Noguchi Minoru, Keino Issei, Takahashi Hitomi, Yamauchi Shota, Fujisawa Mami, Haga Ken, Sakai Tatsuya, Takemiya Atsushi, Kodama Yutaka
Center for Bioscience Research and Education, Utsunomiya University, Tochigi 321-8505, Japan.
Graduate School of Regional Development and Creativity, Utsunomiya University, Tochigi 321-8505, Japan.
J Exp Bot. 2025 May 27;76(8):2309-2319. doi: 10.1093/jxb/eraf040.
Organisms adapt to predictable environmental changes via a biological mechanism called priming. Phototropin is a plant-specific blue light photoreceptor that mediates daily light-induced responses, such as chloroplast relocation, stomatal opening, and phototropism, to optimize photosynthesis. Phototropin also functions as a thermosensor for chloroplast relocation that may sense daily temperature decreases at night, thereby modulating light-induced responses at dawn; however, this hypothesis has not yet been fully explored. Here, we revealed that phototropin mediates daily cold priming to promote stomatal opening and phototropism in Arabidopsis under dawn-mimicking conditions. A cold pretreatment in the dark enhanced subsequent blue light-induced stomatal opening and phototropism at normal temperatures, suggesting that daily cold priming is involved in these physiological responses. Arabidopsis has two phototropin proteins (phot1 and phot2), and we showed that phot2 clearly mediates cold priming of stomatal opening and phototropism. Cold priming appears to be based on phototropin-mediated thermosensing just before dawn, which plants use to optimize their light-induced responses in anticipation of dawn.
生物体通过一种称为“引发”的生物学机制来适应可预测的环境变化。向光素是一种植物特有的蓝光光感受器，它介导日常光诱导的反应，如叶绿体重新定位、气孔开放和向光性，以优化光合作用。向光素还作为叶绿体重新定位的温度传感器，可能感知夜间日常温度的下降，从而在黎明时调节光诱导的反应；然而，这一假设尚未得到充分探索。在这里，我们揭示了向光素在模拟黎明的条件下介导日常冷引发，以促进拟南芥气孔开放和向光性。在黑暗中进行冷预处理可增强随后在正常温度下蓝光诱导的气孔开放和向光性，这表明日常冷引发参与了这些生理反应。拟南芥有两种向光素蛋白（phot1和phot2），我们发现phot2明显介导气孔开放和向光性的冷引发。冷引发似乎基于黎明前向光素介导的温度感知，植物利用这种感知来优化其在黎明前预期的光诱导反应。
