Document Type
Article
Publication Date
10-26-2012
Abstract
The type VI secretion system (T6SS) mediates protein translocation across the cell membrane of Gram-negative bacteria, including Vibrio cholerae - the causative agent of cholera. All V. cholerae strains examined to date harbor gene clusters encoding a T6SS. Structural similarity and sequence homology between components of the T6SS and the T4 bacteriophage cell-puncturing device suggest that the T6SS functions as a contractile molecular syringe to inject effector molecules into prokaryotic and eukaryotic target cells. Regulation of the T6SS is critical. A subset of V. cholerae strains, including the clinical O37 serogroup strain V52, express T6SS constitutively. In contrast, pandemic strains impose tight control that can be genetically disrupted: mutations in the quorum sensing gene luxO and the newly described regulator gene tsrA lead to constitutive T6SS expression in the El Tor strain C6706. In this report, we examined environmental V. cholerae isolates from the Rio Grande with regard to T6SS regulation. Rough V. cholerae lacking O-antigen carried a nonsense mutation in the gene encoding the global T6SS regulator VasH and did not display virulent behavior towards Escherichia coli and other environmental bacteria. In contrast, smooth V. cholerae strains engaged constitutively in type VI-mediated secretion and displayed virulence towards prokaryotes (E. coli and other environmental bacteria) and a eukaryote (the social amoeba Dictyostelium discoideum). Furthermore, smooth V. cholerae strains were able to outcompete each other in a T6SS-dependent manner. The work presented here suggests that constitutive T6SS expression provides V. cholerae with an advantage in intraspecific and interspecific competition. © 2012 Unterweger et al.
Recommended Citation
Unterweger, Daniel, Maya Kitaoka, Sarah T. Miyata, Verena Bachmann, Teresa M. Brooks, Jessica Moloney, Oscar Sosa et al. "Constitutive type VI secretion system expression gives Vibrio cholerae intra-and interspecific competitive advantages." PloS one 7, no. 10 (2012): e48320. https://doi.org/10.1371/journal.pone.0048320
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Publication Title
Plos One
DOI
10.1371/journal.pone.0048320
Comments
Copyright: © 2012 Unterweger et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.