中国学者在PLOS子刊发布植物病毒介体昆虫的卵传新机制

植物病毒大都由介体昆虫传播，该传播过程并非简单地携带和制造侵染伤口，而是具有一定的特异性，即某种病毒只能由某种或某几种昆虫传播，而某种昆虫只能传播某种或某几种病毒。根据昆虫传播的特点又将传播分为持久性传播和非持久性传播等。因此，介体昆虫在获毒和传毒过程中涉及多种互作机制。

水稻条纹叶枯病毒引起的水稻条纹叶枯病对水稻生产造成严重的危害。该病毒由灰飞虱传播，病毒可在灰飞虱体内生存，繁殖并能经过昆虫卵传播至后代昆虫体内。

霍岩等对该病毒的卵传机制进行了深入的研究，结果发现，病毒巧妙地利用昆虫的卵黄蛋白原受体进入昆虫卵巢生殖区的滋养细胞中，再通过连接滋养细胞和卵母细胞的滋养丝进入到昆虫的卵母细胞中，最终侵染后代昆虫。其它可卵传植物病毒可能具有类似的卵传途径。

原文摘要：

Transovarial Transmission of a Plant Virus Is Mediated by Vitellogenin of Its Insect Vector

Yan Huo, Wenwen Liu, Fujie Zhang, Xiaoying Chen, Li Li, Qifei Liu, Yijun Zhou, Taiyun Wei, Rongxiang Fang, Xifeng Wang

Most plant viruses are transmitted by hemipteroid insects. Some viruses can be transmitted from female parent to offspring usually through eggs, but the mechanism of this transovarial transmission remains unclear. Rice stripe virus (RSV), a Tenuivirus, transmitted mainly by the small brown planthopper (Laodelphax striatellus), is also spread to the offspring through the eggs. Here, we used the RSV–planthopper system as a model to investigate the mechanism of transovarial transmission and demonstrated the central role of vitellogenin (Vg) of L. striatellusin the process of virus transmission into the eggs. Our data showed Vg can bind to pc3 in vivoand in vitro and colocalize in the germarium. RSV filamentous ribonucleoprotein particles (RNPs) only accumulated in the terminal filaments and pedicel areas prior to Vg expression and was not present in the germarium until Vg was expressed, where RSV RNPs and Vg had colocalized. Observations by immunoelectron microscopy (IEM) also indicated that these two proteins colocalized in nurse cells. Knockdown of Vg expression due to RNA interference resulted in inhibition of the invasion of ovarioles by RSV. Together, the data obtained indicated that RSV RNPs may enter the nurse cell of the germarium via endocytosis through binding with Vg. Finally, the virus enters the oocytes through nutritive cords, using the same route as for Vg transport. Our results show that the Vg of L. striatellus played a critical role in transovarial transmission of RSV and shows how viruses can use existing transovarial transportation systems in insect vectors for their own purposes.

标签: 植物病毒 昆虫的卵传 水稻条纹叶枯病毒

作者：中科院

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