| Hydrogen peroxide (H2O2) was one of the reactive oxygen species (ROS) produced rapidly during the early stage of plant-pathogen interaction. When plant was infected by microbial pathogen,H2O2 played an important role in many defense responses that followed. So the plant's capability of broad-spectrum pathogen-resistance could be enhanced if H2O2 level was improved by gene transferring methods. Glucose oxidase could catalyze the oxidation of 0 -D-glucose to produce gluconic acid and H2O2. This enzyme had been detected in several bacteria and fungi,but hadn't been found in animals and plants. In order to investigate the possibility of applying the enzyme to rice broad-spectrum disease-resistance gene engineering,we inserted GO gene into a binary vector pCAMBIA1301,which contained selectable marker of hygromycin resistant gene,to produce a new transformation vector,pCAG1301. The vector was introduced into Agrobacterium tumefaciens strain LBA4404 and then used to transform calli derived from mature embryos and immature embryos of rice (Oryza sativd) cultiva Nipponbare. Putative transformed plants were regenerated from hygromycin resistant calli produced. The integration of GO gene and it copies (one or two) were confirmed by Southern blotting analysis on rice genome. The H2O2 generated by the transgenic plants was detected by its characteristic blue color reaction with starch-KI and this proved that the glucose oxidase generated by the expression of GO gene had exerted its function in rice. Based on the advantage that the plant defense responses induced by H2O2 had no species restriction,it could be anticipated that the transgenic rice acquired would have satisfied resistance to many pathogens. The accomplished test showed that the transgenic rice had strong resistance to rice blast disease.
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