress
Project description:Marine cyanobacteria are thought to be the most sensitive of the phytoplankton groups to copper toxicity, yet little is known of the transcriptional response of marine Synechococcus to copper shock. Global transcriptional response to two levels of copper shock was assayed in both a coastal and an open ocean strain of marine Synechococcus using whole genome expression microarrays. Both strains showed an osmoregulatory-like response, perhaps as a result of increasing membrane permeability. This could have implications for marine carbon cycling if copper shock leads to dissolved organic carbon leakage in Synechococcus. The two strains additionally showed a reduction in photosynthetic gene transcripts. Contrastingly, the open ocean strain showed a typical stress response whereas the coastal strain exhibited a more specific oxidative or heavy metal type response. In addition, the coastal strain activated more regulatory elements and transporters, many of which are not conserved in other marine Synechococcus strains and may have been acquired by horizontal gene transfer. Thus, tolerance to copper shock in some marine Synechococcus may in part be a result of an increased ability to sense and respond in a more specialized manner. In this series four conditions have been analyzed. These are moderate copper shock for Synechococcus sp. WH8102 and CC9311 (pCu 11.1 and pCu 10.1, respectively), and high copper shock for WH8102 and CC9311 (pCu 10.1 and pCu 9.1, respectively). For each slide, an experimental RNA sample was labeled with Cy3 or Cy5 and was hybridized with a reference RNA from a non-copper-shocked sample labeled with the other Cy dye. There are six or eight slides per condition, each with two biological replicates. There are three or four technical replicates for each biological replicate including at least one flip-dye comparison. Each slide contains six replicate spots per gene.
2010-05-17 | E-GEOD-13910 | biostudies-arrayexpress
Project description:Eukaryotic chromatin is separated into functional domains differentiated by posttranslational histone modifications, histone variants, and DNA methylation. Methylation is associated with repression of transcriptional initiation in plants and animals, and is frequently found in transposable elements. Proper methylation patterns are critical for eukaryotic development, and aberrant methylation-induced silencing of tumor suppressor genes is a common feature of human cancer. In contrast to methylation, the histone variant H2A.Z is preferentially deposited by the Swr1 ATPase complex near 5' ends of genes where it promotes transcriptional competence. How DNA methylation and H2A.Z influence transcription remains largely unknown. Here we show that in the plant Arabidopsis thaliana, regions of DNA methylation are quantitatively deficient in H2A.Z. Exclusion of H2A.Z is seen at sites of DNA methylation in the bodies of actively transcribed genes and in methylated transposons. Mutation of the MET1 DNA methyltransferase, which causes both losses and gains of DNA methylation, engenders opposite changes in H2A.Z deposition, while mutation of the PIE1 subunit of the Swr1 complex that deposits H2A.Z17 leads to genome-wide hypermethylation. Our findings indicate that DNA methylation can influence chromatin structure and effect gene silencing by excluding H2A.Z, and that H2A.Z protects genes from DNA methylation. Keywords: Affinity-purification on microarray All experiments were done using two channels per chip. DNA methylation experiments compared immunoprecipitated, methylated DNA to control genomic DNA. H2A.Z experiments compared whole micrococcal nuclease-treated affinity-purified chromatin to input chromatin used for affinity purification. Affinity purification was performed using either biotin-tagged H2A.Z, pulled down using streptavidin, or endogenous H2A.Z pulled down using an anti-H2A.Z antibody.
2008-10-02 | E-GEOD-12212 | biostudies-arrayexpress
Project description:DNA methylation is an epigenetic mark associated with transposable element silencing and gene imprinting in flowering plants and mammals. In plants, imprinting occurs in the endosperm, which nourishes the embryo during seed development. We have profiled Arabidopsis DNA methylation genome-wide in the embryo and endosperm. Large-scale methylation changes accompany endosperm development and endosperm-specific gene expression. Transposable element fragments are extensively demethylated in the endosperm. We discovered new imprinted genes by identifying candidate genes associated with the top differentially methylated regions. Our data suggest that imprinting in plants evolved from genome defense against transposable elements. Keywords: Affinity-purification on microarray All experiments were done using two channels per chip. Immunoprecipitated methylated DNA (IP) was compared to control genomic DNA (input). Both the IP and input represent Cy5 and Cy3 labeled Illumina GA libraries.
2009-06-12 | E-GEOD-14570 | biostudies-arrayexpress
Project description:The aim of this work was to analyze the transcriptomic response of Buchnera aphidicola when the aphid host is submitted to depletion in essential amino acids (EAA). This treatment was combined with an increase in sucrose concentration to influence the bacterial growth rate. In this experiment, the dietary amino acids had an EAA:nonEAA ratio of either 1:1 (50% EAA) or 1:3 (25% EAA), giving low and high aphid demand of Buchnera-derived essential amino acids, respectively. This comparison was set in a 2 times 2 factorial design with sucrose concentration at 0.5 M and 1.0 M, supporting high and low aphid growth rates.
2006-04-03 | E-TABM-85 | biostudies-arrayexpress