**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** DESPITE THE RECOGNITION THAT INSECT MICROBIOMES ARE IMPORTANT IN INSECT HEALTH, FEW STUDIES HAVE DELVED INTO THE IMPORTANCE OF THE INSECT MICROBIOME IN ITS INTERACTIONS WITH PLANTS. IN PREVIOUS WORK, WE DEMONSTRATED THAT THE RUSSIAN WHEAT APHID (RWA) MICROBIOME IS CRITICAL TO APHID VIRULENCE. HOWEVER, WHICH MICROBE AND MICROBE FUNCTIONS WITHIN THE MICROBIOME CONTRIBUTE TO RWA VIRULENCE, AND IF THE MICROBES CONTROL RWA BIOTYPE ARE NOT YET KNOWN. THE WORK PROPOSED HERE WILL DISCOVER BACTERIA IMPORTANT TO THIS INTERACTION AND WILL IDENTIFY THE FUNCTIONAL CAPACITIES OF THE ENTIRE MICROBIOME, AS WELL AS OF THE SPECIFIC MEMBERS OF THE MICROBIAL COMMUNITY THAT ARE IMPORTANT CONTRIBUTORS. A MULTI 'OMICS' APPROACH, INCLUDING AMPLICON SEQUENCING, SHOTGUN METAGENOMICS AND METATRANSCRIPTOMICS, WILL BE USED TO IDENTIFY BACTERIAL SPECIES IN THE APHID MICROBIOME ARE IMPORTANT TO THE SUCCESS OF RWA. THE MULTI 'OMICS' DATASETS WILL BE USED TO LINK MICROBIAL FUNCTIONS TO RWA VIRULENCE AND BIOTYPE USING MACHINE LEARNING AND ROBUST STATISTICAL APPROACHES. THIS INFORMATION WILL BE USED TO CONSTRUCT SYNTHETIC COMMUNITIES (SYNCOMS) WHICH WILL BE ADMINISTERED TO RWA FOR PLANT PHENOTYPING EXPERIMENTS DESIGNED TO ASSESS MICROBIAL CONTRIBUTION TO VIRULENCE AND BIOTYPE. STUDIES UTILIZING MRNA SEQUENCING TO DEDUCE EXPRESSION PROFILES OF NON-OBLIGATORY INSECT-ASSOCIATED BACTERIA ARE IN THEIR INFANCY; THIS IS A FIRST ATTEMPT TO FUNCTIONALLY CHARACTERIZE THE ROLE OF THESE BACTERIAL COMMUNITIES. FURTHERMORE, INFORMATION GENERATED FROM THIS WORK WILL BE THE FOUNDATION FOR HARNESSING THE GENOMIC POTENTIAL OF THE RWA MICROBIOME FOR IMPROVED PEST CONTROL.