A selectable marker using cytochrome P450 monooxygenases for Arabidopsis transformation

Abstract

We have developed a selection system for transformation of Arabidopsis thaliana via Agrobacterium tumefaciens. This selection system uses human cytochrome P450 monooxygenases that metabolize herbicides. Herbicide-tolerant seedlings transformed with CYP1A1, CYP2B6, CYP2C9, or CYP2C19 were selected with the herbicides acetochlor, amiprophos-methyl, chlorpropham, chlorsulfuron, norflurazon, and pendimethalin. The herbicide-tolerant plants transformed with CYP1A1, CYP2B6, and CYP2C19 expressed the corresponding P450 cDNAs. Inheritance and segregation of the P450 genes were analyzed in T₂ progeny of herbicide-tolerant T₁ seedlings. Metabolism of [¹⁴C]norflurazon by transgenic T₂ seedlings expressing CYP1A1 produced non-toxic N-demethylated norflurazon. This result suggests that the P450 species expressed in transgenic Arabidopsis plants coordinately functioned as selectable markers because of active metabolism of the herbicides.