Browse Articles

Article|01 Jul 2020|OPEN
Functional analysis of a novel C-glycosyltransferase in the orchid Dendrobium catenatum
Zhiyao Ren1 , Xiaoyu Ji2 , Zhenbin Jiao3,4,5 , Yingyi Luo6 , Guo-Qiang Zhang5 , Shengchang Tao1,7 , Zhouxi Lei1 and Jing Zhang1 , Yuchen Wang1 , Zhong-Jian Liu8,9 , , Gang Wei,1 ,
1School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
2Shantou University Medical College, Shantou 515041, China
3State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
4University of Chinese Academy of Sciences, Beijing 100049, China
5Shenzhen Key Laboratory for Orchid Conservation and Utilization, The National Orchid Conservation Center of China and The Orchid Conservation and Research Center of Shenzhen, Shenzhen 518114, China
6Department of Pharmacy, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou 510120 Guangdong, China
7Shaoguan Institute of Danxia Dendrobium Officinale, Shaoguan 512005, China
8Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization, College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
9Henry Fok College of Biology and Agriculture, Shaoguan University, Shaoguan 512005, China
*Corresponding author. E-mail: zjliu@fafu.edu.cn,weigang021@outlook.com

Horticulture Research 7,
Article number: 111 (2020)
doi: https://doi.org/10.1038/s41438-020-0330-4
Views: 814

Received: 06 Feb 2020
Revised: 20 Apr 2020
Accepted: 28 Apr 2020
Published online: 01 Jul 2020

Abstract

Flavonoids, which are a diverse class of phytonutrients, are used by organisms to respond to nearly all abiotic stresses and are beneficial for human health. Glycosyltransferase, used during the last step of flavonoid biosynthesis, is important in flavonoid enrichment. However, little is known about glycosyltransferase in the orchid Dendrobium catenatum (D. officinale). In this study, we isolated a novel C-glycosyltransferase (designated DcaCGT) from the orchid D. catenatum by identifying and analyzing 82 putative genes in the GT1 family. DcaCGT could specifically catalyze not only di-C-glycosylation but also O-glycosylation. Apart from the normal function of catalyzing 2-hydroxynaringenin and phloretin to the respective di-C-glycosides, DcaCGT also catalyzes apigenin to cosmosiin. Targeted metabolic profiling of the substrates (2-hydroxynaringenin, phloretin, and apigenin) and products (vitexin, isovitexin, vicenin-2, nothofagin, 3’,5’-di-C-glucosylphloretin, and cosmosiin) in different tissues showed that vicenin-2 was the most abundant product of this novel enzyme. Cosmosiin was detected in flowers and flower buds. We also established that DcaCGT functions expanded throughout the evolution of D. catenatum. Residual OGT activity may help D. catenatum resist drought stress. Our study illustrates the function, origin, and differentiation of DcaCGT and provides insights into glycosylation and molecular propagation processes, which can be used to improve the production of flavonoids by the cultivated medicinal plant D. catenatum.