70.4 Friday, Jan. 6 Spatial and temporal patterns among symbiotic Vibrio fischeri: Environment matters! PUNKE, Erin B.*; NISHIGUCHI, Michele K.; New Mexico State University; New Mexico State University firstname.lastname@example.org
The association between Vibrio fischeri (γ-proteobacteria: Vibrionaceae) and the sepiolid squid, Euprymna tasmanica (Mollusca: Cephalopoda), is an ideal model for understanding how abiotic factors can drive this environmentally transmitted symbiosis. V. fischeri are cosmopolitan marine bacteria and are known to environmentally infect the light organ of their squid host during the onset of the symbiosis. Bacterial diversity is high both geographically and temporally, where persistent dominant strains exist throughout both space and time. Free-living vibrios are strongly influenced by environmental conditions, suggesting that constant abiotic fluctuations in areas of thriving Euprymna–Vibrio associations may be a driving factor in both the formation and continuation of this mutualism. Utilizing geographically distinct V. fischeri strains, we experimentally evolved these bacteria to a wide range of temperatures, and examined growth and competitive dominance compared to native wild-type strains. Results show a gain in fitness in the evolved strains, giving further support to temperature adaptation being a dominant factor behind bacterial phenotypic plasticity. Furthermore, we examined whether temperature was an underlying factor controlling patterns of diversity among V. fischeri on a temporal scale. Further understanding of survival limits and temperature thresholds of symbiotic bacteria will provide insight into adaptation of an environmentally transmitted mutualism subjected to daily and seasonal environmental fluctuations.