Diversification of the Light-Harvesting Complex Gene Family via Intra- and Intergenic Duplications in the Coral Symbiotic Alga Symbiodinium

摘要: The light-harvesting complex (LHC) is an essential component in light energy capture and transduction to facilitate downstream photosynthetic reactions plant algal chloroplasts. unicellular dinoflagellate alga Symbiodinium endosymbiont of cnidarian animals, including corals sea anemones, provides carbohydrates generated through photosynthesis host animals. Although possesses a unique LHC gene family, called chlorophyll a-chlorophyll c2-peridinin protein (acpPC), its genome-level diversity evolutionary trajectories have not been investigated. Here, we describe phylogenetic analysis revealing that many the LHCs are encoded by highly duplicated genes with multi-subunit polyprotein structures nuclear genome minutum. This extended list family single organism, 80 loci encoding polyproteins composed 145 subunits recovered tree. In S. minutum, 5 groups Lhcf-type which exclusively conserved algae harboring secondary plastids red origin, were identified. Moreover, Lhcr-type members known be associated PSI Notably, classified within group (group F1) duplicated, may explain presence unusually large number this species. Some units homologous other genes, whereas intergenic homologies between separate conspicuous cases, implying unit ‘shuffling’ conversion and/or rearrangement might driving force for diversification. These results suggest vigorous intra- duplication events resulted genomic framework coral symbiont algae.