Orbicella faveolata 2bRAD sequences from SCTLD Resilience Research Consortium

Stony coral tissue loss disease SCTLD has spread throughout the entirety of Floridas Coral Reef FCR and across the Caribbean, impacting at least 30 coral species. The threatened hermatypic coral, Orbicella faveolata, demonstrates intraspecific variation in SCTLD resistance with some colonies experiencing chronic and active disease lesions, while other nearby O. faveolata colonies appear unaffected with no disease signs. This study evaluated potential genotypic underpinnings of variable susceptibility to SCTLD by monitoring and sampling 90 O. faveolata colonies from southeast Florida and the lower Florida Keys. High resolution analyses of 11000 single nucleotide polymorphisms SNPs generated from 2bRAD sequencing indicated there were no O. faveolata genetic lineages significantly associated with SCTLD resistance or susceptibility. Genotypic differences may still contribute to SCTLD susceptibility; however, these differences were not captured using this reduced representation sequencing approach. Algal symbiont community structure characterized from the 2bRAD data revealed that Durusdinium spp. were more abundant in SCTLD affected colonies as compared to unaffected colonies, suggesting that algal symbiont community make-up may play a significant role in SCTLD resistance. Data generated by this study will be combined with complementary molecular and physiological approaches to further investigate the complex drivers of intraspecific SCTLD susceptibility and resilience.