双链RNA和植物对病毒的抗性

dsRNA-mediated Gene Silence and Antiviral Genetic Engineering

双链RNA能诱导转录后的基因沉默,是生物抵御病毒入侵、维持自身基因稳定的一种自我保护机制.把源自病毒的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,将入侵病毒的同源序列降解,使转基因植株获得对病毒的高抗性.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,因此不存在病毒RNA重组、异源包装及协生作用的潜在风险,具有较高的生物安全性.双链RNA抗病毒转基因正在成为一种高效、安全的植物抗病毒策略.

RNA silencing is a post-transcriptional gene-silencing phenomenon induced by double-stranded RNA(dsRNA).Since its formal discovery in 1998,dsRNA has rapidly developed into one of the most widely applied biotechnologies.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 dsRNA-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.