Analysis of DcGST4 gene related to determination of dark or pale color in Dianthus caryophyllus flower

Abstract

Carnation (Dianthus caryophyllus) petals come in several color and especially pink and red colors consist of anthocyanin. The anthocyanin pathway gene from chalcone synthase through UDPglucose:flavonol 3-O-glucosyltransferase or other sugar addition steps, have been well characterized. However, S gene that was thought to determine dark or pale color in petal has not been clarified. Previously, we isolated GST (Glutathione S-Transferase) gene (DcGST4-1) from dark red carnation. In this study, we isolated two types of mutated DcGST4 (DcGST4-2, DcGST4-3) from pale color carnation. These three DcGST4s were introduced into petal of pale color carnation by particle bombardment and transiently expressed. Only DcGST4-1 formed dark red spots in the petal of pale color carnation. This result indicated that two types of DcGST4 mutation might be cause of pale colors formation in petal of carnation, and that GST4 might be S gene.