Comparison of resistance to Potato virus Y mediated by direct and inverted repeats of the coat protein gene segments in transgenic tobacco plants

It has been demonstrated that RNA-mediated resistance to virus infection in plants is associated with RNA silencing, in which dsRNA in the transgenic plants may play an important role in triggering the silencing process. In this research, we designed cDNA constructs using direct repeat (DR) and inverted repeat (IR) of the coat protein gene segments of Potato virus Y (PVY) ,or introduced these constructs into tobacco plants via Agrobacterium tumefaciens-mediated transformation system. Resistant assays of the transgenic plants showed that highly resistant plants to PVY infection were obtained in both DR- and IR-transgenic plants. However, higher proportion of resistant plants was obtained from the IR-transgenic plants than that from DR-transgenic plants. Further analysis demonstrated that the resistance was RNA-mediated. These results indicate that using IR constructs of viral gene segments as transgenes may be a feasible strategy to produce virus-resistant plants by genetic engineering.