Proteomic Plasticity in the Coral Montipora capitata Gamete Bundles after Parent Thermal Bleaching

Coral reefs are vital to marine biodiversity and human livelihoods, but they face significant threats from climate change. Increased ocean temperatures drive massive "bleaching" events, during which corals lose their symbiotic algae and the important metabolic resources those algae provide. Proteomics is a crucial tool for understanding coral function and tolerance to thermal stress, as proteins drive physiological processes and accurately represent cell functional phenotypes. We examined the physiological condition of coral (Montipora capitata) gametes from parents that either experienced thermal bleaching or were nonbleached controls by comparing data dependent (DDA) and data independent (DIA) acquisition methods and peptide quantification (spectral counting and area-under-the-curve, AUC) strategies. For DDA, AUC captured a broader dynamic range than spectral counting. DIA yielded better coverage of low abundance proteins than DDA and a higher number of proteins, making it the more suitable method for detecting subtle, yet biologically significant, shifts in protein abundance in gamete bundles. Gametes from bleached corals showed a broadscale decrease in metabolic proteins involved in carbohydrate metabolism, citric acid cycle, and protein translation. This metabolic plasticity could reveal how organisms and their offspring acclimatize and adapt to future environmental stress, ultimately shaping the resilience and dynamics of coral populations.