植物部署细胞内受体以抵消抑制细胞表面受体介导的免疫的病原体效应子。病原体在多大程度上操纵细胞内受体介导的免疫,以及植物如何应对这种操纵,仍然未知。拟南芥编码三种类似的ADR1类辅助核苷酸结合域富含亮氨酸的重复受体(ADR1,ADR1-L1和ADR1-L2),在由细胞内受体启动的植物免疫中至关重要。这里,我们报道了丁香假单胞菌效应子AvrPtoB抑制ADR1-L1-和ADR1-L2-介导的细胞死亡。然而,ADR1通过使AvrPtoB靶向的两个泛素化位点多样化来逃避这种抑制。细胞内传感器SNC1与ADR1-L1/L2的CCR结构域相互作用并保护它们。去除ADR1-L1/L2或递送AvrPtoB激活SNC1,然后通过ADR1发出信号以触发免疫。我们的工作阐明了SNC1在防御中的长期追求功能,以及植物如何使用双重策略,序列多样化,和一个多层次的警卫系统,抵抗病原体对核心免疫功能的攻击。
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.