State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.
Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, Davis, CA, 95616, USA.
Nat Commun. 2022 Feb 7;13(1):716. doi: 10.1038/s41467-022-28395-5.
Mitogen-activated protein kinase (MAPK) cascades play an important role in innate immunity against various pathogens in plants and animals. However, we know very little about the importance of MAPK cascades in plant defense against viral pathogens. Here, we used a positive-strand RNA necrovirus, beet black scorch virus (BBSV), as a model to investigate the relationship between MAPK signaling and virus infection. Our findings showed that BBSV infection activates MAPK signaling, whereas viral coat protein (CP) counteracts MAPKKKα-mediated antiviral defense. CP does not directly target MAPKKKα, instead it competitively interferes with the binding of 14-3-3a to MAPKKKα in a dose-dependent manner. This results in the instability of MAPKKKα and subversion of MAPKKKα-mediated antiviral defense. Considering the conservation of 14-3-3-binding sites in the CPs of diverse plant viruses, we provide evidence that 14-3-3-MAPKKKα defense signaling module is a target of viral effectors in the ongoing arms race of defense and viral counter-defense.
丝裂原活化蛋白激酶（MAPK）级联反应在动植物对各种病原体的先天免疫中起着重要作用。然而，我们对 MAPK 级联反应在植物抗病毒防御中的重要性知之甚少。在这里，我们使用正链 RNA 坏死病毒甜菜黑线 scorch 病毒（BBSV）作为模型，研究了 MAPK 信号与病毒感染之间的关系。我们的研究结果表明，BBSV 感染激活了 MAPK 信号通路，而病毒外壳蛋白（CP）则拮抗 MAPKKKα 介导的抗病毒防御。CP 并不直接靶向 MAPKKKα，而是以剂量依赖的方式竞争性地干扰 14-3-3a 与 MAPKKKα 的结合。这导致 MAPKKKα 的不稳定性和 MAPKKKα 介导的抗病毒防御的颠覆。考虑到不同植物病毒 CP 中 14-3-3 结合位点的保守性，我们提供了证据表明，14-3-3-MAPKKKα 防御信号模块是防御和病毒反防御持续军备竞赛中病毒效应子的靶标。
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