Arriaga-Pinon, Z. P. | bioRxiv Science

bioRxiv2026

Within-colony microbial response of three species with different susceptibility to Stony Coral Tissue Loss Disease

Stony coral tissue loss disease (SCTLD), a coral pathology with rapid tissue loss and high mortality rate has affected nearly 30 species with a variable degree of susceptibility across species. It has been suggested that SCTLD has a systemic effect within coral colonies, but little is known about within-colony changes of the microbial communities associated with this disease. Here we evaluate the microbial shifts within coral colonies: apparently healthy tissue and SCTLD tissue. The study was done in three species following a gradient of susceptibility to the disease: Dendrogyra cylindrus (Dcyl, n = 11) and Pseudodiploria strigosa (Pstr, n = 6) two highly susceptible species; and Orbicella faveolata (Ofav, n = 8), a moderately affected species. 16S rRNA Illumina sequences analysis showed differential microbial community structure within two species (Dcyl, p = 0.01, Pstr, p = 0.01) but not for Ofav (p = 0.28). Taxonomic profiles of bacterial groups were species-specific in SCTLD tissue, but healthy tissue shared similarities between species including Pirelullales, NB1-J and SAR324. Our results reveal that the microbial communities effects associated to the disease follow a similar pattern to the species susceptibility to SCTLD, providing new insights into the disease dynamics in the Mexican Caribbean.

microbiology↗

bioRxiv2024

Microbiomes of three coral species in the Mexican Caribbean and their shifts associated with the Stony Coral Tissue Loss Disease

Stony Coral Tissue Loss Disease (SCTLD) has caused widespread coral mortality in the Caribbean Region. However, how the disease presence alters the microbiome community, their structure, composition, and metabolic functionality is still poorly understood. In this study, we characterized the microbial communities of the tissues of apparently healthy and diseased SCTLD colonies of the species Siderastrea siderea, Orbicella faveolata, and Montastraea cavernosa to explore putative changes related to the presence of SCTLD. Gammaproteobacteria, Alphaproteobacteria, and Bacteroidia were the best represented classes in the healthy tissues of all coral species, and alpha diversity did not show significant differences among the species. The microbial community structure between coral species was significantly different (PERMANOVA: F=3.46, p=0.001), and enriched genera were detected for each species: Vibrio and Photobacterium in S. siderea, Spirochaeta2 and Marivivens in O. faveolata and SAR202_clade and Nitrospira in M. cavernosa. Evidence of SCTLD in the microbial communities was more substantial in S. siderea, where differences in alpha diversity, beta diversity, and functional profiles were observed. In O. faveolata, differences were detected only in the community structure, while M. cavernosa samples showed no significant difference. Several microbial groups were found to have enriched abundances in tissue from SCTLD lesions from S. siderea and O. faveolata, but no dominant bacterial group was detected. Our results contribute to understanding microbial diversity associated with three scleractinian coral species and the shifts in their microbiomes associated with SCTLD in the Mexican Caribbean.

microbiology↗