Abstract:Tobacco plants are frequently infected by Tobacco mosaic virus(TMV),Cucumber mosaic virus(CMV),Tobacco etch virus(TEV),Potato virus Y(PVY) and Tobacco vein banding mosaic virus(TVBMV),and sometimes complexly infected in China.Five pairs of specific primers were designed according to the partial coat protein gene sequences of the five viruses.By optimization of primer,template concentration and amplification parameters,the expected fragments of 237 bp(TMV),273 bp(CMV),347 bp(TEV),456 bp(PVY) and 547 bp(TVBMV) were successfully amplified by the multiplex RT-PCR system.The results verified that this system was useful for simultaneous detection of these five viruses from field samples.