title: Metabolic versatility of the Riftia pachyptila endosymbiont revealed through metagenomics.
abstract: The facultative symbiont of Riftia pachyptila, named here Candidatus Endoriftia persephone, has evaded culture to date, but much has been learned regarding this symbiosis over the past three decades since its discovery. The symbiont population metagenome was sequenced in order to gain insight into its physiology. The population genome indicates that the symbionts use a partial Calvin-Benson Cycle for carbon fixation and the reverse TCA cycle (an alternative pathway for carbon fixation) that contains an unusual ATP citrate lyase. The presence of all genes necessary for heterotrophic metabolism, a phosphotransferase system, and dicarboxylate and ABC transporters indicate that the symbiont can live mixotrophically. The metagenome has a large suite of signal transduction, defence (both biological and environmental) and chemotaxis mechanisms. The physiology of Candidatus Endoriftia persephone is explored with respect to functionality while associated with a eukaryotic host, versus free-living in the hydrothermal environment.
authors.affiliation: Scripps Institution of Oceanography, San Diego, CA, USA. jrobidart@oeb.harvard.edu
authors.forename: Julie C
authors.initials: JC
authors.lastname: Robidart
authors.forename: Shellie R
authors.initials: SR
authors.lastname: Bench
authors.forename: Robert A
authors.initials: RA
authors.lastname: Feldman
authors.forename: Alexey
authors.initials: A
authors.lastname: Novoradovsky
authors.forename: Sheila B
authors.initials: SB
authors.lastname: Podell
authors.forename: Terry
authors.initials: T
authors.lastname: Gaasterland
authors.forename: Eric E
authors.initials: EE
authors.lastname: Allen
authors.forename: Horst
authors.initials: H
authors.lastname: Felbeck
mesh_terms: D000818:Animals; D018407:Bacterial Physiological Phenomena; D018247:Helicobacter heilmannii / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D011077:Polychaeta / Q000378:metabolism / Q000382:microbiology* / Q000502:physiology*; D013559:Symbiosis