title: Insights into Dynamic Polymicrobial Synergy Revealed by Time-Coursed RNA-Seq.
abstract: Many bacterial infections involve polymicrobial communities in which constituent organisms are synergistically pathogenic. Periodontitis, a commonly occurring chronic inflammatory disorder, is induced by multispecies bacterial communities. The periodontal keystone pathogenPorphyromonas gingivalisand the accessory pathogenStreptococcus gordoniiexhibit polymicrobial synergy in animal models of disease. Mechanisms of co-adhesion and community formation byP. gingivalisandS. gordoniiare well-established; however, little is known regarding the basis for increased pathogenicity. In this study we used time-coursed RNA-Seq to comprehensively and quantitatively examine the dynamic transcriptional landscape ofP. gingivalisin a model consortium withS. gordonii. Genes encoding a number of potential virulence determinants had higher relative mRNA levels in the context of dual species model communities thanP. gingivalisalone, including adhesins, the Type IX secretion apparatus, and tetratricopeptide repeat (TPR) motif proteins. In contrast, genes encoding conjugation systems and many of the stress responses showed lower levels of expression inP. gingivalis. A notable exception to reduced abundance of stress response transcripts was the genes encoding components of the oxidative stress-related OxyR regulon, indicating an adaptation ofP. gingivalisto detoxify peroxide produced by the streptococcus. Collectively, the results are consistent with evolutionary adaptation ofP. gingivalisto a polymicrobial oral environment, one outcome of which is increased pathogenic potential.
authors.affiliation: Center for Microbial Proteomics and Chemical Engineering, University of Washington Seattle, WA, USA.
authors.forename: Erik L
authors.initials: EL
authors.lastname: Hendrickson
authors.affiliation: Center for Microbial Proteomics and Chemical Engineering, University of WashingtonSeattle, WA, USA; eScience Institute, University of WashingtonSeattle, WA, USA.
authors.forename: David A C
authors.initials: DA
authors.lastname: Beck
authors.affiliation: Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry Louisville, KY, USA.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Miller
authors.affiliation: Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry Louisville, KY, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Molecular Biosciences, University of Texas at Austin Austin, TX, USA.
authors.forename: Marvin
authors.initials: M
authors.lastname: Whiteley
authors.affiliation: Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry Louisville, KY, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lamont
authors.affiliation: Center for Microbial Proteomics and Chemical Engineering, University of Washington Seattle, WA, USA.
authors.forename: Murray
authors.initials: M
authors.lastname: Hackett
keywords: Porphyromonas gingivalis; RNA-Seq; Streptococcus gordonii; model community; time-course profiling