1990 Volume 56 Issue 1 Pages 39-46
RNA profiles of cucumber mosaic virus (CMV) propagated in a resistant melon (Cucumis melo L. var. makuwa cv. Kohimeuri) and a susceptible melon (C. melo L. var. reticulatus cv. Earl's) were analyzed by 2.5% polyacrylamide gel electrophoresis. Relative amount of RNA 1 in RNAs of virus from Kohimeuri melon was markedly reduced in comparison with that from Earl's melon. Moreover, specific infectivity of virus particle and its total RNA from the former was less than that from the latter. Infectivity of total virus RNA from Kohimeuri, however, increased by addition of RNA 1 separated from original CMV. When leaves of Xanthi-nc tobacco were inoculated with virus from Kohimeuri or Earl's melons, the pattern of virus multiplication, symptom expression and RNA profiles in the progeny virus in the leaves were similar each other. When CMV-inoculated Kohimeuri leaves were treated with actinomycin D (10μg/ml), the virus multiplication was stimulated and the deficiency of RNA 1 in the multiplied virus did not occur. These results suggest that the unbalanced synthesis of CMV-RNAs (deficiency of RNA 1) is related to the resistance mechanism of Kohimeuri melon to CMV.