** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** ROOT-KNOT NEMATODES ARE A MAJOR CONCERN FOR GROWERS OF MANY CROPS THROUGHOUT THE USA, INCLUDING IMPORTANTFRUIT, VEGETABLE, AND ORNAMENTALCROPS. THE MOST EFFECTIVE MEANS TO DEAL WITH ROOT-KNOT NEMATODES IS TO USE CHEMICAL CONTROLS, WHICH INCLUDE PRE-PLANT AND POST-PLANT NEMATICIDES. THE CHEMICAL TREATMENTS ARE NOT ONLY VERY EXPENSIVE FOR GROWERS TO USE, BUT THEY ARE ALSO HIGHLY TOXIC AND POSE CONSIDERABLE HEALTH AND ENVIRONMENTAL RISKS. MORE DURABLE AND LESS TOXIC METHODS OF NEMATODE CONTROL ARE URGENTLY NEEDED TO PROMOTE ROBUST CROP YIELDS AND TO PROTECT HUMAN HEALTH.THERE ARE VERY FEW CROP PLANTS THAT ARE NATURALLY RESISTANT TO ROOT-KNOT NEMATODES. THEREFORE, THE RESEARCH PROPOSED HERE WILL BUILD NEW TOOLS FOR PLANT RESISTANCE AND PROTECTION FROM ROOT-KNOT NEMATODE INFECTIONS. THE STARTING POINT OF THIS RESEARCH STEMS FROM THE DECADES OF STUDYING A MODEL FREE-LIVING NEMATODE CALLED C. ELEGANS. WORK IN C. ELEGANS HAS GIVEN US INFORMATION ABOUT NEMATODE BIOLOGY, INCLUDING THE CONSERVEDGENES THAT THE NEMATODES NEED TO MAKE THE FATS REQUIRED FOR GROWTH AND DEVELOPMENT. USING THIS INFORMATION, WE ARE FOCUSING ON FATTY ACID BIOSYNTHESIS GENES THAT WE HAVE IDENTIFIED IN THE ROOT-KNOT NEMATODE M. JAVANICA, BASED LARGELY ON SIMILARITY TO THE GENES IN C. ELEGANS. IN THE PROPOSED EXPERIMENTS, WE PLAN TO USE DSRNA TO KNOCKDOWN THE EXPRESSION OF A SPECIFIC M. JAVANICA FATTY ACID BIOSYNTHESIS GENE(S). ONCE THE ESSENTIAL GENE HAS BEEN KNOCKED DOWN, WE WILL STUDY THE EFFECTS ON THE NEMATODE'S ABILITY TO INFECT PLANTS AND DEVELOP INTO AN ADULT. THUS, THESE EXPERIMENTS WILL BE USING DSRNA AS A POTENTIAL BIOPESTICIDE AGAINST NEMATODES BY TARGETING WHAT WE HYPOTHESIZE IS A KEY DEVELOPMENTAL GENE. AN EXCITING POSSIBLE OUTCOME OF THIS RESEARCH IS A PLANT SPRAY THAT WOULD AFFECT THE ROOT-KNOT NEMATODES WITHOUT HARMING THE PLANT OR OTHER ORGANISMS IN THE SOIL.THE SECOND APPROACH FOR GENERATING DURABLE NEMATODE CONTROL WILL BE THROUGH THE STUDY OF THE NEMATODE DIET. WE KNOW THAT THE NEMATODES ARE GETTING ESSENTIAL NUTRIENTS FROM FEEDING ON THEIR HOST PLANTS, INCLUDING FATS CALLED STEROLS. WE HYPOTHESIZE THAT THE NEMATODES NEED CERTAIN PLANT STEROLS TO TRIGGER MOLTING. THERE IS VERY LITTLE INFORMATION IN REGARD TO THE NEMATODE DIET, INCLUDING WHICH PLANT STEROLS ARE REQUIRED BY THE NEMATODE FOR ITS DEVELOPMENT. BY STUDYING VARIOUS PLANTS THAT MAKE EITHER TOO MUCH OR TOO LITTLE OF SPECIFIC STEROLS, WE PLAN TO FURTHER OUR UNDERSTANDING OF THE NEMATODE DIET. THE COMPOSITION OF THE NEMATODE DIET PROVIDES BASIC, NEEDED INFORMATION ABOUT ROOT-KNOT NEMATODE BIOLOGY. THE INFORMATION ALSO SERVES AS THE STARTING POINT FOR ENGINEERING CROPS IN WHICH THE NEMATODE CANNOT GET ADEQUATE NUTRITION AND DIE, BUT WITHOUT AFFECTING THE OVERALL PLANT GROWTH AND DEVELOPMENT. SUCH TECHNOLOGY COULD OFFER A NOVEL METHOD TO REDUCE NEMATODE POPULATIONS.