Two amino acid substitutions in the tomato mosaic virus 30-kilodalton movement protein confer the ability to overcome the Tm-2(2) resistance gene in the tomato

The Tm-2(2) resistance gene is used in most commercial tomato cultivars for protection against infection with tobacco mosaic virus and its close relative tomato mosaic virus (ToMV). To study the mechanism of this resistance gene, cDNA clones encompassing the complete genome of a ToMV strain (ToMV-2(2)) that was able to break the Tm-2(2) resistance were generated. Chimeric full-length viral cDNA clones were constructed under the control of the...