Molecular genetics of alkaloid biosynthesis in Nicotiana tabacum

Dewey, Ralph E.; Xie, Jiahua

doi:10.1016/j.phytochem.2013.06.002

Cited by 147 publications

(142 citation statements)

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“…MeJA is not only a vital regulator in plant defense responses against biotic and abiotic stresses [22][23][24], but also plays a role in plant physiological processes, such as fruit ripening [25], stomatal closure [26], etc. Moreover, research has indicated that exogenous application of MeJA to plant cell cultures or to the intact plant can stimulate the accumulation of a wide range of plant secondary metabolites [27], including terpenoids [28], flavonoids [29], and alkaloids [30] and up-regulate expression of the genes involved in their biosynthesis [31][32][33]. However, the effect of MeJA on cucurbitane-type terpenoids of S. grosvenorii fruit has not yet been investigated.…”

Section: Introductionmentioning

confidence: 99%

Methyl jasmonate-induced accumulation of metabolites and transcriptional responses involved in triterpene biosynthesis in Siraitia grosvenorii fruit at different growing stages

et al. 2016

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The cucurbitane-type triterpenoid glycosides, mogrosides, are the main active components of Siraitia grosvenorii fruit. Squalene and cucurbitadienol are among the intermediates of the biosynthetic pathway for the formation of cucurbitanetype triterpenoid backbones of mogrosides. It is recognized that the exogenous application of methyl jasmonate (MeJA) increases the accumulation of secondary metabolites in various plant species. Here, the effect of MeJA (50, 200, and 500 μM) on the accumulation of squalene and cucurbitadienol in the fruits of S. grosvenorii at 10, 20, and 30 days after flowering (DAF) was tested for the first time. Since mogroside II E is the main cucurbitane-type triterpenoid present at this time, its concentration was also determined. The results show that MeJA can indeed promote squalene and cucurbitadienol accumulation, the application of 500 μM MeJA at 30 DAF being optimal. The concentration of squalene and cucurbitadienol increased up to 0.43 and 4.71 μg/g dry weight (DW), respectively, both of which were 1.2-fold greater than that of the control. The content of mogroside II E increased by 15% over the untreated group. We subsequently analyzed the expression of key genes involved in the mogroside biosynthetic pathway, including the 3-hydroxy-3-methylglutaryl-coenzyme A reductase gene (SgHMGR), squalene synthetase gene (SgSQS), cucurbitadienol synthase gene (SgCS), and cytochrome P450 (SgCYP450) with quantitative real-time PCR. The results showed that transcriptional levels of these genes were upregulated following the treatment described above. Additionally, their responses in the presence of MeJA was related to the concentration and timing of MeJA treatment.

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Section: Introductionmentioning

confidence: 99%

Methyl jasmonate-induced accumulation of metabolites and transcriptional responses involved in triterpene biosynthesis in Siraitia grosvenorii fruit at different growing stages

et al. 2016

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“…5 Major structural genes involved in the nicotine biosynthesis have been identified and characterized (For a review see ref. 6). In recent years, transcriptional regulators of nicotine biosynthesis have been widely studied resulting in identification of 2 distinct families of transcription factors -the APETALA2 (AP2)/ethylene response factor (ERF) and MYC2-like basic helix-Loop-helix (bHLH) families (For a review see refs.…”

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confidence: 99%

“…[17][18][19] In the nicotine biosynthesis pathway, QPT is a key enzyme catalyzing the rate limited step by converting quinolinic acid to nicotinic acid mononucleotide and serving as the entry point into the pyridine nucleotide cycle. 6 There are 2 members in QPT family: QPT1 and QPT2. QPT2 has been shown to be mainly responsible for nicotine biosynthesis 20,21 while QPT1 is not because it is unresponsive to the genetic, biotic and abiotic factors that regulate nicotine production.…”

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confidence: 99%

“…Additionally, structural genes of the nicotine biosynthesis pathway including QPT2 are regulated by 2 families of transcription factors AP2/ERF and MYC2/bHLH. 6,7 It is worth to investigate whether the expression of nta-miRX27 and nta-eTMX27 is also regulated by these transcription factors or their regulatory roles on nicotine biosynthesis run parallel to these transcription factors.…”

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confidence: 99%

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Nicotine biosynthesis is regulated by two more layers: Small and long non-protein-coding RNAs

Xie

Fan

2016

Plant Signaling & Behavior

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“…Nicotine is synthesized from the amino acids Asp and Orn (Shoji and Hashimoto, 2011a;Dewey and Xie, 2013). Early in the NAD biosynthetic pathway, Asp is metabolized to nicotinate mononucleotide, which is incorporated into the pyridine ring of nicotine by unknown enzyme reactions.…”

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confidence: 99%

Tobacco Nicotine Uptake Permease Regulates the Expression of a Key Transcription Factor Gene in the Nicotine Biosynthesis Pathway

2014

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The down-regulation of a tobacco (Nicotiana tabacum) plasma membrane-localized nicotine uptake permease, NUP1, was previously reported to reduce total alkaloid levels in tobacco plants. However, it was unclear how this nicotine transporter affected the biosynthesis of the alkaloid nicotine. When NUP1 expression was suppressed in cultured tobacco cells treated with jasmonate, which induces nicotine biosynthesis, the NICOTINE2-locus transcription factor gene ETHYLENE RESPONSE FACTOR189 (ERF189) and its target structural genes, which function in nicotine biosynthesis and transport, were strongly suppressed, resulting in decreased total alkaloid levels. Conversely, NUP1 overexpression had the opposite effect. In these experiments, the expression levels of the MYC2 transcription factor gene and its jasmonate-inducible target gene were not altered. Inhibiting tobacco alkaloid biosynthesis by suppressing the expression of genes encoding enzymes in the nicotine pathway did not affect the expression of ERF189 and other nicotine pathway genes, indicating that ERF189 is not regulated by cellular alkaloid levels. Suppressing the expression of jasmonate signaling components in cultured tobacco cells showed that NUP1 acts downstream of the CORONATINE INSENSITIVE1 receptor and MYC2, but upstream of ERF189. These results suggest that although jasmonate-activated expression of MYC2 induces the expression of both NUP1 and ERF189, expression of ERF189 may actually be mediated by NUP1. Furthermore, NUP1 overexpression in tobacco plants inhibited the long-range transport of nicotine from the roots to the aerial parts. Thus, NUP1 not only mediates the uptake of tobacco alkaloids into root cells, but also positively controls the expression of ERF189, a key gene in the biosynthesis of these alkaloids.

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Molecular genetics of alkaloid biosynthesis in Nicotiana tabacum

Cited by 147 publications

References 141 publications

Methyl jasmonate-induced accumulation of metabolites and transcriptional responses involved in triterpene biosynthesis in Siraitia grosvenorii fruit at different growing stages

Methyl jasmonate-induced accumulation of metabolites and transcriptional responses involved in triterpene biosynthesis in Siraitia grosvenorii fruit at different growing stages

Nicotine biosynthesis is regulated by two more layers: Small and long non-protein-coding RNAs

Tobacco Nicotine Uptake Permease Regulates the Expression of a Key Transcription Factor Gene in the Nicotine Biosynthesis Pathway

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