Minor Coat and Heat Shock Proteins Are Involved in the Binding of Citrus Tristeza Virus to the Foregut of Its Aphid Vector, Toxoptera citricida
Minor Coat and Heat Shock Proteins Are Involved in the Binding of Citrus Tristeza Virus to the Foregut of Its Aphid Vector, Toxoptera citricida
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DOI：
10.1128/aem.01914-16
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发表时间：
2016-11-01
影响因子：
4.4
通讯作者：
Dawson, W. O.
中科院分区：
文献类型：
--
作者：
Killiny, N.;Harper, S. J.;Dawson, W. O.
媒介传播是病毒生命周期中的一个关键阶段，然而对于大多数植物病毒来说，它们如何与它们的媒介相互作用是未知的，或者通过与先前描述的亲戚进行类比来解释。在这里，我们研究了柑橘衰退病毒（CTV）的传播机制，其蚜虫载体，橘毒蛾，目的是确定它使用什么病毒编码的蛋白质与载体相互作用。使用荧光标记的病毒粒子，我们证明了CTV特异性结合到蚜虫的食饵室的衬里。通过荧光病毒粒子和游离病毒蛋白之间的体外竞争性结合测定，我们确定次要外壳蛋白参与载体相互作用。我们还发现，两个热休克样蛋白，p61和p65的存在下，减少病毒体结合在体外。此外，用蛋白酶处理解剖的口器不影响CTV病毒体的结合。与此相反，几丁质酶处理减少CTV结合到前肠。最后，与葡萄糖、N-乙酰基-β-D-葡糖胺、壳二糖和壳三糖的竞争降低了结合。这些发现共同表明，CTV结合到蚜虫cibarium的表皮表面的糖部分，和结合涉及三个病毒编码的protein.IMPORTANCELimited信息的协同活动是已知的柑橘衰退病毒和蚜虫载体之间的具体相互作用。这些相互作用对于成功传播的过程是重要的。在这项研究中，我们定位的CTV保留网站作为食饵的蚜虫前肠。此外，我们证明了这些相互作用的性质是蛋白质-碳水化合物结合。病毒蛋白，包括次要外壳蛋白和两种热休克蛋白，与前肠表面的糖部分结合。这些研究结果将有助于了解CTV通过蚜虫媒介的传播机制，并可能有助于制定控制策略，干扰CTV与其昆虫媒介的结合，以阻断传播。
Vector transmission is a critical stage in the viral life cycle, yet for most plant viruses how they interact with their vector is unknown or is explained by analogy with previously described relatives. Here we examined the mechanism underlying the transmission of citrus tristeza virus (CTV) by its aphid vector, Toxoptera citricida, with the objective of identifying what virus-encoded proteins it uses to interact with the vector. Using fluorescently labeled virions, we demonstrated that CTV binds specifically to the lining of the cibarium of the aphid. Through in vitro competitive binding assays between fluorescent virions and free viral proteins, we determined that the minor coat protein is involved in vector interaction. We also found that the presence of two heat shock-like proteins, p61 and p65, reduces virion binding in vitro. Additionally, treating the dissected mouthparts with proteases did not affect the binding of CTV virions. In contrast, chitinase treatment reduced CTV binding to the foregut. Finally, competition with glucose, N-acetyl-beta-D-glucosamine, chitobiose, and chitotriose reduced the binding. These findings together suggest that CTV binds to the sugar moieties of the cuticular surface of the aphid cibarium, and the binding involves the concerted activity of three virus-encoded proteins.IMPORTANCELimited information is known about the specific interactions between citrus tristeza virus and its aphid vectors. These interactions are important for the process of successful transmission. In this study, we localized the CTV retention site as the cibarium of the aphid foregut. Moreover, we demonstrated that the nature of these interactions is protein-carbohydrate binding. The viral proteins, including the minor coat protein and two heat shock proteins, bind to sugar moieties on the surface of the foregut. These findings will help in understanding the transmission mechanism of CTV by the aphid vector and may help in developing control strategies which interfere with the CTV binding to its insect vector to block the transmission.