RESISTANCE AGAINST MULTIPLE PLANT-VIRUSES IN PLANTS MEDIATED BY A DOUBLE-STRANDED-RNA SPECIFIC RIBONUCLEASE

Many plant viruses have single-stranded RNAs as their genomes, During the course of replication, genomic RNAs and their complementary templa te RNAs are likely to form double-stranded (ds) RNA at least transient ly, To attack replication intermediates of many plant RNA viruses spec ifically, me introduced a yeast-derived ds-RNA specific RNase gene cal led pac 1 into plants, The transformed plants showed a decrease in les ion numbers when they were challenged with tomato mosaic virus, and a delay in the appearance of symptoms when inoculated with cucumber mosa ic virus or potato virus Y.