The present invention relates to transgenic citrus trees resistant to Huanglongbing disease (HLB) through overexpression of AtNPR1 either in the phloem tissues (where HLB resides) via utilization of a phloem specific Arabidopsis sucrose-proton symporter 2 (AtSUC2) promoter or a constitutive CaMV 35S promoter for HLB resistance. Evaluation of these transgenic plants demonstrates that overexpressing the AtNPR1 can result in effective HLB resistance in citrus.