Untangling the genomic basis of bacterial symbiosis in gutless worms (360G-Wellcome-213981_Z_18_Z)

Bacterial symbiosis has decisively contributed to the evolution of life on Earth, but also underpins prevalent human disorders related to the digestive system, like obesity and diabetes. However, our understanding of how symbiotic bacteria influence host biology is limited. Siboglinid worms exhibit a remarkable case of symbiosis, where bacteria taken from the environment induce the loss of the gut as the worms harvest the bacteria inside their bodies for nutrients. Therefore, these gutless worms are a unique system to investigate the impact of bacterial symbiosis on gut development and the evolution of extreme dependency on symbiotic microbes. The key goals are: Identify common and lineage-specific genomic adaptations to bacterial symbiosis in siboglinid worms. Identify transcriptome-wide gene regulatory changes associated with symbiosis in the worm Siboglinum fiordicum. I will sequence, assemble, and annotate the genomes of Riftia pachyptila, Osedax rubiplumus and S. fiordicum and perform differential gene expression analyses of asymbiotic gut-containing larvae and symbiotic gutless adults of S. fiordicum. These outcomes will provide the first genomic and transcriptomic insights on bacterial symbiosis on these worms and set the foundations to establish S. fiordicum as a model to dissect the genomic, developmental, and physiological effects of bacterial symbiosis in animal guts.