Transgenic rice containing human CYP2B6 detoxifies various classes of herbicides

The human gene for CYP2B6, a cytochrome P450 monooxygenase that inactivates xenobiotic chemicals, was introduced into Oryza sativa cv. Nipponbare by Agrobacterium-mediated transformation. At germination, R, seeds of transgenic rice plants expressing CYP2136 (CYP2136 rice) showed a high tolerance to 5 mu M metolachlor, a preemergence herbicide that is degraded by CYP2136. Thin-layer chromatography after culture with C-14-Iabeled metolachlor revealed that the amounts of residual metolachlor decreased in plant tissues and the medium of CYP2136 rice faster than those of untransformed Nipponbare. CYP2136 rice plants were able to grow in the presence of 13 out of 17 herbicides: five chloroacetamides and mefenacet, pyributicarb, amiprofos-methyl, trifluralin, pendimethalin, norflurazon, and chlorotoluron. These herbicides differ in their modes of action and chemical structures. Transgenic rice expressing a xenobiotic-degrading human CYP2136, which has broad substrate specificity, should be good not only for developing herbicide tolerant rice but also for reducing the environmental impact of agrochernicals.