PLANTS THAT EXPRESS A POTYVIRUS PROTEINASE GENE ARE RESISTANT TO VIRUS-INFECTION

Transgenic tobacco plants that express the genome-linked protein/prote inase-coding region of the potyvirus tobacco vein mottling virus (TVMV ) were produced and tested for their reaction to inoculation with TVMV and two other potyviruses. These plants did not develop disease sympt oms after being inoculated with large doses of TVMV but were as suscep tible to infection by the other potyviruses as were control plants. Li nes of tobacco that express the coat protein- or the nonstructural cyl indrical inclusion protein-coding regions were also produced. The cost protein transgenic plants were protected against all three potyviruse s, and the cylindrical inclusion transgenic plants were susceptible to all three potyviruses. These results indicate that some, but not all, TVMV genes can be used to confer protection against potyviruses in pl ants. The results also suggest that combinations of viral genes in tra nsgenic plants might improve protection against potyviruses.