王存等《New Phytologist》2023年

论文题目：CBL1/9-CIPK23-NRAMP1 Axis Regulates Manganese Toxicity

论文作者：Zhenqian Zhang,Dali Fu,Dixiang Xie,Zhangqing Wang,Yuqing Zhao,Xuening Ma,Panpan Huang,Chuanfeng Ju,Cun Wang

论文摘要：

Manganese (Mn) is an essential micronutrient in plants. However, excessive Mn absorption in acidic soils can cause Mn toxicity, which adversely affects plant growth and crop yields. At present, acidic soils coverc. 30% of the Earth's surface. However, the mechanism underpinning Mn uptake remains largely unknown.

We identifiedcbl1/9andcipk23mutants exhibiting high-Mn-sensitive phenotype through the reverse genetics method. Furthermore, we identified the CIPK23 phosphorylated NRAMP1 through a variety of protein interaction techniques and protein kinase assays.

Here, we demonstrated that two calcineurin B-like proteins, CBL1/9, and their interacting kinase CIPK23 positively regulated the tolerance of Mn toxicity inArabidopsis. Thecbl1 cbl9double mutant andcipk23mutants exhibited high-Mn-sensitive phenotypes, which manifested as decreased primary root length, biomass, and chlorophyll concentration, and higher accumulation of Mn. In addition, CIPK23 interacted with and phosphorylated the Mn transporter NRAMP1 primarily at Ser20/22invitroandinvivo, and thereby induced clathrin-mediated endocytosis of NRAMP1 to reduce its distribution on the plasma membrane and enhance plant tolerance to Mn toxicity.

In summary, we found that the CBL1/9–CIPK23–NRAMP1 module regulates the tolerance to high-Mn toxicity and provide insight into a mechanism of the tolerance of plants to Mn toxicity.

锰(Mn)是植物体内必需微量元素。然而，在酸性土壤中锰的过量吸收会造成锰毒害，对作物产量造成不利影响。目前，酸性土壤覆盖了地球表面约30%的面积。但植物吸收、转运锰的分子调控机制在很大程度上仍不清楚。

我们通过反向遗传学方法鉴定出具有高锰敏感表型的cbl1/9和cipk23突变体。此外，我们通过各种蛋白质相互作用技术和蛋白激酶鉴定了CIPK23磷酸化NRAMP1。

在这里，我们证明了两个类钙调神经素B亚基蛋白CBL1/9及其互作激酶CIPK23正调控拟南芥对锰毒性的耐受性。cbl1cbl9双突变体和cipk23突变体表现出高锰敏感表型，表现为主根长度、生物量和叶绿素含量降低，Mn积累增加。此外，在体外和体内磷酸化实验中，CIPK23与Mn转运蛋白NRAMP1相互作用并主要磷酸化修饰其Ser20/22位点，从而诱导网格蛋白介导的NRAMP1内噬作用，减少其在质膜上的分布，增强植物对Mn毒害的耐受性。

综上所述，我们发现CBL1/9-CIPK23-NRAMP1模块调节了植物对高锰毒性的耐受性，并为植物对锰毒性的耐受性机制提供了新的见解。

论文链接：http://doi.org/10.1111/nph.18968