CAROTENOIDS ARE CRITICAL IMPORTANT TO HUMAN NUTRITION AND HEALTH BECAUSE THEY ARE PRECURSORS FOR VITAMIN A SYNTHESIS AND DIETARY ANTIOXIDANTS IN OUR FOOD. THERE IS AN INCREASING PUBLIC INTEREST IN CONSUMING FOODS ENRICHED WITH CAROTENOIDS TO IMPROVE HUMAN NUTRITIONAL STATUS AND TO LOWER THE RISKS OF SOME CHRONIC DISEASES. IDENTIFICATION OF GENES RESPONSIBLE FOR CAROTENOID ACCUMULATION AND A THOROUGH UNDERSTANDING OF THEIR CONTROL MECHANISMS ARE CRUCIAL FOR DEVELOPMENT OF CAROTENOID-ENRICHED AGRICULTURE PRODUCTS. HOWEVER, DESPITE OF THE SIGNIFICANT PROGRESS IN CAROTENOID RESEARCH, THE REGULATORY GENES AND THE OVERALL CONTROL MECHANISMS REMAIN LARGELY UNKNOWN.MANY FRUITS AND VEGETABLES ACCUMULATE SUBSTANTIAL LEVELS OF CAROTENOIDS TO GIVE THE VIVID RED, ORANGE, AND YELLOW COLOR. THEY PROVIDE EXCELLENT RESOURCES FOR NOVEL GENE DISCOVERY AND UNDERSTANDING THE BASIS OF CAROTENOID OVERPRODUCTION. IN OUR PREVIOUS COLLABORATIVE RESEARCH, WE FOUND THAT A MELON ORANGE GENE (CMOR) DETERMINES FRUIT FLESH COLOR. INVESTIGATION OF A DIVERSE MELON GERMPLASM COLLECTION REVEALS THAT IF THE MELON PLANTS CONTAIN THE CMORORANGE GENE VARIANT, THEY PRODUCE ORANGE FLESH MELON FRUIT. INTERESTINGLY, WE HAVE RECENTLY IDENTIFIED A RARE MELON VARIETY THAT HAS CMORORANGE GENE VARIANT BUT PRODUCES WHITE FLESH FRUIT. THIS MELON VARIETY APPEARS TO CONTAIN A LONG-SOUGHT GENE THAT INTERFERES THE CMORORANGE INDUCED CAROTENOID PRODUCTION. THIS SPECIAL VARIETY OFFERS US A UNIQUE OPPORTUNITY TO UNRAVEL AN IMPORTANT GENE THAT AFFECTS CAROTENOID ACCUMULATION IN CROPS. IN ADDITION, WE EXPAND THE STUDY OF NOVEL GENE DISCOVERY IN A SPECIFIC ARABIDOPSIS LINE. THE OBJECTIVES OF OUR PROJECT ARE TO IDENTIFY THE IMPORTANT GENES AND ELUCIDATE HOW THEY CONTROL CAROTENOID LEVELS IN MELON FRUIT AND PLANTS. SPECIFICALLY, WE WILL 1) TO CLONE THE GENE THAT SUPPRESSES CMORORANGE FUNCTION, 2) TO INVESTIGATE HOW IT INTERFERES CMORORANGE IN AFFECTING CAROTENOID ACCUMULATION, AND 3) TO IDENTIFY ADDITIONAL NEW PLAYERS IN THE CAROTENOID REGULATORY NETWORK. THE PROPOSED RESEARCH IS EXPECTED TO UNCOVER NOVEL GENETIC TOOLS AND FUNDAMENTAL KNOWLEDGE, WHICH CAN BE TRANSLATED INTO NEW STRATEGIES FOR CAROTENOID ENRICHMENT IN CROPS WITH ENHANCED NUTRITIONAL QUALITY. THUS, OUR PROJECT ALIGNS WELL WITH THE USDA-NIFA-AFRI PHYSIOLOGY OF AGRICULTURAL PLANTS (A1152) PROGRAM AREA PRIORITY - PRIMARY AND SECONDARY METABOLISM IN AGRICULTURALLY-IMPORTANT PLANTS, .... PARTICULAR RELEVANCE TO NUTRITIONAL QUALITY OF FOOD.