Insights into the Cultured Bacterial Fraction of Corals

by Michael Sweet, Helena Villela, Tina Keller-Costa, Rodrigo Costa, Stefano Romano, David Bourne, Anny Cardenas, Megan J. Huggett, Allison H. Kerwin, Felicity Kuek, Monica Medina, Julie L. Meyer, Moritz Muller, Joseph Pollock, Michael S. Rappe, Mathieu Sere, Koty H. Sharp, Christian Voolstra, Nathan Zaccardi, Maren Ziegler, Raquel Peixoto
Scientific paper Year: 2021 DOI: 10.1128/mSystems.01249-20

Extra Information

mSystems, Volume 6, Issue 3, e01249-20


Bacteria associated with coral hosts are diverse and abundant, with recent studies suggesting involvement of these symbionts in host resilience to anthropogenic stress. Despite their putative importance, the work dedicated to culturing coral-associated bacteria has received little attention. Combining published and unpublished data, here we report a comprehensive overview of the diversity and function of culturable bacteria isolated from corals originating from tropical, temperate, and cold-water habitats. A total of 3,055 isolates from 52 studies were considered by our meta survey. Of these, 1,045 had full-length 16S rRNA gene sequences, spanning 138 formally described and 12 putatively novel bacterial genera across the ProteobacteriaFirmicutesBacteroidetes, and Actinobacteria phyla. We performed comparative genomic analysis using the available genomes of 74 strains and identified potential signatures of beneficial bacterium-coral symbioses among the strains. Our analysis revealed >400 biosynthetic gene clusters that underlie the biosynthesis of antioxidant, antimicrobial, cytotoxic, and other secondary metabolites. Moreover, we uncovered genomic features—not previously described for coral-bacterium symbioses—potentially involved in host colonization and host-symbiont recognition, antiviral defense mechanisms, and/or integrated metabolic interactions, which we suggest as novel targets for the screening of coral probiotics. Our results highlight the importance of bacterial cultures to elucidate coral holobiont functioning and guide the selection of probiotic candidates to promote coral resilience and improve holistic and customized reef restoration and rehabilitation efforts.


Symbiosis Coral holobiont Metaorganism Cultured microorganisms Coral reef Coral probiotics Beneficial microbes Genomes