Endozoicomonas genomes reveal functional adaptation and plasticity in bacterial strains symbiotically associated with diverse marine hosts

Abstract
Endozoicomonas bacteria are globally distributed and often abundantly associated with diverse marine hosts including reef-building corals, yet their function remains unknown. In this study we generated novel Endozoicomonas genomes from single cells and metagenomes obtained directly from the corals Stylophora pistillata, Pocillopora verrucosa, and Acropora humilis. We then compared these culture-independent genomes to existing genomes of bacterial isolates acquired from a sponge, sea slug, and coral to examine the functional landscape of this enigmatic genus. Sequencing and analysis of single cells and metagenomes resulted in four novel genomes with 60–76% and 81–90% genome completeness, respectively. These data also confirmed that Endozoicomonas genomes are large and are not streamlined for an obligate endosymbiotic lifestyle, implying that they have free-living stages. All genomes show an enrichment of genes associated with carbon sugar transport and utilization and protein secretion, potentially indicating that Endozoicomonas contribute to the cycling of carbohydrates and the provision of proteins to their respective hosts. Importantly, besides these commonalities, the genomes showed evidence for differential functional specificity and diversification, including genes for the production of amino acids. Given this metabolic diversity of Endozoicomonas we propose that different genotypes play disparate roles and have diversified in concert with their hosts.

Citation
Neave MJ, Michell CT, Apprill A, Voolstra CR (2017) Endozoicomonas genomes reveal functional adaptation and plasticity in bacterial strains symbiotically associated with diverse marine hosts. Scientific Reports 7: 40579. Available: http://dx.doi.org/10.1038/srep40579.

Acknowledgements
We thank the Bigelow Single Cell Genomics Center, Maine, USA, for assistance with the single cell genomics procedure. This research was supported by a KAUST-WHOI Post-doctoral Partnership Award to M.J.N. and a KAUST-WHOI Special Academic Partnership Funding Reserve Award to C.R.V. and A.A. Additional research was supported from baseline funds to C.R.V. by the King Abdullah University of Science and Technology (KAUST).

Publisher
Springer Nature

Journal
Scientific Reports

DOI
10.1038/srep40579

Additional Links
http://www.nature.com/articles/srep40579

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