RNA-Mediated Resistance with Nonstructural Genes from the Tobacco Etch Virus Genome. Sherri Swaney . Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804 U.S.A. Heather Powers (1), Joel Goodwin (1), Laura Silva Rosales (3), and William G. Dougherty (1,2). (1) Department of Microbiology and (2) The Center for Gene Research and Biotechnology, Oregon State University, Corvallis, OR 97331-3804 U.S.A. (3)Departamento de Ing. Genetica, CINVESTAV-IPN, U. Irapuato, Apdo. Postal 629, Irapuato, Gto. 36500, Mexico. MPMI 8:1004-1011. Accepted 6 July 1995. Copyright 1995 The American Phytopathological Society.

Sense RNA-mediated virus resistance has been described for transgenic plants expressing potyviral capsid protein sequences. This study was undertaken to determine if expression of other viral sequences could induce this type of virus resistance. Plants showing highly resistant or 'recovery' phenotypes were generated by expressing the tobacco etch virus (TEV) 6 kDa/21 kDa reading frames. Expression of translatable or untranslatable versions of this TEV sequence produced resistant lines. Highly resistant and recovery phenotype plants had biochemical hallmarks observed with resistant plants expressing TEV coat protein sequences. High transcription rates with low steady-state levels of the transgene transcript generally correlated with resistance. During recovery and induction of the resistance, RNA and protein steady-state levels decreased 5- to 20-fold, while transcription of the transgene continued at a similar level. A posttranscriptional, cellular system eliminating sequences contained in the transgene transcript and viral genome would be consistent with the results.