EUPHYLLIA PARADIVISA Transcriptome

The coral holobiont approach and the dynamic relationship between the host and its associated microbial communities have been recently investigated. However, our understanding of the role of the microbiota and its contribution to the holobiont fitness is still limited, particularly in mesophotic corals. Here we present for the first time the 'core microbiome' of the strictly mesophotic coral E. paradivisa from the Red Sea, Eilat, and its predictive functional role. We generated four morphs of E. paradivisa: symbiotic, apo-symbiotic, “sterile” symbiotic and “sterile” apo-symbiotic, in order to understand the role of coral microbial communities (algae and bacteria) under short-term heat stress. To answer these questions we used metagenomics approaches, microbiology, physiology and metabolic function techniques. The coral host and its associated microbial communities were influenced differentially under a short -term heat-stress challenge. In addition, the presence/absence of algae/bacteria was critical and affected the host and its components, which resulted in different host gene expression, host cellular processes, and changes in bacterial composition. The morph of the symbiont/apo-symbiont was the major affecting parameter, while colony origin and bacteria composition were secondary factors. Our results demonstrate the significance of each component of the holobiont consortium and imply on a coherent link between the algae and bacteria associated symbionts, which affect the coral's molecular and cellular processes, particularly under environmental stress.