Cross protection between strains of cucumber mosaic virus: Effect of host and type of inoculum on accumulation of virions and double-stranded RNA of the challenge strain

Two strains of cucumber mosaic virus (CMV) differed in three characteristics of value for cross-protection experiments. Their virions and also two of their double-stranded RNAs could be separated and distinguished by electrophoresis on polyacrylamide gels, and the symptoms of one strain were milder than the other in tobacco, tomato, and squash. The mild strain, CMV-S, protected plants of these three hosts from the effects of the second strain,...