A chalcone isomerase-like protein enhances flavonoid production and flower pigmentation
A chalcone isomerase-like protein enhances flavonoid production and flower pigmentation
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DOI：
10.1111/tpj.12469
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发表时间：
2014-04-01
期刊：
影响因子：
7.2
通讯作者：
Iida, Shigeru
中科院分区：
文献类型：
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作者：
Morita, Yasumasa;Takagi, Kyoko;Iida, Shigeru
黄酮类化合物是植物中的主要色素，其生物合成途径是研究最多的代谢途径之一。在这里，我们已经确定了一个基因内的三个突变，导致日本牵牛花（Ipomoea nil）的浅色花朵。由于突变导致花瓣中无色类黄酮化合物黄酮醇以及花青素的减少，所鉴定的基因被指定为类黄酮产生增强子（EFP）。EFP编码查尔酮异构酶（CHI）相关蛋白，被分类为IV型CHI蛋白。CHI是类黄酮生物合成途径的第二个关键酶，但是IV型CHI蛋白被认为缺乏CHI酶活性，并且它们的功能仍然未知。EFP和产生类黄酮的编码酶的结构基因的时空表达非常相似。EFP和结构基因的表达由编码R2 R3-MYB和WD 40家族蛋白的基因协同促进。EFP基因广泛分布于陆地植物中，矮牵牛（Petunia hybrida）和猪耳草（Torenia hybrida）中EFP同源物的RNAi敲低突变体具有浅色的花朵和少量的花青素。击倒的矮牵牛花和蓝猪耳花中的黄酮醇和黄酮含量也分别显著降低，表明EFP蛋白在类黄酮生物合成途径的早期步骤中起作用，以确保类黄酮化合物的产生。从这些结果中，我们得出结论，EFP是类黄酮产生和花色素沉着的增强剂，并且其功能在不同陆地植物物种中是保守的。
Flavonoids are major pigments in plants, and their biosynthetic pathway is one of the best-studied metabolic pathways. Here we have identified three mutations within a gene that result in pale-colored flowers in the Japanese morning glory (Ipomoea nil). As the mutations lead to a reduction of the colorless flavonoid compound flavonol as well as of anthocyanins in the flower petal, the identified gene was designated enhancer of flavonoid production (EFP). EFP encodes a chalcone isomerase (CHI)-related protein classified as a typeIV CHI protein. CHI is the second committed enzyme of the flavonoid biosynthetic pathway, but typeIV CHI proteins are thought to lack CHI enzymatic activity, and their functions remain unknown. The spatio-temporal expression of EFP and structural genes encoding enzymes that produce flavonoids is very similar. Expression of both EFP and the structural genes is coordinately promoted by genes encoding R2R3-MYB and WD40 family proteins. The EFP gene is widely distributed in land plants, and RNAi knockdown mutants of the EFP homologs in petunia (Petunia hybrida) and torenia (Torenia hybrida) had pale-colored flowers and low amounts of anthocyanins. The flavonol and flavone contents in the knockdown petunia and torenia flowers, respectively, were also significantly decreased, suggesting that the EFP protein contributes in early step(s) of the flavonoid biosynthetic pathway to ensure production of flavonoid compounds. From these results, we conclude that EFP is an enhancer of flavonoid production and flower pigmentation, and its function is conserved among diverse land plant species.