A Potential Connection Between Coral-Associated Bacteria and Disease Resilience in Acropora cervicornis

Coral restoration efforts in the Florida Keys have shown that some genotypes of Acropora cervicornis (staghorn coral) are more resistant to disease-causing pathogens. Whole microbiome sequencing has demonstrated that the disease-resistant and disease-susceptible genotypes harbor different species of bacteria in their surface mucus layers. Some bacterial species isolated from the surface mucus layer of Acropora palmata have been found to inhibit viral activity and thus can protect the coral host from potential pathogens. In this study, we tested if the disease-resistant genotypes harbor potentially beneficial bacterial isolates distinct from the disease-susceptible genotypes. These isolates may serve an important role in future coral restoration efforts. Bacteria were collected from four genotypes of A. cervicornis, two resistant and two susceptible, and were isolated to single colonies. These colonies were cultured on agar plates and in liquid cultures in order to create a cultured library. The 16S rRNA gene from each isolate was amplified from genomic DNA by PCR and sequenced to determine the identity of the isolate. Bacterial isolates associated only with resistant genotypes will be tested for beneficial properties against coral pathogens. Isolates will be screened for antibiotic production and capabilities to interfere with pathogen motility and metabolic function. Isolates identified to have these beneficial characteristics will then be introduced to disease-susceptible corals to test for a microbial probiotic effect that can be used in future coral restoration efforts to increase coral outplant resilience.