Dissecting the antagonistic interaction between Pseudomonas protegens PBL3 and Burkholderia glumae towards development of biopesticides to control Bacterial Panicle Blight of rice

Plants are affected by diseases caused by diverse groups of microorganisms. When those diseases affect crops, such as rice, they have an enormous negative impact on farmers and food security for a growing human population. A common method to control crop diseases is with synthetic chemical pesticides that can have adverse effects on ecosystems and on human and animal health. An alternative approach involves the use of beneficial microorganisms present in natural environments to counteract the activity of plant pathogens through the production of a variety of molecules known as antimicrobials. A prominent group of environmental bacteria that could be exploited to control plant pathogens are called Pseudomonas; within that group Pseudomonas protegens PBL3 has been effective inhibiting the growth of a plant pathogenic bacterium causing a devastating disease in rice. However, it is not known how P. protegens PBL3 inhibits the growth of the pathogen. Thus, the goal of this project is to identify the specific antimicrobial molecules that P. protegens PBL3 produces and to understand how they inhibit the growth of the pathogen. The results from this project will contribute to developing biologically based solutions to control diseases in crops to reduce crop losses and reduce their economic impact to farmers, while alleviating food insecurity worldwide. In addition, the project will also be used as a platform to provide broad scientific training to emerging scientists at different stages of their careers. Rice is a staple food for more than three billion people worldwide. Rice production is threatened by Bacterial Panicle Blight (BPB) caused by Burkholderia glumae. The absence of completely resistant rice varieties or effective chemical methods to eliminate the pathogen, has paved the way to harness environmental bacteria as sources of effective antimicrobials to control B. glumae. Previously, the environmental bacterium Pseudomonas protegens PBL3 was identified as an antagonistic bacterium against B. glumae, due to antimicrobial molecules that P. protegens PBL3 produces and secretes. However, the specific antimicrobial molecules and their mode of action on B. glumae are unknown. Thus, the proposed project combines multi-disciplinary approaches involving genetics, comparative genomics, metabolomics, and transcriptomics tools to identify genes and pathways in P. protegens PBL3 encoding antimicrobials, elucidate the chemical composition and structure of those antimicrobials and define their mode of action against B. glumae. The project will provide scientific training and professional development activities for a postdoctoral research associate, and a graduate student directly involved with the project. In addition, an important goal of the project is to provide a foundational online course, as well as a hands-on summer research experience to undergraduate students. 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.