Investigating the microbial basis of resilience to stony coral tissue loss disease

Stony coral tissue loss disease (SCTLD) affects at least 22 species of reef-building coral in Florida and the Caribbean. Bacteria are implicated as a primary cause of SCTLD, but the community of bacteria and archaea within coral hosts is diverse and includes taxa that may also contribute to SCTLD resistance. To identify potential mechanisms through which microbes contribute to host resistance to SCTLD, we sequenced metagenomes from 41 Orbicella faveolata colonies from two reefs in the Lower Florida Keys. Before and after tissue collection, we monitored disease prevalence and frequency of in situ amoxicillin treatments. In June 2021, 46.3% of the colonies presented with SCTLD, which increased to 63.4% after two years. Despite proximity to affected colonies, 28.8% of colonies were never diseased. Following in silico removal of coral host, algal symbiont, and other eukaryotic DNA sequences, we had on average 30 million reads per sample that were used for metagenome co-assembly and analysis. Variation in bacterial functions was explained by disease status at sampling, composition of the algal symbiont community, and colony fate within the monitoring period. We hypothesize that genes related to putatively beneficial functions such as nitrogen and sulfur cycling, and vitamin biosynthesis will be enriched in corals that were unaffected despite multiple years of proximity to SCTLD. Future efforts to integrate other ‘omics data collected from the same colonies may further reveal potential mechanisms by which microbes contribute to intraspecies differences in disease resistance.

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Primary Presenter: Cynthia Becker, Ithaca College (cynthiabecker95@gmail.com)

Authors:

Cynthia Becker, Ithaca College  (cynthiabecker95@gmail.com)

Allison Cauvin, University of Florida  (acauvin@ufl.edu)

Karen Neely, Nova Southeastern University  (kneely0@nova.edu)

Brian Walker, Nova Southeastern University  (walkerb@nova.edu)

Julie Meyer, University of Florida  (juliemeyer@ufl.edu)