CPK12 decodes effector-triggered calcium signaling and phosphorylates PIP2;1 to facilitate apoplastic ROS transport into the cytoplasm in Arabidopsis

  • Mol Plant. 2025 Oct 6;18(10):1724-1741. doi: 10.1016/j.molp.2025.08.018.
Zhiyi Jia  1 ,  Weiwei Yu  2 ,  Xijie Guo  1 ,  Jianwei Li  1 ,  Fan Qi  2 ,  Yayun Zhu  1 ,  Xinzhong Cai  1 ,  Xiaoting Li  3 ,  Ning Li  3 ,  Hansong Dong  4 ,  Fucheng Lin  5 ,  Yan Liang  6
Affiliations
  • 1. Zhejiang Provincial Key Laboratory of Agricultural Microbiomics, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
  • 2. Zhejiang Provincial Key Laboratory of Agricultural Microbiomics, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Xianghu Laboratory, Hangzhou 311231, China; State Key Laboratory for Quality and Safety of Agro-Products, Key Laboratory of Agricultural Microbiome (MARA), Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
  • 3. Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
  • 4. College of Plant Protection, Shandong Agricultural University, Tai'an 271018, China.
  • 5. Zhejiang Provincial Key Laboratory of Agricultural Microbiomics, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; Xianghu Laboratory, Hangzhou 311231, China; State Key Laboratory for Quality and Safety of Agro-Products, Key Laboratory of Agricultural Microbiome (MARA), Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. Electronic address: [email protected].
  • 6. Zhejiang Provincial Key Laboratory of Agricultural Microbiomics, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China. Electronic address: [email protected].
PMID: 40908644 DOI: 10.1016/j.molp.2025.08.018
Abstract

Effector-triggered immunity (ETI) in Plants is mediated by intracellular nucleotide-binding leucine-rich repeat receptors (NLRs), which converge on calcium (CA2+) signaling pathways. However, how NLR-induced CA2+ signals initiate downstream immune responses, such as enhancing Reactive Oxygen Species (ROS) signaling, remains largely unclear. In this study, we identified a calcium-dependent protein kinase (CPK) that regulates sustained ROS signaling during ETI. We found that, upon Infection with Pseudomonas syringae pv. tomato (Pst) DC3000 (avrRpm1), CPK12 is activated in a CA2+-dependent manner and governs the transport of ETI-ROS from the apoplast to cytoplasm. Both in vitro and in vivo phosphorylation assays revealed that CPK12 phosphorylates the plasma membrane intrinsic protein PIP2;1, thereby enhancing ROS transport and elevating plant resistance to Pst DC3000 (avrRpm1). Taken together, our findings demonstrate that CPK12 deciphers effector-triggered CA2+ signals to regulate ROS compartmentalization, establishing a crucial link between NLR-mediated CA2+ signaling and the spatial control of ROS responses in plant immunity.

Keywords
CPK; NADPH oxidase; ROS production; calcium signal; plant immunity.
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