VIRAL SATELLITE RNA EXPRESSION IN TRANSGENIC TOMATO CONFERS FIELD TOLERANCE TO CUCUMBER MOSAIC-VIRUS

Field trials of transgenic tomato plants expressing an ameliorative sa tellite RNA of cucumber mosaic virus (CMV) were conducted to test the efficacy of satellite-transgenic technology to protect against CMV inf ection. Three transgenic tomato lines derived from two susceptible gen otypes were evaluated over two growing seasons for viral symptoms and titers, satellite RNA expression, and fruit yield. Satellite-transgeni c lines exhibited mild or no CMV symptoms and low viral titers relativ e to nontransformed plants. A significant negative correlation between satellite RNA levels and disease severity was evident in transgenic l ines. Total marketable yield of CMV-infected satellite-transgenic line s was 40 to 84% greater than that of CMV-infected parent lines. Import antly, yield of CMV-infected satellite-transgenic lines did not differ significantly from mock-inoculated parent lines. Risk assessment resu lts demonstrated low levels of satellite RNA transmission within the t est site and no evidence of satellite RNA-induced damage on surroundin g plants.