Sessile plants encode a large number of small peptides and cell surface-resident receptor kinases, most of which have unknown functions. Here, we report that the Arabidopsis receptor kinase MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) recognizes the conserved signature motif of SERINE-RICH ENDOGENOUS PEPTIDEs (SCOOPs) from Brassicaceae plants as well as proteins present in fungal Fusarium spp. and bacterial Comamonadaceae, and elicits various immune responses. SCOOP signature peptides trigger immune responses and altered root development in a MIK2-dependent manner with a sub-nanomolar sensitivity. SCOOP12 directly binds to the extracellular leucine-rich repeat domain of MIK2 in vivo and in vitro, indicating that MIK2 is the receptor of SCOOP peptides. Perception of SCOOP peptides induces the association of MIK2 and the coreceptors SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3 (SERK3) and SERK4 and relays the signaling through the cytosolic receptor-like kinases BOTRYTIS-INDUCED KINASE 1 (BIK1) and AVRPPHB SUSCEPTIBLE1 (PBS1)-LIKE 1 (PBL1). Our study identifies a plant receptor that bears a dual role in sensing the conserved peptide motif from phytocytokines and microbial proteins via a convergent signaling relay to ensure a robust immune response.

无柄植物编码大量小肽和细胞表面驻留受体激酶，其中大部分功能未知。在这里，我们报告拟南芥受体激酶 MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) 识别来自十字花科植物的富含丝氨酸的内源性肽 (SCOOPs)以及真菌镰刀菌属中存在的蛋白质的保守特征基序。和细菌菊科，并引发各种免疫反应。SCOOP 特征肽以亚纳摩尔灵敏度以 MIK2 依赖性方式触发免疫反应和改变根发育。SCOOP12 在体内和体外直接结合 MIK2 的细胞外富含亮氨酸的重复结构域，表明 MIK2 是 SCOOP 肽的受体。SCOOP 肽的感知诱导 MIK2 与辅助受体 SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3 (SERK3) 和 SERK4 的结合，并通过细胞溶质受体样激酶BOTRYTIS传递信号-诱导激酶 1 (BIK1) 和 AVRPPHB SUSCEPTIBLE1 (PBS1)-LIKE 1 (PBL1)。我们的研究确定了一种植物受体，该受体在通过会聚信号中继感知来自植物细胞因子和微生物蛋白质的保守肽基序方面具有双重作用，以确保强大的免疫反应。