2025-10-03 マックス・プランク研究所
The plant species that produce iridoids and possess a gene copy of the cyclase include (top row from left to right) icepac Carapichea ipecacuanha, fever tree (Cinchona pubescens), golden trumpet (Allamanda cathartica), princess tree (Paulownia tomentosa), (bottom row, from left to right) Carolina jessamine (Gelsemium sempervirens), Madagascar periwinkle (Catharanthus roseus), strychnine tree (Strychnos nux-vomica), and devil pepper (Rauvolfia tetraphylla).
© Eva Rothe, greenhouse of the MPI f. Chemical Ecology (ipecac plant: Maite Colinas)
<関連情報>
- https://www.mpg.de/25499659/final-step-in-the-biosynthesis-of-iridoids-elucidated
- https://www.nature.com/articles/s41477-025-02122-6
イリドイドシクラーゼの発見により、アステリド類におけるイリドイド経路が完成 Discovery of iridoid cyclase completes the iridoid pathway in asterids
Maite Colinas,Chloée Tymen,Joshua C. Wood,Anja David,Jens Wurlitzer,Clara Morweiser,Klaus Gase,Ryan M. Alam,Gabriel R. Titchiner,John P. Hamilton,Sarah Heinicke,Ron P. Dirks,Adriana A. Lopes,Lorenzo Caputi,C. Robin Buell & Sarah E. O’Connor
Nature Plants Published:03 October 2025
DOI:https://doi.org/10.1038/s41477-025-02122-6
Abstract
Iridoids are specialized monoterpenes ancestral to asterid flowering plants1,2 that play key roles in defence and are also essential precursors for pharmacologically important alkaloids3,4. The biosynthesis of all iridoids involves the cyclization of the reactive biosynthetic intermediate 8-oxocitronellyl enol. Here, using a variety of approaches including single-nuclei sequencing, we report the discovery of iridoid cyclases from a phylogenetically broad sample of asterid species that synthesize iridoids. We show that these enzymes catalyse formation of 7S–cis-trans and 7R–cis-cis nepetalactol, the two major iridoid stereoisomers found in plants. Our work uncovers a key missing step in the otherwise well-characterized early iridoid biosynthesis pathway in asterids. This discovery unlocks the possibility to generate previously inaccessible iridoid stereoisomers, which will enable metabolic engineering for the sustainable production of valuable iridoid and iridoid-derived compounds.
