Zhong Chenchen, Li Wenli, Zhang Xinyu, Zhang Dingliang, Wen Zhiyan, Song Wen, Jiang Zhihao, Gao Zongyu, Guo Hailong, Bi Guozhi, Liu Zhiyong, Li Dawei, Dinesh-Kumar Savithramma P, Zhang Yongliang
State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing, China.
Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.
Nat Plants. 2025 Mar;11(3):561-579. doi: 10.1038/s41477-025-01949-3. Epub 2025 Mar 21.
Plants deploy intracellular nucleotide-binding leucine-rich repeats (NLRs) to detect pathogen effectors and initiate immune responses. Although the activation mechanism of some plant NLRs forming resistosomes has been elucidated, whether NLR resistosome assembly is regulated to fine-tune immunity remains enigmatic. Here we used an antiviral coiled coil-nucleotide-binding site-leucine rich repeat, Barley Stripe Resistance 1 (BSR1), as a model and demonstrate that BSR1 is phosphorylated. Using a proximity labelling approach, we identified a wall-associated kinase-like protein 20 (WAKL20) which negatively regulates BSR1-mediated immune responses by directly phosphorylating the Ser470 residue in the NB-ARC domain of BSR1. Mechanistically, Ser470 phosphorylation results in a steric clash of intramolecular domains of BSR1, thereby compromising BSR1 oligomerization. The phosphorylation site is conserved among multiple plant NLRs and our results show that WAKL20 participates in other NLR-mediated immune responses besides BSR1. Together, our data reveal phosphorylation as a mechanism for modulating plant resistosome assembly, and provide new insight into NLR-mediated plant immunity.
植物利用细胞内核苷酸结合富含亮氨酸重复序列（NLRs）来检测病原体效应子并启动免疫反应。尽管一些形成抗病小体的植物NLRs的激活机制已经阐明，但NLR抗病小体的组装是否受到调控以微调免疫反应仍然是个谜。在这里，我们使用一种抗病毒的卷曲螺旋-核苷酸结合位点-富含亮氨酸重复序列，大麦条纹抗性1（BSR1）作为模型，并证明BSR1被磷酸化。使用邻近标记方法，我们鉴定出一种壁相关激酶样蛋白20（WAKL20），它通过直接磷酸化BSR1的NB-ARC结构域中的Ser470残基来负向调节BSR1介导的免疫反应。从机制上讲，Ser470磷酸化导致BSR1分子内结构域的空间冲突，从而损害BSR1的寡聚化。磷酸化位点在多种植物NLRs中是保守的，我们的结果表明WAKL20除了参与BSR1介导的免疫反应外，还参与其他NLR介导的免疫反应。总之，我们的数据揭示了磷酸化是调节植物抗病小体组装的一种机制，并为NLR介导的植物免疫提供了新的见解。
