title: Phylogeny and fitness of Vibrio fischeri from the light organs of Euprymna scolopes in two Oahu, Hawaii populations.
abstract: The evolutionary relationship among Vibrio fischeri isolates obtained from the light organs of Euprymna scolopes collected around Oahu, Hawaii, were examined in this study. Phylogenetic reconstructions based on a concatenation of fragments of four housekeeping loci (recA, mdh, katA, pyrC) identified one monophyletic group ('Group-A') of V. fischeri from Oahu. Group-A V. fischeri strains could also be identified by a single DNA fingerprint type. V. fischeri strains with this fingerprint type had been observed to be at a significantly higher abundance than other strains in the light organs of adult squid collected from Maunalua Bay, Oahu, in 2005. We hypothesized that these previous observations might be related to a growth/survival advantage of the Group-A strains in the Maunalua Bay environments. Competition experiments between Group-A strains and non-Group-A strains demonstrated an advantage of the former in colonizing juvenile Maunalua Bay hosts. Growth and survival assays in Maunalua Bay seawater microcosms revealed a reduced fitness of Group-A strains relative to non-Group-A strains. From these results, we hypothesize that there may exist trade-offs between growth in the light organ and in seawater environments for local V. fischeri strains from Oahu. Alternatively, Group-A V. fischeri may represent an example of rapid, evolutionarily significant, specialization of a horizontally transmitted symbiont to a local host population.
authors.affiliation: Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706-1521, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Wollenberg
authors.forename: Edward G
authors.initials: EG
authors.lastname: Ruby
mesh_terms: D048908:Aliivibrio fischeri / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D000818:Animals; D061006:Bays; D016172:DNA Fingerprinting; D049832:Decapodiformes / Q000254:growth & development / Q000382:microbiology*; D005798:Genes, Bacterial / Q000235:genetics; D006254:Hawaii; D008969:Molecular Sequence Data; D010802:Phylogeny; D011995:Recombination, Genetic; D013559:Symbiosis / Q000502:physiology