Abstract
Flavonoids that provide from yellow to red, blue colorization are most common pigments in flower petals. Flavonoid glycosylation takes place in the cytosol, and the conjugates are stored in the vacuole. Accumulation of chalcones should provide yellow pigmentation to the petals of many ornamental plant species. Carnation yellow petals contain chalcone 2'-O-glucoside.
Now, we isolate full-length cDNA clones of chalcone 2'-glucosyltransferase (C2'GT) and flavonoid 3-glucosyltransferase (F3GT) from yellow and red petals of Carnation. We used degenerate primers designed from conserved regions among GTs in flavonoid and betacyanin biosynthesis, and amplified cDNA by nested PCR. Carnation GTs were expressed in E. coli, and their substrate specificities determined using various flavonoids. C2'GT has broader substrate specificity and glucosylate chalcone, naringenin, flavonols and anthocyanins. The gene involved in flavonoid biosynthesis can be utilized to control biosynthesis and modify flower pigmentation in transgenic plants.
