Isolation and Characterization of the Cytochrome P450 Gene CYP82E5v2 that Mediates Nicotine to Nornicotine Conversion in the Green Leaves of Tobacco

摘要: In the species of genus Nicotiana, nicotine to nornicotine conversion is mediated by closely related N-demethylase (NND) proteins that are encoded CYP82E subfamily cytochrome P450 genes. The diverse number and transcriptional regulation NND genes have created large variations in time rate production various Nicotiana species. tobacco, previous studies identified senescence-inducible CYP82E4 gene as an important factor controlling conversion. Nornicotine undesirable alkaloid because it serves a precursor for N'-nitrosonornicotine, potent carcinogen laboratory animals. objective this study was investigate possible catalytic roles additional shaping profile tobacco. A PCR-based strategy using primers complementary conserved regions yielded cDNA, designated CYP82E5v2, which conferred activity heterologous expression yeast host. PCR amplification CYP82E5v2 orthologs revealed two progenitor donated N. tomentosiformis parent. comparison qualitative real-time analysis demonstrated transcription higher green leaves all tobacco genotypes tested, while dominated senescing converter These results suggest differentially regulated regulate provide tools reduce levels leaves.