Extracellular vesicles (EVs) are important for cell-to-cell communication in animals. EVs also play important roles in plant–microbe interactions, but the underlying mechanisms remain elusive. Here, proteomic analyses of EVs from the soybean (Glycine max) root rot pathogen Phytophthora sojae identify the tetraspanin family proteins PsTET1 and PsTET3, which are recognized by Nicotiana benthamiana to trigger plant immune responses. Both proteins are required for the full virulence of P. sojae. The large extracellular loop (EC2) of PsTET3 is the key region recognized by N. benthamiana and soybean cells in a plant receptor-like kinase NbSERK3a/b dependent manner. TET proteins from oomycete and fungal plant pathogens are recognized by N. benthamiana thus inducing immune responses, whereas plant-derived TET proteins are not due to the sequence divergence of sixteen amino acids at the C-terminal of EC2. This feature allows plants to distinguish self and non-self EVs to trigger active defense responses against pathogenic eukaryotes.

细胞外囊泡（EV）对于动物细胞间的通讯非常重要。 EV 在植物与微生物的相互作用中也发挥着重要作用，但其潜在机制仍然难以捉摸。在这里，对来自大豆 ( Glycine max ) 根腐病病原体大豆疫霉(Phytophthora sojae ) 的 EV 进行蛋白质组学分析，鉴定出四跨膜蛋白家族蛋白 PsTET1 和 PsTET3，它们被本塞姆氏烟草识别以触发植物免疫反应。这两种蛋白质都是酱油假单胞菌充分发挥毒力所必需的。 PsTET3 的大细胞外环 (EC2) 是本塞姆氏烟草和大豆细胞以植物受体样激酶 NbSERK3a/b 依赖性方式识别的关键区域。来自卵菌和真菌植物病原体的 TET 蛋白可被本塞姆氏烟草识别，从而诱导免疫反应，而植物源性 TET 蛋白则不是由于 EC2 C 末端 16 个氨基酸的序列差异所致。这一功能使植物能够区分自体和非自体 EV，从而触发针对致病真核生物的主动防御反应。