Purification,molecular cloning and functional characterization of flavonoid C‐glucosyltransferases from Fagopyrum esculentum M. (buckwheat) cotyledon |
| |
Authors: | Yoshihisa Nagatomo Shiori Usui Takamitsu Ito Akira Kato Makoto Shimosaka Goro Taguchi |
| |
Affiliation: | Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, , Ueda, 386‐8567 Japan |
| |
Abstract: | C‐Glycosides are characterized by their C–C bonds in which the anomeric carbon of the sugar moieties is directly bound to the carbon atom of aglycon. C‐Glycosides are remarkably stable, as their C–C bonds are resistant to glycosidase or acid hydrolysis. A variety of plant species are known to accumulate C‐glycosylflavonoids; however, the genes encoding for enzymes that catalyze C‐glycosylation of flavonoids have been identified only from Oryza sativa (rice) and Zea mays (maize), and have not been identified from dicot plants. In this study, we identified the C‐glucosyltransferase gene from the dicot plant Fagopyrum esculentum M. (buckwheat). We purified two isozymes from buckwheat seedlings that catalyze C‐glucosylation of 2‐hydroxyflavanones, which are expressed specifically in the cotyledon during seed germination. Following purification we isolated the cDNA corresponding to each isozyme [FeCGTa (UGT708C1) and FeCGTb (UGT708C2)]. When expressed in Escherichia coli, both proteins demonstrated C‐glucosylation activity towards 2‐hydroxyflavanones, dihydrochalcone, trihydroxyacetophenones and other related compounds with chemical structures similar to 2′,4′,6′‐trihydroxyacetophenone. Molecular phylogenetic analysis of plant glycosyltransferases shows that flavonoid C‐glycosyltransferases form a different clade with other functionally analyzed plant glycosyltransferases. |
| |
Keywords: | flavonoid C‐glucosyltransferase buckwheat
Fagopyrum esculentum
cotyledon 2‐hydroxyflavanone germination vitexin |
|
|