抄録
Plants have a wide range of volatile compounds which are required for biological interactions with various organisms. Plant volatile compounds are often stored in plants as glycosides (GBV; glycosidically bound volatiles). A group of glycosyltransferases called plant secondary product glycosyltransferases (PSPGs) are responsible for GBV production in plants. One of the characteristic volatile compounds of strawberry, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), exists not only as an aglycon but also in various modified forms. Among them, the glucoside (HDMF 4-O-glucoside) is a well-known compound. To identify the HDMF glycosyltransferases in strawberries, we attempted a comprehensive gene cloning of novel PSPG genes expressed in strawberry receptacles. We found only UGT85K16, isolated as a homolog of UGT85K14, an HDMF glycosyltransferase from grapes. We determined the kinetic parameters of UGT85K16 and compared its catalytic efficiency, indicating that UGT85K16 has a high substrate specificity for HDMF. Gene expression analysis and the accumulation of HDMF glucosides showed a correlation between the expression of UGT85K16 and the accumulation of HDMF glucosides. These results suggest that UGT85K16 may play a key role in HDMF glycosylation. If the functions of UGT85K16 and other PSPGs in strawberries are clarified, the mechanism and physiological role of HDMF glycosylation and regulation of HDMF release could be elucidated in future investigations.
