The metabolic significance of symbiont community composition in the coral-algal symbiosis

Metabolite exchange between coral hosts and their dinoflagellate endosymbionts (family: Symbiodiniaceae) is one of the keys to the ecological success of coral reefs. Due to the physiological variation within Symbiodiniaceae, including amount of organic carbon and stress tolerance provided to the host, symbiont community composition has the potential to influence the nutrition and physiological success of the coral. However, the precise metabolic consequences of harboring different dominant Symbiodiniaceae species in nature is unknown. Using untargeted gas chromatography-mass spectrometry (GC-MS), we compared the metabolite profiles of both the host and symbiont relative to natural variations in the Symbiodiniaceae community composition in the reef coral Montipora capitata. The results show both host and symbiont metabolite profiles were unaffected by Symbiodiniaceae community composition under nonstressful conditions, which suggests that coral-Symbiodiniaceae symbioses have the potential to undergo physiological adjustment overtime to account for differences in their resident symbionts. Here, we discuss the project approach and findings and highlight specific workflow considerations when conducting coral symbiosis metabolomics analyses.