Meeting Abstract
Many types of bacteria increase population diversity by phase variation that allows survival and evolutionary success. One example of such variation is the symbiotic bacterium Vibrio fischeri (g-Proteobacteria: Vibrionaceae) that can switch from a smooth to a wrinkled or rugose phenotype characterized by the secretion of polysaccharides. These changes in colony morphologies also affect the ability of V. fischeri to colonize their animal hosts. Phenotypic variation between smooth and rugose colonies is tightly controlled by changes genetic expression that extend beyond the simple overall morphology. In the present study we conducted a transcriptomic expression profile by RNA sequencing of the rugose and smooth variants of multiple isolates of V. fischeri. Expression profiling led to identification of 130 differentially regulated genes, including overexpression of genes involved in oxidative stress, surface structures, and metabolic processes in the rugose variants. In contrast, there was an increase in expression of genes related to membrane transport in smooth variants. Transcriptome signatures also consisted of upregulated genes involved in biofilm formation, environmental sensing and persistence, and signal transduction, which were shared by both smooth and rugose variants. Bioinformatic analysis of these expression data shows that “rugosity” and “smoothness” are determined by a complex hierarchy of genetic regulators, that provide a better picture for Vibrio ecology, and mechanisms for successful survival in the host and environment.
