Characterization of multi-species bacterial interactions underlying the beneficial symbiosis of a Mediterranean squid.

Animals often use associations with microbes to preserve their health. These mutualisms are maintained by host-microbe communication and though interactions between bacterial symbionts. The squid-vibrio symbiosis has been used for over 30-years to study beneficial host-microbe associations.

However, nearly all studies of the symbiosis have used Euprymna scolopes and its only symbiont, Vibrio fischeri, which precludes examination of how multiple microbial species affect symbiosis.

Using the squid Sepiola affinis, and its two symbionts, V. fischeri and Vibrio logei, the SquidVibrio project proposes to examine the effects of multiple microbial species within a mutualism.

The project is organized into three objectives. 1) Implement a husbandry facility for S. affinis. 2) Quantify the symbiont populations within the S. affinis light organ over seasons and over maturation. 3) Identify how the symbiont populations alter metabolites within the light organ.

First, a husbandry facility will be established at the Banyuls-sur-Mer Oceanographic Observatory that will allow for the maintenance of wild S. affinis and for rearing of the squid. Second, metagenomics will be used to estimate the proportions of V. fischeri and V. logei within the light organ.

Subsequently, light organs of field-caught and reared squid will be imaged using confocal microscopy to identify if the Vibrio spp. inhabit mixed or distinct niches.

The third objective will use LC-MS and mass spectrometry imaging to identify metabolites that are altered by each Vibrio spp. and how localization patterns of these molecules are affected.

These methods will allow for the two-way transfer of knowledge, with the researcher providing squid husbandry techniques and the host institution providing genomics and metabolomics.

The SquidVibrio project will establish S. affinis as a model organism in Europe that can provide insights into how symbionts interact both with each other and their host to underly a mutualism.