Barley stripe mosaic virus infection requires PKA-mediated phosphorylation of γb for suppression of both RNA silencing and the host cell death response
Barley stripe mosaic virus infection requires PKA-mediated phosphorylation of γb for suppression of both RNA silencing and the host cell death response
复制标题
大麦条纹花叶病毒感染需要 PKA 介导的 β 磷酸化来抑制 RNA 沉默和宿主细胞死亡反应
DOI：
10.1111/nph.15065
复制
发表时间：
2018
期刊：
影响因子：
9.4
通讯作者：
Li Dawei
中科院分区：
文献类型：
--
作者：
Zhang Xuan;Dong Kai;Xu Kai;Zhang Kun;Jin Xuejiao;Yang Meng;Zhang Yongliang;Wang Xianbing;Han Chenggui;Yu Jialin;Li Dawei
大麦条纹花叶病毒(BSMV) γ - b蛋白是一种RNA沉默（VSR）病毒抑制因子和症状决定因子。然而，目前尚不清楚翻译后修饰如何影响γ - b的不同功能。在这里，我们证明了γb在Ser - 96位点被PKA -样激酶在体内和体外磷酸化。含有非磷酸化取代的突变病毒（BSMVS96Aor BSMVS96R）由于短暂诱导细胞死亡反应将病毒限制在坏死区域，因此在烟碱苯胺中表现出减少的病毒积累。相比之下，模仿γ - b磷酸化的bsmvs96d突变病毒的传播与野生型病毒相似。此外，S96A突变体由于破坏了其与21 bp dsRNA的结合活性，降低了局部和全身γb VSR活性。然而，其他VSRsin - transorin的过表达未能挽救BSMVS96A诱导的坏死，这表明γ - b磷酸化对细胞死亡的抑制在功能上不同于其RNA沉默抑制活性。这些结果为γ - b磷酸化在调控RNA沉默和BSMV诱导的宿主细胞死亡反应中的功能提供了新的见解，并有助于我们了解病毒在感染宿主植物时如何优化病毒复制和病毒存活之间的平衡。
TheBarley stripe mosaic virus(BSMV) γb protein is a viral suppressor of RNA silencing (VSR) and symptom determinant. However, it is unclear how post‐translational modification affects the different functions of γb.Here, we demonstrate that γb is phosphorylated at Ser‐96 by a PKA‐like kinasein vivoandin vitro. Mutant viruses containing a nonphosphorylatable substitution (BSMVS96Aor BSMVS96R) exhibited reduced viral accumulation inNicotiana benthamianadue to transient induction of the cell death response that constrained the virus to necrotic areas. By contrast, a BSMVS96Dmutant virus that mimics γb phosphorylation spread similarly to the wild‐type virus.Furthermore, the S96A mutant had reduced local and systemic γb VSR activity due to having compromised its binding activity to 21‐bp dsRNA. However, overexpression of other VSRsin transorin cisfailed to rescue the necrosis induced by BSMVS96A, demonstrating that suppression of cell death by γb phosphorylation is functionally distinct from its RNA silencing suppressor activities.These results provide new insights into the function of γb phosphorylation in regulating RNA silencing and the BSMV‐induced host cell death response, and contribute to our understanding of how the virus optimizes the balance between viral replication and virus survival in the host plants during virus infection.