Interaction between Cucumber mosaic virus subgroup I and II in Nicotiana rustica

Interaction among two isolates of Cucumber mosaic virus </em>(CMV), Zin1 and Zin2 belong to CMV subgroup I and II was investigated on Nicotiana rustica </em>plants in current study. Following singly and doubly mechanical inoculation of pure isolates on N. rustica </em>plants, infection rate (frequency of detection) and relative concentration of each CMV isolate were calculated in six different time trials (days post inoculation, dpi) by quantitative ELISA. Statistical analysis of repeated measures data showed a meaningful effect (p<0.05) of treatment and time variants on frequency of detection and relative concentration of each isolates. D/S ratio for each CMV isolate was less than 1 in doubly inoculation treatment. The results showed that the relative concentration of each isolate in singly inoculated plants was significantly (p<0.01) more than doubly inoculated ones at 5, 10 and 18 dpi. The increase in virus titre at 18 dpi was confirmed by western blot analysis. These results demonestrated a cross-protection interaction among CMV subgroups. Variance analysis of data showed that unlike area under the disease progress curve (AUDPC) and concentration of chlorophyll, disease severity index (DSI), height and fresh weight of plants showed a significant difference among different tratments. In aphid transmission assays by Aphis gossypii </em>fed on singly and doubly infected source plants, no significant difference was observed among transmission rate (T) and single aphid transmission efficiency (P*</sup>) of each CMV isolates.