Dual symbiosis with co-occurring sulfur-oxidizing symbionts in vestimentiferan tubeworms from a Mediterranean hydrothermal vent.

摘要: Vestimentiferan Tws colonize hydrothermal vents and cold seeps worldwide. They lack a digestive system gain nutrition from endosymbiotic sulfur-oxidizing bacteria. It is currently assumed that vestimentiferan harbour only single endosymbiont type. A few studies found indications for additional symbionts, but conclusive evidence multiple symbiosis still missing. We investigated Marsili Seamount, vent in the Mediterranean Sea. Molecular morphological analyses identified as Lamellibrachia anaximandri. 16S ribosomal RNA clone libraries revealed two distinct gammaproteobacterial phylotypes were closely related to sequences other symbionts. Catalysed reporter deposition fluorescence situ hybridization with specific probes showed these are also variants of key genes sulfur oxidation carbon fixation, suggesting both symbiont types autotrophic oxidizers. Our results therefore show vestimentiferans can host co-occurring types. Statistical diversity genus, habitat type, water depth geographic region together accounted 27% genetic diversity, had significant effect on its own. Phylogenetic clear grouping according depth, thus confirming important role played shaping diversity.