More than 100 species of gutless worms have been found in marine sediments around the world, and they have formed symbiotic relationships with bacteria that provide them with nutrition and have enabled them to colonize nutrient-poor environments. The symbionts are so efficient at feeding their hosts and recycling their waste compounds that the worms have completely reduced their digestive and excretory systems. While the importance of symbioses between plants and microbes has long been recognized by applied biologists, beneficial associations between animals and microbes have only recently begun to attract their attention. The associations between gutless marine worms and their bacterial symbiont communities are ideal model systems for the study of beneficial animal-microbe symbioses. The best-studied species is O. algarvensis from the Mediterranean and the metagenome of this worm’s microbial consortium was sequenced by the DOE JGI. Studies revealed that the symbionts use energy sources not previously known to play a role in marine symbioses, namely hydrogen and carbon monoxide. More complete genomes of the O. algarvensis symbionts will give better insight into how the use and production of these unexpected energy sources are involved in carbon dioxide fixation and growth in this symbiosis.
Proposer’s Name: Nicole Dubilier & Manuel Kleiner