Max Planck Institute for Marine Microbiology, Bremen, Germany.
MARUM-Center for Marine Environmental Sciences of the University of Bremen, Bremen, Germany.
ISME J. 2021 Oct;15(10):3076-3083. doi: 10.1038/s41396-021-00927-9. Epub 2021 May 10.
The composition and diversity of animal microbiomes is shaped by a variety of factors, many of them interacting, such as host traits, the environment, and biogeography. Hybrid zones, in which the ranges of two host species meet and hybrids are found, provide natural experiments for determining the drivers of microbiome communities, but have not been well studied in marine environments. Here, we analysed the composition of the symbiont community in two deep-sea, Bathymodiolus mussel species along their known distribution range at hydrothermal vents on the Mid-Atlantic Ridge, with a focus on the hybrid zone where they interbreed. In-depth metagenomic analyses of the sulphur-oxidising symbionts of 30 mussels from the hybrid zone, at a resolution of single nucleotide polymorphism analyses of ~2500 orthologous genes, revealed that parental and hybrid mussels (F2-F4 generation) have genetically indistinguishable symbionts. While host genetics does not appear to affect symbiont composition in these mussels, redundancy analyses showed that geographic location of the mussels on the Mid-Atlantic Ridge explained most of the symbiont genetic variability compared to the other factors. We hypothesise that geographic structuring of the free-living symbiont population plays a major role in driving the composition of the microbiome in these deep-sea mussels.
动物微生物组的组成和多样性受到多种因素的影响，其中许多因素相互作用，如宿主特征、环境和生物地理学。杂种带是指两个宿主物种的分布范围相遇并发现杂种的区域，为确定微生物组群落的驱动因素提供了自然实验，但在海洋环境中研究还不够充分。在这里，我们分析了中大西洋脊热液喷口已知分布范围内两种深海贻贝物种共生体群落的组成，重点研究了它们杂交的杂种带。对来自杂种带的 30 只贻贝的硫氧化共生体进行了深度宏基因组分析，分辨率为约 2500 个同源基因的单核苷酸多态性分析，结果表明，亲代和杂交贻贝（F2-F4 代）具有遗传上无法区分的共生体。虽然宿主遗传学似乎不会影响这些贻贝的共生体组成，但冗余分析表明，与其他因素相比，中大西洋脊上贻贝的地理位置解释了共生体遗传变异的大部分。我们假设自由生活的共生体种群的地理结构在驱动这些深海贻贝微生物组的组成中起着重要作用。
