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 expected 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 fromAspergillus niger via PCR and fused it to the pathogen-inducible promoter, Prp1-1. The chimeric gene was cloned into a plant expression vector and conjugated intoAgrobacterium. Twenty-three transgenic potato plants were obtained byAgrobacterium-mediated transformation. The integration ofGO gene was confirmed by Southern hybridization and theGO gene expression was identified with Kl-starch color reaction.Phytophthora infestans inoculation revealed that the expression of the chimeric transgene was induced by pathogen infection. Most of the transgenic plants exhibited various degrees of enhanced disease resistance. Four of them had lesion sizes reduced to less than half of the non-transgenic controls. One plant showed disease resistance of the hypersensitive response. These results testified the feasibility of our strategy of expressingGO transgene under the control of the disease-inducible promoter in engineering crop disease resistance.