Campus Units

Biochemistry, Biophysics and Molecular Biology, Roy J. Carver Department of

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

1-2018

Journal or Book Title

The Plant Journal

Volume

93

Issue

1

First Page

50

Last Page

65

DOI

10.1111/tpj.13756

Abstract

Tripterygium wilfordii has long been used as a medicinal plant, and exhibits impressive and effective anti-inflammatory, immunosuppressive and anti-tumor activities. The main active ingredients are diterpenoids and triterpenoids, such as triptolide and celastrol, respectively. A major challenge to harnessing these natural products is that they are found in very low amounts in planta. Access has been further limited by the lack of knowledge regarding the underlying biosynthetic pathways, particularly for the abeo-abietane tri-epoxide lactone triptolide. Here suspension cell cultures of T. wilfordii were found to produce triptolide in an inducible fashion, with feeding studies indicating that miltiradiene is the relevant abietane olefin precursor. Subsequently, transcriptome data was used to identify eight putative (di)terpene synthases that were then characterized for their potential involvement in triptolide biosynthesis. This included not only biochemical studies that revealed the expected presence of class II diterpene cyclases that produce the intermediate copalyl diphosphate (CPP), along with the more surprising finding of an atypical class I (di)terpene synthase that acts on CPP to produce the abietane olefin miltiradiene, but also their sub-cellular localization and, critically, genetic analysis. In particular, RNA interference targeting either both of the CPP synthases, TwTPS7v2 & TwTPS9v2, or the subsequently acting miltiradiene synthase, TwTPS27v2, led to decreased production of triptolide. Importantly, these results then both confirm that miltiradiene is the relevant precursor and the relevance of the identified diterpene synthases, enabling future studies of the biosynthesis of this important bioactive natural product.

Comments

This is the peer reviewed version of the following article: Su, Ping, Hongyu Guan, Yujun Zhao, Yuru Tong, Meimei Xu, Yifeng Zhang, Tianyuan Hu et al. "Identification and functional characterization of diterpene synthases for triptolide biosynthesis from Tripterygium wilfordii." The Plant Journal 93, no. 1 (2018): 50-65, which has been published in final form at doi: 10.1111/tpj.13756. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

Copyright Owner

The Authors. The Plant Journal, John Wiley & Sons Ltd

Language

en

File Format

application/pdf

Published Version

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