Occurrence of plasmid DNA in the sepiolid squid symbiont Vibrio fischeri

摘要: Because of the importance plasmids in many bacterial associations with plants and animals, we determined occurrence distribution plasmid DNA symbioticVibrio fischeri from light organ sepiolid squidEuprymna scolopes. Analyses 225 isolates symbioticV. 25 individual squids revealed an overall plasmid-carriage rate 56%. A large (≥39 kb) was detected 96% those carrying plasmids, multiple small were found to co-occur one 81% plasmid-carrying strains. In addition, these appear be restricted toV. strains isolated fromE. scolopes seawater at sites squid populations. We unable assign a role or function but they do not carry genes required for establishment symbiosis. conclude that essential symbiotic determinants must encoded on chromosome may are important survival theseV. outside association.