Novel insight into the microbiome composition of three species of scleractinian corals: comparison between Mediterranean and Maldivian regions

First studies on coral microbiome were conducted only 20 years ago; nevertheless, the fundamental importance of microorganisms in influencing coral health and resilience became rapidly clear. For most coral species, especially in the Mediterranean Sea, prokaryotic communities present on their tissues, skeleton and mucus are still not characterized. This study considered three different scleractinian species, Cladocora caespitosa and Madracis pharensis collected in the Mediterranean Sea and Herpolitha limax collected in the Maldives and provides a microbiome characterization and comparison through 16S rRNA gene sequencing on V5-V6 hypervariable regions. Moreover, through the analysis of obtained ASVs, a core microbiome for each coral species and a shared microbiome among the three species was outlined, showing clear distinctions between Mediterranean and Maldivian microbiomes probably linked to the unusual environmental conditions present at sampling time in the Mediterranean basin.