** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** UNDERSTANDING MICROBIOME STRUCTURE IN AGRIFOOD SYSTEMS IS CRITICAL IN HARNESSING THIS VITAL ECOSYSTEM TO PROMOTE CROP GROWTH AND CLIMATE RESILIENCE WHILE MITIGATING PLANT AND ZOONOTIC PATHOGENS AND DISEASES. UBIQUITOUS APPLICATIONS OF NANOMATERIALS (NMS) RAISE CONCERNS ABOUT THEIR IMPACTS ON MICROBIOME STRUCTURE AND PATHOGEN PERSISTENCE IN SOIL AND IRRIGATION WATER. IN THIS PROPOSAL, WE WILL ATTEMPT TO ADDRESS THIS CRITICAL KNOWLEDGE GAP USING A STATE-OF-THE-ART MULTI OMICS AND MACHINE LEARNING (ML) PLATFORM. TWENTY TYPES OF MONODISPERSE NMS WILL BE SYNTHESIZED AND CHARACTERIZED. WE WILL INVESTIGATE HOW NMS ALTER MICROBIOME STRUCTURE IN SOIL AND WATER BY NANOPORE 16S AND 18S RRNA SEQUENCING. ADDITIONAL STUDIES WILL FOCUS ON THE NMS CAUSING THE MOST SIGNIFICANT CHANGES IN PATHOGEN PERSISTENCE. MECHANISM OF NMS-INDUCED PATHOGEN EVOLUTION AND ADAPTION WILL BE REVEALED USING MULTI-OMICS AND ML, INVOLVING NANOPORE WHOLE GENOME SEQUENCING (WGS), WHOLE TRANSCRIPTOME SEQUENCING (WTS), AND METABOLOMICS. ALL EXPERIMENTS WILL INCLUDE CLIMATE SIMULATION TO EXAMINE WHETHER CLIMATE CHANGE AGGRAVATES NMS' RISKS AND IMPLICATIONS IN AGRIFOOD SYSTEMS. THE OUTCOME AND SIGNIFICANCE OF THE STUDY ARE MULTIFACETED. REVEALING DETRIMENTAL EFFECTS WOULD DEMAND RESPONSIBLE INNOVATION IN AGRIFOOD NANOTECHNOLOGY, WHICH MAY REQUIRE BETTER PRACTICES, POLICIES, OR END-OF-LIFE TREATMENT AND RISK MITIGATION. BENEFICIAL EVIDENCE, HOWEVER, WOULD VALIDATE NANOTECHNOLOGY AS THE PROMISING LEVERAGE TO HARNESS THE MICROBIOME FOR FOOD SAFETY AND SECURITY WITH CLIMATE RESILIENCE.