双链RNA激发的植物基因沉默及其在植物育种上的应用  

dsRNA-mediated Gene Silence and Antiviral Genetic Engineering

作　　者：白云凤[1] 王小琦[1] 郭志华[1] 张维锋[1] 

机构地区：[1]山西省农业科学院作物遗传研究所,山西太原030031

出　　处：《山西农业科学》2008年第1期23-27,共5页Journal of Shanxi Agricultural Sciences

基　　金：国家自然科学基金项目(30471102);山西省国际科技合作项目(2007081002);山西省回国留学人员基金项目(200689);山西省农业科学院博士基金项目(YBSJJ0604)

摘　　要：在生物体内,存在大量的非编码RNA(ncRNA),小干扰RNA(siRNA)是其中一种,由双链RNA切割形成,能干扰基因表达,激发转录后的基因沉默。尽管双链RNA干扰是把基因"敲低"而不是"敲除",但它的高效和易操作性使之成为研究植物基因功能的有用工具,并通过转基因途径用于植物改良。与反义RNA技术和共抑制技术相比,RNA干扰对基因的沉默效率高,效果稳定。单基因RNA干扰就可调控多基因家族控制的农艺性状,而不必累积单基因突变。把病毒基因构建成反向重复结构转入植物体内,其转录出的RNA会通过分子内序列互补形成双链结构,激发转基因植物的RNA干扰机制,将入侵病毒的同源序列降解,使转基因植株获得对病毒的抗性。RNA干扰型抗病毒转基因植株中,转病毒基因的mRNA不存在或存在量很少,也不会翻译成有功能的病毒蛋白质,因此不存在病毒RNA重组、异源包装及协生作用的潜在生物风险,具有较高的生物安全性。RNA interference（RNAi） is a post - transcriptional gene - silencing phenomenon induced by double - stranded RNA（dsRNA）. Since its formal discovery in 1998, RNAi has rapidly developed into one of the most widely applied biotechnologles. Although RNAi is not a knockout but a knockdown technology, its high efl3ciency and easy application make it applicable to genome - wide analysis of gene function in plants. For genetic improvement of crop plants, dsRNA delivered by stably transforming plants with transgene that express a self- complementary RNA has induced homologous gene silencing in plants. RNAi has advantages over antisense - mediated gene silencing and co - suppression, in terms of its efficiency and stability. It also offers advantages over mutation - based reverse genetics in its ability to suppress tranagene expression in multigene families in a regulated manner. Plants transformed with constructs that produce RNAs capable of duplex formation containing target virus sequences have induced virus immunity with high efficiency when targeted against viruses. Biotechnological utilization of RNAi - based engineered resistance is appealing for biosafety reasons as well. Since little or no transgene mRNA is accumulated in plant cells, there is essentially no template for events such as complementation, heterologous encapsidation, synergy and recombination.

关 键 词：双链RNA 基因沉默 抗病毒基因工程 

分 类 号：Q78[生物学—分子生物学]