Healthy octocorals have a microbiome that is distinct from the surrounding environment, host genus-specific and defined by so-far uncultured groups of bacteria In contrast, the microbiome of necrotic coral tissue shows large shifts in its community structure compared to healthy tissue and is colonized by seawater bacteria. Functional analysis showed that healthy corals were enriched in microbial genes associated with antiviral defense, host symbiosis recognition, micronutrient acquisition and heat-stress response. This was the first study to apply primer-less, metagenomic sequencing to octocorals which allowed researchers to identify so-far uncultured, likely obligate symbionts as the core members of the octocoral microbiome. These results can be used to guide future studies into coral reef conservation and microbiome therapies for octocorals.
Previously underestimated, complex secondary metabolism is revealed for the recently described bacterial genus Aquimarina, an emerging keystone taxon mediating carbon and nitrogen cycling and host-microbe interactions across multiple marine microniches.
This review inventories the natural products so-far described for octocoral-derived bacteria and fungi, uncovering a true chemical arsenal of terpenes, steroids, alkaloids, and polyketides with antibacterial, antifungal, antiviral, antifouling, anticancer, anti-inflammatory, and antimalarial activities of enormous potential for blue growth.