title: Microbial community compositional shifts in bleached colonies of the Brazilian reef-building coral Siderastrea stellata.
abstract: The association of metazoan, protist, and microbial communities with Scleractinian corals forms the basis of the coral holobiont. Coral bleaching events have been occurring around the world, introducing changes in the delicate balance of the holobiont symbiotic interactions. In this study, Archaea, bacteria, and eukaryotic phototrophic plastids of bleached colonies of the Brazilian coral Siderastrea stellata were analyzed for the first time, using 16S rRNA gene libraries. Prokaryotic communities were slightly more diverse in healthy than in bleached corals. However, the eukaryotic phototrophic plastids community was more diverse in bleached corals. Archaea phylogenetic analyses revealed a high percentage of Crenarchaeota sequences, mainly related to Nitrosopumilus                 maritimus and Cenarchaeum symbiosum. Dramatic changes in bacterial community composition were observed in this bleaching episode. The dominant bacterial group was Alphaproteobacteria followed by Gammaproteobacteria in bleached and Betaproteobacteria in healthy samples. Plastid operational taxonomic units (OTUs) from both coral samples were mainly related to red algae chloroplasts (Florideophycea), but we also observed some OTUs related to green algae chloroplasts (Chlorophyta). There seems to be a strong relationship between the Bacillariophyta phylum and our bleached coral samples as clones related to members of the diatom genera Amphora and Nitzschia were detected. The present study reveals information from a poorly investigated coral species and improves the knowledge of coral microbial community shifts that could occur during bleaching episodes.
authors.affiliation: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro (UFRJ), CCS, 21941-590, Rio de Janeiro, Brazil. monica.barros1@gmail.com
authors.forename: Monica M
authors.initials: MM
authors.lastname: Lins-de-Barros
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Cardoso
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Silveira
authors.forename: Joyce L
authors.initials: JL
authors.lastname: Lima
authors.forename: Maysa M
authors.initials: MM
authors.lastname: Clementino
authors.forename: Orlando B
authors.initials: OB
authors.lastname: Martins
authors.forename: Rodolpho M
authors.initials: RM
authors.lastname: Albano
authors.forename: Ricardo P
authors.initials: RP
authors.lastname: Vieira
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000382:microbiology*; D001105:Archaea / Q000145:classification* / Q000235:genetics; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D001938:Brazil; D000460:Chlorophyta / Q000145:classification / Q000235:genetics*; D058893:DNA Barcoding, Taxonomic; D048028:DNA, Algal / Q000235:genetics; D019641:DNA, Archaeal / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D017377:Diatoms / Q000145:classification / Q000235:genetics; D017753:Ecosystem; D015723:Gene Library; D010802:Phylogeny; D018087:Plastids / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D000461:Rhodophyta / Q000145:classification* / Q000235:genetics; D013559:Symbiosis
chemical_list: D048028:DNA, Algal; D019641:DNA, Archaeal; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S