Microbial characterization of the first occurrence of White Plague disease in the endemic brain coral Mussismilia hispida at Alcatrazes Archipelago, Brazil

Endemic to the Brazilian fauna, the brain coral Mussismilia hispida is the second most widespread zooxanthellate coral of the South-west Atlantic and, most importantly, is within the main reef-building species of the region. Counterintuitively, M. hispida has one of its most abundant populations near its southernmost distributional limit, the Alcatrazes Archipelago off the coast of São Paulo State. On this archipelago, colonies thrive from 2 to over 20 m deep, and in some localities, M. hispida covers more than 50% of the rocky shore. Although more resistant to bleaching than other coral species, a capacity enhanced by colder water resurgence around the archipelago, signs of a coral disease affecting some colonies were recorded in 2019, simultaneously with a severe bleaching event. Diseased corals had tissue loss and a distinct white lesion on the corals’ tissue, suggesting that it may be a White Plague disease. Using 16S rRNA metabarcoding, we compared the microbial community associated with the part of the colonies presenting signs of disease to those apparently healthy. Results indicate that the microbiota genera from healthy and diseased colony portions are highly variable, suggesting community dysbiosis and alterations in the metabolic pathways of the microbiome. While it was not possible to identify a pathogen or a pathogenic consortium associated with the disease, the overall microbial signature, characterized by the presence of Roseimarinus, Carboxylicivirga, Tepidibacter, Vallitalea, and Halodesulfovibrio, is similar to that found in diseased Caribbean massive corals.