RNAi在害虫防治中应用的重要进展及存在问题

RNAi是目前最有可能应用于害虫绿色防控的新技术。2017年6月，美国环境署(EPA)批准了国际上第一例表达昆虫双链RNA(dsRNA)的抗虫转基因玉米MON87411，掀起了利用RNAi技术进行害虫防治研究新的热潮。但是，目前RNAi在害虫防治中的应用还存在一些问题，例如有效靶标基因筛选和应用策略，鳞翅目昆虫对RNAi的敏感性以及双链RNA在环境中的稳定性等等。本文系统总结了RNA干扰现象发现20年来，该技术在害虫防治领域的研究及应用概况，并对RNAi技术应用的可行性、应用方法、存在问题和目前的一些解决办法进行了比较详细的综述。通过对近期研究结果的综合分析发现，dsRNA进入某些鳞翅目昆虫中肠或血淋巴后，被相关核酸酶降解可能是其RNAi效率较低的首要原因。通过对dsRNA进行脂质体修饰，纳米粒子包埋可以在一定程度上解决dsRNA降解的问题，进而提高RNAi效率。

Application of RNAi in insect pest management: important progress and problems

RNAi is regarded as a green pest control strategy most likely to be applied in insect pest control. In June 2017, United States Environmental Protection Agency (EPA) approved the first transgenic insect-resistant maize MON87411 expressing insect double-stranded RNA (dsRNA) in the world, and this brought a new upsurge of research of using RNAi technology in insect pest management. However, there are still some problems to be addressed in the application of RNAi technology in pest control, e.g., screening and application strategies of effective target genes, the sensitivity of lepidopteran insects to RNAi, the stability of dsRNA in environment, etc. In this article, we summarized the research and application of RNAi technology in relation to pest control over the past two decades. We also reviewed the feasibility, application methods, existing problems and some current solutions of RNAi technology. We found that the degradation of dsRNA in the midgut or hemolymph of some lepidopteran insects may be the primary reason of the low RNAi efficiency through a comprehensive analysis of recent research results. Through dsRNA modification or embedding by liposome or nanoparticle, it is possible to solve the problem of dsRNA degradation to a certain extent, thus improving the RNAi efficiency.