Novel N Gene-Associated, Temperature-Independent Resistance to the Movement of Tobacco Mosaic Virus Vectors Neutralized by a Cucumber Mosaic Virus RNA1 Transgene

The N gene conditions for resistance to Tobacco mosaic virus (TMV) but only below 28°C. However, a TMV-based vector expressing green fluorescent protein (TMV-GFP) showed only limited movement at 33°C in tobacco plants harboring the N gene and other genes cointrogressed from Nicotiana glutinosa. TMV-GFP moved efficiently in tobacco plants that either lacked these genes or that contained the N gene but were transgenic for RNA1 of Cucumber mosaic virus. These findings identified novel temperature-independent resistance to the movement of TMV-GFP which could be neutralized by a different viral transgene. Using the N gene and nahG gene-transgenic tobacco, we show that this novel resistance is manifested specifically by the N gene itself and operates via a pathway independent of salicylic acid.