Phytophthora species are the most destructive plant pathogens worldwide and the main threat to agricultural and natural ecosystems; however, their pathogenic mechanism remains largely unknown. Here, we show that Avh113 effector is required for the virulence of Phytophthora sojae and is important for development of Phytophthora root and stem rot (PRSR) in soybean (Glycine max). Ectopic expression of PsAvh113 enhanced viral and Phytophthora infection in Nicotiana benthamiana. PsAvh113 directly associated with the soybean transcription factor GmDPB, inducing its degradation by the 26S proteasome. The internal repeat 2 (IR2) motif of PsAvh113 was important for its virulence and interaction with GmDPB, while silencing and overexpression of GmDPB in soybean hairy roots altered the resistance to P. sojae. Upon binding to GmDPB, PsAvh113 decreased the transcription of the downstream gene GmCAT1, which acts as a positive regulator of plant immunity. Furthermore, we revealed that PsAvh113 suppressed the GmCAT1-induced cell death by associating with GmDPB, thereby enhancing plant susceptibility to Phytophthora. Together, our findings reveal a vital role of PsAvh113 in inducing PRSR in soybean and offer a novel insight into the interplay between defence and counter-defence during the P. sojae infection of soybean.

中文翻译：

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大豆疫霉效应子 PsAvh113 与大豆转录因子 GmDPB 结合抑制过氧化氢酶介导的免疫

疫霉属物种是全世界最具破坏性的植物病原体，也是对农业和自然生态系统的主要威胁；然而，它们的致病机制仍然很大程度上未知。在这里，我们表明 Avh113 效应子是大豆疫霉(Phytophthora sojae)毒力所必需的，并且对于大豆 ( Glycine max )疫霉根茎腐病 (PRSR)的发展很重要。PsAvh113的异位表达增强了本塞姆氏烟草的病毒和疫霉感染。PsAvh113 与大豆转录因子 GmDPB 直接相关，诱导其被 26S 蛋白酶体降解。PsAvh113 的内部重复 2 (IR2) 基序对其毒力和与 GmDPB 的相互作用非常重要，而大豆毛状根中GmDPB的沉默和过度表达改变了对酱油腐病菌的抗性。与 GmDPB 结合后，PsAvh113 降低了下游基因GmCAT1的转录，该基因充当植物免疫的正调节因子。此外，我们发现 PsAvh113通过与 GmDPB 结合抑制GmCAT1诱导的细胞死亡，从而增强植物对疫霉的敏感性。总之，我们的研究结果揭示了 PsAvh113 在诱导大豆 PRSR 中的重要作用，并为大豆P. sojae感染期间防御和反防御之间的相互作用提供了新的见解。