Up-regulation of auxin response factor NbTF7 to decrease nicotine in a plant
Plant metabolism and alkaloid levels can be regulated by transcription factors that regulate the nicotinic alkaloid biosynthetic pathway. In one embodiment, the disclosure provides a transcription factor that negatively regulates alkaloid biosynthesis, such as nicotine biosynthesis. In particular, the present disclosure provides methods for overexpressing NbTF7 to decrease nicotine biosynthesis in plants.
1. A method for up-regulating a NbTF7 transcription factor in a Nicotiana plant, wherein the transcription factor is up-regulated by the method comprising:
(a) introducing into the plant an expression construct comprising a nucleotide sequence selected from the group consisting of:
(i) the nucleotide sequence set forth in SEQ ID NO: 14 or SEQ ID NO: 15; and
(ii) a nucleotide sequence that encodes a polypeptide having the amino acid sequence set forth in SEQ ID NO: 16; and
(b) growing the plant under conditions whereby the expression construct increases levels of the transcription factor in the plant as compared to a control plant grown under similar conditions.
2. The method of claim 1 , further comprising down-regulating at least one of NBB1, A622, quinolate phospho-ribosyltransferase (QPT), putrescine-N-methyltransferase (PMT), and N-methylputrescine oxidase (MPO).
3. The method of claim 1 , further comprising overexpressing within the Nicotiana plant at least one transcription factor that negatively regulates nicotinic alkaloid biosynthesis.
4. The method of claim 1 , further comprising suppressing the expression of at least one transcription factor that positively regulates nicotinic alkaloid biosynthesis.
5. The method of claim 1 , wherein the plant is Nicotiana tabacum.
6. A Nicotiana plant produced by the method of claim 1 , wherein the plant comprises the expression construct.
7. A product comprising the reduced nicotinic alkaloid plant of claim 6 , or portions thereof.
8. The product of claim 7 , wherein the product is selected from the group consisting of a cigarette, cigarette tobacco, cigar tobacco, a cigar, pipe tobacco, chewing tobacco, snuff, snus, lozenges, and reconstituted tobacco.
9. Seeds from the plant of claim 6 , wherein the seeds comprise the expression construct.
10. The method of claim 1 , wherein the nucleotide sequence comprises the nucleotide sequence as set forth in SEQ ID NO: 14.
11. The method of claim 1 , wherein the nucleotide sequence comprises the nucleotide sequence as set forth in SEQ ID NO: 15.
12. The method of claim 2 , wherein NBB1 is down-regulated.
13. The method of claim 2 , wherein A622 is down-regulated.
14. The method of claim 2 , wherein QPT is down-regulated.
15. The method of claim 2 , wherein PMT is down-regulated.
16. The method of claim 2 , wherein MPO is down-regulated.
17. The Nicotiana plant of claim 6 , wherein the plant is a Nicotiana tabacum plant.