Yinai Deng, Peng Yang, Qianle Zhang, Qingwen Wu, Lingfang Feng, Wenjing Shi, Qian Peng, Li Ding, Xukai Tan, Ruoting Zhan, Dongming Ma

Cell Rep.; 2024 Feb 27; 43(2):113725. doi: 10.1016/j.celrep.2024.113725.

Abstract

Flavonoids are a class of secondary metabolites widely distributed in plants. Regiospecific modification by methylation and glycosylation determines flavonoid diversity. A rare flavone glycoside, diosmin (luteolin-4'-methoxyl-7-O-glucosyl-rhamnoside), occurs in Chrysanthemum indicum. How Chrysanthemum plants evolve new biosynthetic capacities remains elusive. Here, we assemble a 3.11-Gb high-quality C. indicum genome with a contig N50 value of 4.39 Mb and annotate 50,606 protein-coding genes. One (CiCOMT10) of the tandemly repeated O-methyltransferase genes undergoes neofunctionalization, preferentially transferring the methyl group to the 4'-hydroxyl group of luteolin with ortho-substituents to form diosmetin. In addition, CiUGT11 (UGT88B3) specifically glucosylates 7-OH group of diosmetin. Next, we construct a one-pot cascade biocatalyst system by combining CiCOMT10, CiUGT11, and our previously identified rhamnosyltransferase, effectively producing diosmin with over 80% conversion from luteolin. This study clarifies the role of transferases in flavonoid diversity and provides important gene elements essential for producing rare flavone.

See https://pubmed.ncbi.nlm.nih.gov/38300800/

Figure 1: Phylogenetic and evolutionary analyses from the viewpoint of the genome