Publication in the Proceedings Royal Society B

Polyclonal symbiont populations in hydrothermal vent tubeworms and the environment

 

Polyclonal symbiont populations in hydrothermal vent tubeworms and the environment

Horizontally transmitted symbioses usually house multiple and variable
symbiont genotypes that are acquired from a much more diverse environmental
pool via partner choice mechanisms. However, in the deep-sea
hydrothermal vent tubeworm Riftia pachyptila (Vestimentifera, Siboglinidae),
it has been suggested that the Candidatus Endoriftia persephone symbiont is
monoclonal. Here, we show with high-coverage metagenomics that adult
R. pachyptila house a polyclonal symbiont population consisting of one
dominant and several low-frequency variants. This dominance of one genotype
is confirmed by multilocus gene sequencing of amplified housekeeping
genes in a broad range of host individuals where three out of four loci (atpA,
uvrD and recA) revealed no genomic differences, while one locus (gyrB) was
more diverse in adults than in juveniles. We also analysed a metagenome of
free-living Endoriftia and found that the free-living population showed
greater sequence variability than the host-associated population. Most juveniles
and adults shared a specific dominant genotype, while other genotypes
can dominate in few individuals. We suggest that although generally
permissive, partner choice is selective enough to restrict uptake of some
genotypes present in the environment.

Proceedings Royal Society B
https://royalsocietypublishing.org/doi/10.1098/rspb.2018.1281

Der Standard
https://derstandard.at/2000098621874/Lebenspartner-in-der-Tiefsee