Insights into the missing apiosylation step in flavonoid apiosides biosynthesis of Leguminosae plants

作者：Haotian Wang, Zilong Wang, Kuan Chen, Mingju Yao, Meng Zhang, Rong-Shen Wang, Jia-He Zhang, Hans Ågren, Fudong Li, Junhao Li, Xue Qiao, Min Ye · 发表于：Nature Communications · 年份：2023 · DOI：10.1038/s41467-023-42393-1 · 被引用次数：50 · 研究领域：Plant biochemistry and biosynthesis、Plant Gene Expression Analysis、Plant Parasitism and Resistance

Apiose is a natural pentose containing an unusual branched-chain structure. Apiosides are bioactive natural products widely present in the plant kingdom. However, little is known on the key apiosylation reaction in the biosynthetic pathways of apiosides. In this work, we discover an apiosyltransferase GuApiGT from Glycyrrhiza uralensis. GuApiGT could efficiently catalyze 2″-O-apiosylation of flavonoid glycosides, and exhibits strict selectivity towards UDP-apiose. We further solve the crystal structure of GuApiGT, determine a key sugar-binding motif (RLGSDH) through structural analysis and theoretical calculations, and obtain mutants with altered sugar selectivity through protein engineering. Moreover, we discover 121 candidate apiosyltransferase genes from Leguminosae plants, and identify the functions of 4 enzymes. Finally, we introduce GuApiGT and its upstream genes into Nicotiana benthamiana, and complete de novo biosynthesis of a series of flavonoid apiosides. This work reports an efficient phenolic apiosyltransferase, and reveals mechanisms for its sugar donor selectivity.