Shenzhen Key Laboratory of Marine Bioresource & Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
Int J Mol Sci. 2018 Nov 3;19(11):3456. doi: 10.3390/ijms19113456.
Potassium (K⁺) is an essential macronutrient of living cells and is the most abundant cation in the cytosol. K⁺ plays a role in several physiological processes that support plant growth and development. However, soil K⁺ availability is very low and variable, which leads to severe reductions in plant growth and yield. Various K⁺ shortage-activated signaling cascades exist. Among these, calcium signaling is the most important signaling system within plant cells. This review is focused on the possible roles of calcium signaling in plant responses to low-K⁺ stress. In plants, intracellular calcium levels are first altered in response to K⁺ deficiency, resulting in calcium signatures that exhibit temporal and spatial features. In addition, calcium channels located within the root epidermis and root hair zone can then be activated by hyperpolarization of plasma membrane (PM) in response to low-K⁺ stress. Afterward, calcium sensors, including calmodulin (CaM), CaM-like protein (CML), calcium-dependent protein kinase (CDPK), and calcineurin B-like protein (CBL), can act in the sensing of K⁺ deprivation. In particular, the important components regarding CBL/CBL-interacting protein kinase (CBL/CIPK) complexes-involved in plant responses to K⁺ deficiency are also discussed.
钾（K⁺）是活细胞的必需大量营养素，也是细胞溶质中含量最丰富的阳离子。K⁺在支持植物生长和发育的几个生理过程中发挥作用。然而，土壤中 K⁺的可用性非常低且变化很大，这导致植物的生长和产量严重减少。存在各种 K⁺短缺激活的信号级联。在这些信号级联中，钙信号是植物细胞内最重要的信号系统。本综述重点介绍了钙信号在植物对低钾胁迫响应中的可能作用。在植物中，细胞内钙水平首先响应 K⁺缺乏而改变，导致表现出时间和空间特征的钙特征。此外，钙通道位于根表皮和根毛区，可以通过质膜（PM）的超极化对低钾胁迫作出反应而被激活。随后，钙传感器，包括钙调蛋白（CaM）、钙调蛋白样蛋白（CML）、钙依赖性蛋白激酶（CDPK）和钙调磷酸酶 B 样蛋白（CBL），可以在感应 K⁺缺乏中发挥作用。特别是，还讨论了与植物对 K⁺缺乏的响应有关的重要组成部分，即 CBL/CBL 相互作用蛋白激酶（CBL/CIPK）复合物。
