Light and temperature are two key environmental factors that coordinately regulate plant growth and development. Although the mechanisms that integrate signaling mediated by cold and red light have been unraveled, the roles of the blue light photoreceptors cryptochromes in plant responses to cold remain unclear. In this study, we demonstrate that the CRYPTOCHROME2 (CRY2)-COP1-HY5-BBX7/8 module regulates blue light-dependent cold acclimation in Arabidopsis thaliana. We show that phosphorylated forms of CRY2 induced by blue light are stabilized by cold stress and that cold-stabilized CRY2 competes with the transcription factor HY5 to attenuate the HY5–COP1 interaction, thereby allowing HY5 to accumulate at cold temperatures. Furthermore, our data demonstrate that B-BOX DOMAIN PROTEIN7 (BBX7) and BBX8 function as direct HY5 targets that positively regulate freezing tolerance by modulating the expression of a set of cold-responsive genes, which mainly occurs independently of the C-repeat-binding factor pathway. Our study uncovers a mechanistic framework by which CRY2-mediated blue-light signaling enhances freezing tolerance, shedding light on the molecular mechanisms underlying the crosstalk between cold and light signaling pathways in plants.

中文翻译：

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CRY2-COP1-HY5-BBX7/8 模块调节拟南芥蓝光依赖性冷驯化

光和温度是协调调节植物生长发育的两个关键环境因素。尽管整合由冷光和红光介导的信号传导的机制已经解开，但蓝光光感受器隐花色素在植物对冷的反应中的作用仍不清楚。在这项研究中，我们证明了 CRYPTOCHROME2 (CRY2)-COP1-HY5-BBX7/8 模块调节拟南芥中依赖蓝光的冷驯化。我们表明，由蓝光诱导的磷酸化形式的 CRY2 在冷应激下得到稳定，并且冷稳定的 CRY2 与转录因子 HY5 竞争以减弱 HY5-COP1 相互作用，从而使 HY5 在低温下积累。此外，我们的数据表明，B-BOX DOMAIN PROTEIN7 (BBX7) 和 BBX8 作为直接 HY5 靶点，通过调节一组冷反应基因的表达来正向调节冷冻耐受性，这主要独立于 C 重复结合因子途径发生. 我们的研究揭示了 CRY2 介导的蓝光信号增强抗冻性的机制框架，揭示了植物中冷光信号通路之间串扰的分子机制。