The project has two objectives: (1) Increase citrus disease resistance by activating the NAD+-mediated defense-signaling pathway. (2) Engineer non-host resistance in citrus to control citrus canker and HLB. For objective 1, both soil drench and foliar spraying of NAD+ have been performed. In the side-by-side experiment with the plant defense activator Actogard, soil drench provided good protection against citrus canker, whereas foliar spraying had limited effects. We are repeating the experiment and trying to find the best approach for NAD+ application. We have also been testing NAD+ analogs to identify potential chemicals for citrus disease control. For objective 2, newly generated transgenic plants are growing in greenhouse. Presence and expression of the transgenes have been tested. All transgenic plants are growing in the greenhouse and will be tested for canker resistance. Citrus homologs of the defense genes have been cloned and sequenced. The will be used for functionality test through complementation experiment.