The Enigmatic Genome of an Obligate Ancient Spiroplasma Symbiont in a Hadal Holothurian.

ABSTRACT: Protective symbiosis has been reported in many organisms, but the molecular mechanisms of the mutualistic interactions between the symbionts and their hosts are unclear. Here, we sequenced the 424-kbp genome of "Candidatus Spiroplasma holothuricola," which dominated the hindgut microbiome of a sea cucumber, a major scavenger captured in the Mariana Trench (6,140 m depth). Phylogenetic relationships indicated that the dominant bacterium in the hindgut was derived from a basal group of Spiroplasma species. In this organism, the genes responsible for the biosynthesis of amino acids, glycolysis, and sugar transporters were lost, strongly suggesting endosymbiosis. The highly decayed genome consists of two chromosomes and harbors genes coding for proteolysis, microbial toxin, restr

SUBMITTER: He LS 

PROVIDER: S-EPMC5734040 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature