Abstract: Late blight, caused by the oomycete Phytophthora infestans (Mont. ) de Bary, is a devastating disease of the two Solanaceous crops, tomato and potato, and caused serious economic loss. Potato late blight resistant genes R3a, R1 and RB were cloned recently. In order to determine whether these resistance
genes have function in tomato plants, R3a, R1 and RB were transferred separately into tomato plants by Agrobacterium-mediated transformation method. The transformants showed hypersensitive response (HR) to 89148-9, the potato late blight isolate race 0. Transgenic tomato p lantswere also inoculated with 5 tomato late blight isolates, and the results demonstrated that R3a and R1 showed resistance to some tomato late blight isolates, while RB showed resistance to all 5 isolates. These results suggested that it be possible to use potato late blight resistance genes RB to protect tomato from late blight

Key words: tomato, potato, transformation, late blight, R3a, R1, RB