** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** FOOD PRODUCTION EFFICIENCY MUST INCREASE TO MEET THE DEMANDS OF A GROWING POPULATION AND ENVIRONMENTAL VOLATILITY. ONE WAY TO MEET THIS GOAL IS TO ENHANCE THE MICROBIAL COMMUNITY OF CROPS ROOTS AND THE SURROUNDING SOILS, WHICH IN TURN BOLSTER PLANT STRESS TOLERANCE AND NUTRIENT ACQUISITION. ARBUSCULAR MYCORRHIZAL FUNGI (AMF) ARE PROMINENT BENEFICIAL FUNGI THAT ARE RECRUITED TO THE ROOTS BY STRUCTURALLY DIVERSE PLANT HORMONES CALLED STRIGOLACTONES (SLS). UNDERSTANDING HOW PLANTS SELECTIVELY SIGNAL TO THESE BENEFICIAL MICROBES BY RELEASING DIVERSE SLS WILL INFORM CROP BREEDING AND ENGINEERING EFFORTS AND PROVIDE GUIDANCE ON THE USE OF INCREASINGLY POPULAR SOIL INOCULANTS. THIS PROJECT WILL INCORPORATE MOLECULAR EVOLUTION, 3D PROTEIN MODELING, MICROSCOPY, MICROBIOME SEQUENCING, AND BIOCHEMICAL ANALYSES TO INCREASE UNDERSTANDING OF SL DIVERSITY AND SELECTIVE RECRUITMENT OF BENEFICIAL MICROBES. THE FINDINGS COULD INCLUDE NEWLY CHARACTERIZED SL BIOSYNTHESIS GENES, GUIDANCE ON THE BEST COMMERCIAL AMF INOCULANT TO USE FOR A CROP, OPTIMAL SL BIOSYNTHESIS GENES FOR CROP ENGINEERING AND BREEDING EFFORTS, AND THE MINIMUM NUMBER OF GENE EDITS FOR A SL-TUNED, NON-GMO CROP. THESE OUTCOMES COULD CONTRIBUTE TO INCREASED CROP YIELD AND REDUCED INPUTS FOR PLANT HEALTH AND PRODUCTION.