Naturally occurring fire coral clones demonstrate a genetic and environmental basis of microbiome composition

The microbiomes associated with reef corals are complex and diverse. Here, the authors investigate fire coral clones naturally occurring in distinct habitats as a model system to disentangle the contribution of host genotype and environment on their microbiome, and predict genomic functions based on taxonomic profiles. Coral microbiomes are critical to holobiont functioning, but much remains to be understood about how prevailing environment and host genotype affect microbial communities in ecosystems. Resembling human identical twin studies, we examined bacterial community differences of naturally occurring fire coral clones within and between contrasting reef habitats to assess the relative contribution of host genotype and environment to microbiome structure. Bacterial community composition of coral clones differed between reef habitats, highlighting the contribution of the environment. Similarly, but to a lesser extent, microbiomes varied across different genotypes in identical habitats, denoting the influence of host genotype. Predictions of genomic function based on taxonomic profiles suggest that environmentally determined taxa supported a functional restructuring of the microbial metabolic network. In contrast, bacteria determined by host genotype seemed to be functionally redundant. Our study suggests microbiome flexibility as a mechanism of environmental adaptation with association of different bacterial taxa partially dependent on host genotype.

Automated summary

This study examines the impact of host genotype and environment on coral microbiomes, revealing a significant contribution of the environment to microbial community structure, as well as an influence of host genotype. Microbiome flexibility is suggested as a mechanism of environmental adaptation, with different bacterial taxa associated partially dependent on host genotype.