GENETICALLY ENGINEERED RESISTANCE TO POTATO VIRUS-S IN POTATO CULTIVAR RUSSET BURBANK

The coat protein gene from potato virus S (PVS) was introduced into potato cultivar Russet Burbank by leaf disk transformation using Agrobacterium tumefaciens. Transgenic plants expressing the viral coat protein were resistant to subsequent infection following mechanical inoculation with the Andean or ME strain of PVS as indicated by a lack of accumulation of virus in the upper leaves. In agreement with previous reports for plants expressing potato virus X coat protein, plants expressing PVS coat protein were also protected from inoculation with PVS RNA, and in addition they also showed a measure of resistance to inoculation with a related carlavirus, potato virus M. The coat protein-mediated protection afforded by these transgenic plants was sufficient to prevent the accumulation of virus in the tissues of nontransformed Russet Burbank shoots that had been grafted onto transgenic plants inoculated with PVS. In reciprocal grafts, shoots from transgenic plants contained significantly lower virus concentrations following grafting onto plants systemically infected with PVS.