THE PRODUCTIVITY OF MAIZE, ONE OF THE WORLD'S MOST ECONOMICALLY IMPORTANT FOOD CROPS, IS LIMITED BY A VARIETY OF DEVASTATING FUNGAL DISEASES, LEADING TO BILLIONS OF DOLLARS IN ANNUAL ECONOMIC LOSS. PHENOLIC SUCROSE ESTERS (PSE), A RECENTLY DISCOVERED CLASS OF MAIZE SECONDARY METABOLITES, WERE SHOWN TO PROVIDE PROTECTION AGAINST FUSARIUM GRAMINEARUM AND OTHER FUNGAL PATHOGENS. HOWEVER, THE GENES UNDERLYING THE PRODUCTION OF THESE PSE ARE CURRENTLY UNKNOWN, MAKING IN-DEPTH RESEARCH OF PSE FUNCTION DIFFICULT AND THEIR UTILIZATION IN BREEDING PROGRAMS AND NEW TRANSGENIC DEVELOPMENT UNFEASIBLE.THIS PROJECT AIMS TO IDENTIFY THE BIOSYNTHETIC AND REGULATORY GENES UNDERLYING PSE METABOLISM, USING METHODS THAT CORRELATE PSE ABUNDANCE WITH GENE EXPRESSION. TO PERFORM THIS ANALYSIS SUCCESSFULLY, A POPULATION OF PLANTS PRODUCING DIFFERENT AMOUNTS OF PSE IS NEEDED. FOR THIS REASON, I WILL GENERATE TWO MAIN DATA SETS - THE FIRST FROM A TIME COURSE FOLLOWING FUNGAL INFECTION, WHICH WILL LEAD TO RISING PSE ABUNDANCE. THE SECOND WILL UTILIZE THE NATURAL VARIATION IN THE MAIZE GERMPLASM AND COMPILED IN THE GOODMAN DIVERSITY PANEL. ONCE THE GENES ARE IDENTIFIED, I WILL SEARCH FOR PREVIOUSLY EXISTING MUTANTS IN THOSE GENES AND USE VIRUS INDUCTION TO REDUCE OR INCREASE THEIR EXPRESSION. THIS WILL ENABLE ME TO VALIDATE THE GENES' FUNCTION IN PSE METABOLISM AND, FOLLOWING THIS, TO EXAMINE ITS EFFECTS ON FUNGAL PATHOGENS. THE RESULTS OF THIS RESEARCH WILL ENABLE THE PRODUCTION OF IMPROVED MAIZE VARIETIES, WHICH WILL REQUIRE FEWER AGRONOMIC INPUTS, THROUGH BREEDING AND/OR TRANSGENIC APPROACHES.