Diversity of bacteria associated with the coral Pocillopora damicornis from the Great Barrier Reef

Abstract

The microbial community associated with the reef building coral Pocillopora damicornis located on the Great Barrier Reef was investigated using culture-independent molecular microbial techniques. The microbial communities of three separate coral colonies were assessed using clone library construction alongside restriction fragment length polymorphism and phylogenetic analysis. Diversity was also investigated spatially across six replicate samples within each single coral colony using 16S rDNA and rpoB-DGGE analysis. Clone libraries demonstrated that the majority of retrieved sequences from coral tissue slurry libraries affiliated with gamma-Proteobacteria. This contrasted with clone libraries of seawater and coral mucus, which were dominated by alpha-Proteobacteria. A number of retrieved clone sequences were conserved between coral colonies; a result consistent with previous studies suggesting a specific microbe-coral association. rpoB-DGGE patterns of replicate tissue slurry samples underestimated microbial diversity, but demonstrated that fingerprints were identical within the same coral. These fingerprints were also conserved across coral colonies. The 16S rDNA-DGGE patterns of replicate tissue slurry samples were more complex, although non-metric multidimensional scaling (nMDS) analysis showed groupings of these banding patterns indicating that some bacterial diversity was uniform within a coral colony. Sequence data retrieved from DGGE analysis support clone library data in that the majority of affiliations were within the gamma-Proteobacteria. Many sequences retrieved also affiliated closely with sequences derived from previous studies of microbial diversity of healthy corals in the Caribbean. Clones showing high 16S rDNA sequence identity to both Vibrio shiloi and Vibrio coralliilyticus were retrieved, suggesting that these may be opportunist pathogens. Comparisons of retrieved microbial diversity between two different sampling methods, a syringe extracted coral mucus sample and an airbrushed coral tissue slurry sample were also investigated. Non-metric multidimensional scaling of clone library data highlighted that clone diversity retrieved from a coral mucus library more closely reflected the diversity of surrounding seawater than a corresponding coral tissue clone library.

Coral symbiotic complex: Hypothesis through vitamin B12 for a new evaluation

“…have been shown to cause coral bleaching and other diseases (Rosenberg et al 2007 and references therein), and therefore the scientific community has taken an interest in coral associated bacteria. Qualitative studies have described the associated bacteria, especially the bacteria living in the mucus on the surface of corals (Ducklow and Mitchell 1979), and some concluded the specificity of these communities (Rohwer et al 2001;Bourne and Munn 2005). Archae were also reported to live in association with corals (Kellogg 2004;Wegley et al 2004).…”

Flow cytometric analysis of virus-like particles and heterotrophic bacteria within coral-associated reef water

“…Corals harbour an abundant, diverse and dynamic consortium of microbial communities within the coral surface microlayer, the layer extending a few millimetres from the coral surface, and within coral tissue (Ducklow & Mitchell, 1979;Paul et al, 1986, Rohwer et al, 2001Kellogg, 2004;Bourne & Munn, 2005). Viruses, while not routinely studied in coral^microbial associations, represent a potentially important yet overlooked community involved in the overall health of corals (Seymour et al, 2005).…”

Identification of a Ciliate (Oligohymenophorea: Scuticociliatia) Associated with Brown Band Disease on Corals of the Great Barrier Reef

“…PCR resulted in amplification of the 18S rRNA genes from protozoa and other eukaryotic organisms (by PCR cycling performed at 95°C for 3 min followed by 30 cycles at 95°C for 1 min, 58°C for 1 min, and 72°C for 1 min and a final extension step of 72°C for 7 min), with the products (ϳ1.8 kb) cloned (TOPO TA cloning kit; Invitrogen) and the insert 18S rRNA gene reamplified from individual clones. Restriction fragment length polymorphism analysis was performed on reamplified products (8), and clones were grouped into operational taxonomic unit (OTU) groups. Clones sequenced from the dominant OTU groups were affiliated with Symbiodinium species within the clade C lineage (98% to 99% sequence identity).…”