Transgenic Tobacco Plants Resistant to Two Viruses via RNA Silencing

Abstract

RNA silencing is a phenomenon of homologous RNA degradation induced by dsRNA, which is an effective strategy to obtain virus resistant plants so far. By means of this strategy, higher bio-security immune transgenic plants were obtained, avoiding recombining and transcapsidating with other virus genes. In this study, the recombinant plant expression vector pBIN438-MPRep (i/r) consisting the inverted repeat of TMV-ΔMP and CMV-ΔRep fusion fragment was transformed into tobacco cultivar K326 via Agrobacterium-mediated. The transformants were selected in the culture medium with 100 mg L^(-1) Kan. One hundred and ninety-six transgenic plants were obtained, one hundred and twenty-eight of which were positive plants, and the resistance to CMV and TMV was tested at the degree of virus. PCR-Southern blot and RT-PCR analysis of the transgenic plants demonstrated that the exogenous DNA was integrated into the tobacco genomic DNA and was expressed in transcriptional level. Resistance assay indicated that about 20.3% transgenic plants were immune to the co-infection with TMV and CMV. This result will provide to crops an important reference for plant anti-viral breeding and for preventing the viral co-infection.