BEAN RUST, CAUSED BY UROMYCES APPENDICULATUS, IS A SIGNIFICANT DISEASE OF DRY AND SNAP BEANS (PHASEOLUS VULGARIS) IN THE UNITED STATES. DESPITE NUMEROUS ADVANCEMENTS IN RESISTANCE BREEDING, U. APPENDICULATUS CONTINUES TO EVOLVE, POSING A SIGNIFICANT THREAT TO BEAN PRODUCTION. THE WIND-BORNE SPORES OF U. APPENDICULATUS CAN TRAVEL ACROSS CONTINENTS TO CAUSE DISEASE EPIDEMICS. THE PROPOSED RESEARCH AIMS TO ADDRESS THESE CHALLENGES BY UNRAVELING THE U. APPENDICULATUS EXTENSIVE POPULATION DIVERSITY THAT ORIGINATED IN THE US OVER THE PAST THREE DECADES USING TRADITIONAL PHENOTYPING AND GENOMICS. THE US ISOLATES WILL BE COMPARED TO GLOBAL ISOLATES COLLECTED FROM THREE ADDITIONAL CONTINENTS AT GENOMIC LEVELS TO STUDY ORIGIN, EVOLUTION, AND SPREAD. THIS PROJECT WILL ALSO DEVELOP PHASED CHROMOSOME-SCALE REFERENCE GENOME ASSEMBLIES OF TWO U. APPENDICULATUS ISOLATES REPRESENTING MESOAMERICAN AND ANDEAN GENE POOLS TO FACILITATE CURRENT AND FUTURE GENOMIC STUDIES. THE PROJECT AIMS TO SAFEGUARD THE US AND GLOBAL FOOD SECURITY BY GENERATING NEW INSIGHTS TO MITIGATE THREATS TO COMMON BEAN PRODUCTION.