Metagenomic analysis of stressed coral holobionts. Environ Microbiol

Department of Biology, San Diego State University, San Diego, CA, USA.
Environmental Microbiology (Impact Factor: 6.2). 05/2009; 11(8):2148-63. DOI: 10.1111/j.1462-2920.2009.01935.x
Source: PubMed


The coral holobiont is the community of metazoans, protists and microbes associated with scleractinian corals. Disruptions in these associations have been correlated with coral disease, but little is known about the series of events involved in the shift from mutualism to pathogenesis. To evaluate structural and functional changes in coral microbial communities, Porites compressa was exposed to four stressors: increased temperature, elevated nutrients, dissolved organic carbon loading and reduced pH. Microbial metagenomic samples were collected and pyrosequenced. Functional gene analysis demonstrated that stressors increased the abundance of microbial genes involved in virulence, stress resistance, sulfur and nitrogen metabolism, motility and chemotaxis, fatty acid and lipid utilization, and secondary metabolism. Relative changes in taxonomy also demonstrated that coral-associated microbiota (Archaea, Bacteria, protists) shifted from a healthy-associated coral community (e.g. Cyanobacteria, Proteobacteria and the zooxanthellae Symbiodinium) to a community (e.g. Bacteriodetes, Fusobacteria and Fungi) of microbes often found on diseased corals. Additionally, low-abundance Vibrio spp. were found to significantly alter microbiome metabolism, suggesting that the contribution of a just a few members of a community can profoundly shift the health status of the coral holobiont.

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Available from: Rebecca Vega Thurber, Jul 11, 2014
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    • "This enables corals to thrive in oligotrophic tropical seas and retain a high productivity despite limiting nutrient concentrations ( " Darwin Paradox " ; Darwin 1897, Sammarco et al. 1999). Recent advances in molecular studies are emphasizing the importance of identifying functional changes within the coral holobiont to provide insights into the limitations of physiological adaptation and plasticity in coral holobionts (Thurber et al. 2009; Bay and Palumbi 2015; Rädecker et al. 2015). As high-tech sampling tools and molecular techniques are advancing, specialized coral-endosymbiont communities have been discovered; these specializations include thermal tolerance, as recently found in the " world´s hottest reefs " in the "
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    • "Coral nubbins were thawed slowly on ice and removed from the RNA - later solution using sterile forceps and kimwipes to remove excess solution ( Vega Thurber et al . , 2009 ) . Replicate nubbins from the same donor colony ( A , B , or C ) were pooled and placed into sterile 150 mL conical flasks containing 15 mL sterile - autoclaved calcium and magnesium free seawater plus 10 mM EDTA ( CMFSWE ) . The surfaces of the nubbins were airbrushed using 80 psi with a sterile 1 mL barrier tip ( fresh tip for each n"
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