A detection method based on reverse transcription loop-mediated isothermal amplification for a genetically heterogeneous plantago asiatica mosaic virus

A reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed to detect plantago asiatica mosaic virus (PlAMV), one of the most damaging lily-infecting viruses and a member of the genus Potexvirus in the family Alphaflexiviridae. A set of six primers was designed based on the central core region of the coat protein gene of the Li1 isolate of PlAMV, which detected the isolate most efficiently at 65 °C. The RT-LAMP assay specifically detected several PlAMV isolates with a high level of genetic and biological variation, but not potato virus X (another virus species in the same Potexvirus genus). The sensitivity of the RT-LAMP was tenfold higher than that of conventional RT-PCR. Moreover, with a simple method using a toothpick, PlAMV was directly detected from infected lily leaves using the RT-LAMP assay without RNA extraction. This simple and highly sensitive method can be used for rapid surveys for PlAMV.