Kelsey Sponholz, “Enhancing the Production of Antimicrobial Metabolites in Pseudomonas Soli for Sustainable Agricultural Disease Control”
Mentor: Ching-Hong Yang, Biological Sciences
Poster #188

The bacterium Erwinia amylovora is responsible for fire blight, a disease affecting economically significant crops like apples and pears. The application of clinical antibiotics, such as streptomycin, to combat this infection has led to increased antibiotic resistance in both the fire blight pathogen, Erwinia amylovora, and the natural microbiota. The escalating issue of antibiotic resistance globally necessitates the discovery of new antibacterial compounds for managing diseases in agricultural crops. A promising development is the identification of a Pseudomonas soli strain T3-07, which produces an antimicrobial metabolite named RejuAgroA (RAA). Demonstrated to be effective in preventing various agricultural diseases, RejuAgroA can be commercially produced and applied. Our research aims to enhance the production of RAA from P. soli T3-07 through mutagenesis, using ethyl methanesulfonate treatment (EMS). Post-EMS treatment, we screen the resulting colonies for those exhibiting the largest zones of inhibition against E. amylovora. Colonies with potential high production of RAA are further examined by inoculating them into a solution containing E. amylovora tagged with green fluorescent protein (GFP), facilitating the quantification of RAA production. Additionally, we monitor RAA production in high-yielding colonies over several hours by sampling cultures. Through these methods, we have identified several mutants with higher RAA production capabilities than the original P. soli T3-07 strain. Our ongoing efforts aim to discover a strain that produces at least 50% more RAA than the original. Enhanced RAA-producing strains will reduce the production costs for large-scale applications, benefiting farmers with a more economical solution for field use. This approach and protocol can be adapted to other antimicrobial-producing microbes, potentially increasing the production of antimicrobial metabolites in microbial species for commercial purposes.