16S amplicon sequencing in tubeworm symbionts

Vestimentiferan tubeworms are key taxa in deep-sea chemosynthetic habitats worldwide. As adults they depend nutritionally on their sulfide-oxidizing bacterial endosymbionts, which are acquired from the environment. The current paradigm holds that every tubeworm harbors only one endosymbiotic 16S phylotype and that symbiont and host species are not specific to each other. However, as traditional Sanger sequence analyses are biased towards the most abundant bacterial type, it is likely that genetic diversity and specificity in tubeworm endosymbionts has been overlooked by previous studies. To address these issues, we applied 16S-V4 amplicon sequencing to populations of the co-occurring tubeworm species Lamellibrachia barhami and Escarpia spicata.