Meeting Abstract

86.6  Monday, Jan. 6 11:15  Ecological Diversification of Vibrio fischeri During the Planktonic Phase & Subsequent Consequences for Squid Host Colonization SOTO, W*; TRAVISANO, M; NISHIGUCHI, M.K.; University of Minnesota, Twin Cities; University of Minnesota, Twin Cities; New Mexico State University nish@nmsu.edu

Stable microcosm experiments with bacteria have become model systems for studying microbial ecological diversification, whereby standing liquid cultures founded by planktonic, water-column inhabiting cells that form smooth colonies (smooth morphs) on agar plates differentiate into alternative types due to resource competition as a result of mutations. These variant cell types can either establish pellicle and/or benthic populations in structured, undisturbed, and heterogeneous microcosms. When grown on agar plates, the derived cell types can form wrinkled and fuzzy colonies (wrinkly-spreaders and fuzzy spreaders). Bacteria in the family Vibrionaceae are gram-negative bacteria living in marine and brackish waters as planktonic cells and biofilms attached to abiotic surfaces or eukaryotic host cells. In particular, Vibrio fischeri is a marine bioluminescent microbe that exists mutualistically with sepiolid squids and monocentrid fishes. Although V. fischeri has been well studied as a beneficial bacterium during host colonization, adaptive radiation during the free-living phase due to mutations and the accompanying effects on animal host colonization are poorly understood. V. fischeri wrinkly-spreaders that evolve in stable microcosms as free-living cells are competitively superior during squid colonization relative to their smooth morph ancestors, indicating that simple de novo mutations can significantly affect symbiosis. Understanding how bacteria are capable of adapting to fluctuating conditions in the environment may provide insight to how organisms accommodate these changes to their dual life history between planktonic and symbiotic states.