THE WESTERN CORN ROOTWORM (WCR: DIABROTICA VIRGIFERA VIRGIFERA) IS CURRENTLY THE GREATEST INSECT THREAT TO US CORN PRODUCTION. EVOLVED WCR RESISTANCE HAS OVERCOME CONTROL MEASURES INCLUDING CROP ROTATION AND TRANSGENIC DELIVERY OF BACILLUS THURINGIENSIS(BT) TOXINS. VIEWED AS AN INDEPENDENT CHALLENGE, FUSARIUM FUNGI CONSTITUTE THE GREATEST PRESSURE DRIVING DISEASE-ASSOCIATED LOSSES OF CORN. HOWEVER, THESE ARE NOT UNRELATED CHALLENGES, BECAUSE WOUND DAMAGE TO ROOTS CAUSED BY WCR LARVAE FEEDING BREACHES THE PHYSICAL BARRIERS OF THE PLANT AND VECTORS ROOT-ROTTING FUSARIUM FUNGI. ROOT MASS INFLUENCES LODGING AND YIELD, BUT MECHANISMS ENABLING ROOT VIGOR UNDER COMPLEX FIELD PRESSURES REMAIN LARGELY UNKNOWN. THE AFRI PROGRAM PRIORITY SEEKS ELUCIDATION OF FUNDAMENTAL ECOLOGICAL, MOLECULAR, BIOLOGICAL, AND CHEMICAL PROCESSES AFFECTING ABUNDANCE AND SPREAD OF PLANT-ASSOCIATED INSECTS AND PATHOGENS. IN CLOSE ALIGNMENT, THE GOAL OF THIS PROJECT IS TO UNDERSTAND MECHANISMS REGULATING HERBIVORE(WCR)-ROOT(CORN)-FUNGUS(FUSARIUM) INTERACTIONS AND EMPIRICALLY DEMONSTRATE THE GENETIC AND BIOCHEMICAL BASIS OF MAIZE RESISTANCE. THIS WILL ENABLE IMPROVEMENT OF CORN RESISTANCE TO BOTH WCR HERBIVORY AND FUSARIUM DISEASE BY ENGINEERING NOVEL METABOLIC TRAITS. SPECIFIC OBJECTIVES ARE: 1) ESTABLISH A FOUNDATIONAL KNOWLEDGE OF MAIZE BIOCHEMICAL AND GENETIC PATHWAYS THAT MEDIATE WESTERN CORN ROOTWOM AND FUSARIUM INTERACTIONS. 2) DEMONSTRATE THE ROLE OF BIOCHEMICAL NETWORKS ON WESTERN CORN ROOTWORM GROWTH AND SURVIVAL, FUSARIUM SPREAD AND PLANT RESISTANCE. 3) CREATE NOVEL MAIZE BIOCHEMICAL NETWORKS THAT RESTORE RESISTANCE TO PEST COMPLEXES (WESTERN CORN ROOTWORM-FUSARIUM). PLANS TO ACCOMPLISH GOALS INCLUDE: 1) COMPREHENSIVE METABOLIC PROFILING AND GENETIC MAPPING TO IDENTIFY UNSTUDIED ROOT DEFENSES AND RELEVANT BIOSYNTHETIC GENES FOR CHARACTERIZATION, 2) BIOASSAYS OF NATURAL AND OR ENGINEERED MUTANTS LACKING THESE SPECIALIZED METABOLITES TO ASSESS THE GROWTH AND SURVIVAL OF ALL THREE INTERACTING ORGANISMS IN CONTROLLED ADDITIVE EXPERIMENTS, AND 3) CREATION OF NOVEL MAIZE METABOLIC NETWORKS USING TRANSGENIC 'NEW-TO-MAIZE' GENES TO ENHANCE RESISTANCE TO PEST COMPLEXES (WESTERN CORN ROOTWORM-FUSARIUM).