Host under epigenetic control: A novel perspective on the interaction between microorganisms and corals

Coral reefs have been challenged by the current rate and severity of environmental change that might outpace their ability to adapt and survive. Current research focuses on understanding how microbial communities and epigenetic changes separately affect phenotypes and gene expression of corals. Here, we provide the hypothesis that coral-associated microorganisms may directly or indirectly affect the coral's phenotypic response through the modulation of its epigenome. Homologs of ankyrin-repeat protein A and internalin B, which indirectly cause histone modifications in humans, as well as Rv1988 histone methyltransferase, and the DNA methyltransferases Rv2966c, Mhy1, Mhy2, and Mhy3 found in coral-associated bacteria indicate that there are potential host epigenome-modifying proteins in the coral microbiome. With the ideas presented here, we suggest that microbiome manipulation may be a means to alter a coral's epigenome, which could aid the current efforts to protect coral reefs.