Activation of Toll Immune Pathway in an Insect Vector Induced by a Plant Virus.
Activation of Toll Immune Pathway in an Insect Vector Induced by a Plant Virus.
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植物病毒诱导昆虫Toll免疫通路的激活
DOI：
10.3389/fimmu.2020.613957
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发表时间：
2020
影响因子：
7.3
通讯作者：
Li JM
中科院分区：
文献类型：
--
作者：
He YJ;Lu G;Qi YH;Zhang Y;Zhang XD;Huang HJ;Zhuo JC;Sun ZT;Yan F;Chen JP;Zhang CX;Li JM
Toll途径在防御包括病毒在内的各种病原微生物感染中起重要作用。目前对Toll信号通路的研究主要局限于哺乳动物和果蝇、蚊子等模式昆虫。植物病毒是否也能激活病媒昆虫中的Toll信号通路仍然是未知的。本研究以水稻条纹病毒（rice stripe virus，RSV）及其昆虫载体灰飞虱（Laodelphax striatellus）为模型，发现Toll途径在RSV感染后被激活。在含病毒和非含病毒的稻飞虱的比较中，我们发现四个Toll途径核心基因（Toll，Tube，MyD88和Dorsal）在含病毒的稻飞虱中上调。当稻飞虱感染RSV后，Toll和MyD88的表达在早期（感染后1和3天）迅速上调，而Dorsal的表达在后期（感染后9天）上调。此外，Toll途径的诱导是通过Toll受体与RSV核衣壳蛋白（NP）之间的相互作用启动的。Toll基因的敲除增加了RSV在昆虫体内的增殖，dsToll处理的昆虫比dsGFP处理的昆虫表现出更高的死亡率。我们的研究结果首次证明了昆虫介体的Toll信号通路可能通过Toll受体与植物病毒编码的蛋白质之间的直接相互作用而被激活，表明Toll免疫通路是昆虫介体抵抗植物病毒感染的重要策略。
The Toll pathway plays an important role in defense against infection of various pathogenic microorganisms, including viruses. However, current understanding of Toll pathway was mainly restricted in mammal and some model insects such as Drosophila and mosquitoes. Whether plant viruses can also activate the Toll signaling pathway in vector insects is still unknown. In this study, using rice stripe virus (RSV) and its insect vector (small brown planthopper, Laodelphax striatellus) as a model, we found that the Toll pathway was activated upon RSV infection. In comparison of viruliferous and non-viruliferous planthoppers, we found that four Toll pathway core genes (Toll, Tube, MyD88, and Dorsal) were upregulated in viruliferous planthoppers. When the planthoppers infected with RSV, the expressions of Toll and MyD88 were rapidly upregulated at the early stage (1 and 3 days post-infection), whereas Dorsal was upregulated at the late stage (9 days post-infection). Furthermore, induction of Toll pathway was initiated by interaction between a Toll receptor and RSV nucleocapsid protein (NP). Knockdown of Toll increased the proliferation of RSV in vector insect, and the dsToll-treated insects exhibited higher mortality than that of dsGFP-treated ones. Our results provide the first evidence that the Toll signaling pathway of an insect vector is potentially activated through the direct interaction between Toll receptor and a protein encoded by a plant virus, indicating that Toll immune pathway is an important strategy against plant virus infection in an insect vector.