Department of Entomology, National Taiwan University, Taipei, Taiwan.
Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung, Taiwan.
PLoS One. 2021 Mar 3;16(3):e0247500. doi: 10.1371/journal.pone.0247500. eCollection 2021.
Thrips and thrips-transmitted tospoviruses cause significant losses in crop yields worldwide. The melon thrips (Thrips palmi) is not only a pest of cucurbit crops, but also a vector that transmits tospoviruses, such as the watermelon silver mottle virus (WSMoV). Vector transmission of tospoviruses has been well studied in the tomato spotted wilt virus (TSWV)-Frankliniella occidentalis model system; however, until now the transmission mode of WSMoV by T. palmi has not been sufficiently examined. The results of the transmission assays suggest that T. palmi transmits WSMoV in a persistent manner, and that the virus is mainly transmitted by adults, having been ingested at the first-instar larval stage. Complementary RNAs corresponding to the NSm and NSs genes of WSMoV were detected in viruliferous thrips by reverse transcription-polymerase chain reaction; NSs protein was also detected in viruliferous thrips by western blotting, verifying the replication of WSMoV in T. palmi. Furthermore, we demonstrated that in thrips infected with WSMoV at the first-instar larval stage, the virus eventually infected various tissues of the adult thrips, including the primary salivary glands. Taken together, these results suggest that T. palmi transmits WSMoV in a persistent-propagative mode. The results of this study make a significant contribution to the understanding of the transmission biology of tospoviruses in general.
蓟马和蓟马传播的番茄斑萎病毒会在全球范围内导致作物产量的重大损失。瓜蓟马不仅是葫芦科作物的害虫，还是一种传播番茄斑萎病毒的媒介，如西瓜银斑驳病毒（WSMoV）。番茄斑萎病毒在番茄斑萎病毒-西方盲走甲模型系统中的媒介传播已经得到了很好的研究；然而，到目前为止，WSMoV 由瓜蓟马传播的模式还没有得到充分的研究。传播试验的结果表明，瓜蓟马以持续的方式传播 WSMoV，并且病毒主要通过成虫传播，在第一龄幼虫期就已经被摄入。通过反转录-聚合酶链反应，在带毒蓟马中检测到了 WSMoV 的 NSm 和 NSs 基因的互补 RNA；通过 Western blot，在带毒蓟马中也检测到了 NSs 蛋白，验证了 WSMoV 在瓜蓟马中的复制。此外，我们证明了在第一龄幼虫期感染 WSMoV 的蓟马中，病毒最终感染了成年蓟马的各种组织，包括初级唾液腺。综上所述，这些结果表明，瓜蓟马以持续增殖的方式传播 WSMoV。本研究的结果对理解番茄斑萎病毒的传播生物学有重要贡献。
