** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** PLANT VIRUSES ENCODE MOVEMENT PROTEIN (MP) FOR CELL-TO-CELL MOVEMENT THAT PROMOTE SYSTEMIC INFECTION OF PLANTS. A RECENT OUTBREAK OF A NEW TOBAMOVIRUS, TOMATO BROWN RUGOSE FRUIT VIRUS (TOBRFV) THREATENS THE GLOBAL TOMATO INDUSTRY. TOBRFV OVERCOMES ALL KNOWN TOBAMOVIRUS RESISTANCES IN TOMATOES, INCLUDING THE DURABLE TM-2(2)-MEDIATED RESISTANCE. THE TM-2(2) RECOGNIZES TOBAMOVIRUS MP TO CONFER RESISTANCE. HOWEVER, TM-2(2) FAILS TO RECOGNIZE THE TOBRFV MP AND HENCE TOBRFV CAN CAUSE DISEASE.THE GOAL OF THIS PROJECT IS TO UNDERSTAND HOW MP OF TOBRFV CAUSES DISEASE. WE WILL DETERMINE ELEMENTS IN MP THAT BOTH REGULATE VIRAL MOVEMENT AND PROMOTE EVASION OF HOST IMMUNITY (OBJECTIVE 1). WE WILL CHARACTERIZE NOVEL MP-INTERACTING PROTEINS USING GENETIC, CELLULAR AND BIOCHEMICAL APPROACHES TO UNDERSTAND THEIR ROLE IN TOBAMOVIRUS PATHOGENESIS AND EVASION OF HOST IMMUNITY (OBJECTIVE 2). USING CRISPR/CAS9, WE WILL MUTATE GENES ENCODING MP INTERACTORS IN TOMATO AND TEST THEIR FUNCTION IN TOBAMOVIRUS RESISTANCE (OBJECTIVE 3).AT THE COMPLETION OF THE PROJECT, WE EXPECT TO GAIN FUNDAMENTAL INSIGHTS ON THE MECHANISMS UNDERLYING MP FUNCTION IN VIRAL PATHOGENESIS AND IMMUNITY.