Broad range of herbicide tolerance of glutinous upland rice variety 'Yumenohatamochi' carrying human cytochrome P450 genes

Abstract

We generated three types of herbicide-tolerant Yumenohatamochi rice plants (Oryza sativa L cv. ‘Yumenohatamochi’) transformed with pIES1A1, pIJ2B6, or pIKBACH that express human cytochrome P450 gene CYP1A1 or CYP2B6 or co-express CYP1A1, CYP2B6, and CYP2C19, respectively. The transformed plants were screened by a combination of hygromycin resistance, PCR, and herbicide tolerance. We compared the tolerance towards various herbicides with different modes of action. The herbicides tested include photosynthesis inhibitors (chlorotoluron, diuron), very long-chain fatty acid (VLCFA) synthesis inhibitors (acetochlor, alachlor, metolachlor, and mefenacet), a carotenoid biosynthesis inhibitor (norflurazon), and microtubule assembly inhibitors (pendimethalin, trifluralin, and amiprophos-methyl). The pIES1A1- or pIJ2B6-transformed Yumenohatamochi showed tolerance towards five and four different chemical classes of herbicides, respectively. The spectrum of herbicide tolerance of pIKBACH-transformed Yumenohatamochi was broader compared to transformants expressing the single human P450 gene. Transformed rice plants expressing P450s involved in xenobiotic metabolism may become useful tools for the breeding of herbicide-tolerant crops.