Identification of Specific Glycosyltransferases Involved in Flavonol Glucoside Biosynthesis in Ginseng Using Integrative Metabolite Profiles, DIA Proteomics, and Phylogenetic Analysis

Ginseng contains a variety of flavonol
glycosides that possess
diverse biological activities; however, scant information of flavonoid
glycosylation was reported in ginseng. We found that panasenoside
and kaempferol 3-O-glucoside were commonly accumulated
along with cultivation years in leaves. In order to explore the procedure
of flavonol glycosylation in ginseng, 50 UDP-glycosyltransferases
(UGTs) were screened out using differentiated data-independent acquisition
(DIA) proteomics and phylogenetic analysis. UGT92A10 and UGT94Q4 were
found contributing to the formation of kaempferol 3-O-glucoside. UGT73A18, UGT74T4, and UGT75W1 could catalyze galactosylation
of kaempferol 3-O-glucoside. Ser278, Trp335, Gln338,
and Val339 were found forming hydrogen bonds with UDP-galactose in
UGT75W1 by docking. MeJA induced transcripts of UGT73A18 and UGT74T4
by over fourfold, consistent with the decrease of kaempferol 3-O-glucoside, which indicated that these genes may be related
to resisting adversity stress in ginseng. These results highlight
the significance of integrative metabolite profiles, proteomics, and
phylogenetic analysis for exploring flavonol glycosylation in ginseng.