Multiplex RT-PCR to simultaneously detect three viruses that infect peach.

Peach is a major crop in China, and like any other stone fruit, virus and virus-like diseases can reduce the yield and quality of the fruit. Herein, we developed a multiplex RT-PCR (mRT-PCR) assay for simultaneously detecting three viruses known to infect peach: peach-associated luteovirus (PaLV), peach virus D (PeVD) and nectarine stem-pitting-associated virus (NSPaV). Plant nad5 mRNA was used as the internal control. Field samples that were co-infected with PaLV, PeVD and NSPaV were used; we identified three primer pairs to be the most specific for detecting these viruses, followed by determining the ideal concentration of each primer pair and optimizing the annealing temperature for mRT-PCR. We also assessed the detection limit using serial dilutions of RNA and cDNA. The newly developed mRT-PCR assay could simultaneously detect PaLV, PeVD and NSPaV. To validate the reliability of mRT-PCR for virus detection, mRT-PCR was used to detect viruses in the leaves of 21 peach plants collected in Liaoning Province, China. The obtained results revealed the presence of single and co-infections. To conclude, the mRT-PCR assay developed herein is sensitive, reliable and economical, and we believe that it can thus be used for large-scale surveys of PaLV, PeVD and NSPaV. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we developed a multiplex reverse transcriptase PCR (mRT-PCR) assay for simultaneously detecting three viruses that infect peach: peach-associated luteovirus (PaLV), peach virus D (PeVD) and nectarine stem-pitting-associated virus (NSPaV). This assay is simple, easy to perform, reliable and cost-effective, and can thus be applied for large-scale surveys of PaLV, PeVD and NSPaV.