背景回顾：The ginkgo tree (Ginkgo biloba) is considered a living fossil due to its 200 million year’s history under morphological stasis. Its resilience is partly attributed to its unique set of specialized metabolites, in particular, ginkgolides and bilobalide, which are chemically complex terpene trilactones. 

主要发现：Here, we use a gene cluster-guided mining approach in combination with co-expression analysis to reveal the primary steps in ginkgolide biosynthesis. 

结果1-细胞色素P450：We show that five multifunctional cytochrome P450s with atypical catalytic activities generate the tert-butyl group and one of the lactone rings, characteristic of all G. biloba trilactone terpenoids. 

结果2-中间产物：The reactions include scarless C–C bond cleavage as well as carbon skeleton rearrangement (NIH shift) occurring on a previously unsuspected intermediate. 

结果3-P450s演化：The cytochrome P450s belong to CYP families that diversifies in pre-seed plants and gymnosperms, but are not preserved in angiosperms. 

结论：Our work uncovers the early ginkgolide pathway and offers a glance into the biosynthesis of terpenoids of the Mesozoic Era.

 摘 要 

银杏被认为是一种活化石植物，其形态已经保持了超过2亿年。银杏的形态恢复能力部分是由于其独特的特化代谢物，尤其是萜内酯类化合物银杏内酯（ginkgolides）和白果内酯（bilobalide）。本文中，作者利用一个基因集引导的挖掘方法，结合共表达网络分析，鉴定了银杏内酯生物合成的早期步骤。作者发现5个具有非典型催化活性的多功能性细胞色素P450s，能够产生所有银杏萜内酯类化合物特征结构，即叔丁基和内酯环。包括无痕C-C键断裂和碳骨架重排（即NIH迁移）在内的反应都发生在一个之前未曾预料到的中间体上。此类细胞色素P450s属于一个在前种子植物和裸子植物中发生多样化、但在被子植物中未曾保留的CYP家族。本文的研究结果揭示了银杏内酯生物合成的早期步骤，并且为中生代的萜类生物合成提供了新的视野。

** Irini Pateraki **