Although plant cold acclimation (CA) requires low temperature and light to increase the plant’s freezing tolerance, how the light spectra affect the process of CA is not yet fully understood. Here we show that blue light and its photoreceptor, cryptochrome (CRY), regulate signal pathways associated with the early process of CA in Arabidopsis. When cold-acclimated for 1 day under different monochromatic light conditions, the greatest increases in freezing tolerance of wild type plants, evaluated by a photosynthesis quantum efficiency index (Fv/Fm), occurred in plants exposed to blue light and the blue light effect could not be maintained in cry1cry2 mutants. Unexpectedly, freezing tolerance evaluated by a plasma membrane stability parameter (electrolyte leakage, EL) and post-thaw plant growth was higher in cry1cry2 plants than in wild type plants after CA. During CA, blue light irradiation resulted in increases of transcript levels of elongated hypocotyl 5 (HY5) and anthocyanin biosynthesis genes and, in fact, affected anthocyanin contents during the CA process. In contrast, blue light reduced transcript levels of C-repeat binding factor (CBF) and cold regulated (COR) genes. These results collectively suggest that there are multiple CRY-regulated CA pathways and the blue light–CRY system affects CA pathways in complex manners.

尽管植物的冷驯化（CA）需要低温和光照来提高植物的冷冻耐受性，但光谱如何影响CA的过程尚未完全了解。在这里，我们显示了蓝光及其光感受器隐铬（CRY）调节与拟南芥中CA早期过程相关的信号通路。当在不同的单色光条件下冷适应1天时，在暴露于蓝光的植物中，通过光合作用量子效率指数（Fv / Fm）评估，野生型植物的耐寒性最大增加。不能在cry1cry2中维护突变体。出乎意料的是，在CA后，cry1cry2植物中通过质膜稳定性参数（电解质泄漏，EL）和融化后植物生长评估的冷冻耐受性高于野生型植物。在CA期间，蓝光照射导致伸长的下胚轴5（HY5）和花色苷生物合成基因的转录水平增加，并且实际上在CA过程中影响了花色苷含量。相反，蓝光降低了C重复结合因子（CBF）和冷调节（COR）基因。这些结果共同表明，存在多种CRY调控的CA途径，并且蓝光– CRY系统以复杂的方式影响CA途径。