**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** TOMATO IS AMONG THE HIGHEST VALUE VEGETABLE CROPS IN THE US AND IS A MODEL PLANT FOR STUDYING FRUIT DEVELOPMENT AND RIPENING. IN THE US, FRESH MARKET TOMATO GROSSED $1.22 BILLION IN 2015 AND DEMAND HAS BEEN STEADILY RISING SINCE 2000 AT A RATE FASTER THAN US POPULATION GROWTH. EARLY FRUIT RIPENING COULD BE A DESIRED TRAIT IN THE TOMATO INDUSTRY AND GENETIC/MOLECULAR APPROACHES ARE ESSENTIAL FOR THIS REALIZATION. US GROWERS NEED ACCESS TO VARIETIES THAT WILL EXTEND THE LENGTH OF THEIR PRODUCTION SEASON BY RIPENING EARLIER THAN THE VARIETIES CURRENTLY AVAILABLE. A MOLECULAR APPROACH WILL ALLOW US TO QUICKLY AND DIRECTLY ADDRESS THIS MARKET SHORTCOMING BY ALTERING FRUIT RIPENING VIA THE PRECISE MANIPULATION OF KEY FACTORS THAT CONTROL FRUIT RIPENING. WE HAVE RECENTLY FOUND THAT A TOMATO PROTEIN, CALLED NAC1 (SLNAC1) TRANSCRIPTION FACTOR, IS AN IDEAL CANDIDATE TO TARGET FRUIT TRAITS GIVEN ITS SPECIFICALLY HIGH EXPRESSION IN IMMATURE GREEN FRUITS AND DRASTICALLY-ALTERED FRUIT PHENOTYPES INTOMATO PLANTS WITH MANIPULATED SLNAC1 EXPRESSION. HOWEVER, SINCE SLNAC1 ALSO PLAYS IMPORTANT ROLES IN OTHER DIVERSE PHYSIOLOGICAL PROCESSES, CAUTION SHOULD BE TAKEN TO AVOID UNDESIRED SIDE-EFFECTS CAUSED BY THE MANIPULATION OF SLNAC1. PARTICULARLY, CONSTITUTIVE OVEREXPRESSION CAUSES UNDESIRABLE GROWTH ABNORMALITIES AND, THUS, IT IS CRITICAL AND NECESSARY TO CONDITIONALLY MANIPULATE SLNAC1 ONLY IN TARGETED TISSUE - IN THIS CASE, FRUIT. THUS, IN ORDER TO UNDERSTAND WHAT GENES CONTROL THE COMPLEX PROCESS OF TOMATO FRUIT DEVELOPMENT AND RIPENING, WITH THE ULTIMATE GOAL OF GENERATING FAVORABLE EARLY-RIPENING FRUIT BY MANIPULATION OF SLNAC1 IN TOMATO, WE PROPOSE TWO RESEARCH OBJECTIVES: 1.) DETERMINE THE ROLE OF THE TRANSCRIPTION FACTOR SLNAC1 IN FRUIT DEVELOPMENT AND RIPENING; 2.) MANIPULATE SLNAC1 FOR EARLY FRUIT RIPENING WITHOUT UNDESIRED SIDE EFFECTS.IN BRIEF, THE PROPOSED PROJECT WILL HELP US UNDERSTAND THE MOLECULAR BASIS OF FRUIT DEVELOPMENT AND RIPENING AND EVENTUALLY USE THE EVOLVED KNOWLEDGE TO DEVELOP NOVEL AND INNOVATIVE WAYS FOR MAKING TOMATO RIPEN EARLY WITHOUT UNWANTED SIDE EFFECTS ON THE GROWTH OF TOMATO PLANTS.