LonB mutant
Ontology highlight
ABSTRACT:
ORGANISM(S): Pseudomonas syringae pv. tomato str. DC3000
PROVIDER: GSE6121 | GEO | 2007/10/15
SECONDARY ACCESSION(S): PRJNA97615
REPOSITORIES: GEO
Similar Datasets
Project description:The bacterial Lon protease participates in a variety of biological processes. In Pseudomonas syringae, mutation of lon is known to activate hrpL and a few hrpL-regulated genes in the rich medium. The elevated expression of hrpL and hrpL-regulated genes results from of increased stability of HrpR, the transcriptional activator of hrpL, in the lon mutant. Here we conducted a microarray analysis to determine genes that are differently expressed in the lon- mutant of P. s. pv. tomato DC3000 grown in the rich medium KB. Most genes induced in the lon- mutant belong to the HrpL-regulon or are related to the transcription, protein synthesis, and energy metabolism. The major group of genes reduced in the lon- mutant is related to cell wall biogenesis. The HrpL-regulated genes exhibit different induction patterns in the lon- mutant, suggesting the involvement of regulators additional to HrpL in regulating these genes. Compared with the wild type bacteria, the lon- mutants exhibit elevated hrpL expression in KB medium but reduced hrpL expression in the minimal medium (MM). The reduced hrpL RNA is correlated with the reduced hrpR and hrpS RNAs, suggesting that the Lon-mediated regulation of hrpL involves different mechanisms in KB and MM. Consistent with the reduced expression of the hrpL in MM, the lon- mutants are less pathogenic on host plants. Keywords: Expression profiles of lonB mutant in KB three samples ( biological replicates) of mutation were analyzed
2007-10-14 | E-GEOD-6121 | biostudies-arrayexpress
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:Pseudomonas syringae pv. tomato DC3000 is a model pathogen infecting tomato and Arabidopsis plants. Genes encoding the type III secretion system and substrate proteins (collectively called TTSS genes) of this bacterium are induced in plants and in minimal medium (MM). The induction of TTSS genes is mediated by HrpL, an alternative sigma factor recognizing the hrp box in the promoter of TTSS genes. The transcription of hrpL is activated by HrpR and HrpS, two homologous DNA binding proteins encoded by the hrpRS operon. Microarray analysis was conducted to evaluate the DC3000 genes regulated by hrpL and hrpRS in MM. The analysis identified a number of novel hrpLactivated genes with a putative TTSS-independent function. Genes regulated by hrpL were mostly regulated by hrpRS in the same manner, but a large number of genes regulated by hrpRS were hrpL-independent, indicating that hrpL represents one branch of the regulatory pathways downstream of hrpRS. The induction of the TTSS genes was associated with down-regulation of the house-keeping genes, indicating that the activation of the TTSS has a cost on the basic cellular activities. The novel genes/pathways identified by the microarray provide new insight into the bacterial functions coordinating with the TTSS.
2006-08-01 | GSE4848 | GEO
Project description:ChIP-seq for HrpR, HrpS, and HrpL
| PRJNA408144 | ENA
Project description:Pseudomonas syringae, a Gram-negative plant pathogen, infects more than 50 crops with its type III secretion system (T3SS) and causes severe economic losses around the world. Although the mechanisms of virulence-associated regulators of P. syringae T3SS have been studied for decades, the crosstalk and network underlying these regulators are still elusive. Previously, we have individually studied a group of T3SS regulators, including AefR, HrpS, and RhpRS. In the present study, we found 4 new T3SS regulator genes (envZ, ompR, tsiS and phoQ) via transposon-mediated mutagenesis. Two-component systems EnvZ and TsiS natively regulate T3SS. In order to uncover the crosstalk between 16 virulence-associated regulators, (including AefR, AlgU, CvsR, GacA, HrpL, HrpR, HrpS, MgrA, OmpR, PhoP, PilR, PsrA, RhpR, RpoN, TsiR and Vfr) in P. syringae, we mapped an intricate network named PSVnet (Pseudomonas syringae Virulence Regulatory Network) by combining differentially expression genes in RNA-seq and binding loci in ChIP-seq of all regulators.
2021-03-29 | GSE138204 | GEO
Project description:Lon protease plays vital roles in many biological processes in Pseudomonas syringae, including type III secretion systems (T3SS), transcription regulation, protein synthesis and energy metabolism. Lon also functions as a transcriptional regulator in other bacterial species (e.g., Escherichia coli and Brevibacillus thermoruber). Therefore, we hypothesise that Lon has dual functions in P. syringae. To reveal the molecular mechanisms of Lon as a transcriptional regulator and protease under different environmental conditions, we used a combination of transcriptome sequencing (RNA-seq), chromatin immunoprecipitation sequencing (ChIP-seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the genes or proteins regulated by Lon. As a transcriptional regulator, Lon bound to the promoter regions of PSPPH_4788, gacA, fur, gntR, clpS, lon and glyA and consequently regulated 1-dodecanol oxidation activity, motility, pyoverdine production, gluconokinase activity, N-end rule pathway, lon expression and serine hydroxymethyltransferase (SHMT) activity in King’s B medium (KB). In minimal medium (MM), Lon regulated SHMT activity and lon expression by binding to the promoter regions of glyA and lon, respectively. As a protease, Lon regulated the T3SS and metabolic pathways (e.g., amino acid metabolism). In MM, Lon regulated the polysaccharide metabolic process by controlling PSPPH_0514, AlgA, CysD and PSPPH_4991. Taken together, these data demonstrate that Lon acts as a transcriptional regulator or protease in different environments and tunes its virulence and metabolic functions accordingly.
2020-06-30 | GSE137273 | 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
Project description:Background Dickeya dadantii is a necrotrophic pathogen causing disease in many plants. Previous studies have demonstrated that the type III secretion system (T3SS) of D. dadantii is required for full virulence. HrpL is an alternative sigma factor that binds to the hrp box promoter sequence of T3SS genes to up-regulate their expression. Methodology/Principal Findings To explore the inventory of HrpL-regulated genes of D. dadantii 3937 (3937), transcriptome profiles of wild-type 3937 and a hrpL mutant grown in a T3SS-inducing medium were examined. Using a cut-off value of 1.5, significant differential expression was observed in sixty-three genes, which are involved in various cellular functions such as type III secretion, chemotaxis, metabolism, regulation, and stress response. A hidden Markov model (HMM) was used to predict candidate hrp box binding sites in the intergenic regions of 3937, including the promoter regions of HrpL-regulated genes identified in the microarray assay. In contrast to biotrophic phytopathgens such as Pseudomonas syringae, among the HrpL up-regulated genes in 3937 only those within the T3SS were found to contain a hrp box sequence. Moreover, direct binding of purified HrpL protein to the hrp box was demonstrated for hrp box-containing DNA fragments of hrpA and hrpN using the electrophoretic mobility shift assay (EMSA). In this study, a putative T3SS effector DspA/E was also identified as a HrpL-upregulated gene, and shown to be translocated into plant cells in a T3SS-dependent manner. Conclusion/Significances We provide the genome-wide study of HrpL-regulated genes in a necrotrophic phytopathogen (D. dadantii 3937) through a combination of transcriptomics and bioinformatics, which led to identification of several effectors. Our study indicates the extent of differences for T3SS effector protein inventory requirements between necrotrophic and biotrophic pathogens, and may allow the development of different strategies for disease control for these different groups of pathogens.
2010-10-21 | GSE17185 | GEO
Project description:Background Dickeya dadantii is a necrotrophic pathogen causing disease in many plants. Previous studies have demonstrated that the type III secretion system (T3SS) of D. dadantii is required for full virulence. HrpL is an alternative sigma factor that binds to the hrp box promoter sequence of T3SS genes to up-regulate their expression. Methodology/Principal Findings To explore the inventory of HrpL-regulated genes of D. dadantii 3937 (3937), transcriptome profiles of wild-type 3937 and a hrpL mutant grown in a T3SS-inducing medium were examined. Using a cut-off value of 1.5, significant differential expression was observed in sixty-three genes, which are involved in various cellular functions such as type III secretion, chemotaxis, metabolism, regulation, and stress response. A hidden Markov model (HMM) was used to predict candidate hrp box binding sites in the intergenic regions of 3937, including the promoter regions of HrpL-regulated genes identified in the microarray assay. In contrast to biotrophic phytopathgens such as Pseudomonas syringae, among the HrpL up-regulated genes in 3937 only those within the T3SS were found to contain a hrp box sequence. Moreover, direct binding of purified HrpL protein to the hrp box was demonstrated for hrp box-containing DNA fragments of hrpA and hrpN using the electrophoretic mobility shift assay (EMSA). In this study, a putative T3SS effector DspA/E was also identified as a HrpL-upregulated gene, and shown to be translocated into plant cells in a T3SS-dependent manner. Conclusion/Significances We provide the genome-wide study of HrpL-regulated genes in a necrotrophic phytopathogen (D. dadantii 3937) through a combination of transcriptomics and bioinformatics, which led to identification of several effectors. Our study indicates the extent of differences for T3SS effector protein inventory requirements between necrotrophic and biotrophic pathogens, and may allow the development of different strategies for disease control for these different groups of pathogens. Analysis used aerobic steady state RNA from wild-type as control samples for comparison to the experimental samples of hrpL mutant taken 6 h post-inoculation in T3SS inducible minimum media. The microarray results are based on the geomean of ten normalized expression values derived from three biological replicates and two dye-swap experiments with a technology replicate for each array.
2010-10-21 | E-GEOD-17185 | biostudies-arrayexpress
Project description:ChIP-seq and RNA-seq for RhpR in KB and MM medium
| PRJNA505809 | ENA