王存等《Science China Life Sciences》2023年

论文题目：Calcium dependent protein kinase CPK21 and CPK23 phosphorylate and activate the iron-regulated transporter IRT1 to regulate iron deficiency in Arabidopsis

论文作者：Zhangqing Wang, Yanting Zhang, Yisong Liu, Dali Fu, Zhang You, Panpan Huang, Huiling Gao, Zhenqian Zhang, Cun Wang

论文摘要：

Iron (Fe) is an essential micronutrient for all organisms. Fe availability in the soil is usually much lower than that required for plant growth, and Fe deficiencies seriously restrict crop growth and yield. Calcium (Ca²⁺) is a second messenger in all eukaryotes; however, it remains largely unknown how Ca²⁺ regulates Fe deficiency. In this study, mutations in CPK21 and CPK23, which are two highly homologous calcium-dependent protein kinases, conferred impaired growth and root development under Fe-deficient conditions, whereas constitutively active CPK21 and CPK23 enhanced plant tolerance to Fe-deficient conditions. Furthermore, we found that CPK21 and CPK23 interacted with and phosphorylated the Fe transporter IRON-REGULATED TRANSPORTER1 (IRT1) at the Ser149 residue. Biochemical analyses and complementation of Fe transport in yeast and plants indicated that IRT1 Ser149 is critical for IRT1 transport activity. Taken together, these findings suggest that the CPK21/23-IRT1 signaling pathway is critical for Fe homeostasis in plants and provides targets for improving Fe-deficient environments and breeding crops resistant to Fe-deficient conditions.

铁（Fe）是所有生物体必需的微量营养素。土壤中的铁有效性通常远低于植物生长所需的有效性，而铁缺乏严重限制了作物的生长和产量。钙（Ca²⁺）是所有真核生物中的第二信使；然而，目前还不清楚Ca²⁺是如何调节铁缺乏的。在本研究中，CPK21和CPK23是两种高度同源的钙依赖性蛋白激酶，它们的突变在缺铁条件下导致生长和根系发育受损，而组成型活性的CPK21或CPK23增强了植物对缺铁条件的耐受性。此外，我们发现CPK21和CPK23在Ser149残基处与铁转运蛋白铁调节转运蛋白1（IRT1）相互作用并磷酸化。酵母和植物中Fe转运的生化分析和互补性表明，IRT1 Ser149对IRT1转运活性至关重要。总之，这些发现表明，CPK21/23-IRT1信号通路对植物中的铁稳态至关重要，并为改善缺铁环境和培育对缺铁条件具有抗性的作物提供了靶点。

论文链接：https://engine.scichina.com/doi/10.1007/s11427-022-2330-4