Herbicide-Resistant Tobacco Plants Expressing the Fused Enzyme between Rat Cytochrome P4501A1 (CYP1 A l ) and Yeast NADPH-Cytochrome P450 Oxidoreductase

Transgenic tobacco (Nicotiana tabacum cv Xanthi) plants expressing a genetically engineered fused enzyme between rat cytochrome P4501A1 (CYPlAl) and yeast NADPH-cytochrome P450 oxidoreductase were produced. The expression plasmid pCFC2 for the fused enzyme was constructed by insertion of the corresponding cDNA into the expression vector pNCOl under the control of the cauliflower mosaic virus 35.5 promoter and nopaline synthase gene terminator. l h e fused enzyme cDNA was integrated into tobacco genomes by Agrobaderium infection techniques. In transgenic tobacco plants, the fused enzyme protein was localized primarily in the microsomal fraction. l h e microsomal monooxygenase activities were approximately 10 times higher toward both 7-ethoxycoumarin and benzo[a]pyrene than in the control plant. The transgenic plants also showed resistance to the herbicide chlortoluron.