NSF Postdoctoral Fellowship in Biology: Characterizing the genetic mechanisms of bacteria-phage coevolution in Listeria and Salmonella

Lewis, Jordan A, Atlanta GA

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2022, Broadening Participation of Groups Underrepresented in Biology. The Fellowship supports a research and training plan for the Fellow that will increase the participation of groups underrepresented in biology. Each year infectious bacteria cause billions of dollars in lost revenue in the food and agricultural industry in addition to millions of deaths globally. Historically, antibiotics have served as the primary means to control these agents, but the rise in antibiotic resistance threatens to undermine these methods. More recently, bacteria-specific viruses called phages have been used as antimicrobial control agents, but many questions remain regarding the nature of their roles with industry relevant bacteria. Characterizing the relationship (coevolution) between phages and bacteria, and their tendency to develop cross infectivity and resistance, respectively, is important for the planning and use of phages for antimicrobial control. The fellow will conduct experiments with Listeria and Salmonella, two important foodborne bacteria, and an array of their phages. Results will provide information about bacteria-phage coevolution using agriculturally relevant systems while expanding the general knowledge about phage biology. To increase participation of underrepresented groups, the fellow will teach an undergraduate course focusing on how evolutionary biology intersects with world issues and will develop a mentoring network for African Americans in Ecology & Evolutionary Biology (EEB). The fellow will utilize classic serial passaging techniques combined with genomic data to characterize the coevolution between phage and bacteria. Replicate populations of Salmonella enterica and Listeria monocytogenes will be passaged in monoculture paired with a specific phage. After passaging, the fellow will utilize whole-genome sequencing and time shift assays to categorize the genetic dynamics of coevolution and its phenotypic results. Following this initial experiment, the final generation of each bacteria treatment will be assayed against novel phages to determine the specificity of its evolved defenses, before being paired with a new phage and passaged using methods identical to the first experiment. This will examine how past coevolution impacts future adaptability. The second experiment will also be followed by whole genome sequencing and time shift assays. The fellow will encourage participation of underrepresented groups in biology through the creation of a formal mentoring network for African Americans in EEB, with the goal of supporting those seeking PhDs and professorships in the field while fostering inclusivity within EEB. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.