Transgenerational metabolomic signatures of bleaching resistance in corals

Coral bleaching is one of the greatest climate-driven threats to the persistence of tropical reef ecosystems. This necessitates the identification of attributes associated with coral resistance and resilience to thermal stress both within and between generations. Here, we used metabolomics to demonstrate that biochemical signatures associated with heat-induced bleaching of Montipora capitata are passed between generations. There were metabolomic signatures of parental bleaching phenotype in sperm, eggs, embryos, larvae, and subsequent juvenile corals formed by selectively breeding bleaching resistant or susceptible parents. Metabolome source mapping showed that these thermal tolerance signatures were from both the coral host and the algal symbiont and spanned a variety of molecular families. One of the strongest markers of transgenerational heat tolerance was the saturation state of DGCC betaine lipids, a molecular family previously associated with thermal tolerance in dinoflagellate symbionts of corals. Though the saturation state of the DGCC lipids was strongly linked to algal genotypes, which are known to be vertically transmitted in M. capitata , even coral progeny that contained the more thermally susceptible Cladocopium algae showed increased saturation of this lipid group if their parents had resisted recent bleaching events. This work provides evidence for biochemical inheritance as a potential mechanism for transgenerational acclimatization to warming oceans, which has implications for reef restoration and resilience in the face of climate change.