Sun Yujia, Gao Lei, Han Yiping, Feng Changxin, Liu Zebin, Li Chunyan, Dong Yuxin, Yin Shuxin, Liu Laihao, Yang Ming, Niu Qi, Kong Dongdong, Liu Liangyu, Zhang Jingbo, Tian Wang, Luan Sheng, Li Legong, Hou Congcong
College of Life Sciences, Capital Normal University, and Beijing Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Beijing 100048, China.
State Key Laboratory of Nutrient Use and Management, College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, China Agricultural University, Beijing 100193, China.
Mol Plant. 2025 Jul 7;18(7):1130-1142. doi: 10.1016/j.molp.2025.06.001. Epub 2025 Jun 4.
Extracellular adenosine triphosphate (eATP) functions as a damage-associated molecular pattern in plant immunity. P2K1, a purinergic receptor with a cytoplasmic serine/threonine kinase domain, initiates ATP-responsive signaling cascades characterized by a rapid spike in cytosolic Ca²⁺, which acts as a critical second messenger. In this study, we identified the cyclic nucleotide-gated channel complex CNGC2-CNGC4 as essential for eATP-induced calcium signaling and bacterial resistance in plants. A biochemical link between eATP perception and CNGC2-CNGC4 function was established by demonstrating the physical association between the channel complex and the eATP receptor P2K1 at the plasma membrane. Furthermore, we discovered that P2K1 phosphorylates the CNGC2 subunit of the CNGC2-CNGC4 channel in response to eATP, establishing a phosphorylation-dependent mechanism that connects eATP perception to calcium influx. Through AlphaFold-Multimer prediction, electrophysiological assay, and genetic analysis, we identified serine residues S705 and S718 in CNGC2 as the key phosphorylation sites mediating P2K1-dependent channel activation and eATP-triggered immunity. Notably, P2K1 selectively phosphorylates CNGC2, in contrast to BIK1 that phosphorylates CNGC4 during pathogen-associated molecular pattern-triggered immunity. Together, these findings indicate that the CNGC2-CNGC4 channel complex serves as a core component of calcium-dependent plant immunity, with distinct kinases phosphorylating different subunits in response to specific immune elicitors.
细胞外三磷酸腺苷（eATP）在植物免疫中作为一种损伤相关分子模式发挥作用。P2K1是一种具有细胞质丝氨酸/苏氨酸激酶结构域的嘌呤能受体，它启动以胞质Ca²⁺快速峰值为特征的ATP响应信号级联反应，Ca²⁺作为关键的第二信使。在本研究中，我们确定环核苷酸门控通道复合体CNGC2 - CNGC4对植物中eATP诱导的钙信号传导和细菌抗性至关重要。通过证明通道复合体与质膜上的eATP受体P2K1之间的物理关联，建立了eATP感知与CNGC2 - CNGC4功能之间的生化联系。此外，我们发现P2K1在eATP作用下使CNGC2 - CNGC4通道的CNGC2亚基磷酸化，建立了一种将eATP感知与钙内流联系起来的磷酸化依赖性机制。通过AlphaFold - Multimer预测、电生理分析和遗传分析，我们确定CNGC2中的丝氨酸残基S705和S718是介导P2K1依赖性通道激活和eATP触发免疫的关键磷酸化位点。值得注意的是，与在病原体相关分子模式触发的免疫过程中使CNGC4磷酸化的BIK1不同，P2K1选择性地使CNGC2磷酸化。总之，这些发现表明CNGC2 - CNGC4通道复合体是钙依赖性植物免疫的核心组成部分，不同的激酶响应特定的免疫激发子使不同的亚基磷酸化。
