Responses of ferns to red light are mediated by an unconventional photoreceptor
Responses of ferns to red light are mediated by an unconventional photoreceptor
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DOI：
10.1038/nature01310
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发表时间：
2003-01-16
期刊：
影响因子：
64.8
通讯作者：
Wada, M
中科院分区：
文献类型：
--
作者：
Kawai, H;Kanegae, T;Wada, M
高效的光合作用对植物的生存至关重要。为了优化光合作用，植物已经开发了几种光响应。茎向光源弯曲（向光性），叶绿体移动到适当的光强度的地方（叶绿体光迁移），气孔打开吸收二氧化碳。这些反应是由拟南芥中的蓝光受体phototropin 1（phot 1）和phototropin 2（phot 2）介导的（参考文献1-5）。在某些蕨类植物中，向光性和叶绿体光致位移受红光和蓝光控制（6）。然而，到目前为止，还没有确定介导这些红光反应的光感受器。蕨类铁线蕨有一种非常规的感光体，光敏色素3（phy 3），它是红光/远红光受体光敏色素和光致蛋白的嵌合体（7）。通过突变分析和互补作用，我们确定了phy 3在红光诱导的向光性和红光诱导的叶绿体光迁移中的功能。由于PHY 3在定向叶片和叶绿体中极大地增强了对白色光的敏感性，并且PHY 3同源物存在于各种蕨类植物中，因此这种嵌合光感受器可能在低光冠层条件下蕨类植物的分化和增殖中发挥了核心作用。
Efficient photosynthesis is essential for plant survival. To optimize photosynthesis, plants have developed several photo-responses. Stems bend towards a light source (phototropism), chloroplasts move to a place of appropriate light intensity (chloroplast photorelocation) and stomata open to absorb carbon dioxide. These responses are mediated by the blue-light receptors phototropin 1 (phot1) and phototropin 2 (phot2) in Arabidopsis (refs 1-5). In some ferns, phototropism and chloroplast photorelocation are controlled by red light as well as blue light(6). However, until now, the photoreceptor mediating these red-light responses has not been identified. The fern Adiantum capillus-veneris has an unconventional photoreceptor, phytochrome 3 (phy3), which is a chimaera of the red/far-red light receptor phytochrome and phototropin(7). We identify here a function of phy3 for red-light-induced phototropism and for red-light-induced chloroplast photorelocation, by using mutational analysis and complementation. Because phy3 greatly enhances the sensitivity to white light in orienting leaves and chloroplasts, and PHY3 homologues exist among various fern species, this chimaeric photoreceptor may have had a central role in the divergence and proliferation of fern species under low-light canopy conditions.