AUTHOR=Chen Xiao , Chen Junfeng , Feng Jingxian , Wang Yun , Li Shunuo , Xiao Ying , Diao Yong , Zhang Lei , Chen Wansheng 

TITLE=Tandem UGT71B5s Catalyze Lignan Glycosylation in Isatis indigotica With Substrates Promiscuity

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.637695

DOI=10.3389/fpls.2021.637695

ISSN=1664-462X

ABSTRACT=<p>Lignans are a class of chemicals formed by the combination of two molecules of phenylpropanoids with promising nutritional and pharmacological activities. Lignans glucosides, which are converted from aglycones catalyzed by uridine diphosphate (UDP) glycosyltransferases (UGTs), have abundant bioactivities. In the present study, two UGTs from <italic>Isatis indigotica</italic> Fort., namely <italic>Ii</italic>UGT71B5a and <italic>Ii</italic>UGT71B5b, were characterized to catalyze the glycosylation of lignans with promiscuities toward various sugar acceptors and sugar donors, and pinoresinol was the preferred substrate. <italic>Ii</italic>UGT71B5a was capable of efficiently producing both pinoresinol monoglycoside and diglycoside. However, <italic>Ii</italic>UGT71B5b only produced monoglycoside, and exhibited considerably lower activity than <italic>Ii</italic>UGT71B5a. Substrate screening indicated that ditetrahydrofuran is the essential structural characteristic for sugar acceptors. The transcription of <italic>IiUGT71B5s</italic> was highly consistent with the spatial distribution of pinoresinol glucosides, suggesting that <italic>Ii</italic>UGT71B5s may play biological roles in the modification of pinoresinol in <italic>I. indigotica</italic> roots. This study not only provides insights into lignan biosynthesis, but also elucidates the functional diversity of the UGT family.</p>