Meeting Abstract

P3.1  Jan. 6  The roles of UDP-glucose-6-dehydrogenase and mshA in colonization of the squid-luminescent bacterial symbiosis. ARIYAKUMAR, D*; ALVILLAR, R; NISHIGUCHI, M.K; New Mexico State University; New Mexico State University; New Mexico State University donsanji@nmsu.edu

Mutualistic associations between the sepiolid squid Euprymna tasmanica (Mollusca: Cephalopoda) and the luminescent bacterium Vibrio fischeri have been extensively studied as a model to understand gene expression, phylogeography, and cospeciation. Juvenile squids lack symbiont bacteria, but obtain their Vibrio symbionts within a few hours after hatching. Although this colonization event is specific, symbiotic bacteria must overcome several obstacles to successfully attach and colonize the light organ. Here we examine the effects of two symbiotic genes that are responsible for initial attachment and biofilm formation in squid light organs. UDPDH (Uranyl diphospahte-6-dehydrogenase) and mshA (mannose sensitive hemagglutinin) mutants were generated in V. fischeri by single recombinant techniques, to determine whether each have an effect on host colonization and specificity. Growth curves were generated to determine generation times for mutant and wild types, as well as bioluminescence measurements for light emission. Biofilm assays were also completed to confirm differences in phenotypes of UDPDH and mshA mutants. This study reveals the importance of UDPDH and mshA gene expression for successful light organ colonization by V. fischeri, and also aids in the understanding of host specificity in an environmentally transmitted symbiosis.