Small RNA-mediated RNA silencing is an important antiviral mechanism in higher plants. It has been shown that RNA silencing components can be upregulated by viral infection. However, the mechanisms underlying the upregulation remain largely unknown. Here, we show that jasmonate (JA) signaling transcriptionally activates Argonaute 18 (AGO18), a core RNA silencing component that promotes rice antiviral defense through sequestering miR168 and miR528, which repress key antiviral defense proteins. Mechanistically, the JA-responsive transcription factor JAMYB directly binds to the AGO18 promoter to activate AGO18 transcription. Rice stripe virus (RSV) coat protein (CP) triggers JA accumulation and upregulates JAMYB to initiate this host defense network. Our study reveals that regulatory crosstalk exists between the JA signaling and antiviral RNA silencing pathways and elucidates a molecular mechanism for CP-mediated viral resistance in monocot crops.

小 RNA 介导的 RNA 沉默是高等植物中重要的抗病毒机制。已经表明 RNA 沉默成分可以被病毒感染上调。然而，上调背后的机制在很大程度上仍然未知。在这里，我们表明茉莉酸酯 （JA） 信号转导转录激活 Argonaute 18 （AGO18），这是一种核心 RNA 沉默成分，通过隔离抑制关键抗病毒防御蛋白的 miR168 和 miR528 来促进水稻抗病毒防御。从机制上讲，JA 反应性转录因子 JAMYB 直接与 AGO18 启动子结合以激活 AGO18 转录。水稻条纹病毒 （RSV） 外壳蛋白 （CP） 触发 JA 积累并上调 JAMYB 以启动该宿主防御网络。我们的研究表明，JA 信号传导和抗病毒 RNA 沉默途径之间存在调节串扰，并阐明了单子叶植物作物中 CP 介导的病毒抗性的分子机制。