VpsT Is a Transcriptional Regulator Required for Expression of <i>vps</i> Biosynthesis Genes and the Development of Rugose Colonial Morphology in <i>Vibrio cholerae</i> O1 El Tor

Abstract

Vibrio cholerae switches between smooth and rugose colonial variants. The rugose variant produces more vibrio polysaccharides (VPS(El Tor)) and forms well-developed biofilms. Both phenotypes depend on expression of vps biosynthesis genes. We identified a positive transcriptional regulator of vps gene expression, VpsT, which is homologous to response regulators of two-component regulatory systems. Disruption of vpsT in the rugose variant yields smooth colonies, prevents formation of mature biofilms, and decreases vps gene expression. The interaction between VpsT and VpsR, a previously identified positive regulator of vps genes, was also investigated.