The plant immune receptor SNC1 monitors helper NLRs targeted by a bacterial effector

• Published in: Cell host & microbe 2023-11, Vol.31 (11), p.1792-1803.e7
• Main Authors: Wang, Ming-Yu, Chen, Jun-Bin, Wu, Rui, Guo, Hai-Long, Chen, Yan, Li, Zhen-Ju, Wei, Lu-Yang, Liu, Chuang, He, Sheng-Feng, Du, Mei-Da, Guo, Ya-long, Peng, You-Liang, Jones, Jonathan D.G., Weigel, Detlef, Huang, Jian-Hua, Zhu, Wang-Sheng
• Format: Article
• Language: English
• ISSN: 1931-3128; 1934-6069
• DOI: 10.1016/j.chom.2023.10.006

Plants deploy intracellular receptors to counteract pathogen effectors that suppress cell-surface-receptor-mediated immunity. To what extent pathogens manipulate intracellular receptor-mediated immunity, and how plants tackle such manipulation, remains unknown. Arabidopsis thaliana encodes three similar ADR1 class helper nucleotide-binding domain leucine-rich repeat receptors (ADR1, ADR1-L1, and ADR1-L2), which are crucial in plant immunity initiated by intracellular receptors. Here, we report that Pseudomonas syringae effector AvrPtoB suppresses ADR1-L1- and ADR1-L2-mediated cell death. ADR1, however, evades such suppression by diversifying into two ubiquitination sites targeted by AvrPtoB. The intracellular sensor SNC1 interacts with and guards the CCR domains of ADR1-L1/L2. Removal of ADR1-L1/L2 or delivery of AvrPtoB activates SNC1, which then signals through ADR1 to trigger immunity. Our work elucidates the long-sought-after function of SNC1 in defense, and also how plants can use dual strategies, sequence diversification, and a multi-layered guard-guardee system, to counteract pathogen's attack on core immunity functions.