FIG. 4.

The novel resistance is specifically associated with the N gene. (A) At 25°C and at 7 dpi with TMV-GFP, NLL were observed in inoculated leaves of the progeny from the cross between tobacco cultivar Samsun nn plants transgenic for CMV RNA1 (nn-TG) and plants transgenic for the N gene (SR1::NN), yielding nn-TG × SR1::NN (right leaf). In the inoculated leaf of parental CMV RNA1-transgenic tobacco cultivar Samsun nn, no visible NLL were produced (not shown), whereas in the inoculated leaf of parental SR1:: NN tobacco, very small NLL were visible (SR1:: NN) (left leaf). (B) At 33°C and at 12 dpi with TMV-GFP, the spread of virus in the whole plant was assessed with a UV lamp. Each row of leaves shows the detached inoculated leaf (i.l.) followed by the detached four consecutive leaves (numbered 1 to 4 in ascending order).