** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** WHEAT CULTIVARS AND THEIR ASSOCIATED MICROBIAL COMMUNITIES, OR MICROBIOMES,REPRESENT A VERSATILE AND COMPACT TOOLBOX TO ENHANCE YIELD AND IMPROVE RESILIENCE TO ABIOTIC AND BIOTIC STRESSORS. DETERMINING HOST GENOTYPE IMPACT ON THE PLANT MICROBIOME IS CRUCIAL, AS HOST GENOTYPE CAN BE EASILY CHANGED IN A FIELD SETTING, WHEREAS OTHER FACTORS THAT INFLUENCE PLANT MICROBIOMES ARE LESS EASILY MANIPULATED. WHEAT, DUE TO ITS SELF-POLLINATION AND TRAIT STABILITY, SERVES AS AN EXCELLENT CANDIDATE FOR EXAMINATION OF THE RHIZOSPHERE MICROBIOME IN THE CONTEXT OF DROUGHT STRESS. THE OVERARCHING GOAL OF THIS PROJECT IS TO INCREASE BASIC KNOWLEDGE OF HOW HOST GENOTYPE AND PHENOTYPE INFLUENCE THE ROOT ASSOCIATEDMICROBIAL COMMUNITY UNDER DROUGHT STRESS. THE PROPOSED RESEARCH WILL UTILIZE DROUGHT SUSCEPTIBLE AND TOLERANT WHEAT CULTIVARS BRED IN THE PACIFIC NORTHWEST TO PROVIDE USEFUL CONTRAST OF DROUGHT TOLERANCE PHENOTYPES. BY UTILIZING A GENOTYPE-BY-ENVIRONMENT FRAMEWORK, WE AIM TO DETERMINE HOW HOST GENOTYPE AND DROUGHT STRESS IMPACTROOT ASSOCIATEDMICROBIAL COMMUNITIES OF WHEAT IN THE CONTEXT OF INDIVIDUAL CULTIVARS AND CULTIVAR MIXTURES OF CONTRASTING DROUGHT PHENOTYPES. OUR OVERARCHING GOAL IS TO EVALUATE POTENTIAL TRANSLATIONAL SOLUTIONS FOR IMPROVING DROUGHT TOLERANCE OF CURRENTLY AVAILABLE WHEAT CULTIVARS.