Screening of Transgenic Tobacco for Resistance Against Cucumber mosaic virus

摘要

Coat protein ( CP ), Movement Protein ( MP ) and Overlapping ( OVG ) genes were isolated from a Malaysian Cucumber mosaic virus (CMV) isolate via RT-PCR and transformed into Nicotiana tabacum through Agrobacterium tumefaciens- mediated transformation. Out of the thirty six independently transformed lines developed from the three different genes and the mutants of MP and OVG , five lines were tested for resistance against CMV by challenge inoculations using three different concentrations (1:10, 3:10 and 5:10) of CMV macerated in 0.1 M sodium phosphate buffer (pH 7.0). The transgenic lines exhibiting complete resistance remained symptomless even when re-inoculated with 1:10 concentration of virus. The level of viral RNA accumulation in inoculated leaves was significantly (at least 2-3 times) lower compared to the control untransformed plants. The upper leaves which were analysed for systemic spread of the infection had much lower levels of viral RNA accumulation compared to the inoculated leaves. Amongst the three genes and two mutant lines that were generated in this study, we found that the CP and MP genes were able to provide a better level of resistance to the plants compared to the overlapping gene.