Development and comparison of reverse transcription-loop-mediated isothermal amplification assay (RT-LAMP), RT-PCR and real time PCR for detection ofPotato spindle tuber viroidin potato

Potato spindle tuber viroid(PSTVd) is an important pathogen of potato infecting leaves, tubers as well as true potato seeds. We developed and validated a reverse transcription-loop mediated isothermal amplification (RT-LAMP) platform for visual, rapid, specific, and sensitive detection of PSTVd. The optimization of RT-LAMP reaction conditions and reagents concentrations were carried out with time, temperature, MgSO4, dNTPs, andWarmStart Bst2.0 polymerase. The assay is very simple and rapid which provide detectable results in less than 50 min by incubating all the reagents at 65 degrees C. The detection of RT-LAMP results could be accomplished as ladder-like bands in an agarose gel or visualized by naked eyes with inclusion of a SYBR Green I dye. The target specificity of RT-LAMP primers was assessed with an introduction of a simple restriction digestion step after the RT-LAMP assay. The RT-LAMP assay demonstrated absence of any cross-reaction with other, potato viruses. The analytical sensitivity of the assay was greater than RT-PCR either the test template was plasmid or total RNA. The detection of RT-LAMP was validated in potato samples and compared with real time PCR and RT-PCR. The RT-LAMP assay developed in this study has the potential as a beneficial tool in detection of PSTVd in a low-cost laboratory due to its simplicity, rapidness, and application in large samples.