BGPI, Université de Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France.
Université de Lyon, INSA-Lyon, INRA, BF2I, UMR0203, Villeurbanne, France.
J Virol. 2018 Jun 29;92(14). doi: 10.1128/JVI.00432-18. Print 2018 Jul 15.
Plant viruses transmitted by insects cause tremendous losses in most important crops around the world. The identification of receptors of plant viruses within their insect vectors is a key challenge to understanding the mechanisms of transmission and offers an avenue for future alternative control strategies to limit viral spread. We here report the identification of two cuticular proteins within aphid mouthparts, and we provide experimental support for the role of one of them in the transmission of a noncirculative virus. These two proteins, named Stylin-01 and Stylin-02, belong to the RR-1 cuticular protein subfamily and are highly conserved among aphid species. Using an immunolabeling approach, they were localized in the maxillary stylets of the pea aphid and the green peach aphid , in the acrostyle, an organ earlier shown to harbor receptors of a noncirculative virus. A peptide motif present at the C termini of both Stylin-01 and Stylin-02 is readily accessible all over the surface of the acrostyle. Competition for binding to the acrostyle was observed between an antibody targeting this peptide and the helper component protein P2 of Furthermore, silencing the but not gene through RNA interference decreased the efficiency of transmission by These results identify the first cuticular proteins ever reported within arthropod mouthparts and distinguish Stylin-01 as the best candidate receptor for the aphid transmission of noncirculative plant viruses. Most noncirculative plant viruses transmitted by insect vectors bind to their mouthparts. They are acquired and inoculated within seconds when insects hop from plant to plant. The receptors involved remain totally elusive due to a long-standing technical bottleneck in working with insect cuticle. Here we characterize the role of the two first cuticular proteins ever identified in arthropod mouthparts. A domain of these proteins is directly accessible at the surface of the cuticle of the acrostyle, an organ at the tip of aphid stylets. The acrostyle has been shown to bind a plant virus, and we consistently demonstrated that one of the identified proteins is involved in viral transmission. Our findings provide an approach to identify proteins in insect mouthparts and point at an unprecedented gene candidate for a plant virus receptor.
植物病毒通过昆虫传播，给世界上大多数重要作物造成巨大损失。鉴定昆虫媒介中植物病毒的受体是理解传播机制的关键挑战，也为未来限制病毒传播的替代控制策略提供了途径。我们在此报告在蚜虫口器中鉴定到两种表皮蛋白，并为其中一种在非循回病毒传播中的作用提供了实验支持。这两种名为 Stylin-01 和 Stylin-02 的蛋白属于 RR-1 表皮蛋白亚家族，在蚜虫物种中高度保守。使用免疫标记方法，它们在豌豆蚜和绿桃蚜的上颌刺上以及触角原基中被定位，触角原基是先前被证明含有非循回病毒受体的一个器官。在 Stylin-01 和 Stylin-02 的 C 末端存在的一个肽基序在触角原基的整个表面都很容易接近。针对该肽基序的抗体与辅助成分蛋白 P2 竞争结合触角原基时，观察到了竞争结合。此外，通过 RNA 干扰沉默 但不沉默 基因降低了 的传播效率 。这些结果鉴定了首次在节肢动物口器中报告的表皮蛋白，并将 Stylin-01 鉴定为非循回植物病毒在蚜虫中的最佳候选受体。大多数由昆虫媒介传播的非循回植物病毒都与它们的口器结合。当昆虫从一株植物跳到另一株植物时，它们在几秒钟内被获取并接种。由于昆虫表皮处理方面的长期技术瓶颈，涉及的受体仍然完全难以捉摸。在这里，我们描述了首次在节肢动物口器中鉴定到的两种表皮蛋白的作用。这些蛋白的一个结构域在触角原基的表皮表面直接可及，触角原基是蚜虫刺的顶端的一个器官。已经证明触角原基可以结合一种植物病毒，我们一致证明鉴定到的一种蛋白参与了病毒的传播。我们的研究结果提供了一种在昆虫口器中鉴定蛋白的方法，并指出了一个前所未有的植物病毒受体候选基因。
