Interaction of Lettuce Virus X and Lettuce Isolate of Rubus Chlorotic Mottle Virus on two Chenopodium Species

Mixed infection of plants with more than one virus results in different types of interactions. Interaction between two recently identified lettuce infecting viruses in Iran, Lettuce X potexvirus (LeVX) and Rubus Chlorotic Mottle sobemovirus (RuCMV), was studied on co-infected Chenopodium murale and Chenopodium quinoa plants. Plants were mechanically inoculated with either LeVX, RuCMV or both. Co-infected plants of C. quinoa developed much more severe symptoms than the singly infected ones, with enhanced RuCMV accumulation level, as determined by quantitative ELISA and Western blot assay, indicating that the interaction of RuCMV with LeVX is synergistic in C. quinoa. Co-infection of C. murale plants resulted in symptom severity while with no detectable increase in RuCMV accumulation level, indicating that RuCMV interaction with LeVX is not synergistic in this plant. Conversely, LeVX accumulation level in either of C. quinoa or C. murale dually infected plants was significantly reduced, suggesting that LeVX interacts with RuCMV antagonistically in co-infected plants of both Chenopodium species.