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Cyclic‐diGMP signal transduction systems in Vibrio cholerae : modulation of rugosity and biofilm formation
Author(s) -
Lim Bentley,
Beyhan Sinem,
Meir James,
Yildiz Fitnat H.
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05106.x
Subject(s) - biofilm , vibrio cholerae , biology , phosphodiesterase , signal transduction , microbiology and biotechnology , gene , mutant , biochemistry , genetics , bacteria , enzyme
Summary Cyclic di‐guanylic acid (c‐diGMP) is a second messenger that modulates the cell surface properties of several microorganisms. Concentrations of c‐diGMP in the cell are controlled by the opposing activities of diguanylate cyclases and phosphodiesterases, which are carried out by proteins harbouring GGDEF and EAL domains respectively. In this study, we report that the cellular levels of c‐diGMP are higher in the Vibrio cholerae rugose variant compared with the smooth variant. Modulation of cellular c‐diGMP levels by overexpressing proteins with GGDEF or EAL domains increased or decreased colony rugosity respectively. Several genes encoding proteins with either GGDEF or EAL domains are differentially expressed between the two V. cholerae variants. The generation and characterization of null mutants of these genes ( cdgA–E , rocS and mbaA ) revealed that rugose colony formation, exopolysaccharide production, motility and biofilm formation are controlled by their action. Furthermore, epistasis analysis suggested that cdgC , rocS and mbaA act in convergent pathways to regulate the phenotypic properties of the rugose and smooth variants, and are part of the VpsR, VpsT and HapR signal transduction pathway.