Transcriptomic profiling of the PhzIR quorum sensing, Gac- and PtrA- regulons of Pseudomonas chlororaphis PA23
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ABSTRACT:
ORGANISM(S): Pseudomonas chlororaphis
PROVIDER: GSE114924 | GEO | 2018/05/26
REPOSITORIES: GEO
Similar Datasets
Project description:The GacS/GacA two component regulatory system globally activates the production of secondary metabolites including phenazines in Pseudomonas chlororaphis 30-84. To better understand the regulatory role of the Gac system, we conducted RNA-seq analyses to determine the regulon of the response regulator GacA. Transcriptome analyses identified over 700 genes differentially regulated by GacA. Consistent with our previous findings, phenazine biosynthetic genes were significantly down-regulated in a gacA mutant. The expression levels of phenazine regulatory genes such as phzI, phzR, iopA, iopB, rpoS and pip were also decreased. Moreover, the expression of three none-coding RNAs (ncRNAs) including rsmX, rsmY and rsmZ was significantly decreased by gacA mutation consistent with the presence of GacA binding sites in their promoters. Our results also demonstrated that over-expression of rsmZ from a non-gac regulated promoter resulted in the restoration of AHL and phenazine production as well as the expression of other secondary metabolites in gac mutants. The role of RsmA and RsmE in phenazine production was also investigated. Over-expression of rsmE, but not rsmA, resulted in decreased AHL production and phenazine gene expression in P. chlororaphis. Consistently, a mutation in rsmE bypassed the requirement of GacA in phenazine gene expression. On the contrary, constitutive expression of the phzI/phzR quorum sensing system was not able to rescue phenazine production in the gacA mutant indicating the direct impact of Gac system on the transcript stability of phenazine biosynthetic genes. Together, these results indicate that the Gac system regulates phenazine production at multiple levels and exerts its positive effect on AHL and phenazine biosynthesis via RsmZ and RsmE. A model is proposed to illustrate the GacA regulon in P. chlororaphis 30-84. A total of 6 samples were analyzed in AB medium + 2% casamino acids, Pseudomonas chlororaphis wild type strain (3 replicates); Pseudomonas chlororaphis gacA mutant (3 replicates).
2014-12-11 | E-GEOD-43083 | biostudies-arrayexpress
Project description:The GacS/GacA two component regulatory system globally activates the production of secondary metabolites including phenazines in Pseudomonas chlororaphis 30-84. To better understand the regulatory role of the Gac system, we conducted RNA-seq analyses to determine the regulon of the response regulator GacA. Transcriptome analyses identified over 700 genes differentially regulated by GacA. Consistent with our previous findings, phenazine biosynthetic genes were significantly down-regulated in a gacA mutant. The expression levels of phenazine regulatory genes such as phzI, phzR, iopA, iopB, rpoS and pip were also decreased. Moreover, the expression of three none-coding RNAs (ncRNAs) including rsmX, rsmY and rsmZ was significantly decreased by gacA mutation consistent with the presence of GacA binding sites in their promoters. Our results also demonstrated that over-expression of rsmZ from a non-gac regulated promoter resulted in the restoration of AHL and phenazine production as well as the expression of other secondary metabolites in gac mutants. The role of RsmA and RsmE in phenazine production was also investigated. Over-expression of rsmE, but not rsmA, resulted in decreased AHL production and phenazine gene expression in P. chlororaphis. Consistently, a mutation in rsmE bypassed the requirement of GacA in phenazine gene expression. On the contrary, constitutive expression of the phzI/phzR quorum sensing system was not able to rescue phenazine production in the gacA mutant indicating the direct impact of Gac system on the transcript stability of phenazine biosynthetic genes. Together, these results indicate that the Gac system regulates phenazine production at multiple levels and exerts its positive effect on AHL and phenazine biosynthesis via RsmZ and RsmE. A model is proposed to illustrate the GacA regulon in P. chlororaphis 30-84.
2014-12-11 | GSE43083 | GEO
Project description:To characterize the molecular basis of cytotoxicity of different Pseudomonas species and strains, we analyzed the protein content of secretomes of three P. chlororaphis strains (CIP63, CIP75 and the reference strain PA23) and of six P. entomophila strains (L48 WT, or deleted for various virulence factors: the global activator GacA, the pore-forming toxin Mnl, the pore-forming toxin ExlA, and double mutants for these genes).
2022-07-25 | PXD029397 | Pride
Project description:Transcriptomic profiling of the PhzIR quorum sensing, Gac- and PtrA- regulons of Pseudomonas chlororaphis PA23
| PRJNA473137 | ENA
Project description:Background: The biological control agent Pseudomonas chlororaphis PA23 is effective at protecting Brassica napus (canola) from the necrotrophic fungus Sclerotinia sclerotiorum via direct antagonism. Despite the growing importance of biocontrol bacteria in plant protection from fungal pathogens, little is known about how the host plant responds to bacterial priming on the leaf surface or about changes in gene activity genome-wide in the presence and absence of S. sclerotiorum. Results: PA23 priming of mature canola plants reduced the number of lesion forming petals by 90%. Global RNA sequencing of the host pathogen interface showed a reduction in the number of genes uniquely upregulated in response to S. sclerotiorum by 16-fold when pretreated with PA23. Upstream defense-related gene patterns suggest MAMP-triggered immunity via surface receptors detecting PA23 flagellin and peptidoglycans. Although systemic acquired resistance was induced in all treatment groups, a response centered around a glycerol-3-phosphate (G3P)-mediated pathway was exclusively observed in plants treated with PA23 alone. Activation of these defense mechanisms by PA23 involved mild reactive oxygen species production as well as pronounced thylakoid membrane structures and plastoglobule formation in leaf chloroplasts. Conclusion: Further to the direct antibiosis that it exhibits towards the pathogen S. sclerotiorum, PA23 primes defense responses in the plant through the induction of unique local and systemic defense regulatory networks. This study has shed light on the potential effects of biocontrol agents applied to the plant phyllosphere. Understanding these interactions will aid in the development of biocontrol systems as a viable alternative to chemical pesticides in the protection of important crop systems.
2016-07-25 | GSE84798 | GEO
Project description:Plant growth promoting bacteria (PGPB) are a growing subset of agricultural adjuncts which can be used to increase crop yield and plant productivity. Although, substantial research has been conducted on the metabolites and active molecules secreted by PGPBs; relatively little is known about their effects on the global transcriptome of the host plant. The present study was carried out to investigate changes in the gene expression landscape of early vegetative Brassica napus following treatment with Pseudomonas chlororaphis PA23. This PGPB was isolated from the soybean rhizosphere and has been extensively studied as a biocontrol agent. However, little is known about its effects on plant growth and development. Using a combination of RNA-sequencing and physiological analyses, we identified increased abundance of mRNA transcripts associated with photosynthesis and phytohormone response. Phenotypically we observed increased photosynthetic rates and larger root and shoot systems in B. napus following P. chlororaphis PA23 treatment. Lastly, we identified auxin production by P. chlororaphis PA23 which likely contributes to changes in gene expression and observed phenotypic differences in root and shoot structures. Together, the results of our study suggest that PA23 is a potent plant growth promoting agent with the potential for field applications as an agricultural adjunct.
2020-07-14 | GSE154315 | GEO
Project description:Background: The biological control agent Pseudomonas chlororaphis PA23 is effective at protecting Brassica napus (canola) from the necrotrophic fungus Sclerotinia sclerotiorum via direct antagonism. Despite the growing importance of biocontrol bacteria in plant protection from fungal pathogens, little is known about how the host plant responds to bacterial priming on the leaf surface or about changes in gene activity genome-wide in the presence and absence of S. sclerotiorum. Results: PA23 priming of mature canola plants reduced the number of lesion forming petals by 90%. Global RNA sequencing of the host pathogen interface showed a reduction in the number of genes uniquely upregulated in response to S. sclerotiorum by 16-fold when pretreated with PA23. Upstream defense-related gene patterns suggest MAMP-triggered immunity via surface receptors detecting PA23 flagellin and peptidoglycans. Although systemic acquired resistance was induced in all treatment groups, a response centered around a glycerol-3-phosphate (G3P)-mediated pathway was exclusively observed in plants treated with PA23 alone. Activation of these defense mechanisms by PA23 involved mild reactive oxygen species production as well as pronounced thylakoid membrane structures and plastoglobule formation in leaf chloroplasts. Conclusion: Further to the direct antibiosis that it exhibits towards the pathogen S. sclerotiorum, PA23 primes defense responses in the plant through the induction of unique local and systemic defense regulatory networks. This study has shed light on the potential effects of biocontrol agents applied to the plant phyllosphere. Understanding these interactions will aid in the development of biocontrol systems as a viable alternative to chemical pesticides in the protection of important crop systems. Mature canola leaf tissue treated with combinations of PA23 or S. sclerotiorum ascospores (3 treatment groups) was compared to a water treated control (all treatments done in triplicate).
2016-07-25 | E-GEOD-84798 | biostudies-arrayexpress
Project description:Pseudomonas chlororaphis strain 30-84 is an effective biological control agent against take-all disease of wheat. Phenazines, bacterial secondary metabolites produced by 30-84, are essential for 30-84 to inhibit fungal pathogens, form biofilms, and effectively colonize the rhizosphere. However, how the bacteria themselves respond to phenazines remains unknown. In this study, we conducted an RNA-seq analysis by comparing the wild type strain with a phenazine deficient mutant. RNA-seq analysis identified over 200 genes differentially regulated by phenazines. Consistent with previous findings in Pseudomonas aeruginosa PAO1, phenazines positively contribute to the expression of their own biosynthetic genes. Moreover, phenazine regulatory genes including the phzI/phzR quorum sensing system and the rpeB response regulatory were also expressed at high levels in the presence of phenazines. Besides phenazine biosynthesis and regulatory genes, genes involved in secondary metabolism, exopoysaccharide production and iron uptake as well as amino acid transport were identified as the major components under phenazine control, including many novel genes. We have also demonstrated that mutation of the primary siderophore gene pvdA resulted in up-regulation of phenazine genes when grown in iron-limiting media. These findings implicate phenazines as signaling molecules to regulate gene expression and hence alter metabolism in P. chlororaphis strain 30-84. A total of 4 samples were analyzed in AB medium + 2% casamino acids, Pseudomonas chlororaphis wild type strain (2 replicates); Pseudomonas chlororaphis ZN mutant (2 replicates).
2014-11-25 | E-GEOD-45247 | biostudies-arrayexpress
Project description:Pseudomonas chlororaphis strain:PA23 Genome sequencing
| PRJNA247768 | ENA
Project description:Pseudomonas species are ubiquitous in plant-associated environments and produce an array of volatiles, enzymes and antimicrobials. The biosynthesis of many metabolites is regulated by the GacS/GacA two-component regulatory system. Transcriptome analysis of Pseudomonas fluorescens SBW25 revealed that 702 genes were differentially regulated (fold change>4, P<0.0001) in a gacS::Tn5 mutant, with 300 and 402 genes up- and down-regulated, respectively. Genes that were significantly down-regulated are involved in viscosin biosynthesis (viscABC), protease production (aprA), motility, biofilm formation, and secretory systems. Genes that were significantly up-regulated are involved in siderophore biosynthesis and oxidative stress. In contrast to previous studies with gac-mutants of other Pseudomonas species/strains, the gacS mutant of SBW25 inhibited growth of oomycete, fungal and bacterial pathogens significantly more than parental strain SBW25. A potential candidate for this enhanced antimicrobial activity was a large nonribosomal peptide synthetase (NRPS) gene cluster predicted to encode for an 8-amino-acid ornicorrugatin-like peptide. Site-directed mutagenesis of an NRPS gene in this cluster, however, did not lead to a reduction in the antimicrobial activity of the gacS mutant. Collectively these results indicate that a mutation in the GacS/GacA regulatory system causes major transcriptional changes in P. fluorescens SBW25 and significantly enhances its antimicrobial activities by yet unknown mechanisms.
2013-06-17 | GSE43443 | GEO