Control of competence in Vibrio fischeri.

Control of competence in Vibrio fischeri. Appl Environ Microbiol. 2021 Jan 04;: Authors: Cohen JJ, Eichinger SJ, Witte DA, Cook CJ, Fidopiastis PM, Tepavčević J, Visick KL Abstract Vibrio species, including the squid symbiont Vibrio fischeri, become competent to take up DNA under specific conditions. For example, V. fischeri becomes competent when grown in the presence of chitin oligosaccharides or upon overproduction of the competence regulatory factor TfoX. While little is known about the regulatory pathway(s) that control V. fischeri competence, this microbe encodes homologs of factors that control competence in the well-studied V. cholerae To further develop V. fischeri as a genetically-tractable organism, we evaluated the roles of some of these competence homologs. Using TfoX-overproducing cells, we found that competence depends upon LitR, the homolog of V. cholerae master quorum sensing and competence regulator HapR, and on homologs of putative pili genes that in V. cholerae facilitate DNA uptake. Disruption of genes for negative regulators upstream of LitR, namely the LuxO protein and the sRNA Qrr1, resulted in increased transformation frequencies. Unlike LitR-controlled light production, however, competence did not vary with cell density under tfoX-overexpressing conditions. Analogous to V. cholerae, the requirement for LitR could be suppressed by loss of the Dns nuclease. We also found a role for the putative competence re...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research