低温是全球性的环境灾害，严重影响植物的生长发育。植物对低温的响应依赖于转录因子DREB1s/CBFs冷信号通路，但是低温对CBFs蛋白水平的调控机理尚不清楚。我们通过酵母双杂交技术筛选，获得了一个与CBFs互作的蛋白激酶PRK1，能够在体外磷酸化CBFs蛋白。拟南芥prk1突变体具有明显的冻敏感表型，初步认为该蛋白激酶是植物冷信号通路中的正调控因子。本项目计划对PRK1响应低温的分子机制进行解析；通过研究PRK1与CBFs的互作机理，阐明PRK1对CBFs蛋白稳定性和转录活性的调控机制；利用生化手段对PRK1磷酸化CBFs进一步分析，明确磷酸化修饰对CBFs蛋白功能的影响；借助CRISPR/Cas9技术建立PRK1与CBFs的遗传关系，分析CBFs磷酸化对植物抗冻性的重要性。本项目的目标是从新的层面揭示CBF信号通路调控植物低温应答的分子机制，为提高植物的抗冷性提供理论依据。

Cold stress is a major environmental factor that adversely affects plant growth and development. Currently, the best understood cold signaling pathway is DREB1s/CBFs transcriptional regulatory cascade. However, how cold modulates CBFs proteins stability and transcriptional activity is still elusive. Recently, we isolate an interaction protein of CBFs named PRK1 (Protein Kinase1) by yeast-two-hybrid screening. Loss-of-function of prk1 leads to a significant reduction in plant freezing tolerance, indicating that PRK1 is likely a novel positive regulator in plant cold response. Here, we propose to determine the exact role of protein kinase PRK1 in cold signaling and reveal the mechanism of how PRK1 mediates the phosphorylation of CBFs. Furthermore, the biological significance of the interaction between PRK1 and CBF will be explored in details. CRISPR/Cas9 system will also be used to build the genetic relationship between PRK1 and CBFs. This study will allow us to dissect a novel molecular mechanism of plant responses to cold stress, and provide new information for molecular breeding and crop improvement.