Characterizing the Role of 2-OH-PCA in P. chlororaphis Pathogenesis

Abigail Toothman, The College of Wooster


Due to the rise in drug resistant bacteria there is a need for novel antimicrobial drugs. In order to begin producing new drugs it is first important to find proteins within bacteria that will act as functional drug targets. This research looked to characterize the unique role of phenazines, a group of colorful heterocyclic metabolites, in bacterial virulence to determine if the proteins responsible for their production or regulation would be good targets for new drugs. Specifically, this research focused on 2-OH-PCA, the orange phenazine, and characterization was completed within 2 P. chlororaphis strains, Byrd1 and 48G9. First, C. elegans virulence assays were done to confirm virulence and identify differences in pathogenesis between the two strains. Next, 2-OH-PCA production regulation by Pip, the phenazine inducing protein, was attempted to be monitored. Finally, the importance of 2-OH-PCA production for pathogenesis was tested by attempting to create 2-OH-PCA knockout clones of the two bacterial strains, via PhzO function removal, a protein vital for 2-OH-PCA formation, and completing subsequent C. elegans virulence assays with the WT and mutant bacterial strains. Despite being unable to fully answer the overall research question due to experimental complications, this study made important conclusions that further progresses this area of research. First, the presence of the PhzO gene and the Pip gene in 48G9 and Byrd1 was confirmed, and the interesting possibility of 2 variable versions of the PhzO gene was identified. In addition, Byrd1 and 48G9 were proven to be virulent, specifically exhibiting a strong inhibitory effect on the growth and motility of C. elegans upon their ingestion. Finally, evidence to support 2-OH-PCA as a toxic virulence factor was also observed. Each of these conclusions will be helpful for future studies looking to further characterize the production and regulation of 2-OH-PCA in the context of bacterial pathogenesis.


© Copyright 2013 Abigail Toothman