method of obtaining a tobacco plant, or cell or part thereof, having reduced levels of nornicotine, tobacco product, method of making a tobacco product, isolated polynucleotide, expression cassette, isolated polypeptide and method of obtaining a plant, or part of this plant, of the genus nicotiana

摘要

method of obtaining a tobacco plant, or cell or part thereof, having reduced levels of nornicotine, tobacco product, method of making a tobacco product, isolated polynucleotide, expression cassette, isolated polypeptide and method of obtaining a plant, or part of this plant, of the nicotian genus, compositions and methods are available to reduce the level of nornicotine and n'-nitrosonornicotine (nnn) in nicotian plants and parts of plants. the compositions comprise isolated polynucleotides and polypeptides for cytochrome p450s that participate in the metabolic conversion of nicotine to nornicotine in these plants. expression cassettes, vectors, plants and plant parts comprising inhibitory sequences targeting the expression or function of the discovered cytochrome p450 polypeptides are also made available. methods are also available to use these new sequences to inhibit the expression or function of cytochrome p450 polypeptides that participate in this metabolic conversion. the methods can be used in the manufacture of tobacco products that have lower levels of nornicotine and its carcinogenic metabolite, nnn, and therefore that have less carcinogenic potential for individuals who consume these tobacco products or who are exposed to secondary smoke derived from these products.