EXPRESSION PROFILES OF THE DIHYDROFLAVONOL 4-REDUCTASE (DFR) GENE IN THE SEPALS AND PETALS OF DENDROBIUM SONIA EARSAKUL

Dendrobium Sonia Earsakul is a purple-flower orchid with a white base of the sepals and petals. To improve flower color using metabolic engineering, the molecular basis of genes involved in anthocyanin biosynthesis is required. In this study, we analyzed the expression profiles of the dihydroflavonol 4-reductase (DFR) gene in the sepals and petals at different flower developmental stages. The RT-PCR analysis showed that the expression of the DFR gene in the sepals and petals was developmentally regulated and corresponded to anthocyanin accumulation. No transcript of DFR was detected in either the sepals or petals at the fullyopened flower stage. The regulation of the DFR expression was different between the sepals and petals at the early and late stages of flower development. In the white tissues of the petals of the flower buds, the expression of the DFR gene was repressed and low levels of anthocyanins were detected. This indicates that the purple and white tissues of the D. Sonia Earsakul petals are attributed to differential regulation of the DFR expression.