Association of Coral-Microbes, and the Ecological Roles of Microbial Symbionts in Corals

Corals are sessile marine invertebrates and they form a unique ecosystem, which supports diverse marine organisms. They host a wide variety of microorganisms such as bacteria, archaea and fungi. The interactions between corals and associated microbes are likely to play an important role in coral health. These microbial communities respond and quickly adapt to changes and also have central roles in ecological function. They are also involved in the biogeochemical cycling, particularly nitrogen, sulfur, phosphorus as well as in host defense. A complex web of interactions exists between the coral-associated microbes and each of them is linked with one another. So, characterizing these links is fundamental to understand coral reef resilience and to improve to predict ecological change. The culture-independent methods have recorded high proportions of novel coral-associated microbes and also species-specific microbial communities. Metagenomics-based investigations have also revealed the dynamics in the genomic diversity of the microbes upon environmental changes. Eventhough, their complete roles are not currently accounted and only less culturable microbes have been isolated, especially from the stony corals. So, it is necessary to develop novel techniques to increase the culturables as well as explore the shaping factors of coral-associated microbes and their central functions in corals.