TRANSGENIC POTATO PLANTS EXPRESSING MAMMALIAN 2'-5' OLIGOADENYLATE SYNTHETASE ARE PROTECTED FROM POTATO VIRUS-X INFECTION UNDER FIELD CONDITIONS

We cloned and sequenced a rat cDNA encoding the 2'-5' oligoadenylate s ynthetase, a component of the mammalian interferon-induced antiviral r esponse, and used Agrobacterium-mediated transformation to generate tr ansgenic potato clones expressing this mammalian enzyme. In transgenic plants infected with potato virus X and followed under field conditio ns, virus concentrations in leaves and in tubers were significantly lo wer than in nontransgenic controls. Additionally, virus concentration in the leaves of five transgenic clones and in tubers of one clone was also lower than in transgenic potatoes expressing potato virus X coat protein.