MICROBIAL PATHOGENS CAUSE SEVERE CROP LOSSES AND SIGNIFICANT FINANCIAL DAMAGE AROUND THE WORLD. A WARMING CLIMATE, INCREASING PESTICIDE RESISTANCE, AND ENVIRONMENTAL DAMAGE FROM PESTICIDE OVERUSE FURTHER NECESSITATES THE NEED FOR NEW PATHOGEN CONTROL STRATEGIES. SPRAY-INDUCED GENE SILENCING (SIGS), WHICH RELIES UPON RNA INTERFERENCE, IS AN EFFECTIVE AND ECO-FRIENDLY METHOD OF DISEASE CONTROL. HOWEVER, SIGS REMAINS LIMITED BY A DEPENDENCE ON PASSIVE MICROBIAL RNA UPTAKE AND THE INSTABILITY OF RNA IN THE ENVIRONMENT. BUILDING UPON HOW NANOPARTICLES CAN PROTECT AND DELIVER RNA IN VACCINES, THIS PROJECT WILL DEVELOP PLANT-DERIVED NANOVESICLES (PDNVS) AS A NEW NANOPARTICLE PLATFORM FOR DELIVERING RNA AND OTHER BIOACTIVE MOLECULES TO STUDY AND COMBAT MICROBIAL PATHOGENS. PDNVS FROM VARIOUS PLANT SOURCES WILL BE EXAMINED FOR THEIR ABILITY TO IMPROVE RNA DELIVERY TO PATHOGENS WITH VARYING INHERENT RNA UPTAKE CAPABILITIES. RNA-LOADED PDNVS WILL THEN BE USED FOR SIGS TO DETERMINE IF THEY CAN EFFECTIVELY REDUCE PATHOGENICITY AND PROVIDE PROLONGED DISEASE PROTECTION ON PLANTS. ANALYSIS OF THE DIFFERENT PDNV COMPOSITIONS WILL IDENTIFY KEY FEATURES THAT CONTROL RNA LOADING IN NANOPARTICLES AND SUBSEQUENT VESICLE UPTAKE BY MICROBES. THIS WORK WILL DEMONSTRATE HOW PDNVS, WHICH ARE ECO-FRIENDLY, ECONOMICAL, AND EASILY SCALABLE, CAN BE USED TO IMPROVE AND EXTEND SIGS TO PREVIOUSLY RECALCITRANT MICROBES. UNDERSTANDING WHAT FEATURES CONTROL NANOPARTICLE LOADING AND MICROBIAL UPTAKE WILL FACILITATE THE DESIGN OF MORE EFFECTIVE AND ROBUST ANTIMICROBIAL STRATEGIES FOR AGRICULTURE AND HUMAN HEALTH.