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Analysis of phototropin family signal pathway in chloroplast relocation movement

叶绿体迁移运动中向光素家族信号通路分析

基本信息

批准号：
17370013
负责人：
KAGAWA Takatoshi
金额：
$ 9.95万
依托单位：
National Institute for Basic Biology (2007)University of Tsukuba (2005-2006)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Phototropin family is a photoreceptor for chloroplast avoidance and accumulation movement, phototropism and leaf flatting. In Arabidopsis, the phototropin consist with two LOV domain and kinase. In fern Adinatum capilus-veneris has two phototropin genes and unique phototropin gene, NEO1. The C-terminus of NEO1 shares high homology with the full length sequence of the phototropin, although the first third of the N-terminus is similar to the light-absorbing domain of phytochrome.To understand phot2 function in Arabidopsis, we examined whether phot2 accumulation levels affect phototropin-regulated BL responses including chloroplast avoidance movement. The avoidance velocity increased with the accumulation of more phot2-GFP fusion protein or with a rise in the fluence rate of irradiation. These results suggest that not only is the amount of phot2 normally enough but also the components of the signaling pathway have accumulated sufficiently. As with the chloroplast avoidance movement, phot2-regulated phototropism was also found to have a dependency on phot2 accumulation. However, the transgenic lines that showed P2G accumulation less than phot2 amounts of WT were saturated flatten level of leaves. Therefore, it is unknown that leaf flattening was dependent on phot2 amounts.The phytochrome-light-absorbing region of neochrome 1 with phytochromobilin showed typical red/far-red light photoreversibility and dark reversion of the Pfr form with a half life of about 30 min. The entire photosensory region of phytochrome 3, which consists of the phytochrome-light-absorbing region and the LOV domains showed photoreversibility and the phytochrome photoconversion was not affected by the LOV domains. Though blue light irradiation induced photobleaching of the LOV domains and Pfr formation, the LOV domains did not contribute to Pfr formation. These results indicate that the phytochrome light-absorbing region and LOV domains are independent for light absorption.

向光素家族是叶绿体回避和积累运动、向光性和叶片扁平化的光感受器。在拟南芥中，向光素由两个 LOV 结构域和激酶组成。在蕨类植物 Adinatum capilus-veneris 中，有两个向光素基因和独特的向光素基因 NEO1。 NEO1 的 C 端与向光素的全长序列具有高度同源性，尽管 N 端的前三分之一与光敏色素的光吸收结构域相似。为了了解拟南芥中 phot2 的功能，我们研究了 phot2 积累水平是否影响向光素调节的 BL 反应，包括叶绿体回避运动。随着更多phot2-GFP融合蛋白的积累或随着照射注量率的增加，回避速度增加。这些结果表明，不仅phot2的量正常足够，而且信号通路的成分也已经足够积累。与叶绿体回避运动一样，phot2 调节的向光性也被发现依赖于 phot2 的积累。然而，显示P2G积累量低于WT的phot2量的转基因品系的叶片达到饱和扁平化水平。因此，尚不清楚叶片扁平化是否取决于 phot2 的量。带有光敏色素的 Neochrome 1 的光敏色素光吸收区域显示出典型的红/远红光光可逆性和 Pfr 形式的暗回复性，半衰期约为 30 分钟。光敏色素3的整个光感应区域由光敏色素光吸收区和LOV结构域组成，表现出光可逆性，并且光敏色素的光转换不受LOV结构域的影响。尽管蓝光照射诱导了 LOV 域的光漂白和 Pfr 的形成，但 LOV 域对 Pfr 的形成没有贡献。这些结果表明光敏色素光吸收区域和LOV区域对于光吸收是独立的。