灰飞虱miRNA-184-3p靶向Ken促进水稻黑条矮缩病毒侵染介体的机制

由灰飞虱传播的水稻黑条矮缩病毒（RBSDV）侵染引起的水稻黑条矮缩病，对我国水稻生产威胁巨大。昆虫microRNA（miRNA）参与调控动物病毒的侵染，然而关于昆虫miRNA调控植物病毒侵染介体的机制尚不明确。本项目前期发现，灰飞虱高表达的miR-184-3p可促进RBSDV在介体内侵染，并初步明确了其靶基因Ken&Barbie（Ken）抑制RBSDV在介体内侵染的功能。本项目拟利用分子生物学和细胞生物学等技术手段，探索miR-184-3p靶基因Ken对灰飞虱获毒及传毒的影响，解析Ken调控RBSDV在介体灰飞虱内复制过程中的作用，探究Ken的亚细胞定位及其所参与的FOXO通路对RBSDV侵染介体的机制，最终明确灰飞虱miR-184-3p靶向Ken促进RBSDV在介体内侵染的分子模型。本项目对于阐明昆虫miRNA调控植物病毒侵染介体的机制及介体昆虫与植物病毒的互作具有重要的科学意义。

Rice black streaked dwarf virus (RBSDV), which is transmitted by small brown planthopper (Laodelphax striatellus Fallén) in a persistent propagative manner, causes a great threat to grain yields in China. MicroRNA (miRNA) of insect vector is involved in the regulation of viral infection, however, the mechanism of insect vector miRNA regulating plant virus infection remains unclear. Here, we used high expressed miRNA-184-3p (miR-184-3p) of L. striatellus and RBSDV to explore how a miRNA of insect vector regulates the plant virus infection in its insect vector. We found miR-184-3p was upregulated under the infection of RBSDV and the miRNA gain of function increased the viral accumulation in its insect vector. The endogenous candidate targets of miR-184-3p related to RBSDV infection were predicted by bioinformatics. The candidate target, Ken&Barbie (Ken), the key gene of Forkhead box O pathway was identified, screened and verified by the gain of function and loss of function study of miR-184-3p, and the direct interaction of L. striatellus miR-184-3p with Ken, will be verified by dual luciferase report system. And we found that the RNA interference induced by dsKen significantly increased the viral titer of RBSDV in its insect vector. Next, we will further investigate the effect of miR-184-3p on RBSDV accumulation in L. striatellus by RT-qPCR and immunofluorescence microscopy assay. It is especially important that the mechanism of Ken and its related pathway regulating RBSDV infection progress, such as replication and dissemination in its insect vector, would be explored by means of molecular biology, cellular biology and biochemistry assays. Finally, the mechanism of L. striatellus miR-184-3p targets Ken to promote RBSDV infection in its insect vector would be elucidated, which will be significant in revealing the mechanism of miRNA regulating plant virus infection in its insect vector and may provide insights into novel approaches to attenuate viral epidemics.