Ecological differences among hydrothermal vent symbioses may drive contrasting patterns of symbiont population differentiation

• DOI: 10.1128/msystems.00284-23
• Publication Date: 2023-07-26T14:52:31Z
• Authors: Corinna Breusing; Yao Xiao; Shelbi L. Russell; Russell B. Corbet...; Sixuan Li; Jin Sun; Chong Chen; Yi Lan; Pei-Yuan Qian; Roxanne A. Beinart
• Keywords: Mutualism

The intra-host composition of horizontally transmitted microbial symbionts can vary across host populations due to interactive effects genetics, environmental, and geographic factors. While adaptation local habitat conditions drive subdivision symbiont strains, it is unknown how differences in ecological characteristics among host-symbiont associations influence the genomic structure populations. To address this question, we sequenced metagenomes different deep-sea mussel Bathymodiolus septemdierum, which are common at Western Pacific hydrothermal vents show characteristic patterns niche partitioning with sympatric gastropod symbioses. septemdierum lives close symbiotic relationship sulfur-oxidizing chemosynthetic bacteria but supplements its symbiotrophic diet through filter-feeding, enabling occupy niches little exposure geochemical reductants. Our analyses indicate that associated B. structuring by location, dominant strain uncorrelated vent site. These contrast co-occurring Alviniconcha Ifremeria symbioses exhibit greater nutritional dependence habitats higher spatial variability environmental conditions. results suggest relative homogeneity combined sufficient dispersal mixing might promote persistence similar strains locations, while mixotrophy decrease selective pressures on affiliate locally adapted strains. Overall, these data contribute our understanding potential mechanisms influencing population a spectrum marine contrasting niches. IMPORTANCE Beneficial relationships between animals organisms (symbionts) ubiquitous nature. In ocean, typically acquired from environment their locations often shaped However, currently generalizable systems have characteristics. compared mussels ecologically distinct snail species. less partitioned geography do not demonstrate evidence for adaptation. We posit mussel's mixotrophic feeding mode may lower need microhabitat stability likely favors locations. Altogether, findings further shaping environmentally