CORN DISEASE GOSS'S WILT HAS RE-EMERGED IN MAJOR MAIZE-PRODUCING AREAS OF THE US AND CANADA AND REPRESENTS A THREAT TO MAIZE PRODUCTION. CMN, THE CAUSAL AGENT FOR GW, IS A MEMBER OF THE ACTINOBACTERIA (A PHYLUM OF GRAM-POSITIVE BACTERIA). THE GENETICALLY CLOSE BACTERIAL SPECIES CAUSES TWO OTHER IMPORTANT PLANT DISEASES TOMATO CANKER AND POTATO RING ROT, AS WELL AS DISEASES OF WHEAT, ALFALFA, AND COMMON BEAN. HOWEVER, GENETIC INFORMATION OF PATHOGENICITY AND PLANT HOST DEFENSE FOR THESE GRAM-POSITIVE BACTERIUM RELATED DISEASES ARE POORLY UNDERSTOOD, RESTRICTING EMPLOYMENT OF DISEASE CONTROLLING STRATEGIES. GENETIC MATERIALS AND GENOMIC INFORMATION REGARDING BOTH CORN AND CMN HAVE BECOME AVAILABLE, ALLOWING GOSS'S WILT TO BECOME A TRACTABLE SYSTEM TO STUDY BOTH THE GENETICS OF HOST RESISTANCE AND BACTERIAL VIRULENCE. THIS PROPOSAL AIMS TO ELUCIDATE THE GENETIC BASIS OF PLANT RESISTANCE TO THE GOSS'S WILT DISEASE; IMPROVE UNDERSTANDING OF VIRULENCE MECHANISMS OF CMN; AND DISSECT THE INTERPLAY OF BACTERIAL VIRULENCE AND HOST RESISTANCE GENES. THE PROJECT WILL DEEPEN OUR UNDERSTANDING OF THIS IMPORTANT, BUT UNDERSTUDIED, PATHOSYSTEM, AND, UNDOUBTEDLY, PROVIDE INSIGHTS INTO OTHER CLOSELY RELATED DISEASES, PARTICULARLY THOSE CAUSED BY ACTINOBACTERIA. IMPORTANTLY, THE IDENTIFICATION OF PLANT RESISTANCE GENES WILL ENABLE THE DEVELOPMENT OF IMPROVED CORN VARIETIES FOR GOSS'S WILT RESISTANCE, AND CONSEQUENTLY REDUCE RISK OF DISEASE AND ASSOCIATED YIELD LOSSES.