Leaf positioning of Arabidopsis in response to blue light
Leaf positioning of Arabidopsis in response to blue light
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DOI：
10.1093/mp/ssm001
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发表时间：
2008-01-01
期刊：
影响因子：
27.5
通讯作者：
Shimazaki, Ken-ichiro
中科院分区：
文献类型：
--
作者：
Inoue, Shin-ichiro;Kinoshita, Toshinori;Shimazaki, Ken-ichiro
适当的叶片位置对于优化光合作用和植物生长至关重要。然而，还没有阐明绿色叶子如何到达并保持它们的位置以捕获光。我们在这里展示了蓝光刺激下叶片定位的调节。将生长在白色光下的1周龄拟南芥幼苗转移到红光（25 μ mol m（-2）s（-1））下5 d，出现的新叶柄几乎是水平的，它们的叶子卷曲并向下倾斜。然而，当弱蓝光（0.1 μ mol m（-2）s（-1））从上面叠加在红光，新的叶柄斜向上生长，叶片是平的和水平的。叶片定位需要向光蛋白1（phot 1）和非向光性下胚轴3（NPH 3），并导致增强植物生长。在nph 3突变体中，既没有发现最佳的叶片定位，也没有发现蓝光使叶片变平，并且蓝光诱导的生长增强显著降低。当蓝光从0.1 μ mol m（-2）s（-1）增加到5 μ mol m（-2）s（-1）时，在phot 1和nph 3突变体中诱导了正常的叶片定位和叶片扁平化，这表明phot 2信号传导开始发挥作用，并且在这些反应中该信号传导独立于phot 1和nph 3。当植物用蓝光（0.1 μ mol m（-2）s（-1））从侧面和红光从上面照射时，新叶变得朝向蓝光源。当我们将这些植物从上方转移到蓝光和红光时，叶片表面在几个小时内改变了其方向，而叶柄最初没有变化，但随后逐渐旋转，这表明叶片定位响应蓝光的可塑性。我们通过卷曲螺旋结构域和C-末端区域显示了NPH 3的组织表达及其质膜定位。我们的结论是，NPH 3介导的向光素信号优化光感知的效率，诱导最佳的叶片定位和叶片展平，并提高植物生长。
Appropriate leaf positioning is essential for optimizing photosynthesis and plant growth. However, it has not been elucidated how green leaves reach and maintain their position for capturing light. We show here the regulation of leaf positioning under blue light stimuli. When 1-week-old Arabidopsis seedlings grown under white light were transferred to red light (25 mu mol m(-2) s(-1)) for 5 d, new petioles that appeared were almost horizontal and their leaves were curled and slanted downward. However, when a weak blue light from above (0.1 mu mol m(-2) s(-1)) was superimposed on red light, the new petioles grew obliquely upward and the leaves were flat and horizontal. The leaf positioning required both phototropin1 (phot1) and nonphototropic hypocotyl 3 (NPH3), and resulted in enhanced plant growth. In an nph3 mutant, neither optimal leaf positioning nor leaf flattening by blue light was found, and blue light-induced growth enhancement was drastically reduced. When blue light was increased from 0.1 to 5 mu mol m(-2) s(-1), normal leaf positioning and leaf flattening were induced in both phot1 and nph3 mutants, suggesting that phot2 signaling became functional and that the signaling was independent of phot1 and NPH3 in these responses. When plants were irradiated with blue light (0.1 mu mol m(-2) s(-1)) from the side and red light from above, the new leaves became oriented toward the source of blue light. When we transferred these plants to both blue light and red light from above, the leaf surface changed its orientation to the new blue light source within a few hours, whereas the petioles initially were unchanged but then gradually rotated, suggesting the plasticity of leaf positioning in response to blue light. We showed the tissue expression of NPH3 and its plasma membrane localization via the coiled-coil domain and the C-terminal region. We conclude that NPH3-mediated phototropin signaling optimizes the efficiency of light perception by inducing both optimal leaf positioning and leaf flattening, and enhances plant growth.