Abstract
Burley tobaccos (Nicotiana tabacum) display a nitrogen-use-deficiency phenotype that is associated with the accumulation of high levels of nitrate within the leaf, a trait correlated with production of a class of compounds referred to as tobacco-specific nitrosamines (TSNAs). Two TSNA species, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN), have been shown to be strong carcinogens in numerous animal studies. We investigated the potential of molecular genetic strategies to lower nitrate levels in burley tobaccos by overexpressing genes encoding key enzymes of the nitrogen-assimilation pathway. Of the various constructs tested, only the expression of a constitutively active nitrate reductase (NR) dramatically decreased free nitrate levels in the leaves. Field-grown tobacco plants expressing this NR variant exhibited greatly reduced levels of TSNAs in both cured leaves and mainstream smoke of cigarettes made from these materials. Decreasing leaf nitrate levels via expression of a constitutively active NR enzyme represents an exceptionally promising means for reducing the production of NNN and NNK, two of the most well-documented animal carcinogens found in tobacco products.
Document Type
Article
Publication Date
6-13-2016
Digital Object Identifier (DOI)
https://doi.org/10.1111/pbi.12510
Funding Information
Research described in this article was supported by Philip Morris International.
Repository Citation
Lu, Jianli; Zhang, Leichen; Lewis, Ramsey S.; Bovet, Lucien; Goepfert, Simon; Jack, Anne M.; Crutchfield, James D.; Ji, Huihua; and Dewey, Ralph E., "Expression of a Constitutively Active Nitrate Reductase Variant in Tobacco Reduces Tobacco-Specific Nitrosamine Accumulation in Cured Leaves and Cigarette Smoke" (2016). Kentucky Tobacco Research and Development Center Faculty Publications. 18.
https://uknowledge.uky.edu/ktrdc_facpub/18
Supporting Information: Figure S1-S6.
pbi12510-sup-0002-TableS1-S4.docx (153 kB)
Supporting Information: Table S1-S4.
Notes/Citation Information
Published in Plant Biotechnology Journal, v. 14, issue 7, p. 1500-1510.
© 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.