钾是植物生长发育所必须的矿质营养元素之一。植物中K+的吸收和转运过程主要是由钾通道蛋白和钾转运体蛋白调控完成。本实验室前期工作发现CBL1/9-CIPK23参与拟南芥低钾萌发生长过程中的钾营养调节, 但传统的生化技术只确证了个别下游底物蛋白及磷酸化位点。以质谱为主的磷酸化蛋白质组学研究和功能基因组学研究相结合将大大推动这一领域的研究进展。本研究拟以拟南芥作为实验系统，通过非标记定量磷酸化蛋白质组学技术与LC-MS相结合，对CIPK23和CBL1/9不同材料在钾营养吸收利用过程中的蛋白质磷酸化进行精确定量分析，筛选CIPK23调控的下游目的蛋白。通过生化技术和遗传学技术，对目的蛋白进行功能验证，为探讨钾营养吸收机理提供理论依据。

Potassium (K+) is one of the essential mineral elements for plant growth and development. The K+ uptake and translocation in plants are primarily mediated by K+ transporters or channels together with their upstream regulators. Our previous studies have been shown that CBL1/9-CIPK23 is involved in the signaling transduction of low-K+ stress in Arabidopsis. However, classical biochemical approaches have so far revealed only a few candidate proteins and even fewer phosphorylation sites. Mass spectrometry provides a powerful tool for the in-depth analysis of systems biology. In this study, we will perform a global quantitative phosphoproteomic analysis of the Arabidopsis mutants reveals low-K+ stress responsive proteins and identifies substrates of CIPK23. To demonstrate the molecular mechanisms, we will analysis the interaction of CIPK23 and its targets by biochemical and genetic approaches, which will be combined with the phosphoproteomic data to investigate the potassium uptake mechanisms.