Enhanced late blight resistance of transgenic potato expressing glucose oxidase under the control of pathogen-inducible promoter

To engineer crop disease resistance by utilizing natural defense mechanism that was expressed in the incompatible host-pathogen interactions is expect ed to result in a durable and broad-spectrum resistance. In order to prove this viewpoint, we amplified the coding region of the glucose oxidase (GO) gene from Aspergillus niger via PCR and fused it to the pathogen-inducible promoter, Prp1-1. The chimeric gene was cloned into a plant expression vect or and conjugated into Agrobacterium. Twenty-three transgenic potato plants were obtained by Agrobacterium-mediated transformation. The integration of GO gene was confirmed by Southern hybridization and the GO gene expression was identified with KI-starch color reaction. Phytophthora infestans inocu lation revealed that the expression of the chimeric transgene was induced b y pathogen infection. Most of the transgenic plants exhibited various degre es of enhanced disease resistance. Four of them had lesion sizes reduced to less than half of the non-transgenic controls. One plant showed disease re sistance of the hypersensitive response. These results testified the feasib ility of our strategy of expressing GO transgene under the control of the d isease-inducible promoter in engineering crop disease resistance.