Biolistic transfection of plants by infectious cDNA clones of Plum pox virus

Plant biolistic transfection by two Plum pox virus (PPV) infectious cDNA clones (strains PPV-M and PPV-D) using the gene gun apparatus PDS 1000-He was optimized. Nicotiana benthamiana plants were germinated on Petri dishes with MS growth medium. At the age of four weeks the plants were subjected to biolistic transfection and three days later were transplanted into common soil substrate. The plant survival after transplantation was about 70 %, the transfection efficiency was over 80 % (compared to 6 – 10 % efficiency reached by mechanical plant inoculation). The plants showed typical PPV symptoms two weeks post transfection. The virus presence was confirmed by immunoblotting, RTPCR, as well as by successful transmission by sap to healthy plants. The co-transfection of N. benthamiana plants by PPV-M and PPV-D led to mixed infections with PPV-D strongly prevalent. We assumed the properties of cDNA constructs responsible for this behaviour.