The present disclosure provides compositions and methods related to tobacco plants. In particular, the present disclosure provides novel methods for producing tobacco plants, and any related tobacco products, having low nicotinic alkaloid content. Tobacco plants produced according to the methods of the present disclosure exhibit reduced levels of nicotinic alkaloids (e.g., nicotine) compared to both naturally-occurring and transgenic tobacco plants, and thus represent a commercially valuable alternative to currently available tobacco varieties.

The present application provides tobacco inbred plants dS1746, dS1746MS, dS1564 and dS1564MS. The present application also provides parts of such plants and products made from those parts. The present application also includes progeny of the provided plants including hybrids.

The invention discloses a tobacco NtbHLH13 gene mutant as well as a molecular identification method and application thereof. The tobacco NtbHLH13 gene mutant is Ntbhlhl3, and G at the 215th site of a tobacco Ntbhlhl3 gene is mutated into A to form a termination codon, so that the gene is terminated in advance, and the nucleotide sequence of the tobacco NtbHLH13 gene mutant is as shown in SEQ ID No. 1. After the gene of the tobacco NtbHLH13 gene mutant Ntbhlhl3 is mutated, the nicotine content of tobacco can be obviously increased, the tobacco quality is remarkably improved, and the gene mutanthas great value in tobacco breeding.

The present invention provides a method for modulating the alkaloid content of a plant (e.g. a tobacco plant), the method comprising modifying said plant by modulating the activity or expression of a homeodomain-like, Myb domain protein. The present invention also provides for the use of a homeodomain-like, Myb domain protein for modulating the alkaloid content of a plant, as well as tobacco cells, plants, plant propagation materials, harvested leaves, processed tobaccos, or tobacco products obtainable in accordance with the invention.

The present invention provides a method for modulating the alkaloid content of a plant (e.g. a tobacco plant), the method comprising modifying said plant by modulating the activity or expression of a protein kinase. The present invention also provides for the use of a protein kinase for modulating the alkaloid content of a plant, as well as tobacco cells, plants, plant propagation materials, harvested leaves, processed tobaccos, or tobacco products obtainable in accordance with the invention.

The present disclosure provides tobacco having genetic modification(s) in a group of ERF genes. Also provided are tobacco plants with altered total alkaloid and nicotine levels and commercially acceptable leaf grade, their development via breeding or transgenic approaches, and production of tobacco products from these tobacco plants. Further provided are compositions and methods for producing tobacco plants having novel mutations or alleles to reduce nicotine levels. Further provided are sequence polymorphisms and molecular markers for breeding tobacco with reduced nicotine or alkaloids while maintaining tobacco leaf grade and tobacco product quality.

Provided herein are genetic markers and a coding sequence associated with a low- or ultra-low anatabine trait in tobacco.

There is described herein a plant cell (i) a polynucleotide comprising, consisting or consisting essentially of a sequence having at least 60% sequence identity to SEQ ID NO: 1 (NtSULTR3;1A-S), SEQ ID NO: 3 (NtSULTR3;1A-T), SEQ ID NO: 5 (NtSULTR3;1B-S), SEQ ID NO: 7 (NtSULTR3;1B-T), SEQ ID NO: 15 (NtSULTR3;3-T), SEQ ID NO: 17 (NtSULTR3;4A-S), SEQ ID NO: 19 (NtSULTR3;4A-T) or SEQ ID NO: 23 (NtSULTR3;4B-T); (ii) a polypeptide encoded by the polynucleotide set forth in (i); (iii) a polypeptide comprising, consisting or consisting essentially of a sequence having at least 87% sequence identity to SEQ ID NO: 2 (NtSULTR3;1A-S) or at least 87% sequence identity to SEQ ID NO: 4 (NtSULTR3;1A-T) or at least 87% sequence identity to SEQ ID NO: 6 (NtSULTR3;1B-S), or at least 88% sequence identity to SEQ ID NO: 8 (NtSULTR3;1B-T), or at least 70% sequence identity to SEQ ID NO: 16 (NtSULTR3;3-T), or at least 84% sequence identity to SEQ ID NO: 18 (NtSULTR3;4A-S) or at least 79% sequence identity to SEQ ID NO: 20 (NtSULTR3;4A-T); or at least 87% sequence identity to SEQ ID NO: 24 (NtSULTR3;4B-T); or (iv) a construct, vector or expression vector comprising the isolated polynucleotide set forth in (i), wherein said plant cell comprises at least one modification which modulates (a) the expression or activity of the polynucleotide or (b) the expression or activity of the polynucleotide the polypeptide, as compared to a control plant cell in which the expression or activity of the polynucleotide or polypeptide has not been modified.

Compositions and methods for reducing the level of nornicotine and N-nitrosonornicotine (NNN) in tobacco plants and plant parts thereof are provided. The compositions comprise isolated polynucleotides and polypeptides for a root-specific nicotine demethylases, CYP82E10, and variants thereof, that are involved in the metabolic conversion of nicotine to nornicotine in these plants. Compositions of the invention also include tobacco plants, or plant parts thereof, comprising a mutation in a gene encoding a CYP82E10 nicotine demethylase, wherein the mutation results in reduced expression or function of the CYP82E10 nicotine demethylase. Seed of these tobacco plants, or progeny thereof, and tobacco products prepared from the tobacco plants of the invention, or from plant parts or progeny thereof, are also provided. Methods for reducing the level of nornicotine, or reducing the rate of conversion of nicotine to nornicotine, in a tobacco plant, or plant part thereof are also provided. The methods comprise introducing into the genome of a tobacco plant a mutation within at least one allele of each of at least three nicotine demethylase genes, wherein the mutation reduces expression of the nicotine demethylase gene, and wherein a first of these nicotine demethylase genes encodes a root-specific nicotine demethylase involved in the metabolic conversion of nicotine to nornicotine in a tobacco plant or a plant part thereof. The methods find use in the production of tobacco products that have reduced levels of nornicotine and its carcinogenic metabolite, NNN, and thus reduced carcinogenic potential for individuals consuming these tobacco products or exposed to secondary smoke derived from these products.

The present invention provides a method for modulating the alkaloid content of a plant (e.g. a tobacco plant), the method comprising modifying said plant by modulating the activity or expression of at least one protein kinase. The present invention also provides for the use of at least protein kinase gene for modulating the alkaloid content of a plant, as well as tobacco cells, plants, plant propagation materials, harvested leaves, processed tobaccos, or tobacco products obtainable in accordance with the invention.