Cao Hongrui, Cui Rongxiu, Guo Huan, Xia Qiuchen, Zhang Jianing, Liu Wenxin, Yang Zhong-Bao
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education; Shandong Key Laboratory of Precision Molecular Crop Design and Breeding; School of Life Science, Shandong University (Qingdao), Qingdao, P. R. China.
Nat Commun. 2025 Jun 5;16(1):5225. doi: 10.1038/s41467-025-60426-9.
Calcium (Ca) signalling is critical for plant responses to aluminum (Al) stress, with STOP1-mediated ALMT1 expression playing a crucial role in Arabidopsis Al resistance. However, the specific intracellular Ca sensors responsible for transducing Al signals in this process remain unclear. In this study, we identified CPK21 and CPK23, members of the CPK family, as key regulators promoting STOP1-mediated ALMT1 expression under Al stress, significantly influencing malate exudation from roots to limit Al accumulation in root tips. Al stress triggers rapid Ca-dependent accumulation of CPK21 and CPK23 in the plasma membrane, cytoplasm and nucleus of root apical cells. The Al-activated CPK21 and CPK23 subsequently phosphorylate STOP1 in both the cytoplasm and nucleus of root apical cells, stabilizing STOP1 by preventing its interaction with RAE1, ultimately enhancing Al resistance. This entire process is Ca-dependent. The study unveils a previously undisclosed regulatory network in which CPKs integrate Al-evoked Ca signals and transcriptional reprogramming through the Ca-CPK21/23-STOP1 cascade to effectively respond to and adapt to Al stress in plants.
钙（Ca）信号传导对于植物对铝（Al）胁迫的响应至关重要，其中STOP1介导的ALMT1表达在拟南芥抗铝性中起着关键作用。然而，在此过程中负责转导铝信号的特定细胞内钙传感器仍不清楚。在本研究中，我们鉴定出CPK家族成员CPK21和CPK23是在铝胁迫下促进STOP1介导的ALMT1表达的关键调节因子，显著影响从根部渗出苹果酸以限制根尖中铝的积累。铝胁迫触发CPK21和CPK23在根尖细胞的质膜、细胞质和细胞核中快速依赖钙的积累。随后，铝激活的CPK21和CPK23在根尖细胞的细胞质和细胞核中使STOP1磷酸化，通过阻止其与RAE1相互作用来稳定STOP1，最终增强抗铝性。整个过程依赖于钙。该研究揭示了一个以前未公开的调控网络，其中CPK通过Ca-CPK21/23-STOP1级联整合铝诱发的钙信号和转录重编程，以有效响应和适应植物中的铝胁迫。
