Multiple Single-Cell Genomes Provide Insight into Functions of Uncultured <i>Deltaproteobacteria</i> in the Human Oral Cavity

<div><p>Despite a long history of investigation, many bacteria associated with the human oral cavity have yet to be cultured. Studies that correlate the presence or abundance of uncultured species with oral health or disease highlight the importance of these community members. Thus, we sequenced several single-cell genomic amplicons from <i>Desulfobulbus</i> and <i>Desulfovibrio</i> (class <i>Deltaproteobacteria</i>) to better understand their function within the human oral community and their association with periodontitis, as well as other systemic diseases. Genomic data from oral <i>Desulfobulbus</i> and <i>Desulfovibrio</i> species were compared to other available deltaproteobacterial genomes, including from a subset of host-associated species. While both groups share a large number of genes with other environmental <i>Deltaproteobacteria</i> genomes, they encode a wide array of unique genes that appear to function in survival in a host environment. Many of these genes are similar to virulence and host adaptation factors of known human pathogens, suggesting that the oral <i>Deltaproteobacteria</i> have the potential to play a role in the etiology of periodontal disease.</p>