A vacuolar iron transporter in tulip, TgVit1, is responsible for blue coloration in petal cells through iron accumulation
A vacuolar iron transporter in tulip, TgVit1, is responsible for blue coloration in petal cells through iron accumulation
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DOI：
10.1111/j.1365-313x.2009.03879.x
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发表时间：
2009-08-01
期刊：
影响因子：
7.2
通讯作者：
Nishimura, Mikio
中科院分区：
文献类型：
--
作者：
Momonoi, Kazumi;Yoshida, Kumi;Nishimura, Mikio
花的蓝色主要是由花青素引起的，其中很大一部分是金属络合的花青素。然而，金属离子运输到液泡和随后的花色发展的机制还没有得到充分的探讨。以前，我们研究了蓝色的发展机制，特别是在内部花被底部的紫色郁金香花瓣的郁金香品种。村崎水庄我们发现铁含量的差异与蓝色和紫色细胞的发育有关。在这里，我们确定了一个液泡铁转运蛋白T。gesneriana（TgVit1），并分析了该转运蛋白在郁金香花瓣中的定位和功能。TgVit1的氨基酸序列与拟南芥液泡铁转运蛋白AtVIT1的氨基酸序列有85%的相似性，并且与酵母中的AtVIT1同源物Ca2+敏感交叉互补蛋白1（CCC1）也显示出相似性。基因TgVit1只在蓝色表皮细胞中表达，蛋白水平随着mRNA表达和蓝色着色的增加而增加。瞬时表达实验表明，TgVit1定位于液泡膜，并负责紫色细胞中蓝色的形成。TgVit1在酵母中的表达挽救了ccc1突变体细胞在高浓度FeSO4存在下的生长缺陷。我们的研究结果表明，TgVit1起着至关重要的作用，在郁金香花瓣的蓝色着色作为液泡铁转运。这些结果表明一个新的作用，参与液泡铁转运蛋白在蓝色花的颜色发展。
P>Blue color in flowers is due mainly to anthocyanins, and a considerable part of blue coloration can be attributed to metal-complexed anthocyanins. However, the mechanism of metal ion transport into vacuoles and subsequent flower color development has yet to be fully explored. Previously, we studied the mechanism of blue color development specifically at the bottom of the inner perianth in purple tulip petals of Tulipa gesneriana cv. Murasakizuisho. We found that differences in iron content were associated with the development of blue- and purple-colored cells. Here, we identify a vacuolar iron transporter in T. gesneriana (TgVit1), and characterize the localization and function of this transporter protein in tulip petals. The amino acid sequence of TgVit1 is 85% similar that of the Arabidopsis thaliana vacuolar iron transporter AtVIT1, and also showed similarity to the AtVIT1 homolog in yeast, Ca2+-sensitive cross-complementer 1 (CCC1). The gene TgVit1 was expressed exclusively in blue-colored epidermal cells, and protein levels increased with increasing mRNA expression and blue coloration. Transient expression experiments revealed that TgVit1 localizes to the vacuolar membrane, and is responsible for the development of the blue color in purple cells. Expression of TgVit1 in yeast rescued the growth defect of ccc1 mutant cells in the presence of high concentrations of FeSO4. Our results indicate that TgVit1 plays an essential role in blue coloration as a vacuolar iron transporter in tulip petals. These results suggest a new role for involvement of a vacuolar iron transporter in blue flower color development.