scholarly journals Derivative of plant phenolic compound inhibits the type III secretion system ofDickeya dadantiivia HrpX/HrpY two-component signal transduction and Rsm systems

2014 ◽  
Vol 16 (2) ◽  
pp. 150-163 ◽  
Author(s):  
Yan Li ◽  
William Hutchins ◽  
Xiaogang Wu ◽  
Cuirong Liang ◽  
Chengfang Zhang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Phenolic Compound ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii ◽  
Two Component ◽  
Two Component Signal Transduction

scholarly journals The Plant Phenolic Compound p-Coumaric Acid Represses Gene Expression in the Dickeya dadantii Type III Secretion System

2008 ◽  
Vol 75 (5) ◽  
pp. 1223-1228 ◽  
Author(s):  
Yan Li ◽  
Quan Peng ◽  
Dija Selimi ◽  
Qi Wang ◽  
Amy O. Charkowski ◽  
...  
Keyword(s):  
Phenolic Compound ◽  
Type Iii Secretion ◽  
Bacterial Pathogens ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Hydroxyl Group ◽  
Coumaric Acid ◽  
Dickeya Dadantii ◽  
Type Iii

ABSTRACT The type III secretion system (T3SS) is a major virulence factor in many gram-negative bacterial pathogens. This secretion system translocates effectors directly into the cytosol of eukaryotic host cells, where the effector proteins facilitate bacterial pathogenesis by interfering with host cell signal transduction and other cellular processes. Plants defend themselves against bacterial pathogens by recognizing either the type 3 effectors or their actions and initiating a cascade of defense responses that often results in programmed cell death of the plant cell being attacked. Here we show that a plant phenolic compound, p-coumaric acid (PCA), represses the expression of T3SS genes of the plant pathogen Dickeya dadantii, suggesting that plants can also defend against bacterial pathogens by manipulating the expression of the T3SS. PCA repressed the expression of T3SS regulatory genes through the HrpX/Y two-component system, a core regulator of the T3SS, rather than through the global regulator GacS/A, which indirectly regulates the T3SS. A further analysis of several PCA analogs suggests that the para positioning of the hydroxyl group in the phenyl ring and the double bond of PCA may be important for its biological activity.

scholarly journals OmpR Regulates the Two-Component System SsrA-SsrB in Salmonella Pathogenicity Island 2

2000 ◽  
Vol 182 (3) ◽  
pp. 771-781 ◽  
Author(s):  
Anthea K. Lee ◽  
Corrella S. Detweiler ◽  
Stanley Falkow
Keyword(s):  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Regulatory System ◽  
Systemic Infection ◽  
Pathogenicity Island ◽  
Secretion System ◽  
Host Cells ◽  
Type Iii ◽  
Two Component ◽  
Footprint Analysis

ABSTRACT Salmonella pathogenicity island 2 (SPI-2) encodes a putative, two-component regulatory system, SsrA-SsrB, which regulates a type III secretion system needed for replication inside macrophages and systemic infection in mice. The sensor and regulator homologs,ssrAB (spiR), and genes within the secretion system, including the structural gene ssaH, are transcribed after Salmonella enters host cells. We have studied the transcriptional regulation of ssrAB and the secretion system by using gfp fusions to the ssrA andssaH promoters. We found that early transcription ofssrA, after entry into macrophages, is most efficient in the presence of OmpR. An ompR mutant strain does not exhibit replication within cultured macrophages. Furthermore, footprint analysis shows that purified OmpR protein binds directly to thessrA promoter region. We also show that minimal medium, pH 4.5, induces SPI-2 gene expression in wild-type but notompR mutant strains. We conclude that the type III secretion system of SPI-2 is regulated by OmpR, which activates expression of ssrA soon after Salmonella enters the macrophage.

The roles of SsrA–SsrB and OmpR–EnvZ in the regulation of genes encoding the Salmonella typhimurium SPI-2 type III secretion system

Microbiology ◽  
2003 ◽  
Vol 149 (9) ◽  
pp. 2385-2396 ◽  
Author(s):  
Junkal Garmendia ◽  
Carmen R. Beuzón ◽  
Javier Ruiz-Albert ◽  
David W. Holden
Keyword(s):  
Gene Expression ◽  
Salmonella Typhimurium ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Regulatory System ◽  
Secretion System ◽  
Host Cells ◽  
Environmental Signals ◽  
Type Iii ◽  
Two Component

The type III secretion system (TTSS) encoded by Salmonella typhimurium pathogenicity island 2 (SPI-2) is expressed after bacterial entry into host cells. The SPI-2 TTSS secretes the translocon components SseBCD, which translocate across the vacuolar membrane a number of effector proteins whose action is required for intracellular bacterial replication. Several of these effectors, including SifA and SifB, are encoded outside SPI-2. The two-component regulatory system SsrA–SsrB, encoded within SPI-2, controls the expression of components of the SPI-2 TTSS apparatus as well as its translocated effectors. The expression of SsrA–B is in turn regulated by the OmpR–EnvZ two-component system, by direct binding of OmpR to the ssrAB promoter. Several environmental signals have been shown to induce in vitro expression of genes regulated by the SsrA–B or OmpR–EnvZ systems. In this work, immunoblotting and flow cytometry were used to analyse the roles of SsrA–B and OmpR–EnvZ in coupling different environmental signals to changes in expression of a SPI-2 TTSS translocon component (SseB) and two effector genes (sifA and sifB). Using single and double mutant strains the relative contribution of each regulatory system to the response generated by low osmolarity, acidic pH or the absence of Ca2+ was determined. SsrA–B was found to be essential for the induction of SPI-2 gene expression in response to each of these individual signals. OmpR–EnvZ was found to play a minor role in sensing these signals and to require a functional SsrA–B system to mediate their effect on SPI-2 TTSS gene expression.

scholarly journals Regulation of the Type III Secretion System in Phytopathogenic Bacteria

2006 ◽  
Vol 19 (11) ◽  
pp. 1159-1166 ◽  
Author(s):  
Xiaoyan Tang ◽  
Yanmei Xiao ◽  
Jian-Min Zhou
Keyword(s):  
Signal Transduction ◽  
Hypersensitive Response ◽  
Type Iii Secretion ◽  
Pathogenic Bacteria ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Host Cells ◽  
Plant Pathogenic Bacteria ◽  
Type Iii ◽  
Hrp Genes

The type III secretion system (TTSS) is a specialized protein secretion machinery used by numerous gram-negative bacterial pathogens of animals and plants to deliver effector proteins directly into the host cells. In plant-pathogenic bacteria, genes encoding the TTSS were discovered as hypersensitive response and pathogenicity (hrp) genes, because mutation of these genes typically disrupts the bacterial ability to cause diseases on host plants and to elicit hypersensitive response on nonhost plants. The hrp genes and the type III effector genes (collectively called TTSS genes hereafter) are repressed in nutrient-rich media but induced when bacteria are infiltrated into plants or incubated in nutrient-deficient inducing media. Multiple regulatory components have been identified in the plant-pathogenic bacteria regulating TTSS genes under various conditions. In Ralstonia solanacearum, several signal transduction components essential for the induction of TTSS genes in plants are dispensable for the induction in inducing medium. In addition to the inducing signals, recent studies indicated the presence of negative signals in the plant regulating the Pseudomonas syringae TTSS genes. Thus, the levels of TTSS gene expression in plants likely are determined by the interactions of multiple signal transduction pathways. Studies of the hrp regulons indicated that TTSS genes are coordinately regulated with a number of non-TTSS genes.

scholarly journals S higella IpaD has a dual role: signal transduction from the type III secretion system needle tip and intracellular secretion regulation

2013 ◽  
Vol 87 (3) ◽  
pp. 690-706 ◽  
Author(s):  
A. Dorothea Roehrich ◽  
Enora Guillossou ◽  
Ariel J. Blocker ◽  
Isabel Martinez‐Argudo
Keyword(s):  
Signal Transduction ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Dual Role ◽  
Type Iii ◽  
Secretion Regulation

scholarly journals Ca 2+ -Induced Two-Component System CvsSR Regulates the Type III Secretion System and the Extracytoplasmic Function Sigma Factor AlgU in Pseudomonas syringae pv. tomato DC3000

2017 ◽  
Vol 200 (5) ◽  
Author(s):  
Maxwell R. Fishman ◽  
Johnson Zhang ◽  
Philip A. Bronstein ◽  
Paul Stodghill ◽  
Melanie J. Filiatrault
Keyword(s):  
Pseudomonas Syringae ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Dependent Manner ◽  
Tomato Dc3000 ◽  
Content Type ◽  
Type Iii ◽  
Two Component ◽  
Two Component Systems

ABSTRACT Two-component systems (TCSs) of bacteria regulate many different aspects of the bacterial life cycle, including pathogenesis. Most TCSs remain uncharacterized, with no information about the signal(s) or regulatory targets and/or role in bacterial pathogenesis. Here, we characterized a TCS in the plant-pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 composed of the histidine kinase CvsS and the response regulator CvsR. CvsSR is necessary for virulence of P. syringae pv. tomato DC3000, since Δ cvsS and Δ cvsR strains produced fewer symptoms than the wild type (WT) and demonstrated reduced growth on multiple hosts. We discovered that expression of cvsSR is induced by Ca 2+ concentrations found in leaf apoplastic fluid. Thus, Ca 2+ can be added to the list of signals that promote pathogenesis of P. syringae pv. tomato DC3000 during host colonization. Through chromatin immunoprecipitation followed by next-generation sequencing (ChIP-seq) and global transcriptome analysis (RNA-seq), we discerned the CvsR regulon. CvsR directly activated expression of the type III secretion system regulators, hrpR and hrpS , that regulate P. syringae pv. tomato DC3000 virulence in a type III secretion system-dependent manner. CvsR also indirectly repressed transcription of the extracytoplasmic sigma factor algU and production of alginate. Phenotypic analysis determined that CvsSR inversely regulated biofilm formation, swarming motility, and cellulose production in a Ca 2+ -dependent manner. Overall, our results show that CvsSR is a key regulatory hub critical for interaction with host plants. IMPORTANCE Pathogenic bacteria must be able to react and respond to the surrounding environment, make use of available resources, and avert or counter host immune responses. Often, these abilities rely on two-component systems (TCSs) composed of interacting proteins that modulate gene expression. We identified a TCS in the plant-pathogenic bacterium Pseudomonas syringae that responds to the presence of calcium, which is an important signal during the plant defense response. We showed that when P. syringae is grown in the presence of calcium, this TCS regulates expression of factors contributing to disease. Overall, our results provide a better understanding of how bacterial pathogens respond to plant signals and control systems necessary for eliciting disease.

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