A genome-wide survey of highly endangered staghorn coral in the Caribbean has identified 10 genomic regions associated with resilience against white band disease – an emergent infectious disease responsible for killing up to 95% of Caribbean Acropora species, including staghorn corals (A. cervicornis). The findings could be used as a conservation tool to improve disease resistance in the wild and nursery stocks of staghorn corals used to repopulate damaged coral reefs throughout Caribbean waters. Over the last several decades, Earth's reef corals have experienced unprecedented declines. Increased anthropogenic carbon dioxide emissions have led to ocean warming worldwide, which has had a particularly devastating effect on tropical reef corals by increasing the frequency and severity of thermal bleaching events and disease outbreaks. White band disease (WBD) is an emergent infectious disease in Caribbean corals that causes high morality levels. Although it's known that WBD-resistant A. cervicornis genotypes exist, the genetic underpinning of coral disease resistance is not known. An understanding could enable strategies that allow reef corals to adapt to future climate warming. To address this question, Steven Vollmer and colleagues conducted a genome-wide association study (GWAS) to identify genetic variants associated with WBD resistance in two geographically distant populations of A. cervicornis – Florida (nursery grown) and Panama (wild). Combining tank-based disease transmission experiments with a resequencing of 76 A. cervicornis genotypes, Vollmer et al. identified 10 genomic regions and 73 single-nucleotide polymorphisms (SNPs) associated with disease resistance. Of these, four SNPs resulted in identifiable protein-coding changes in genes known to be involved in the coral immune response. According to the findings, polygenic scores from the top ten SNPs and genomic regions can accurately predict observed disease resistance in a particular coral. "Vollmer et al.'s identification of adaptive polygenic variation in disease resistance in Florida and Panama populations of A. cervicornis indicates that the genetic variation for disease resistance is present across the Caribbean, which brings hope for the persistence of this critically endangered species," write Laura Mydlarz and Erinn Muller in a related Perspective.
For reporters interested in trends, an August 2022 story published on AAAS.org highlights several recent Science Advances studies focused on various research efforts currently underway to better understand and improve coral reef resilience worldwide.
