Affiliation:
1. Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Jiangsu Province Engineering Research Center of Eco-Cultivation and High-Value Utilization of Chinese Medicinal Materials, Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden, Mem. Sun Yat-Sen), Nanjing 210014, China
Abstract
Flavonoids are ubiquitous polyphenolic compounds that play a vital role in plants’ defense response and medicinal efficacy. UV-B radiation is a vital environmental regulator governing flavonoid biosynthesis in plants. Many plants rapidly biosynthesize flavonoids as a response to UV-B stress conditions. Here, we investigated the effects of flavonoid biosynthesis via UV-B irradiation in Euphorbia lathyris. We found that exposure of the E. lathyris callus to UV-B radiation sharply increased the level of one O-methyltransferase (ElOMT1) transcript and led to the biosynthesis of several methylated flavonoids. The methyltransferase ElOMT1 was expressed heterologously in E. coli, and we tested the catalytic activity of recombinant ElOMT1 with possible substrates, including caffeic acid, baicalin, and luteolin, in vitro. ElOMT1 could efficiently methylate when the hydroxyl groups were contained in the core nucleus of the flavonoid. This molecular characterization identifies a methyltransferase responsible for the chemical modification of the core flavonoid structure through methylation and helps reveal the mechanism of methylated flavonoid biosynthesis in Euphorbiaceae. This study identifies the O-methyltransferase that responds to UV-B irradiation and helps shed light on the mechanism of flavonoid biosynthesis in Euphorbia lathyris.
Funder
Natural Science Foundation of Jiangsu Province
Jiangsu Provincial Key Research and Development Program
National Natural Science Foundation of China
Jiangsu Institute of Botany Talent Fund
Open Fund of Jiangsu Key Laboratory for the Research and Utilization of Plant Resources
Subject
Inorganic Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Computer Science Applications,Spectroscopy,Molecular Biology,General Medicine,Catalysis