Key message

NbWRKY22 and NbWRKY25 are required for full activation of bacteria-associated pattern- and effector-triggered immunity as well as for the response to other non-bacterial defense elicitors.

Abstract

Plants defend themselves against pathogens using a two-layered immune system. Pattern-triggered immunity (PTI) can be activated upon recognition of epitopes from flagellin including flg22. Pseudomonas syringae pv. tomato (Pst) delivers effector proteins into the plant cell to promote host susceptibility. However, some plants express resistance (R) proteins that recognize specific effectors leading to the activation of effector-triggered immunity (ETI). Resistant tomato lines such as Rio Grande-PtoR (RG-PtoR) recognize two Pst effectors, AvrPto and AvrPtoB, and activate ETI through the Pto/Prf protein complex. Using RNA-seq, we identified two tomato WRKY transcription factor genes, SlWRKY22 and SlWRKY25, whose expression is increased during Pst-induced ETI. Silencing of the WRKY25/22 orthologous genes in Nicotiana benthamiana led to a delay in programmed cell death normally associated with AvrPto recognition or several non-bacterial effector/R protein pairs. An increase in disease symptoms was observed in silenced plants infiltrated with Pseudomonas syringae pv. tabaci expressing AvrPto or HopQ1-1. Expression of both tomato WRKY genes is also induced upon treatment with flg22 and callose deposition and cell death suppression assays in WRKY25/22-silenced N. benthamiana plants supported their involvement in PTI. Our results reveal an important role for two WRKYs as positive regulators of plant immunity against bacterial and potentially non-bacterial pathogens.

中文翻译：

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WRKY22 和 WRKY25 转录因子是本氏烟草防御反应的正调节因子。

关键信息

NbWRKY22 和 NbWRKY25 是完全激活与细菌相关的模式和效应器触发的免疫以及对其他非细菌防御引发剂的反应所必需的。

抽象的

植物使用两层免疫系统保护自己免受病原体的侵害。模式触发免疫 (PTI) 可在识别来自鞭毛蛋白（包括 flg22）的表位后被激活。丁香假单胞菌光伏。番茄( Pst ) 将效应蛋白输送到植物细胞中以促进宿主易感性。然而，一些植物表达的抗性 (R) 蛋白可识别特定效应子，从而激活效应子触发的免疫 (ETI)。Rio Grande-PtoR (RG-PtoR) 等抗性番茄系可识别两种Pst效应器 AvrPto 和 AvrPtoB，并通过 Pto/Prf 蛋白复合物激活 ETI。使用 RNA-seq，我们鉴定了两个番茄 WRKY 转录因子基因，SlWRKY22和SlWRKY25，其表达在Pst诱导的 ETI 期间增加。本氏烟草中WRKY25/22直系同源基因的沉默导致程序性细胞死亡延迟，这通常与 AvrPto 识别或几个非细菌效应器/R 蛋白对相关。在用Pseudomonas syringae pv浸润的沉默植物中观察到疾病症状的增加。表达 AvrPto 或 HopQ1-1 的烟粉虱。在WRKY25/22沉默的本氏烟草中，在用 flg22 和胼胝质沉积和细胞死亡抑制试验处理后，两种番茄WRKY基因的表达也被诱导。植物支持他们参与 PTI。我们的研究结果揭示了两种 WRKY 作为植物对细菌和潜在非细菌病原体免疫的正调节剂的重要作用。