锰是植物生长发育所必需的微量元素，但酸性土壤造成的锰毒害会严重影响作物产量。目前酸性土壤约占全球土壤面积的30%。因此，研究植物应答锰毒害的分子机制具有重要意义。钙离子感受器CBL-CIPK复合体参与植物多种生命过程，但其是否调控植物对锰毒害的响应尚不清楚。申请人前期研究表明，拟南芥定位于液泡膜的CBLα/β基因的双突变体表现为高锰胁迫耐受表型，而且锰含量显著低与野生型植株。与CBLα/β互作的CIPKβ基因的突变体也表现为高锰胁迫耐受表型。多种蛋白互作分析结果表明CIPKβ与锰转运体MTP8和MTP11互作。本项目拟在此基础上，研究CBLα/β-CIPKβ能否磷酸化MTP8和MTP11并鉴定其磷酸化位点，再通过酵母锰离子转运活性分析等实验研究CBLα/β-CIPKβ对锰转运体MTP8和MTP11活性的影响。从而解析CBLα/β-CIPKβ调控锰转运的分子机制，以期为作物育种奠定理论基础。

Manganese (Mn) is an essential micronutrient for growth and development in plants. However, manganese toxicity caused by acid soil seriously adversely affect crop yield. At present, acidic soil accounts for approximately 30% of the global soil. Therefore, it is of great significance to explore the molecular mechanism of plant response to manganese toxicity. Calcium sensor CBL-CIPK complex is involved in a variety of life processes in plants. However, whether the complex involved in response to manganese toxicity remain obscure. Our previous results demonstrated that the double mutant of Arabidopsis tonoplast-localized CBLα and its homologous protein CBLβ exhibited a high-Mn stress tolerance phenotype and reduced Mn content compared with wild-type (WT). CIPKβ can interact with CBLα or CBLβ, and the cipkβ mutant also exhibited tolerant phenotype to Mn toxicity compared with WT. Furthermore, the multiple of protein interaction analyses indicated that CIPKβ interacted with the manganese transporters MTP8 and MTP11. Based on these findings, whether CIPKs phosphorylate MTP8 and MTP11 will be analyzed in this project, and the phosphorylation sites of the substrates will also be identified. And then the effects of CBLα/β-CIPKβ on the activities of Mn transports MTP8 and MTP11 will be determined through the yeast transport assay for manganese. The project aims at unveiling the molecular mechanism of the CBLα/β-CIPKβ complex in regulating the manganese utilization and transport in plants, in order to lay a theoretical foundation for crop breeding improvement.