THIS PROPOSAL ADDRESSES THE GOALS SET IN FY2019 AND 2020 PROGRAM AREA PRIORITY A1103 - FOUNDATIONAL KNOWLEDGE OF PLANT PRODUCTS, SPECIFICALLY IN "PRIMARY AND SECONDARY METABOLISM REGULATING THE SYNTHESIS OF PLANT METABOLITES AND ITS CHEMICAL INGREDIENTS THAT IMPROVE THE QUALITY OF FOOD AND/OR FEED;" WHILE ALSO MORE BROADLY FACILITATING PRODUCTION OF "PLANT-BASED CHEMICALS THAT HAVE INDUSTRIAL AND/OR PHARMACEUTICAL RELEVANCE". PHYTONUTRIENTS DERIVED FROM PHE COMPRISE ONE OF THE MOST WIDELY OCCURRING GROUPS OF BIOACTIVE COMPOUNDS. HOWEVER, THE PHE METABOLIC NETWORK IS TIGHTLY REGULATED, WHICH PREVENTS PRODUCTION OF HIGH LEVELS OF DOWNSTREAM PHYTONUTRIENTS. THUS, INFORMATION ABOUT THE REGULATORY PROPERTIES OF THE PHE METABOLIC NETWORK GAINED FROM COMPLETION OF THIS PROJECT WILL ALLOW US TO OVERCOME CONSTRAINTS OF FEEDBACK REGULATION AND ENHANCE PHE LEVELS FOR PRODUCTION OF IMPORTANT PHE-DERIVED PHYTONUTRIENTS. THIS WILL PROVIDE NEW STRATEGIES FOR NUTRITIONAL IMPROVEMENT THAT DO NOT REQUIRE INTRODUCTION OF FOREIGN GENES. IN ADDITION, OBTAINED INFORMATION WILL CONTRIBUTE TO THE FUNDAMENTAL KNOWLEDGE ABOUT THE REGULATION OF AROMATIC AMINO ACID BIOSYNTHESIS IN GENERAL, AND WILL ANSWER A LONG-STANDING QUESTION ABOUT HOW FLUX INTO THE SHIKIMATE PATHWAY IS REGULATED IN PLANTS.THESE STUDIES WILL ALSO HAVE A SUBSTANTIAL PRACTICAL IMPACT BY DRAWING FROM NEWLY OBTAINED BASIC KNOWLEDGE ON UNDERSTANDING PHE METABOLIC NETWORK REGULATION TO IMPLEMENT A NOVEL STRATEGY TO GENERATE TOMATO FRUITS WITH BOTH IMPROVED NUTRITIONAL VALUE AND LIKELY PALATABILITY, KEY ATTRIBUTES THAT MUST BE IMPROVED SIMULTANEOUSLY IN ORDER TO COMBAT THE DECLINE IN CONSUMPTION OF NUTRITIONAL FOODS NECESSARY FOR FULFILLING DIETARY REQUIREMENTS. THIS WORK WILL ALSO EVALUATE THE NATIVE CAPACITY OF TOMATO FRUITS TO SUSTAINABLY PRODUCE HIGH VALUE PHENYLPROPANOID COMPOUNDS. FURTHERMORE, THIS RESEARCH WILL CREATE A PLATFORM FOR IDENTIFICATION OF ADDITIONAL BOTTLENECKS LIMITING PRODUCTION OF HIGH VALUE PHYTONUTRIENTS. THE OBTAINED KNOWLEDGE WILL ENABLE TARGETED SELECTION OF INDIVIDUALS WITH HIGH BIOSYNTHETIC POTENTIAL FROM AVAILABLE PLANT POPULATIONS AND IN BREEDING PROGRAMS.