** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** FRUIT PHOTOSYNTHESIS CONTRIBUTES TO YIELD AND FRUIT NUTRIENT QUALITY AS DEMONSTRATED IN A WIDE RANGE OF FLESHY FRUITS, EARS OF CEREALS, OIL SEEDS, LEGUMES ETC. TOMATO IS ONE OF THE WORLD'S MOST CONSUMED VEGETABLES WITH $1.78 BILLION ECONOMIC VALUE IN THE US IN 2022 (USDA-NASS). TOMATO SERVES AS A GREAT MODEL TO STUDY FLESHY FRUIT DEVELOPMENT, INCLUDING CHLOROPLAST DEVELOPMENT AND CHLOROPHYLL ACCUMULATION IN FRUITS. ALTHOUGH LEAVES ARE THE PRIMARY PHOTOSYNTHETIC ORGANS, UP TO 20% OF THE CARBON IN TOMATO FRUIT IS DERIVED FROM FRUIT PHOTOSYNTHESIS ITSELF, IMPACTING YIELD, NUTRIENT CONTENT, FLAVOR, AND OVERALL FRUIT QUALITY. THIS HAS BEEN VALIDATED IN THE UNIFORM RIPENING (U) MUTATION IN TOMATO, WHERE THE TRANSCRIPTION FACTOR (TF) GOLDEN 2-LIKE (SLGLK2) IS DISABLED. SLGLK2 DETERMINES CHLOROPLAST DEVELOPMENT, AND CHLOROPHYLL ACCUMULATION IN A DEVELOPING FRUIT THEREBY CONTRIBUTING TO IMPROVED FRUIT QUALITY. THE SELECTION OF 'U' IN MODERN TOMATO VARIETIES INADVERTENTLY COMPROMISED RIPE FRUIT QUALITY FOR DESIRABLE PRODUCTION TRAITS. PD'S RESEARCH IDENTIFIED ANOTHER TF, TKN4 IN TOMATO, A CLASS I KNOTTED-LIKE HOMEOBOX (KNOX) GENE THAT ALSO INFLUENCES CHLOROPLAST DEVELOPMENT AND CHLOROPHYLL ACCUMULATION IN FRUIT THROUGH REGULATION OF SLGLK2 EXPRESSION. THE IDENTIFICATION OF KNOX REGULATORY MODULE HIGHLIGHTS AN ENTIRELY NOVEL ROLE FOR KNOX TFS IN FRUIT DEVELOPMENT, WHICH NEEDS TO BE DECIPHERED. BY UTILIZING A TOMATO DIVERSITY PANEL, WE WILL IDENTIFY GENOME-WIDE LOCI UNDERLYING FRUIT CHLOROPHYLL ACCUMULATION BYGENOME-WIDE ASSOCIATION STUDIES (GWAS). WE WILL PERFORM TARGETED TRANSCRIPTOME ANALYSES OF KNOX MUTANTS AND INTEGRATE WITH GWAS RESULTS TO CONSTRUCT GENE REGULATORY NETWORKS GOVERNING FRUIT CHLOROPHYLL ACCUMULATION. WE WILL IDENTIFY GENOME-WIDE BINDING SITES FOR KNOX AND OTHER KEY TFS INVOLVED IN FRUIT CHLOROPLAST DEVELOPMENT. MOLECULAR BASIS OF CHLOROPLAST DEVELOPMENT AND CHLOROPHYLL ACCUMULATION IN FRUITS IDENTIFIED THROUGH THIS PROJECT CAN POTENTIALLY TRANSLATE INTO CROP VARIETIES WITH IMPROVED YIELD AND FRUIT QUALITY THROUGH BREEDING/ GENE-EDITING. PROGRESS IN THIS AREA HAS THE LONG-RUN POTENTIAL TO FAVORABLY ENGINEER PHOTOSYNTHESIS CONTRIBUTING TO YIELD AND QUALITY OF FOOD CROPS.