Pseudomonas syringae Virulence Regulatory Network construction
Ontology highlight
ABSTRACT:
ORGANISM(S): Pseudomonas savastanoi pv. phaseolicola 1448A
PROVIDER: GSE138204 | GEO | 2021/03/29
REPOSITORIES: GEO
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Project description:The type III secretion system (T3SS) is the main machinery for Pseudomonas syringae and other Gram-negative bacteria to invade plant cells. HrpR/HrpS heterodimer are key factors to activate HrpL which induces all T3SS genes by binding to a ‘hrp box’ in promoters. However, the molecular mechanisms of HrpRS on T3SS or non-T3SS genes have not been fully understood. Following by chromatin immunoprecipitation coupled to high-throughput DNA sequencing (ChIP-seq), we found that HrpRSL had 8, 38, and 36 targets on the genome, respectively. HrpS directly bound to the promoter regions of T3SS genes (hrpK1, hrpA2 and hopAJ1) as well as a group of non-T3SS genes (PSPPH_1496, PSPPH_1525, PSPPH_3494 and PSPPH_3495). Subsequent biochemical and genetic assays showed that HrpS independently regulated these genes in a hrpL deletion strain. In addition, a HrpS-binding motif (GTGCCAAA) in the hrpL promoter was identified by truncation, which was verified by EMSA in vitro and lux-reporter assay in vivo. On the contrary, HrpR alone couldn’t activate hrpL. Overall, our results demonstrated that HrpS directly regulated a group of T3SS and non-T3SS genes, which is independent on HrpL. HrpS functions as the center of the regulatory cascade in T3SS. This work deciphered the key HrpRSL-T3SS regulatory network, which provides insights to develop new strategies to control P. syringae infection in the future.
2018-06-30 | GSE103921 | GEO
Project description:Bacteria use a variety of mechanisms, such as two‐component regulatory systems (TCSs), to rapidly sense and respond to distinct conditions and signals in their host organisms. For example, a type III secretion system (T3SS) is the key determinant of the virulence of the model plant pathogen Pseudomonas syringae and contains the TCS RhpRS as a key regulator. However, the signal sensed by RhpRS remains unknown. We found that RhpRS directly senses plant-generated polyphenols and responds by switching off P. syringae T3SS via crosstalk with alternative histidine kinases. Through a chemical screen, we identified three natural polyphenols (tannic acid, 1,2,3,4,6-pentagalloylglucose and epigallocatechin gallate) that induced the expression of the rhpRS operon in a RhpS-dependent manner.
2021-09-20 | GSE160492 | GEO
Project description:Regulatory networks including virulence-related transcriptional factors (TFs) determine bacterial pathogenicity in response to different environmental cues. Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen of humans, recruits numerous TFs in quorum sensing (QS) system, type III secretion system (T3SS) and Type VI secretion system (T6SS) to mediate the pathogenicity. Although many virulence-related TFs have been illustrated individually, very little is known about their crosstalks and regulatory network. Here, based on chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) and transcriptome profiling (RNA-seq), we primarily focused on understanding the crosstalks of 20 virulence-related TFs, which led to construction of a virulence regulatory network named PAGnet (Pseudomonas aeruginosa Genomic integrated regulatory network), including 82 crosstalk targets. The PAGnet uncovered the intricate mechanism of virulence regulation and revealed master regulators in QS, T3SS and T6SS pathways. In particular, GacA and ExsA showed novel functions in QS and nitrogen metabolism. In addition, an online PAGnet platform was provided to analyze these TFs and more virulence factors. Taken together, the present study revealed the function-specific crosstalks of virulence regulatory network, which might provide new strategies for treating infections in P. aeruginosa in the future.
2019-07-16 | GSE128430 | GEO
Project description:Purpose: The outcome of host–pathogen interactions is thought to reflect the offensive and defensive capabilities of both players. When plants interact with Pseudomonas syringae, several well-characterized virulence factors contribute to early bacterial pathogenicity, including the type III secretion system (T3SS), which must be activated by signals from the plant and environment to allow the secretion of virulence effectors. The manner in which these signals regulate T3SS activity is still unclear. Conlusion: the analysis revealed that the perception of plant signals from kiwifruit or tomato extracts anticipates T3SS expression in P. syringae pv. actinidiae compared to apoplast-like conditions
2022-08-25 | GSE211939 | GEO
Project description:Pseudomonas syringae uses HrpRSL to regulate the expression of type III secretion system (T3SS) genes and bacterial virulence. However, the molecular mechanism and the regulons of HrpRSL have yet to be fully elucidated. Here, we performed chromatin immunoprecipitation followed by high-throughput DNA sequencing (ChIP-seq) on HrpRSL and Lon. The direct regulation of these genes by corresponding regulator has been confirmed by Electrophoretic mobility shift assays (EMSAs) and quantitative real-time polymerase chain reactions (qRT-PCR). Binding motifs are found by using MEME suite and verified by footprint assays in vitro. Collectively, this work provides new cues to better understand the detailed regulatory networks of T3SS systems in P. syringae. ChIP-seq analysis of HrpRSL and Lon in Pseudomonas syringas
2015-12-31 | E-GEOD-65437 | biostudies-arrayexpress
Project description:Bacteria relies on two-component systems (TCSs) to respond to a wide range of stimuli or environmental cues for their survival and virulence. However, the functions and synergistic actions of TCSs in genomic level remains unclear. Here, in model phytopathogen Pseudomonas syringae, by integrating multiomics data, we developed a network-based PSTCSome (Pseudomonas syringae two-component systems regulome) to identify functions and crosstalk among global TCSs under either virulence suppressing (King’s B medium, KB) or activating conditions (minimal medium, MM). Transcriptome profiling identifies 2,099 differentially expressed genes (DEGs) in KB and 1,250 DEGs in MM, while ChIP-seq identifies 1,628 target genes across the whole genome. The multiomics results are applied to perform not only gene ontology (GO) analysis to detect the biological processes that TCSs involved in, but also subnetworks and co-expression analysis of 8 virulence-related pathways to decipher the TCSs regulated pathogenic behaviors. The following phenotypic experiments newly confirmed 8 TCSs that regulates type III secretion system (T3SS) (PSPPH_0253, PSPPH_2606, PSPPH_4416, and PSPPH_4451) and surface attachment (PSPPH_0253, PSPPH_3041, PSPPH_3473, PSPPH_3736, PSPPH_4001). We then compute 259 functional genes in KB and 161 in MM for those cluster TCSs. Analysis of cluster TCSs regulons led to the identification of either novel functions or 2 master regulatory TCSs (RhpS/RhpR and PSPPH_4827/4828) toward virulence. Our results show that TCSs in P. syringae dynamically adjust their regulatory networks by sensing the external environment, and then switch bacteria between pathogenic and non-pathogenic states in a sophisticated way. Furthermore, we present an online platform of PSTCSome to facilitate updating, network visualization and user-customized analyses.
2022-10-04 | GSE148104 | GEO
Project description:Pseudomonas syringae uses HrpRSL to regulate the expression of type III secretion system (T3SS) genes and bacterial virulence. However, the molecular mechanism and the regulons of HrpRSL have yet to be fully elucidated. Here, we performed chromatin immunoprecipitation followed by high-throughput DNA sequencing (ChIP-seq) on HrpRSL and Lon. The direct regulation of these genes by corresponding regulator has been confirmed by Electrophoretic mobility shift assays (EMSAs) and quantitative real-time polymerase chain reactions (qRT-PCR). Binding motifs are found by using MEME suite and verified by footprint assays in vitro. Collectively, this work provides new cues to better understand the detailed regulatory networks of T3SS systems in P. syringae.
2015-12-31 | GSE65437 | GEO
Project description:Pseudomonas syringae uses two-component system RhpRS to regulate the expression of type III secretion system (T3SS) genes and bacterial virulence. However, the molecular mechanism and the regulons of RhpRS have yet to be fully elucidated. Here we show that RhpS functions as an autokinase, an RhpR kinase, and a P-RhpR phosphatase. RhpR can also be phosphorylated by small phosphodonor acetyl phosphate. A specific RhpR-binding site containing an inverted repeat (IR) motif GTATC-N6-GATAC, was mapped to its own promoter by DNase I footprint analysis. Electrophoretic mobility shift assay (EMSA) indicated that P-RhpR has higher binding activity than RhpR to the IR motif. To identify additional targets of RhpR in P. syringae, we performed chromatin immunoprecipitation followed by high-throughput DNA sequencing (ChIP-seq), which detected 167 enriched loci including the hrpR promoter, indicating the direct regulation of T3SS cascade genes by RhpR. Genome-wide microarray analysis showed that, besides the T3SS cascade genes, RhpR differentially regulates a large set of genes of various functions in response to different growth conditions. Together, these results suggested that RhpRS is a global regulator that allows P. syringae to sense and respond to environmental changes to coordinate the T3SS and many other biological processes. ChIP-seq analysis of RhpR
2014-10-01 | E-GEOD-58533 | biostudies-arrayexpress
Project description:Pseudomonas syringae uses two-component system RhpRS to regulate the expression of type III secretion system (T3SS) genes and bacterial virulence. However, the molecular mechanism and the regulons of RhpRS have yet to be fully elucidated. Here we show that RhpS functions as an autokinase, an RhpR kinase, and a P-RhpR phosphatase. RhpR can also be phosphorylated by small phosphodonor acetyl phosphate. A specific RhpR-binding site containing an inverted repeat (IR) motif GTATC-N6-GATAC, was mapped to its own promoter by DNase I footprint analysis. Electrophoretic mobility shift assay (EMSA) indicated that P-RhpR has higher binding activity than RhpR to the IR motif. To identify additional targets of RhpR in P. syringae, we performed chromatin immunoprecipitation followed by high-throughput DNA sequencing (ChIP-seq), which detected 167 enriched loci including the hrpR promoter, indicating the direct regulation of T3SS cascade genes by RhpR. Genome-wide microarray analysis showed that, besides the T3SS cascade genes, RhpR differentially regulates a large set of genes of various functions in response to different growth conditions. Together, these results suggested that RhpRS is a global regulator that allows P. syringae to sense and respond to environmental changes to coordinate the T3SS and many other biological processes.
2014-10-01 | GSE58533 | GEO
Project description:Pseudomonas syringae, the leading cause of crop diseases world-wide, uses type III secretion system (T3SS) to invade host plants. Our previous studies demonstrate that two-component system RhpRS enable P. syringae to coordinate T3SS gene expression, which is dependent on the phosphorylation state of RhpR in different environmental conditions. Homologs of RhpRS are distributed in a wide range of bacterial species, indicating a general regulatory mechanism. However, it remains elusive that how RhpRS relies on external signals and phosphorylation state to exercise its regulatory functions. To this end, we performed ChIP-seq assays to identify specific binding sites of RhpR and RhpRD70A in either King’s B (KB, T3SS-inhibiting medium) or minimal medium (MM, T3SS-inducing medium). Through data analysis, we identified 125 KB-dependent binding sites and 188 phosphorylation-dependent binding sites of RhpR. In KB, RhpR directly positively regulated cytochrome c550 production (via ccmA) and alcohol dehydrogenase activity (via adhB), but negatively regulated anthranilate synthase activity (via trpG) and protease activity (via hemB). Besides, phosphorylated RhpR (RhpR-P) directly negatively regulated T3SS (via hrpR and hopR1), swimming motility (via flhA), c-di-GMP level (via PSPPH_2590) and biofilm formation (via algD), while positively regulated twitching motility (via fimA) and lipopolysaccharide production (via PSPPH_2653). Our RNA-seq analyses newly identified 474 and 840 genes that regulated by RhpR in KB and MM respectively. Collectively, the present study revealed that rich nutrient condition allows RhpR to directly regulate the multiple metabolic pathways of P. syringae, while phosphorylation enables RhpR to specifically control virulence and cell envelope. RhpRS governs both virulence and multiple metabolic pathways by tuning its phosphorylation and sensing environmental signals in KB, respectively.
2019-03-01 | GSE122629 | GEO