A multi-omics approach to the analysis of coral health

Tropical coral reefs support approximately 25% of known marine species, protect coastlines from storms and erosion, and provide economic prosperity to local communities, establishing their value at $375 billion, annually. However, the massive biodiversity encompassed by tropical coral reef ecosystems is continually threatened by anthropogenic climate change. While estimates vary, one third of reefs are headed for extinction in the immediate future. The success of coral reef ecosystems is dependent on the symbiotic consortium known as the coral holobiont, dictated by the microbiome, photosymbionts, and coral genome, together constituting the coral phenotype. Discernment of the roles and responses between each holobiont component is crucial for comprehending how each coral population will react to the changing ocean conditions. In particular, the integration of metagenomic, metatranscriptomic, and metabolomic data is an unexplored area with regard to understanding coral health in the face of climate change. A general recipe of health based on microbiome players has proven ineffective, but the same cannot be said for the holobiont metabolome. The coral metabolome has the potential to offer a wealth of knowledge and insight as to how stress affects metabolic activity of the holobiont. The chemical signatures of stress responses in the holobiont, such as dimethylsuphoniopropionate, offer a more concrete measure of coral health. The major roadblock in this area of coral research is the deficiency of known coral metabolites. In response to this problem, a database of holobiont metabolites is currently being created in the Bhattacharya Lab, following data collected from Hawaiian Montipora capitata in May 2019 grown under both ambient and high temperatures. From these nubbins, metatransciptome and metagenome libraries, in addition to untargeted metabolomic analyses, have been generated over the course of the animal’s bleaching response. Preliminary LC-MS metabolite data has identified the cytotoxin Montiporic acid, indicating the effectiveness of our approach. Chemical signatures of multiple other metabolites linked to heat stress have also been found and their structures are being determined. I will present these results and the opportunities they offer to aid coral conservation.