A method for obtaining a transgenic nicotine plant, a method for obtaining a seed; RECOMBINANT NUCLEIC ACID CONSTRUCTION; NICOTINE CONVERSION REDUCTION METHOD IN NORNICOTINE IN A NICOTINE PLANT

摘要

nicotiana transgenic plant, seed, recombinant nucleic acid construct and method of reducing the conversion of nicotine to nornicotine in a nicotiana plant. Compositions and methods for reducing the level of nornicotine and n'-nitrosonornicotine (nnn) in nicotiana plants and part of plants are presented. The compositions comprise polynucleotides and polypeptides isolated from cytochrome p450 involved in the metabolic conversion of nicotine to nornicotine in these plants. Expression cassettes, vectors, plants, and plant parts comprising inhibitor sequences targeting the expression or function of the discovered cytochrome p450 polypeptides are also disclosed. Methods for using these novel sequences to inhibit the expression or function of cytochrome p450 polypeptides involved in this metabolic conversion are also presented. The methods are used in the production of tobacco products that have reduced levels of nornicotine and its carcinogenic metabolite, nnn, and therefore a reduced carcinogenic potential for individuals who consume or are exposed to secondary smoke derived from these products.