** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** TERPENOIDS REPRESENT ONE OF THE LARGEST CLASSES OF PLANT METABOLITES, ENCOMPASSING MORE THAN 80,000 COMPOUNDS PLAYINGVARIOUS ROLES IN PLANT PHYSIOLOGY AND ECOLOGY. TERPENOIDS ALSO CONTRIBUTE TO MANY TRAITS THAT CONSUMERS FIND APPEALING IN FRUITS AND VEGETABLES, INCLUDING COLOR, AROMA, TASTE, AND PHYTONUTRITIONAL CONTENT. HOWEVER, THESE CHARACTERISTICS HAVE BEEN LOST IN MANY CROPS BECAUSE TRADITIONAL BREEDING PROGRAMS HAVE LARGELY FOCUSED ON AGRONOMIC TRAITS, LIKE YIELD, RESISTANCE TO ENVIRONMENTALSTRESSES, AND POST-HARVEST STORAGE AND HANDLING. THEREFORE, THE FOCUS OF THIS PROPOSAL IS TO ENHANCE THE CAPACITY FOR PRODUCING TERPENOID-DERIVED FLAVOR COMPOUNDS AND PHYTONUTRIENTS IN TOMATO FRUITS. WE AND OTHERS PREVIOUSLY ATTEMPTED TO ADDRESS THIS PROBLEM, BUT THOSE EFFORTS LED TO UNEXPECTED RESULTS (E.G.REDUCED LYCOPENE AND CAROTENOID CONTENT) AND RAISED NEW QUESTIONS. HERE, WE PROPOSE TO USE NOVEL APPROACHES BUILT ON OUR RECENT WORK TO FILL GAPS IN BASIC KNOWLEDGE ABOUT TERPENOID METABOLISM IN FRUITS. KNOWLEDGE GENERATED IN THIS PROJECT WILL PROVIDE KEY INFORMATION ABOUTTHE CAPACITY OF THE MEVALONIC ACID (MVA) AND METHYLERYTHRITOL PHOSPHATE (MEP) PATHWAYSTO PROVIDE PRECURSORS FOR TERPENOID BIOSYNTHESIS IN TOMATO FRUITS. WE WILL ALSO TEST NOVEL METABOLIC ENGINEERING STRATEGIESTO HARNESS THE MVA PATHWAY FOR PRODUCING TERPENOIDS IN TOMATO, LEADING TO MORE FLAVORFUL AND NUTRITIOUS FRUITS.