CAULIFLOWER IS A HEALTHY CRUCIFEROUS VEGETABLE, ENRICHED IN VITAMINS, FIBER, AND PHYTONUTRIENTS WITH NUMEROUS NUTRITIONAL AND HEALTH BENEFITS. WHILE ALL ECONOMICALLY IMPORTANT TYPES OF CAULIFLOWER PRODUCE EDIBLE WHITE HEADS OR CURDS, THERE ARE COLORED VARIETIES. THESE COLORED CAULIFLOWERS NOT ONLY ENHANCE VISUAL APPEAL WITH BEAUTIFUL HUES, BUT ALSO ADD NUTRITIONAL AND HEALTH VALUES. MOREOVER, THEY PROVIDE INTERESTING AND UNIQUE GENETIC RESOURCES TO STUDY THE BASIS OF COLOR FORMATION AS WELL AS NUTRIENT AND PHYTONUTRIENT ACCUMULATION.GREEN CAULIFLOWER RESULTS FROM CHLOROPLAST DEVELOPMENT IN THE OTHERWISE WHITE CURD. SINCE CHLOROPLAST IS THE SITE FOR MANY NUTRIENT AND PHYTONUTRIENT BIOSYNTHESIS AND ACCUMULATION, GREEN CAULIFLOWER PROVIDES ADDITIONAL HEALTH BENEFITS COMPARING TO WHITE CURD CAULIFLOWER. HOWEVER, THE CAUSAL GENE AND HOW IT INDUCES CHLOROPLAST DEVELOPMENT IN THE CURD TISSUE ARE UNKNOWN. RECENTLY, VIA QTL-SEQ ANALYSIS AND FINE GENETIC MAPPING, WE IDENTIFIED A MAJOR GENOMIC REGION CONTAINING A FEW BEST CANDIDATES FOR THE GREEN GENE (GR). THE PROPOSED RESEARCH AIMS TO CLONE THE GR GENE AND UNDERSTAND HOW IT CONTROLS CHLOROPLAST DEVELOPMENT. THREE SPECIFIC OBJECTIVES ARE PROPOSED: 1) TO CONFIRM THE IDENTITY OF GR VIA PHENOTYPIC COMPLEMENTATION, 2) TO CHARACTERIZE THE GR GENE, AND 3) TO UNCOVER ITS REGULATORY MECHANISMS IN MEDIATING CHLOROPLAST DEVELOPMENT AND CONCOMITANTLY NUTRIENT ACCUMULATION. THE PROPOSED RESEARCH IS EXPECTED TO DISCOVER A NEW GENE AND NEW MECHANISMS IN CONTROLLING CHLOROPLAST DEVELOPMENT IN PLANTS. THE NEW GENE AND FUNDAMENTAL KNOWLEDGE GENERATED CAN BE TRANSLATED INTO NEW GENETIC TOOLS AND STRATEGIES TO PRODUCE MORE NUTRITIOUS CROPS, BENEFICIAL TO HUMAN NUTRITION AND HEALTH. THE PROPOSED RESEARCH ADDRESSES THE PROGRAM AREA PRIORITY OF FOUNDATIONAL KNOWLEDGE OF PLANT PRODUCTS (A1103).