Meeting Abstract

75.5  Tuesday, Jan. 6 11:15  The tale of two apicomplexans: Are associations between scleractinian corals and apicomplexans (Alveolata) specific? KIRK, NL*; SLAPETA, J; LINARES, M; THORNHILL, DJ; KEMP, DW; FITT, WK; SANTOS, SR; Oregon State University; University of Sydney, New South Wales Australia; University of Sydney, New South Wales Australia; Defenders of Wildlife, Washington DC; University of Georgia; University of Georgia; Auburn University, Alabama kirknat@gmail.com

Apicomplexa are ubiquitous parasites of vertebrates and invertebrates and at least one lineage commonly associates with corals at high prevalence. Apicomplexans contain the causative agents of malaria as well as opportunistic human pathogens Toxoplasma gondii and Cryptospordium spp. To infer evolutionary origin of the coral-associated Apicomplexa, 18S-rDNA were amplified from a broad sampling of scleractinian and gorgonian corals from the Caribbean Sea and Great Barrier Reef. Phylogenetic trees confirmed monophyly of all coral-associated Apicomplexa, which is basal to the coccidian lineage. Using 18S-rDNA there was little evidence of coevolution within the coral-associated apicomplexan clade as constraint trees mirroring host phylogeny were significantly worse. To further examine the extent of host specificity of coral-associated Apicomplexa, highly variable ITS1 rDNA (~45% similarity) were amplified from the scleractinian corals Porites astreoides, Orbicella (=Montastraea) faveolata and O. annularis across 5 reefs in the Caribbean Sea. Although other types were detected, two distinct host-adapted ITS genotypes of coral-associated apicomplexans were recovered at all examined reefs. These data suggest specificity between coral host and Apicomplexa indicating a complex interaction between partners.