** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE POTATO CYST NEMATODE (PCN) GLOBODERA PALLIDA WAS FIRST DETECTED IN THE UNITED STATES IN 2006 AND HAS BEEN ONE OF THE MAJOR PRODUCTION CONSTRAINTS FOR POTATO AND CAN CAUSE UP TO 100% YIELD LOSS. TO SUCCESSFULLY INFEST AND COLONIZE POTATO ROOTS, PCN PRODUCES PROTEINS, CALLED EFFECTORS, AND USES THE STYLET, A NEEDLE-LIKE APPARATUS, TO DELIVER THEM INTO POTATO ROOT CELLS. ONE OF THE MAJOR FUNCTIONS OF THESE EFFECTORS IS TO DESTROY PLANT DEFENSE SYSTEM, INCLUDING THE ONE CALLED PATTERN-TRIGGERED IMMUNITY (PTI) WHICH IS CONFERRED BY PATTERN RECOGNITION RECEPTOR (PRR). WE HAVE FOUND PCN USED A SPECIFIC EFFECTOR RHA1B THAT CAN DEGRADE THE POTATO PRR TERMED STNILR1 THEREBY OVERCOMING POTATO DEFENSE. THUS, WE WILL USE THE COMBINATION OF BIOCHEMICAL AND GENETIC APPROACHES TO ENGINEER STNILR1 PROTEIN - MAKE IT NOT DEGRADABLE BY RHA1B EFFECTOR, AND TRANSFER THIS NEW ENGINEERED STNILR1 GENE INTO POTATO TO POSSIBLY MAKE IT RESISTANT TO PCN. TOWARD THIS END, WE PROPOSE TWO RESEARCH OBJECTIVES: 1.) ENGINEER RHA1B DEGRADATION RESISTANT STNILR1 MUTANTS; 2.) MANIPULATE THE STNILR1 GENE IN POTATO TOWARDS RESISTANCE TO PCN.