Possible core symbiosis-related genes in early life stages of Acropora tenuis inoculated with Symbiodinium microadriaticum

Abstract Due to the ecological importance of mutualisms between reef-building corals and symbiotic algae (Family Symbiodiniaceae), various transcriptomic studies on coral-algal symbiosis have been performed; however, molecular mechanisms, especially essential genes in these symbioses remain unknown. We investigated transcriptomic responses of Acropora tenuis to inoculation with the native algal symbiont, Symbiodinium microadriaticum, during early life stages, and identified possible “core” symbiosis-related genes. Genes involved in immune suppression, defense against oxidative stress, and metabolic interactions between partners are particularly important for symbiosis during Acropora early life stages. In addition, molecular phylogenetic analysis revealed that some core symbiosis-related genes originated by gene duplication in the Acropora lineage, suggesting that gene duplication may have been the driving force to establish stable mutualism in Acropora, and that symbiotic molecular mechanisms may vary depending on each coral lineage.