拟南芥Ca2+-CPK21/CPK23-NRAMP1信号通路应答低锰胁迫的分子机制

锰是植物生长发育的必需微量元素，缺锰会限制作物的产量和品质。然而，植物吸收转运锰的分子机制缺乏深入研究，限制了利用基因编辑等技术提高作物耐受低锰胁迫的潜力。Ca2+信号以及Ca2+依赖蛋白激酶CPKs参与植物众多非生物逆境胁迫，但其是否参与调控低锰胁迫的科学问题还未解决。申请人前期研究发现，拟南芥cpk21cpk23双突变体对低锰胁迫显著敏感。通过BiFC、LCI、Pull-down和Co-IP实验技术发现CPK21、CPK23与高亲和锰转运体NRAMP1互作，并且体外磷酸化NRAMP1的S20和T498位点，暗示CPKs可能通过磷酸化修饰NRAMP1调控低锰胁迫信号转导。本项目拟在此基础上，揭示Ca2+-CPK21/CPK23-NRAMP1信号通路应答低锰胁迫的分子机制，解析NRAMP1的功能磷酸化位点，为作物耐受低锰胁迫的分子育种和培育有益重金属超富集作物提供理论依据和技术支持。

Manganese (Mn) is an essential trace element for plant growth and development, Mn deficiency seriously limits the yield and quality of crops. However, the molecular mechanisms underlying Mn uptake and transport in plants remain very rudimentary, which limit the potential genome editing and other biotechnology to improve crops tolerance to Mn deficiency. Ca2+ signal and CPKs (Calcium-dependent Protein Kinases) are involved in a wide array of abiotic stresses in plants, but whether they regulate low Mn stress remain unknown. In this study, the applicant has found that cpk21cpk23 double mutant displayed a significantly sensitive phenotype under Mn deficiency condition in Arabidopsis. Furthermore, using BiFC、LCI、Pull-down and Co-IP techniques, we validated that CPK21 and CPK23 interacted with the highly affinity Mn transporter NRAMP1, and phosphorylated NRAMP1 primarily at S20 and T498, suggesting that CPKs may regulate Mn deficiency by phosphorylation of NRAMP1. Based on these findings, the project aims to explore the molecular mechanism of Ca2+-CPK21/CPK23-NRAMP1 signaling pathway in response to Mn deficiency, unveiling the functional phosphorylation sites of NRAMP1, and hope to provide theoretical basis and technical support for the molecular breeding for crop tolerant to Mn deficiency and cultivation of plants with hyper-accumulation of beneficial heavy metals.