EFFICIENT PATHOGEN-DERIVED RESISTANCE INDUCED BY INTEGRATED POTATO VIRUS-Y COAT PROTEIN GENE IN TOBACCO

The coat protein (CP) gene from potato virus Y (Hungarian isolate, PVY -H) was engineered into Agrobacterium tumefaciens binary vector for ex pression in different tobacco lines. Three different Nicotiana tabacum breeding lines were transformed and the integration of the CP gene wa s confirmed by PCR technique using genomic DNA preparations. The trans cription and expression of the integrated CP gene was detected by Nort hern and Western blots. Pathogen-derived resistance was demonstrated b y inoculation of the R1 progeny of the transformed lines with purified PVY-H. The efficiency of protection varied between different transgen ic plants ranging from almost complete to no protection. Five CP expre ssing tobacco lines were resistant to challenge infection with PVY-H a s indicated by attenuation or absence of symptom development associate d with reduction or lack of detectable virus accumulation. Data from W estern blots showed that there is no correlation between the level of the expressed CP and the extent of protection. This suggests that the mechanism of the observed resistance is independent of the level of CP accumulation in the transgenic tobacco plants.