Abstract
Background: Marine symbioses are predominantly established through horizontal acquisition of microbial symbionts from the environment. However, genetic and functional comparisons of free-living populations of symbionts to their host-associated counterparts are sparse. Here, we assembled the first genomes of the chemoautotrophic gammaproteobacterial symbionts affiliated with the deep-sea snail Alviniconcha hessleri from two separate hydrothermal vent fields of the Mariana Back-Arc Basin. We used phylogenomic and population genomic methods to assess sequence and gene content variation between free-living and host-associated symbionts. Results: Our phylogenomic analyses show that the free-living and host-associated symbionts of A. hessleri from both vent fields are populations of monophyletic strains from a single species. Furthermore, genetic structure and gene content analyses indicate that these symbiont populations are differentiated by vent field rather than by lifestyle. Conclusion: Together, this work suggests that, despite the potential influence of host-mediated acquisition and release processes on horizontally transmitted symbionts, geographic isolation and/or adaptation to local habitat conditions are important determinants of symbiont population structure and intra-host composition. [MediaObject not available: see fulltext.]
Original language | English (US) |
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Article number | 106 |
Journal | Microbiome |
Volume | 11 |
Issue number | 1 |
DOIs | |
State | Published - Dec 2023 |
Keywords
- Alviniconcha
- Hydrothermal vents
- Mariana Back-Arc
- Microbial biogeography
- Population genomics
- Symbiosis
ASJC Scopus subject areas
- Microbiology
- Microbiology (medical)