** 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 GRAFTING OF SCION TO ROOTSTOCK IS AN ESTABLISHED HORTICULTURAL METHOD TO IMPART NEW AGRICULTURAL TRAITS SUCH AS PATHOGEN RESISTANCE TO ECONOMICALLY DESIRABLE YET SUSCEPTIBLE PLANT CULTIVARS. PHENOTYPES CONFERRED BY GRAFTING ARE GENERALLY ATTRIBUTABLE TO SPECIFIC ROOTSTOCK - SCION COMBINATIONS, INDICATING THAT THE GENETIC BACKGROUND OF BOTH GRAFT SPECIES CAN CONTRIBUTE TO THE DESIRED PHENOTYPE. FURTHERMORE, THERE IS GROWING EVIDENCE THAT SPECIFIC GRAFT COMBINATIONS CAN INDUCE NOVEL RESISTANCE WITHIN THE SCION AGAINST FOLIAR INFECTING PATHOGENS INCLUDING VIRUSES AND FUNGI. TO INVESTIGATE GRAFT-INDUCED RESISTANCE WE DEVELOPED A NOVEL HETEROGRAFT SYSTEM THAT CONFERS ROOTSTOCK TRANSMISSIBLE RESISTANCE AGAINST VIRUS INFECTIONS. IN THIS SYSTEMS, SPECIFIC TOMATO ROOTSTOCKS WERE FOUND TO CONFER VIRUS RESISTANCE TO THE NORMALLY SUSCEPTIBLE N. BENTHAMIANA SCION. ADDITIONAL FINDINGS INDICATE THAT GRAFT INDUCED RESISTANCE IS MODULATED BY ROOTSTOCK - SCION TRANSCRIPTIONAL RESPONSES AND ROOTSTOCK SPECIFIC MOBILE TRANSCRIPTS. EFFORTS IN THIS PROJECT FOCUS ON: (1) IDENTIFY THE ROLE GRAFT MOBILE MRNAS PLAY IN INDUCED RESISTANCE, (2) DETERMINE IF SCION DERIVED MOBILE RNA ELEMENTS ALSO CONTRIBUTE TO GRAFT INDUCED RESISTANCE AND (3) EXAMINE THE ABILITY OF IDENTIFIED GRAFT-MOBILE MRNAS TO CONFER RESISTANCE IN NOVEL ROOTSTOCK - SCION COMBINATIONS. COMBINED EFFORTS IN THIS STUDY WILL SIGNIFICANTLY EXPAND OUR UNDERSTANDING OF GRAFT TRANSMISSIBLE SIGNALS AND THEIR ROLE IN CONFERRING NOVEL FORMS OF DISEASE RESISTANCE.