WE PROPOSE TO IDENTIFY AND CHARACTERIZE POLYPHOSPHATE ACCUMULATING MICROORGANISMS (PAOS) WITHIN THE RHIZOMICROBIOME AND ELUCIDATE THEIR ROLES AND METABOLIC ACTIVITIES INVOLVED IN SOIL PHOSPHORUS (P) SEQUESTRATION, CYCLING AND PLANT P UPTAKE, WITH THE ULTIMATE GOAL TO EXPLOIT PAOS FOR THEIR MULTIPLE ROLES IN P RECOVERY AND STORAGE TO ENHANCE CROP PRODUCTION. THE SPECIFIC OBJECTIVES ARE: 1) DISCOVER IDENTITY AND FUNCTIONS OF PAOS IN THE RHIZOSPHERE WITH NOVEL FUNCTION-TARGETED PHENOTYPING AND GENOTYPING TECHNIQUES; 2)INVESTIGATING THE POPULATION AND ACTIVITY DYNAMICS OF PAOS IN THE RHIZOSPHERE ACROSS EDAPHIC GRADIENTS, IN RELATION TO PLANT GROWTH AND NUTRITION; 3) EXPLORING PAOS AUGMENTATION FOR ENHANCING BIOAVAILABLE P AND PLANT P UTILIZATION. TO CIRCUMVENT THE LIMITATIONS OF AMPLICON AND SHOTGUN METAGENOMICS SEQUENCING OF HYPERDIVERSE SOIL COMMUNITIES AND TO DEDUCE GENOTYPE-FUNCTION RELATIONSHIPS, WE WILL EMPLOY A NOVEL SEQUENTIAL FLOW CYTOMETRY CELL SORTING AND RAMAN MICROSPECTROSCOPY APPROACH THAT ENABLES PHENOTYPE-BASED CELL SORTING FOLLOWED BY "SINGLE CELL" METAGENOMICS ANALYSIS. THIS WILL ALLOW US TO INVESTIGATE A DIVERSE SELECTION OF AGRICULTURALLY IMPORTANT CROPS IN US TO IDENTIFY CROPS AND SOIL CONDITIONS THAT HAVE ASSOCIATIONS WITH HIGH PAO ABUNDANCE AND ACTIVITY, AND ELUCIDATE THE IMPORTANT AND VERSATILE FUNCTIONS AND ROLES OF POLYPHOSPHATE AND PAOS IN P CYCLE AND PLANT NUTRIENT UTILIZATION THAT PRESENT PROMISES IN ITS BENEFICIAL USE IN AGRICULTURAL ENHANCEMENT. THIS STUDY ADDRESSES FOUR OF THE PRIORITY AREAS IDENTIFIED BY AFRI THAT WILL SUPPORT SUSTAINABLE ANIMAL AND PLANT PRODUCTION PRACTICES THAT WILL, OVER THE LONG-TERM, ACHIEVE THE GOALS OF ACHIEVING ECONOMIC AND SUSTAINABLE AGRICULTURE FOR FOOD SECURITY WITH ENHANCED ENVIRONMENTAL QUALITY AND CONSERVATION OF NATURAL RESOURCE.