Shimada Y, Nakano-Shimada R, Ohbayashi M, Okinaka Y, Kiyokawa S, Kikuchi Y
Plant Functions Laboratory, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama, Japan.
FEBS Lett. 1999 Nov 19;461(3):241-5. doi: 10.1016/s0014-5793(99)01425-8.
Flavonoid-3',5'-hydroxylase (F3'5'H), a member of the cytochrome P450 family, is the key enzyme in the synthesis of 3', 5'-hydroxylated anthocyanins, which are generally required for blue or purple flowers. A full-length cDNA, TG1, was isolated from prairie gentian by heterologous hybridization with a petunia cDNA, AK14, which encodes F3'5'H. To investigate the in vivo function of TG1 and AK14, they were subcloned into a plant expression vector and expressed under the control of the CaMV35S promoter in transgenic tobacco or petunia, both of which originally lack the enzyme. Transgenic petunia plants had a dramatic change in flower color from pink to magenta with a high content of 3',5'-hydroxylated anthocyanins. In contrast, transgenic tobacco plants had minimal color change with at most 35% 3',5'-hydroxylated anthocyanin content. These results indicate that the products of TG1 and AK14 have F3'5'H activity in planta and that interspecific gene transfer alters anthocyanin pigment synthesis. The difference in apparent F3'5'H activity between tobacco and petunia is discussed.
类黄酮 - 3'，5'-羟化酶（F3'5'H）是细胞色素P450家族的成员之一，是合成3'，5'-羟基化花青素的关键酶，而蓝色或紫色花朵通常需要这种花青素。通过与矮牵牛编码F3'5'H的cDNA（AK14）进行异源杂交，从草原龙胆中分离出全长cDNA（TG1）。为了研究TG1和AK14在体内的功能，将它们亚克隆到植物表达载体中，并在CaMV35S启动子的控制下在原本缺乏该酶的转基因烟草或矮牵牛中表达。转基因矮牵牛植株的花色从粉红色显著变为品红色，3'，5'-羟基化花青素含量很高。相比之下，转基因烟草植株的颜色变化极小，3'，5'-羟基化花青素含量最高为35%。这些结果表明，TG1和AK14的产物在植物中具有F3'5'H活性，种间基因转移改变了花青素色素的合成。文中还讨论了烟草和矮牵牛之间明显的F3'5'H活性差异。
