ニコチンの完全な生合成経路を解明(Researchers Elucidate Complete Biosynthesis of Nicotine)

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2026-04-10 中国科学院(CAS)

本研究は、中国科学院分子植物科学卓越センターの研究チームが、植物アルカロイドであるニコチンの完全な生合成経路を初めて解明した成果である。対象は野生タバコ(Nicotiana attenuata)で、情報理論に基づくマルチオミクス解析により、最終段階を担う5成分の動的メタボロン(酵素複合体)を特定した。NaAO2遺伝子をはじめ、糖転移酵素や還元酵素など複数の因子が協働し、グリコシル化/脱グリコシル化を介した巧妙な反応経路でニコチンが合成されることを解明。さらに、この過程が液胞膜上で行われ、有害中間体の蓄積を防ぐ仕組みも明らかになった。本成果は植物代謝の理解を深化させるとともに、天然物の効率的合成を可能にする合成生物学への応用が期待される。

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ニコチンの完全な生合成 Complete biosynthesis of nicotine

Lijing Chang ∙ Zhen Xu ∙ Purong Deng ∙ … ∙ Ian T. Baldwin ∙ Yu Zhang ∙ Dapeng Li
Cell  Published:April 1, 2026
DOI:https://doi.org/10.1016/j.cell.2026.03.034

Graphical abstract

ニコチンの完全な生合成経路を解明(Researchers Elucidate Complete Biosynthesis of Nicotine)

Highlights

  • Information-theory-guided omics identifies glycosylation in nicotine biosynthesis
  • NAMN hydrolase supplies nicotinic acid via an NAD-cycle-independent route
  • A vacuolar five-component metabolon channels nicotine biosynthesis and transport
  • MATE transporter enables efficient nicotine engineering in heterologous plants

Summary

Nicotine, tobacco’s addictive and potent insecticidal alkaloid, has shaped human history, agriculture, and the plants that produce it. However, the enzymatic steps and reaction mechanisms involved in nicotine biosynthesis remain elusive. Here, we reveal that the final coupling reaction is stabilized by glycosylation via a uridine diphosphate (UDP)-glycosyltransferase, reduced and activated by an A622, condensed through a stereoselective intermolecular Mannich-like reaction, sequentially oxidized by a berberine bridge enzyme-like (BBL), and finally deglycosylated by a β-glucosidase to yield nicotine. A 5-component metabolon assembles at vacuolar membranes to channel both nicotine biosynthesis and its transport. We reconstituted this metabolon both in vitro and heterologously in vivo. Abrogating any of these components depletes nicotine accumulations. A multidrug and toxic compound extrusion (MATE) transporter is essential for efficiently engineering nicotine production in heterologous plant species, which confers pest resistance. This work completes the nicotine biosynthesis pathway and provides critical insights into the intermolecular Mannich-like reaction, a fundamental mechanism for scaffold formation in many plant alkaloids.

生物化学工学
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