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Sequential glucosylation of a furofuran lignan, (+)‐sesaminol, by Sesamum indicum UGT71A9 and UGT94D1 glucosyltransferases
Author(s) -
Noguchi Akio,
Fukui Yuko,
IuchiOkada Asako,
Kakutani Saki,
Satake Honoo,
Iwashita Takashi,
Nakao Masahiro,
Umezawa Toshiaki,
Ono Eiichiro
Publication year - 2008
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2008.03428.x
Subject(s) - sesamum , lignan , glucoside , glycoside , chemistry , glucosyltransferases , aglycone , biochemistry , flavonoid , stereochemistry , biology , enzyme , medicine , alternative medicine , antioxidant , pathology , horticulture
Summary (+)‐Sesaminol 2‐ O ‐triglucoside is the most abundant water‐soluble furofuran lignan in sesame seeds ( Sesamum indicum ) and is considered to be a beneficial compound for human health. The biosyntheses and physiological roles of lignan glycosides, however, remain elusive. Here we report the molecular identification and biochemical characterization of two Sesamum uridine diphosphate (UDP) glucose:lignan glucosyltransferases. Sesamum indicum UGT71A9 preferentially glucosylated at the 2‐hydroxyl group of (+)‐sesaminol, resulting in (+)‐sesaminol 2‐ O ‐glucoside. Similarly, two UGT71A9 homologs from Sesamum radiatum (UGT71A10) and Sesamum alatum (UGT71A8) also showed (+)‐sesaminol glucosylating activity, evidencing the functional conservation of (+)‐sesaminol 2‐ O ‐glucosyltransferases in the Sesamum genus. In addition, S. indicum UGT94D1 specifically glucosylated at the 6′‐hydroxyl group of the sugar moiety of (+)‐sesaminol 2‐ O ‐glucoside but not at that of flavonoid glucosides. The gene expression patterns of UGT71A9 and UGT94D1 during seed development were correlated with the glucosylating activities toward (+)‐sesaminol in planta , suggesting that the two lignan UDP‐glycosyltransferases participate in the sequential glucosylation steps in the biosynthesis of (+)‐sesaminol 2‐ O ‐triglucoside.