TRANSGENIC POTATO-VIRUS-Y RESISTANCE IN POTATO - EVIDENCE FOR AN RNA-MEDIATED CELLULAR-RESPONSE

This study was undertaken to assess the potential of transgenic RNA-me diated virus resistance in potato. Transgenes that expressed various v ersions of the potato virus Y (PVY) coat protein (CP) open reading fra me (ORF) were constructed and expressed in potato. Plants highly resis tant to PVY infection could be generated by expressing transgenes from which either mRNA and CP or only an untranslatable mRNA were made. An inverse correlation between transgene transcript accumulation and vir us resistance was often noted when translatable or untranslatable vers ion:; of the PVY CP ORF were expressed. The data suggest that virus re sistance is likely mediated by a host cell response. A dominant negati ve phenotype resulting from the transgene product competing with the v iral-encoded product is not supported by the data.