Use of trichosanthin to reduce infection by turnip mosaic virus

Exogenous application of recombinant trichosanthin (TCS) inhibited local lesion formation by turnip mosaic virus (TuMV) in leaves of Nicotiana tabacum and caused a delay in the development of mosaic symptoms by TuMV in Brassica parachinensis. A dose-response relationship was observed in the latter case. To produce transgenic plants expressing a TCS cDNA, a chimeric gene which contains a fusion between the cauliflower mosaic virus 35S promoter, the TCS-encoding cDNA and the octopine synthase 3' polyadenylation sequence (ocs 3') was constructed. The chimeric gene was then cloned into a binary vector and introduced into the genome of N. tabacum cv. 'Wisconsin 38' via Agrobacterium tumefaciens-mediated transformation. Three transgenic tobacco plants which synthesized TCS protein in the cytosol were completely resistant to mechanical inoculation of TuMV.