** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** EMERGING PLANT DISEASES CAN INCUR ECONOMIC AND ENVIRONMENTAL COSTS BY LEADING TO EPIDEMICS OR THE PERSISTENT APPEARANCE OF LOW LEVELS OF NEW DISEASES. IDENTIFYING THE RISK FACTORS FAVORING THE EMERGENCE OF PLANT PATHOGENS IS IMPORTANT TO PREDICTING, MONITORING, MITIGATING, AND MANAGING DISEASES. THE TRANSMISSION OF BACTERIAL PLANT PATHOGENS BY BEETLES MAY POSE AN UNRECOGNIZED, YET MAJOR, RISK FOR DISEASE EMERGENCE BECAUSE BEETLES PICK UP AND SPREAD BACTERIA WITH RELATIVE EASE, NAMELY BY FEEDING WITH SUBSEQUENT FECAL TRANSMISSION. BEETLES ALSO HARBOR BACTERIAL SPECIES THAT ARE WELL ADAPTED TO BOTH THE INSECT GUT AND PLANT ENVIRONMENTS, AND THEY ARE PRONE TO INVASIVENESS, GEOGRAPHIC RANGE EXPANSION, AND PATHOGEN SPREAD AMONG MULTIPLE PLANT SPECIES DUE TO OFTEN INDISCRIMINATE FEEDING. THE GOAL OF THIS PROJECT IS TO UNDERSTAND THE FACTORS DRIVING THE ADAPTATION, PERSISTENCE, AND EMERGENCE OF BEETLE-TRANSMITTED BACTERIAL PATHOGENS. AS A STUDY SYSTEM, THE PROJECT WILL USE A BACTERIAL WILT PATHOGEN OF COMMERCIALLY IMPORTANT CUCURBIT SPECIES (E.G., CUCUMBERS, SQUASH, AND MUSKMELONS) AND BEETLES THAT TRANSMIT THE PATHOGEN. THE PROJECT WILL EXPLORE MECHANISMS INFLUENCING THE SHORT-TERM EVOLUTIONARY POTENTIAL OF THE PATHOGEN AND MECHANISMS DRIVING CHANGE IN PRESENT-DAY POPULATIONS BY EXAMINING BARRIERS TO ACQUISITION AND SPREAD BY BEETLES AND GENOMIC VARIATION IN NATIVE POPULATIONS IN PLANTS AND BEETLES. COLLECTIVELY, THE RESULTS WILL HELP WITH NEW PATHOGEN-BASED STRATEGIES TO PREVENT AND MANAGE BEETLE-TRANSMITTED BACTERIAL PLANT DISEASES. THE RESULTS WILL ALSO HELP IDENTIFY EVOLUTIONARY HOTSPOTS WITHIN NATURAL AND AGRICULTURAL ENVIRONMENTS THAT FAVOR PATHOGEN EMERGENCE AND THUS HELP ASSESS THE EMERGENCE RISK FOR SUCH PATHOGENS.