** 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 EVIDENCE SHOWS THAT THE MICROBIOME OF PLANTS INFLUENCES THEIR PRODUCTIVITY, HEALTH, DROUGHT TOLERANCE, AND REPRODUCTIVE FITNESS. THE PROPOSED RESEARCH WILL USE A FUNCTION FOCUSED APPROACH LEVERAGING NOVEL TECHNIQUES AND FIELD EXPERIMENTS TO UNDERSTAND PLANT-MICROBE INTERACTIONS IN RESPONSE TO FERTILIZATION AND DROUGHT USING MISCANTHUS &TIMES; GIGANTEUS AS A MODEL BIOENERGY CROP. MISCANTHUS X GIGANTEUS IS A PROMISING FEEDSTOCK FOR SUSTAINABLE BIOENERGY DUE TO ITS HIGH PRODUCTIVITY AND ROBUST GROWTH ON SUB OPTIMAL SOIL. IN COMPARISON TO OTHER CANDIDATE BIOENERGY CROPS SUCH AS CORN AND SWITCHGRASS, MISCANTHUS HAS HIGHER BIOMASS AND ENERGY YIELDS AND LOWER CULTIVATION GREENHOUSE GAS EMISSIONS. INDEED, MISCANTHUS CAN ENHANCE SOIL CARBON (C) STOCKS MAKING THE CROP C-NEGATIVE, THAT IS, A SYSTEM THAT CUMULATIVELY STORES MORE C THAN IT RESPIRES TO THE ATMOSPHERE. APPALACHIA, IS AN IDEAL REGION TO PERFORM RESEARCH ON MICROBIOMES OF BIOENERGY CROPS ON MARGINAL LANDS DUE TO THE REGIONALLEGACY OF COAL ENERGY PRODUCTION. THE ENVIRONMENTALLY DISRUPTIVE NATURE OF COAL MINING HAS RESULTED IN AN ABUNDANCE (~4 MILLION ACRES) OF LAND THAT IS UNSUITABLE FOR THE GROWTH OF MOST ECONOMICALLY VALUABLE CROPS (I.E. MARGINAL LAND). HOWEVER, RECENT EVIDENCE SUGGESTS THAT MARGINAL LAND IS SUITABLE FOR BIOENERGY CROP PRODUCTION, PARTICULARLY CROPS LIKE MISCANTHUS THAT GROW ROBUSTLY EVEN UNDER HARSH CONDITIONS. ESTIMATES SUGGEST THAT ~3.5 MILLION HECTARES OF LAND MARGINALIZED BY SURFACE MINING COULD BE UTILIZED FOR GROWING BIOENERGY CROPS, MOST OF WHICH IS IN APPALACHIA. AS THE ENERGY INDUSTRY SHIFTS AWAY FROM COAL AND TOWARD RENEWABLE SOURCES, APPALACHIA POSSESSES THE UNIQUE OPPORTUNITY TO UTILIZE THE AGRICULTURAL POTENTIAL OF OUR MINED LANDS TO PRODUCE BIOFUEL CROPS LIKE MISCANTHUS. EFFORTS TO UTILIZE MARGINAL LANDS FOR BIOFUEL PRODUCTION WOULD DIVERSIFY THE ECONOMY OF APPALACHIA, A REGION ECONOMICALLY DEPRESSED WITH THE DECLINING AVAILABILITY OF JOBS IN THE FOSSIL FUEL SECTOR. THE FIRST AIM TO IDENTIFY AND CHARACTERIZE THE FUNCTION OF THE MISCANTHUS CORE MICROBIOME (I.E., ORGANISMS THAT RELIABLY ASSOCIATE WITH THE HOST PLANT) ON MARGINAL APPALACHIAN SOILS. THE CORE MICROBIOME OF MISCANTHUS PROVIDES THE PLANT WITH WATER AND NUTRIENTS IN EXCHANGE FOR CARBON RICH ROOT EXUDATES. IF FERTILIZATION REDUCES ROOT COLONIZATION BY BENEFICIAL MEMBERS OF THE MICROBIOME AND CHANGES MICROBIOME FUNCTION THIS MAY REDUCE THE CROPS ABILITY TO WITHSTAND DROUGHT STRESS. TO TEST THIS HYPOTHESIS, WE WILL USE A FIELD EXPERIMENT AND CUTTING-EDGE MOLECULAR TOOLS TO CHARACTERIZE PLANT MICROBIOME INTERACTIONS. LASTLY, WE WILL ASSESS IF MICROBIOME MANIPULATION, THROUGH THE ADDITION OF BENEFICIAL MICROORGANISMS CAN ENHANCE YIELD AND DROUGHT TOLERANCE IN A FIELD TRIAL. IN SUMMARY, THE PROPOSED WILL ADVANCE OUR THEORETICAL UNDERSTANDING OF PLANT-MICROBIOMES AND PROVIDE PRACTICAL GUIDANCE FOR BIOENERGY CROP PRODUCTION. THE RESULTS OF THIS WORK WILL HELP BUILD A PREDICTIVE UNDERSTANDING OF THE MISCANTHUS MICROBIOME FUNCTION AS WELL AS PLANT-MICROBIOME RESPONSES TO FERTILIZATION AND DROUGHT STRESS.