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Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation.

Publication ,  Journal Article
Hung, C-Y; Fan, L; Kittur, FS; Sun, K; Qiu, J; Tang, S; Holliday, BM; Xiao, B; Burkey, KO; Bush, LP; Conkling, MA; Roje, S; Xie, J
Published in: Plant Physiol
February 2013

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme of the tetrahydrofolate (THF)-mediated one-carbon (C1) metabolic network. This enzyme catalyzes the reduction of 5,10-methylene-THF to 5-methyl-THF. The latter donates its methyl group to homocysteine, forming methionine, which is then used for the synthesis of S-adenosyl-methionine, a universal methyl donor for numerous methylation reactions, to produce primary and secondary metabolites. Here, we demonstrate that manipulating tobacco (Nicotiana tabacum) MTHFR gene (NtMTHFR1) expression dramatically alters the alkaloid profile in transgenic tobacco plants by negatively regulating the expression of a secondary metabolic pathway nicotine N-demethylase gene, CYP82E4. Quantitative real-time polymerase chain reaction and alkaloid analyses revealed that reducing NtMTHFR expression by RNA interference dramatically induced CYP82E4 expression, resulting in higher nicotine-to-nornicotine conversion rates. Conversely, overexpressing NtMTHFR1 suppressed CYP82E4 expression, leading to lower nicotine-to-nornicotine conversion rates. However, the reduced expression of NtMTHFR did not affect the methionine and S-adenosyl-methionine levels in the knockdown lines. Our finding reveals a new regulatory role of NtMTHFR1 in nicotine N-demethylation and suggests that the negative regulation of CYP82E4 expression may serve to recruit methyl groups from nicotine into the C1 pool under C1-deficient conditions.

Duke Scholars

Published In

Plant Physiol

DOI

EISSN

1532-2548

Publication Date

February 2013

Volume

161

Issue

2

Start / End Page

1049 / 1060

Location

United States

Related Subject Headings

  • Sequence Homology, Nucleic Acid
  • Sequence Homology, Amino Acid
  • Sequence Analysis, DNA
  • Reverse Transcriptase Polymerase Chain Reaction
  • RNA Interference
  • Plants, Genetically Modified
  • Plant Proteins
  • Plant Leaves
  • Plant Biology & Botany
  • Nicotine
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Hung, C.-Y., Fan, L., Kittur, F. S., Sun, K., Qiu, J., Tang, S., … Xie, J. (2013). Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation. Plant Physiol, 161(2), 1049–1060. https://doi.org/10.1104/pp.112.209247
Hung, Chiu-Yueh, Longjiang Fan, Farooqahmed S. Kittur, Kehan Sun, Jie Qiu, She Tang, Bronwyn M. Holliday, et al. “Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation.Plant Physiol 161, no. 2 (February 2013): 1049–60. https://doi.org/10.1104/pp.112.209247.
Hung, Chiu-Yueh, et al. “Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation.Plant Physiol, vol. 161, no. 2, Feb. 2013, pp. 1049–60. Pubmed, doi:10.1104/pp.112.209247.
Hung C-Y, Fan L, Kittur FS, Sun K, Qiu J, Tang S, Holliday BM, Xiao B, Burkey KO, Bush LP, Conkling MA, Roje S, Xie J. Alteration of the alkaloid profile in genetically modified tobacco reveals a role of methylenetetrahydrofolate reductase in nicotine N-demethylation. Plant Physiol. 2013 Feb;161(2):1049–1060.

Published In

Plant Physiol

DOI

EISSN

1532-2548

Publication Date

February 2013

Volume

161

Issue

2

Start / End Page

1049 / 1060

Location

United States

Related Subject Headings

  • Sequence Homology, Nucleic Acid
  • Sequence Homology, Amino Acid
  • Sequence Analysis, DNA
  • Reverse Transcriptase Polymerase Chain Reaction
  • RNA Interference
  • Plants, Genetically Modified
  • Plant Proteins
  • Plant Leaves
  • Plant Biology & Botany
  • Nicotine