Cucumber mosaic virus (CMV) movement in L113 and L57 pepper lines resistant to this virus was studied. The virus presence was confirmed only in the blades and petioles epidermis of CMV inoculated leaves while the rest parts of the plants were virus free. On these leaves of L113, necrotic local lesions (typical hypersensitive response -HR) were formed whereas in L57 chlorotic spots appeared and a few days later the leaves fell. Despite the fact of only L113 possesses HR-mediated resistance to CMV, virus long-distance movement was similarly restricted in both pepper lines. El-microscopic observations have found regions consisting of optically almost empty dead cells in symptomless areas near the necrotic (L113) and chlorotic (L57) spots. The walls of these cells are incidentally crossed by dark-coloured plasmodesmata. The structural changes in plasmodesmata in still alive leaf cells also testify for their active participation in the virus movement through the leaf cells of CMV inoculated leaves. These cell changes were observed only in CMV inoculated leaves of both resistant pepper lines.

Tomato plants (Solanum lycopersicum L.) cv. Moperou, which possess gene Tm-2 for resistance against tomato mosaic virus (ToMV), were pre-inoculated with compatible pathotype P2 or incompatible pathotype P0 strains of ToMV and subsequently challenge infected with Pseudomonas syringae pv. tomato and Xanthomonas vesicatoria. It was found that both types of virus strains, compatible and incompatible, induced systemic acquired resistance (SAR), which protected plants from subsequent pathogen infection. The percentage of protection of the compatible ToMV pathotype P2 strain was 100% against both bacterial infections, while that of the incompatible ToMV pathotype P0 strain varied from 26 to 77% within the timeline and depended on the pathogen races. The SAR induced by ToMV was confirmed by the increased antioxidant defense and hydrogen peroxide content in the leaves of tomato plants inoculated with compatible and incompatible ToMV strains.