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Dual symbiosis with co‐occurring sulfur‐oxidizing symbionts in vestimentiferan tubeworms from a M editerranean hydrothermal vent
Author(s) -
Zimmermann Judith,
Lott Christian,
Weber Miriam,
Ramette Alban,
Bright Monika,
Dubilier Nicole,
Petersen Jillian M.
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12427
Subject(s) - biology , hydrothermal vent , chemosynthesis , symbiosis , extreme environment , host (biology) , sulfur , autotroph , ecology , zoology , bacteria , hydrothermal circulation , genetics , paleontology , chemistry , organic chemistry
Summary Vestimentiferan Tws colonize hydrothermal vents and cold seeps worldwide. They lack a digestive system and gain nutrition from endosymbiotic sulfur‐oxidizing bacteria. It is currently assumed that vestimentiferan Tws harbour only a single endosymbiont type. A few studies found indications for additional symbionts, but conclusive evidence for a multiple symbiosis is still missing. We investigated Tws from M arsili S eamount, a hydrothermal vent in the M editerranean S ea. Molecular and morphological analyses identified the Tws as L amellibrachia anaximandri . 16S ribosomal RNA clone libraries revealed two distinct gammaproteobacterial phylotypes that were closely related to sequences from other L amellibrachia symbionts. Catalysed reporter deposition fluorescence in situ hybridization with specific probes showed that these sequences are from two distinct symbionts. We also found two variants of key genes for sulfur oxidation and carbon fixation, suggesting that both symbiont types are autotrophic sulfur oxidizers. Our results therefore show that vestimentiferans can host multiple co‐occurring symbiont types. Statistical analyses of vestimentiferan symbiont diversity revealed that host genus, habitat type, water depth and geographic region together accounted for 27% of genetic diversity, but only water depth had a significant effect on its own. Phylogenetic analyses showed a clear grouping of sequences according to depth, thus confirming the important role water depth played in shaping vestimentiferan symbiont diversity.