**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** LOW PHOSPHATE (PI) AVAILABILITY IN SOILS AND LOW PHOSPHORUS USE EFFICIENCY (PEU) BY PLANTS ARE TWO MAJOR CONSTRAINTS FOR CROP PRODUCTION.APPROXIIEMATELY 70% OF GLOBAL CULTIVATED LAND IS DEFICIENT IN PI. PI FERTILIZERS ARE WIDELY USED TO INCREASE CROP PRODUCTION, BUT THIS PRACTICE IS UNSUSTAINABLE BECAUSE IT ACCELERATES NOT ONLY PRODUCTION COSTS, BUT ALSO DEPLETION OF NON-RENEWABLE P RESERVES. THE GLOBAL PI FERTILIZER MARKET WAS ESTIMATED TO BE $61.6 BILLION IN 2018. USING A FRACTION LESS OF PI FERTILIZERS WOULD AMOUNT TO HUNDREDS OF MILLIONS OF DOLLARS IN SAVINGS FOR AGRICULTURAL PRODUCTION IN THE UNITED STATES. THEREFORE, DEVELOPING CROPS WITH TOLERANCE TO LOW PI AND INCREASED PUE WOULD BRING TREMENDOUS SOCIETAL BENEFITS ECONOMICALLY AND ENVIRONMENTALLY. A BETTER UNDERSTANDING OF THE MECHANISMS BY WHICH CROP PLANTS ADAPT TO PI DEFICIENCY WILL FACILITATE GREATLY THE DEVELOPMENT OF CULTIVARS WITH DECREASED P DEPENDENCY. HOWEVER, CURRENT KNOWLEDGE IS RATHER LIMITED REGARDING THE MECHANISM BY WHICH PLANTS OPTIMIZE P USE, AND THE ROLE OF P DEPRIVATION-INDUCED METABOLIC ADAPTATION IN CROP PLANT PRODUCTION. THIS PROJECT FOCUSES ON A NEW MEMBRANE LIPID REMODELING PROCESS INVOLVING SPHINGOLIPIDS IN THE MAJOR OILSEED CROP CANOLA. DEMAND FOR CANOLA OIL IN THE U.S. HAS INCREASED DRAMATICALLY IN RECENT YEARS BECAUSE OF ITS HEALTH BENEFITS. CANOLA OIL HAS THE LEAST SATURATED FATTY ACIDS OF ALL CULINARY OILS AND HAS HIGH LEVELS OF MONOUNSATURATED AND OMEGA-3 FATTY ACIDS. CANOLA MEALS ARE THE SECOND LARGEST PROTEIN MEAL PRODUCED IN THE WORLD FOR ANIMAL FEED. INCREASED DEMAND FOR CANOLA PRODUCTS HAS RESULTED IN INCREASING CANOLA ACREAGE IN THE U.S. AND THE CULTIVATION OF CANOLA REQUIRES NUTRIENT-RICH SOIL. THUS, THE USE OF CANOLA TO INVESTIGATE THE METABOLISM AND FUNCTION OF SPHINGOLIPID CHANGES UNDER PI DEFICIENCY PROVIDES EXCELLENT OPPORTUNITIES TO INTEGRATE BASIC KNOWLEDGE ADVANCEMENT WITH APPLICATIONS TO INCREASING CROP PRODUCTION. THE PROPOSED STUDY ADDRESSES THE PRIORITIES OF PHYSIOLOGY OF AGRICULTURAL PLANTS (A1152), PARTICULARLY IN RELATION TO NUTRIENT UTILIZATION AND PHOSPHORUS EFFICIENCY. THE BIOCHEMICAL, MOLECULAR, AND PHYSIOLOGICAL ANALYSES OF LIPID METABOLISM WILL ADVANCE UNDERSTANDING OF THE MECHANISMS BY WHICH PLANTS OPTIMIZE P USE IN RESPONSE TO PI DEPRIVATION. IN ADDITION, IT WILL EXPLORE WHETHER LIPID REMODELING ENABLES PLANTS TO BE LESS-DEPENDENT ON P FOR GROWTH AND PRODUCTION, THUS DECREASING USE OF PI FERTILIZERS. SUCH PROGRESS WOULD FACILITATE THE DEVELOPMENT OF CROP VARIETIES WITH IMPROVED GROWTH RESILIENCE TO ADVERSE ENVIRONMENTAL CONDITIONS.