Meeting Abstract
The siboglinid Lamellibrachia luymesi van der Land and Nørrevang 1975 is a tubeworm found on cold seeps in the Gulf of Mexico. Like other siboglinids, L. luymesi lacks a digestive system and relies on chemoautotrophic sulfide-oxidizing bacterial endosymbionts for nutrition. Phylogenetic studies show that symbiont lineages are specific to major groups of siboglinids, implying some degree of adaptation by the holobiont to different habitats and resources. Despite previous studies, the dependence and metabolic contributions between the host and symbiont are still poorly understood. A recent study on the hydrothermal vent mussel Bathymodiolus azoricus analyzed the amino acid biosynthesis pathway in the mollusk and its bacteria endosymbiont, and found that most of the genes required for the production of amino acids were absent in the host but present in the endosymbiont, suggesting that the symbionts are capable of providing all the required amino acids to the host. Similarly, we hypothesize that L. luymesi endosymbionts supply most of the amino acids required by the host. To address this issue, we have sequenced the genomes of L. luymesi and its endosymbiont. A “blastp”- based bioinformatic pipeline was used to identify amino acid biosynthesis related genes. Preliminary results show that 95% (73 out of 75) of the genes associated with amino acid biosynthesis were found in the endosymbiont, while only 13% were found in the host. Interestingly, this study suggests evolutionary convergence in the biosynthesis of amino acids between two very different organisms.
