A more sensitive and rapid multiplex RT-PCR assay combining with magnetic nanobeads for simultaneous detection of viruses in sweet potato

An improved multiplex RT-PCR assay combined with magnetic nanobeads (MNB-RT-PCR) was developed for simultaneous detection of four sweet potato viruses, Sweet potato virus G (SPVG), Sweet potato feathery mottle virus (SPFMV), Sweet potato virus C (SPVC) and Sweet potato chlorotic fleck virus (SPCFV). Four primer pairs specific for each virus were designed and the corresponding PCR products were 169, 357, 516 and 900 bp in length for SPVG, SPFMV, SPVC and SPCFV, respectively. The specificity of the method was tested using different combinations of virus templates, and the identities of the amplification products were confirmed by sequencing. The limits of detection for all four viruses by single and multiplex MNB-RT-PCR assays were comparable. The assay was further evaluated using laboratory and field samples compared with a conventional CTAB-RT-PCR assay, and the comparative results showed that the MNB-RT-PCR assay was more rapid and sensitive. These results suggest that the multiplex MNB-RT-PCR assay is an effective and preferable method for virus detection in sweet potato.