The Phototropic Response is Locally Regulated Within the Topmost Light-Responsive Region of the Arabidopsis thaliana Seedling.
The Phototropic Response is Locally Regulated Within the Topmost Light-Responsive Region of the Arabidopsis thaliana Seedling.
复制标题
向光性响应在拟南芥幼苗的最顶部光响应区域内受到局部调节。
DOI：
10.1093/pcp/pct184
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Nagatani A.
中科院分区：
文献类型：
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作者：
Yamamoto K;Suzuki T;Aihara Y;Haga K;Sakai T;Nagatani A.
向光性是由植物器官（例如茎）的照射侧和阴影侧之间的细胞伸长差异引起的。人们普遍认为，生长素在两侧之间的不均匀分布至关重要地参与了这种反应。植物特有的蓝光光感受器，光致蛋白（phototropins）（phot1和phot2），介导这种反应。在禾本科植物胚芽鞘中，光感知和向光弯曲的位点在空间上是分离的。然而，这些网站是不太清楚区分双子叶植物。此外，每个向光信号传导因子的作用的确切位置仍然未知。在这里，我们调查了向光性的空间方面使用聚光灯照射黄化拟南芥幼苗。结果表明，下胚轴的约1.1mm的最上部构成光反应区，其中光感知和实际弯曲都发生。此外，子叶和茎尖的反应被抑制。因此，双子叶植物的反应比单子叶植物更具有区域自治性。接下来我们检测了向光反应过程中下胚轴的伸长速率、phot1水平和生长素报告基因的沿着表达。光反应区比非反应区对所有这些参数都更活跃。
Phototropism is caused by differential cell elongation between the irradiated and shaded sides of plant organs, such as the stem. It is widely accepted that an uneven auxin distribution between the two sides crucially participates in this response. Plant-specific blue-light photoreceptors, phototropins (phot1 and phot2), mediate this response. In grass coleoptiles, the sites of light perception and phototropic bending are spatially separated. However, these sites are less clearly distinguished in dicots. Furthermore, the exact placement of the action of each phototropic signaling factor remains unknown. Here, we investigated the spatial aspects of phototropism using spotlight irradiation with etiolated Arabidopsis seedlings. The results demonstrated that the topmost part of about 1.1 mm of the hypocotyl constituted the light-responsive region in which both light perception and actual bending occurred. In addition, cotyledons and the shoot apex were dispensable for the response. Hence, the response was more region autonomous in dicots than in monocots. We next examined the elongation rates, the levels of phot1 and the auxin–reporter gene expression along the hypocotyl during the phototropic response. The light-responsive region was more active than the non-responsive region with respect to all of those parameters.