Dataset Information

Novel virulence gene of Pseudomonas syringae pv. tomato strain DC3000.

ABSTRACT: Previously, we conducted a mutant screen of Pseudomonas syringae pv. tomato strain DC3000 to identify genes that contribute to virulence on Arabidopsis thaliana plants. Here we describe the characterization of one mutant strain, DB4H2, which contains a single Tn5 insertion in PSPTO3576, an open reading frame that is predicted to encode a protein belonging to the TetR family of transcriptional regulators. We demonstrate that PSPTO3576 is necessary for virulence in DC3000 and designate the encoded protein TvrR (TetR-like virulence regulator). TvrR, like many other TetR-like transcriptional regulators, negatively regulates its own expression. Despite the presence of a putative HrpL binding site in the tvrR promoter region, tvrR is not regulated by HrpL, an alternative sigma factor that regulates the expression of many known DC3000 virulence genes. tvrR mutant strains grow comparably to wild-type DC3000 in culture and possess an intact type III secretion system. However, tvrR mutants do not cause disease symptoms on inoculated A. thaliana and tomato plants, and their growth within plant tissue is significantly impaired. We demonstrate that tvrR mutant strains are able to synthesize coronatine (COR), a phytotoxin required for virulence of DC3000 on A. thaliana. Given that tvrR mutant strains are not defective for type III secretion or COR production, tvrR appears to be a novel virulence factor required for a previously unexplored process that is necessary for pathogenesis.

SUBMITTER: Preiter K

PROVIDER: S-EPMC1280305 | biostudies-literature | 2005 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Novel virulence gene of Pseudomonas syringae pv. tomato strain DC3000.

Preiter Karen K Brooks David M DM Penaloza-Vazquez Alejandro A Sreedharan Aswathy A Bender Carol L CL Kunkel Barbara N BN

Journal of bacteriology 20051101 22

Previously, we conducted a mutant screen of Pseudomonas syringae pv. tomato strain DC3000 to identify genes that contribute to virulence on Arabidopsis thaliana plants. Here we describe the characterization of one mutant strain, DB4H2, which contains a single Tn5 insertion in PSPTO3576, an open reading frame that is predicted to encode a protein belonging to the TetR family of transcriptional regulators. We demonstrate that PSPTO3576 is necessary for virulence in DC3000 and designate the encoded ...[more]

PMID: 16267304

Similar Datasets

Project description:UnlabelledPlant-pathogenic bacteria are able to integrate information about their environment and adjust gene expression to provide adaptive functions. AlgU, an extracytoplasmic function (ECF) sigma factor encoded by Pseudomonas syringae, controls expression of genes for alginate biosynthesis and genes involved with resisting osmotic and oxidative stress. AlgU is active while these bacteria are associated with plants, where its presence supports bacterial growth and disease symptoms. We found that AlgU is an important virulence factor for P. syringae pv. tomato DC3000 but that alginate production is dispensable for disease in host plants. This implies that AlgU regulates additional genes that facilitate bacterial pathogenesis. We used transcriptome sequencing (RNA-seq) to characterize the AlgU regulon and chromatin immunoprecipitation sequencing (ChIP-seq) to identify AlgU-regulated promoters associated with genes directly controlled by this sigma factor. We found that in addition to genes involved with alginate and osmotic and oxidative stress responses, AlgU regulates genes with known virulence functions, including components of the Hrp type III secretion system, virulence effectors, and the hrpL and hrpRS transcription regulators. These data suggest that P. syringae pv. tomato DC3000 has adapted to use signals that activate AlgU to induce expression of important virulence functions that facilitate survival and disease in plants.ImportancePlant immune systems produce antimicrobial and bacteriostatic conditions in response to bacterial infection. Plant-pathogenic bacteria are adapted to suppress and/or tolerate these conditions; however, the mechanisms controlling these bacterial systems are largely uncharacterized. The work presented here provides a mechanistic explanation for how P. syringae pv. tomato DC3000 coordinates expression of multiple genetic systems, including those dedicated to pathogenicity, in response to environmental conditions. This work demonstrates the scope of AlgU regulation in P. syringae pv. tomato DC3000 and characterizes the promoter sequence regulated by AlgU in these bacteria.

Dataset Information

Novel virulence gene of Pseudomonas syringae pv. tomato strain DC3000.

Publications

Novel virulence gene of Pseudomonas syringae pv. tomato strain DC3000.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets