Phot2-regulated relocation of NPH3 mediates phototropic response to high-intensity blue light in Arabidopsis thaliana
Phot2-regulated relocation of NPH3 mediates phototropic response to high-intensity blue light in Arabidopsis thaliana
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Phot2 调节的 NPH3 重定位介导拟南芥对高强度蓝光的向光性反应
DOI：
10.1111/jipb.12639
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发表时间：
2018-07-01
影响因子：
11.4
通讯作者：
Zhang, Xiao
中科院分区：
文献类型：
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作者：
Zhao, Xiang;Zhao, Qingping;Zhang, Xiao
两个冗余的蓝光受体，称为向光蛋白（phototropins）（phot 1和phot 2），影响各种生理反应，包括向光性，叶绿体定位，和气孔开放在拟南芥。phot 1在低强度和高强度蓝光（HBL）中都起作用，而phot 2主要在HBL中起作用。在这里，我们的目的是阐明phot 2的特定功能，通过筛选HBL不敏感的突变体之间的诱变拟南芥phot 1突变体。其中一个phot 2信号相关（p2 sa）的双突变体，phot 1 p2 sa 2，表现出向光性缺陷，可以恢复组成型表达非向光性下胚轴3（NPH 3），表明P2 SA 2是等位基因的NPH 3。观察到NPH 3-GFP信号在黑暗中主要定位于并聚集在质膜上。这种NPH 3在质膜上的聚集不受编码与NPH 3相互作用的蛋白质的基因突变的影响，所述蛋白质包括PHOT 1、PHOT 2和根向光性2（RPT 2）。然而，HBL辐射介导的NPH 3蛋白释放到细胞质中的抑制phot 1突变体和增强phot 2和rpt 2 -2突变体。此外，HBL诱导的下胚轴向光性在phot 1突变体中增强，在phot 2和rpt 2 -2突变体中抑制。我们的研究结果表明，phot 1调节NPH 3从质膜的解离，而phot 2介导的稳定和搬迁的NPH 3的质膜，以适应HBL。
Two redundant blue-light receptors, known as phototropins (phot1 and phot2), influence a variety of physiological responses, including phototropism, chloroplast positioning, and stomatal opening in Arabidopsis thaliana. Whereas phot1 functions in both low- and high-intensity blue light (HBL), phot2 functions primarily in HBL. Here, we aimed to elucidate phot2-specific functions by screening for HBL-insensitive mutants among mutagenized Arabidopsis phot1 mutants. One of the resulting phot2 signaling associated (p2sa) double mutants, phot1 p2sa2, exhibited phototropic defects that could be restored by constitutively expressing NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3), indicating that P2SA2 was allelic to NPH3. It was observed that NPH3-GFP signal mainly localized to and clustered on the plasma membrane in darkness. This NPH3 clustering on the plasma membrane was not affected by mutations in genes encoding proteins that interact with NPH3, including PHOT1, PHOT2 and ROOT PHOTOTROPISM 2 (RPT2). However, the HBL irradiation-mediated release of NPH3 proteins into the cytoplasm was inhibited in phot1 mutants and enhanced in phot2 and rpt2-2 mutants. Furthermore, HBL-induced hypocotyl phototropism was enhanced in phot1 mutants and inhibited in the phot2 and rpt2-2 mutants. Our findings indicate that phot1 regulates the dissociation of NPH3 from the plasma membrane, whereas phot2 mediates the stabilization and relocation of NPH3 to the plasma membrane to acclimate to HBL.