Cymbidium hybrida dihydroflavonol 4-reductase does not efficiently reduce dihydrokaempferol to produce orange pelargonidin-type anthocyanins |
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Authors: | Eric T Johnson Hankuil Yi Byongchul Shin Boung-Jun Oh Hyeonsook Cheong Giltsu Choi |
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Institution: | Kumho Life and Environmental Science Laboratory, Kwangju, Korea. |
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Abstract: | Some angiosperms are limited to a range of possible flower colors. This limitation can be due to the lack of an anthocyanin biosynthetic gene or to the substrate specificity of a key anthocyanin biosynthetic enzyme, dihydroflavonol 4-reductase (DFR). Cymbidium hybrida orchid flowers primarily produce cyanidin-type (pink to red) anthocyanins and lack the pelargonidin-type (orange to brick-red) anthocyanins. To investigate the underlying molecular mechanism of this flower color range, we cloned a Cymbidium DFR gene and transformed it into a DFR- petunia line. We found that the Cymbidium DFR did not efficiently reduce dihydrokaempferol (DHK), which is an essential step for pelargonidin production. Phylogenetic analysis of a number of DFR sequences indicate that the inability to catalyze DHK reduction has occurred at least twice during angiosperm evolution. Our results indicate that developing a pelargonidin-type orange flower color in Cymbidium may require the transformation of a DFR gene that can efficiently catalyze DHK reduction. |
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