Transformation of Nicotiana tabacum cv. Samsun by the coat protein gene ofPVYNTN

Potato tuber necrotic ringspot disease, caused by a strain of potato virus Y (PVYNTN) has been reported in many countries in the last decade. It is on e of the most harmful potato pathogens shown to have infected potato crops in Slovenia, cv. Igor being the worst affected. The long term aim of our st udy is to develop virus-resistant transgenic lines of cv. Igor expressing p athogen-derived sequences. The tobacco plants (Nicotiana tabacum cv. Samsun ) served as a model species for transformation and resistance studies. The coat protein (CP) gene of PVYNTN was cloned into a pUC plasmid and then int o a pROK2 plasmid which was mobilised in Agrobacterium tumefaciens strain L BA 4404. The presence of CP gene in the regenerated plants was checked by P CR and all primary transformants tested were found to be transgenic. Inocul ated plants of the transgenic tobacco lines were tested for resistance to P VYNTN but developed symptoms of PVYNTN appear to have no virus resistance.