Rajarapu Swapna Priya, Ben-Mahmoud Sulley, Benoit Joshua B, Ullman Diane E, Whitfield Anna E, Rotenberg Dorith
Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, 27695, USA.
Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA.
Insect Biochem Mol Biol. 2022 Oct;149:103843. doi: 10.1016/j.ibmb.2022.103843. Epub 2022 Sep 14.
Successful transmission of tomato spotted wilt virus (TSWV) by Frankliniella occidentalis requires robust infection of the salivary glands (SGs) and virus delivery to plants during salivation. Feeding behavior and transmission efficiency are sexually-dimorphic traits of this thrips vector species. Proteins secreted from male and female SG tissues, and the effect of TSWV infection on the thrips SG proteome are unknown. To begin to discern thrips factors that facilitate virus infection of SGs and transmission by F. occidentalis, we used gel- and label-free quantitative and qualitative proteomics to address two hypotheses: (i) TSWV infection modifies the composition and/or abundance of SG-expressed proteins in adults; and (ii) TSWV has a differential effect on the male and female SG proteome and secreted saliva. Our study revealed a sex-biased SG proteome for F. occidentalis, and TSWV infection modulated the SG proteome in a sex-dependent manner as evident by the number, differential abundance, identities and generalized roles of the proteins. Male SGs exhibited a larger proteomic response to the virus than female SGs. Intracellular processes modulated by TSWV in males indicated perturbation of SG cytoskeletal networks and cell-cell interactions, i.e., basement membrane (BM) and extracellular matrix (ECM) proteins, and subcellular processes consistent with a metabolic slow-down under infection. Several differentially-abundant proteins in infected male SGs play critical roles in viral life cycles of other host-virus pathosystems. In females, TSWV modulated processes consistent with tissue integrity and active translational and transcriptional regulation. A core set of proteins known for their roles in plant cell-wall degradation and protein metabolism were identified in saliva of both sexes, regardless of virus infection status. Saliva proteins secreted by TSWV-infected adults indicated energy generation, consumption and protein turnover, with an enrichment of cytoskeletal/BM/ECM proteins and tricarboxylic acid cycle proteins in male and female saliva, respectively. The nonstructural TSWV protein NSs - a multifunctional viral effector protein reported to target plant defenses against TSWV and thrips - was identified in female saliva. This study represents the first description of the SG proteome and secretome of a thysanopteran and provides many candidate proteins to further unravel the complex interplay between the virus, insect vector, and plant host.
西花蓟马成功传播番茄斑萎病毒（TSWV）需要唾液腺（SGs）被强烈感染，且在取食时将病毒传递给植物。取食行为和传播效率是这种蓟马传毒介体物种的性别二态性特征。雄性和雌性SG组织分泌的蛋白质，以及TSWV感染对蓟马SG蛋白质组的影响尚不清楚。为了开始识别促进SGs病毒感染和西花蓟马传播的蓟马因子，我们使用了凝胶和无标记定量及定性蛋白质组学来验证两个假设：（i）TSWV感染会改变成虫中SG表达蛋白的组成和/或丰度；（ii）TSWV对雄性和雌性SG蛋白质组及分泌唾液有不同影响。我们的研究揭示了西花蓟马性别偏向的SG蛋白质组，TSWV感染以性别依赖的方式调节SG蛋白质组，这从蛋白质的数量、差异丰度、身份和一般作用中可以明显看出。雄性SGs对病毒的蛋白质组反应比雌性SGs更大。TSWV在雄性中调节的细胞内过程表明SG细胞骨架网络和细胞间相互作用受到干扰，即基底膜（BM）和细胞外基质（ECM）蛋白，以及与感染下代谢减缓一致的亚细胞过程。感染的雄性SGs中几种差异丰富的蛋白质在其他宿主 - 病毒病理系统的病毒生命周期中起关键作用。在雌性中，TSWV调节的过程与组织完整性以及活跃的翻译和转录调控一致。无论病毒感染状态如何，在两性的唾液中都鉴定出一组以在植物细胞壁降解和蛋白质代谢中发挥作用而闻名的核心蛋白质。TSWV感染的成虫分泌的唾液蛋白表明能量产生、消耗和蛋白质周转，雄性和雌性唾液中分别富集细胞骨架/BM/ECM蛋白和三羧酸循环蛋白。在雌性唾液中鉴定出了非结构TSWV蛋白NSs——一种多功能病毒效应蛋白，据报道它靶向植物对TSWV和蓟马的防御。这项研究首次描述了缨翅目昆虫的SG蛋白质组和分泌蛋白质组，并提供了许多候选蛋白，以进一步揭示病毒、昆虫介体和植物宿主之间的复杂相互作用。
