MOLECULAR-CLONING AND CHARACTERIZATION OF ROSA-HYBRIDA DIHYDROFLAVONOL 4-REDUCTASE GENE

A full length cDNA clone encoding rose dihydroflavonol 4-reductase (DF R) was isolated from a cDNA library derived from rose petals by screen ing with the cDNA of Petunia hybrida DFR. Sequence comparison of the r ose DFR with reported DFR genes revealed that they are homologous to e ach other. The amount of DFR mRNA in rose petals was developmentally r egulated and paralleled anthocyanin production in petals. Sepals, thor ns, styles and stamens also contained anthocyanins and DFR mRNA. No DF R mRNA was observed in mature leaves and a small. amount of the transc ript was detected in young leaves. A petunia cultivar, whose colour wa s pale pink due to a deficiency in flavonoid 3'-hydroxylase and flavon oid 3',5'-hydroxylase, was transformed with a binary vector containing a rose DFR cDNA cloned behind a constitutive promoter. Petals and ant hers of the resultant transgenic petunia plants were salmon pink and c ontained pelargonidin, an anthocyanidin rarely found in petunia.