病毒诱导的基因沉默及其在植物基因功能研究中的应用

RNA介导的基因沉默是近年来在生物体中发现的一种基于核酸水平高度保守的特异性降解机制.病毒诱导的基因沉默（virus induced gene silencing, VIGS）是指携带植物功能基因cDNA的病毒在侵染植物体后,可诱导植物发生基因沉默而出现表型突变，进而可以研究该目的基因功能.至今，已经建立了以RNA病毒、DNA病毒、卫星病毒和DNA卫星分子为载体的VIGS体系，这些病毒载体能在多种寄主植物（包括拟南芥、番茄和大麦）上有效抑制功能基因的表达.VIGS已开始应用于N基因和Pto基因介导的抗性信号途径中关键基因的功能研究、抗病毒相关的寄主因子研究以及植物代谢和发育调控研究.在当前植物基因组或EST序列大量测定的情况下，VIGS为植物基因功能鉴定提供了有效的技术平台.

Virus Induced Gene Silencing And Its Application for Analysis of Genomic Function in Plants

RNA silencing is a high conserved mechanism in organisms that involves sequence-specific RNA degradation. For virus induced gene silencing (VIGS), it is induced by infecting a plant with a plant virus that has had its genome modified to include a sequence identical to that in RNA transcribed from the host gene to be silenced. Up to now, various VIGS vectors based on RNA virus, DNA virus, satellite virus or DNA satellite have been established, these VIGS vectors could suppress gene expression effectively in many important plants including Arabidopsis, tomato and barley. VIGS vectors have been used to study function of genes involved in the signal transduction of N-mediated or Pto-mediated resistance, anti-virus mechanism, and plant development and metabolism. With the determination of complete genome sequences or expressed sequence tags, VIGS has recently emerged as a powerful method for identification of gene functions in plants.