Coral larval proteomics at onset of metamorphosis highlights innate immunity maturation in parallel to neuro-sensing and skeletal development

NanoLC-MS/MS data analysis identified a total of 5,570 coral proteins, of which 1,119 occurred only either in planula or settler. Label-free quantification revealed 102 differentially enriched proteins (DEPs, log2 fold change > |2| p-value < 0.05), categorized into 7 predicted functional groups: adhesion and cytoskeleton remodeling, neurosensing, biocalcification toolkit, metabolism, morphogenesis, innate immunity, and antioxidant stress defense. Additionally, 98 aboral unique proteins and 25 aboral DEPs were quantified in the bisected planula, consistent with the presence of specialized aboral cell types involved in sensing of environmental cues. These results reveal the activation of coral innate immunity during larval metamorphosis, providing better knowledge of coral settlement physiology, with potential future ecological applications.