应用免疫荧光技术研究水稻条纹病毒(RSV)侵染介体灰飞虱卵巢的过程

摘要

Rice stripe disease, caused by Rice stripe virus (RSV), has led to severe losses in many rice-cultured countries and regions. RSV is transmitted by the small brown planthopper (SBPHs), Laodelphax striatellus Fallen, in a persistent-propagative, and it also can be transmitted transovarially (vertically) by the small brown planthoppers to their offspring. In order to study the transovarial transmission characteristics of RSV by SBPH vectors, we tested viral infections in internal organs and in ovaries of SBPHs with RT-PCR assay and immunofluorescence for virus antigens. Our results showed that only 5.3% of SBPHs contained virus antigens in the ovaries with immunofluorescence for virus antigens, although the virus was detected by RT-PCR in 28.6% of SBPHs that had access to infected plants. Thus, the ovaries would form the transovarial rntransmission barrier for RSV, which might determine the efficiency of the transovarial transmission of RSV by SBPH vectors. We further investigated the sequential infection of RSV in the ovaries of SBPH vectors with immunofluorescence for virus antigens. Immunofluorescence studies revealed that RSV initially infected the oviduct, and then progressed to the follicular cells of ovarioles. RSV also could accumulate in the germarium and the nutritive cord of the ovary and in the blastodermal cells of the eggs after oviposition. All these results suggested that RSV might spread into the oocyte together with the nutrition transport from the follicular cells of the ovarioles and germarium to the developing oocytes. Based on the fact that the germarium would develop to oocytes and follicular cells, we deduced that RSV might initially infect germarium, which finally formed viruliferous oocytes, although RSV might also spread into oocytes when accompanied by the nutrition transport. Taken together, our results provide a possible mechanism that RSV can exploit the pathway for the nutrition transport into the oocytes, and finally transport into the blastodermal cells of the eggs.%由水稻条纹病毒(Rice stripe virus,RSV)引起的水稻条纹叶枯病,在许多水稻种植区引起严重的减产,水稻条纹病毒由灰飞虱(Laodelphax striatellus Fallén)以持久增殖型传播,并可以经卵传播方式以较高的比例传给子代灰飞虱.为研究水稻条纹病毒的经卵传播特性及其侵染介体昆虫卵巢的过程,分别利用RT-PCR和免疫荧光技术检测虫体各个器官以及卵巢的带毒率,结果表明,饲毒后尽管灰飞虱的带毒率有28.6％,但是仅有5.3％的卵巢被病毒侵染.同时在利用免疫荧光技术对饲毒后不同时间灰飞虱卵巢中的RSV进行定位,发现RSV首先在卵巢管柄位置出现,随后侵染滤室细胞及生殖区,最后转移到胚盘细胞.结果认为,病毒可能是在滤泡细胞以及生殖区向正在发育的卵母细胞提供营养时,伴随这些营养物质进入卵母细胞.且生殖区的卵原细胞可发育成卵母细胞和滤泡细胞,我们推测,尽管RSV可伴随营养输送进入卵母细胞,但是最初带毒卵母细胞的病毒可能来源于位于卵巢生殖区的病毒.研究结果提示,RSV可能通过营养输送途径运送至卵母细胞,并最终侵染卵的胚盘细胞