WITH REGARD TO GENETIC IMPROVEMENT FOR DEVELOPING DISEASE RESISTANCE, TREE SPECIES IN COMPARISON TO ANNUALS REPRESENT A SERIOUS CHALLENGE. CITRUS BACTERIAL CANKER CAUSED BY XANTHOMONAS CITRI SSP. CITRI (XCC) IS ONE OF THE MOST DEVASTATING DISEASES OF CITRUS IN THE WORLD AND DEVELOPING RESISTANCE TO THIS DISEASE IS A DAUNTING TASK. GENERATING CANKER RESISTANT CITRUS VARIETIES WOULD BE THE MOST SUSTAINABLE AND ECONOMICAL SOLUTION TO CONTROL CANKER. HOWEVER, CITRUS BREEDING HAS OFTEN BEEN HINDERED BY POLYEMBRYONY, POLLEN-OVULE STERILITY, SEXUAL AND GRAFT INCOMPATIBILITIES, AND EXTENDED JUVENILITY. HERE, WE PROPOSE TO EXPLOIT CRISPR TECHNOLOGY AND A SPECIFIC DISEASE-SUSCEPTIBILITY GENE IN CITRUS TO GENERATE CANKER RESISTANT PLANTS. CSLOB1 (CITRUS SINENSIS LATERAL ORGAN BOUNDARIES), WHICH IS A CRITICAL CITRUS SUSCEPTIBILITY GENE THAT THE CITRUS CANKER PATHOGEN XCC TARGETS, IS A MEMBER OF THE LATERAL ORGAN BOUNDARIES DOMAIN (LBD) GENE FAMILY OF TRANSCRIPTION FACTORS. ALL STRAINS OF XCC ENCODE A TRANSCRIPTION ACTIVATOR-LIKE (TAL) EFFECTOR THAT RECOGNIZES AN EFFECTOR BINDING ELEMENT (EBE) IN THE PROMOTER OF CSLOB1 AND INDUCES GENE EXPRESSION. CITRUS CANKER REPRESENTS A MODEL DISEASE FOR THE ASSESSMENT OF GENOME EDITING FOR THE ENHANCEMENT OF TREE GERMPLASM. THE PROJECT WILL GENERATE EDITED PLANTS AND ASSESS THE CONSEQUENCES OF EDITING. FURTHERMORE, EXPERIMENTS ARE PROPOSED THAT WILL PROVIDE INSIGHT INTO THE ABILITY OF THE PATHOGEN TO OVERCOME EDITING BY ADAPTATION. ACCOMPLISHMENTS FROM THIS PROJECT WILL PAVE THE WAY FOR GENERATING NON-TRANSGENIC PLANTS IN OTHER TREE CROPS FOR IMPROVING TRAITS SUCH AS DISEASE RESISTANCE, FLOWERING TIME, AND YIELD.