Meeting Abstract
The beneficial association between squids in the family Sepiolidae (Mollusca: Cephalopoda) and bioluminescent bacteria in the family Vibrionaceae form a unique relationship that provides a model to study the interactions between animals and bacteria. Sepiolid squids from the Mediterranean Sea (genus Sepiola) are unique in that these squids serve as hosts for two bioluminescent bacterial species: Vibrio logei and Vibrio fischeri. Quorum sensing, or cell-to-cell communication regulates luminescence genes in both bacterial species, which generate the appropriate amount of bioluminescence within the squid to match any down- welling moonlight. Interestingly, little is known about how these two species are capable of communicating between each other during symbiosis. Therefore, we examined the mechanisms of quorum sensing between V. fischeri and V. logei, two luminescent symbionts found in Sepiola light organs. We created a null mutation on the response regulator gene luxO to determine whether mutations at this locus affect the ability of bacteria to communicate within and between both species during symbiosis. Our results demonstrated that luxO is required for luminescence production, but additional secondary regulatory genes are responsible for luxO regulation after a 24-hour time period. Understanding how bacteria are able to communicate within a closed system such as the sepiolid squid-Vibrio symbiosis will provide a window as to how mutualistic bacteria evolve cooperative mechanisms in a complex beneficial association.
