CytR Is a Global Positive Regulator of Competence, Type VI Secretion, and Chitinases in Vibrio cholerae

PLoS One. 2015 Sep 24;10(9):e0138834. doi: 10.1371/journal.pone.0138834. eCollection 2015.

Abstract

The facultative pathogen Vibrio cholerae transitions between its human host and aquatic reservoirs where it colonizes chitinous surfaces. Growth on chitin induces expression of chitin utilization genes, genes involved in DNA uptake by natural transformation, and a type VI secretion system that allows contact-dependent killing of neighboring bacteria. We have previously shown that the transcription factor CytR, thought to primarily regulate the pyrimidine nucleoside scavenging response, is required for natural competence in V. cholerae. Through high-throughput RNA sequencing (RNA-seq), we show that CytR positively regulates the majority of competence genes, the three type VI secretion operons, and the four known or predicted chitinases. We used transcriptional reporters and phenotypic analysis to determine the individual contributions of quorum sensing, which is controlled by the transcription factors HapR and QstR; chitin utilization that is mediated by TfoX; and pyrimidine starvation that is orchestrated by CytR, toward each of these processes. We find that in V. cholerae, CytR is a global regulator of multiple behaviors affecting fitness and adaptability in the environment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Bacterial Secretion Systems / genetics*
  • Chitinases / metabolism*
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial
  • Microbial Viability / genetics
  • Nucleosides / metabolism
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Transcriptome / genetics
  • Vibrio cholerae / enzymology*
  • Vibrio cholerae / genetics

Substances

  • Bacterial Proteins
  • Bacterial Secretion Systems
  • CytR protein, Vibrio cholerae
  • Nucleosides
  • Repressor Proteins
  • Chitinases

Grant support

S Watve, J Thomas, and BK Hammer were supported by a grant MCB-1149925 from the National Science Foundation (http://www.nsf.gov). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.