** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** GROWING HUMAN POPULATION AND CLIMATE CHANGE NECESSITATE SUSTAINABLE SOLUTIONS THAT REDUCE OUR RELIANCE ON AGROCHEMICALS, WHILE INCREASING AGRICULTURAL PRODUCTIVITY. PLANT GROWTH-PROMOTING RHIZOBACTERIA IS A SUSTAINABLE APPROACH TO INCREASE CROP YIELDS. HOWEVER, THE UNKNOWN INTERACTIONS AMONG THE PLANT HOST, ENVIRONMENT, AND MICROBES CREATE CHALLENGES FOR THE SUPPLEMENTATION AND PERSISTENCE OF DESIRABLE AGRICULTURAL MICROBIOMES WITH ROBUST PLANT BENEFITS.THE OVERARCHING GOAL OF THIS PROJECT IS TO OPTIMIZE AGRICULTURAL MICROBIOMES VIA PLANT ROOT EXUDATE ENGINEERING FOR SUSTAINABLE IMPROVEMENT OF CROP YIELDS, FOCUSING ON NUTRIENT USE EFFICIENCY. WE WILL FIRST IDENTIFY SPECIFIC PLANT-BACTERIA COMMUNICATION MOLECULES WITH DETERMINISTIC INFLUENCE OVER SOIL MICROBIAL COMMUNITY ASSEMBLY MITIGATING PLANT NUTRIENT STRESS. TO UNDERSTAND THE SIGNAL EXCHANGE INVOLVED IN PLANT MICROBIOME ASSEMBLY, WE WILL DEVELOP HIGH-THROUGHPUT TOOLS FOR TESTING BACTERIA CHEMOTAXIS AND GROWTH. NEXT, WE WILL ELUCIDATE HOW THESE MOLECULES INFLUENCE BACTERIAL INTERSPECIES COMPETITION AND COMMUNITY DYNAMICS IN AGRICULTURAL SOILS VIA MULTI-OMICS. LASTLY, WE WILL CHARACTERIZE THE FUNCTIONALITY OF THE ENRICHED MICROBIOME TO CONFER INCREASED PLANT NUTRIENT USE EFFICIENCY, INFORMING FUTURE PLANT BREEDING AND ENGINEERING EFFORTS.OUR INTERDISCIPLINARY TEAM WITH CROSS-CUTTING EXPERTISE IN CHEMISTRY AND PLANT BIOENGINEERING (DEMIRER), MICROBIOLOGY (NEWMAN), AND SOIL MULTI-OMICS (KARTHIKEYAN) WILL FILL MAJOR KNOWLEDGE GAPS IN AGRICULTURAL MICROBIOMES, ALLEVIATE CHALLENGES ASSOCIATED WITH BIOFERTILIZERS, AND REDUCE OVERALL NEGATIVE IMPACTS OF AGRICULTURE.