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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #362871

Research Project: Non-Antibiotic Strategies to Control Priority Bacterial Infections in Swine

Location: Virus and Prion Research

Title: Contribution of the BvgR and RisAS regulons to Bordetella bronchiseptica biology

Author
item Waack, Ursula - Oak Ridge Institute For Science And Education (ORISE)
item Chen, Qing - Food And Drug Administration(FDA)
item Stibitz, Scott - Food And Drug Administration(FDA)
item Merkel, Tod - Food And Drug Administration(FDA)
item Bearson, Brad - US Department Of Agriculture (USDA)
item Nicholson, Tracy

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/8/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The majority of virulence gene expression in Bordetella is regulated by a two-component sensory transduction system encoded by the bvgAS locus. BvgAS controls expression of a spectrum of phenotypic phases transitioning between a virulent (Bvg+) phase and a non-virulent (Bvg¯) phase, a process referred to as phenotypic modulation. Production of BvgR in Bvg+ phase is required for repression of virulence-repressed genes (vrgs). In addition to the BvgAS system, another two-component system RisAS has recently been shown to exert additional control for B. pertussis, where RisA is necessary for the activation of vrgs. B. bronchiseptica is the evolutionary predecessor of B. pertussis and shares many of the same regulatory pathways. Studies involving B. bronchiseptica offer an evolutionary biology perspective for how bacterial pathogens evolve and become host-restricted yet still retain similar disease and transmission traits. In this study we characterized the B. bronchiseptica BvgR and RisAS regulons by constructing a series of isogenic mutants Delta bvgR, Delta risA, Delta risS, Delta risAS, and risAD60N followed by measuring the transcriptional responses of each mutant compared to wild-type during modulating or nonmodulating conditions. To further explore the phenotypic contribution of each mutation, metabolic phenotypes were measured using Biolog analysis and oxidative stress, adherence, biofilm, and motility assays were performed. In addition to defining a bvgR regulon, our data highlights differences between each mutant and suggests that more proteins may be involved. Specifically, one or more proteins may interact with both RisS and RisA, and a RisA protein is required, versus just a functional active site, for the regulation of some B. bronchiseptica genes. Our work is an important key in understanding the complex regulation surrounding the virulence pathways in B. bronchiseptica and other Bordetella species.