Photosensory adaptation mechanisms in hypocotyl phototropism: how plants recognize the direction of a light source
Photosensory adaptation mechanisms in hypocotyl phototropism: how plants recognize the direction of a light source
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下胚轴向光性的光感应适应机制：植物如何识别光源的方向
DOI：
10.1093/jxb/erad015
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发表时间：
2023
影响因子：
6.9
通讯作者：
Sakai Tatsuya
中科院分区：
文献类型：
--
作者：
Haga Ken;Sakai Tatsuya
植物能识别光源的方向并表现出趋光性反应。生理学研究预测，胚芽鞘或下胚轴的受照射侧和受遮蔽侧的细胞接收到的光强度的差异会导致光产物数量的差异。这种假设的光产物似乎调节了一种控制细胞伸长的信号通路，其中低光强下的细胞比高光强下的细胞更长。这导致了朝向光源的弯曲生长，并被提出作为趋光性的光产物梯度模型。在这篇综述中，我们总结了最近关于蓝光光感受器、光致性蛋白1 （photot1）、ROOT PHOTOTROPISM2、非光致性HYPOCOTYL3 （NPH3）和另一个光感受器家族光敏色素的光感觉适应机制的研究进展。目前的证据表明，除了photo1 - nph3光感受器复合物向活性状态的转变外，一定数量的photo1 - nph3复合物的存在即使在光环境中也表现出稳定的状态，这对于识别光源方向在趋光性中是必不可少的。这与光产物梯度模型一致，并且在该模型中，phot1-NPH3络合物的解离状态将被认为是假设的光产物的实体。
Plants recognize the direction of a light source and exhibit phototropic responses. Physiological studies have predicted that differences in the light intensity received by the cells on the irradiated and shaded sides of a coleoptile or hypocotyl cause differences in the amounts of photoproduct. This hypothetical photoproduct appears to regulate a signaling pathway that controls cell elongation in which cells under lower light intensity elongate more than those under higher light intensity. This results in a bending growth toward a light source and has been proposed as the photoproduct-gradient model of phototropism. In this review, we summarize recent findings on the photosensory adaptation mechanisms involving a blue-light photoreceptor, phototropin1 (phot1), ROOT PHOTOTROPISM2, NONPHOTOTROPIC HYPOCOTYL3 (NPH3), and another photoreceptor family, the phytochromes. The current evidence demonstrates that, in addition to the transition of the phot1–NPH3 photoreceptor complexes to their active state, the presence of a certain population of the phot1–NPH3 complexes showing a steady state, even in a light environment, is essential for recognition of the light source direction in phototropism. This is consistent with the photoproduct-gradient model, and a dissociation state of the phot1–NPH3 complex would be considered an entity of the hypothetical photoproduct in this model.