CYTOCHEMICAL AND AUTORADIOGRAPHIC STUDIES ON THE GENOME AND SITE(S) OF REPLICATION OF BARLEY YELLOW STRIATE MOSAIC VIRUS IN BARLEY PLANTS

The nature and site(s) of repliccation of barley yellow striate mosaic virus (BYSMV) genome have been studied by enzymatic digestion with pronase. RNAse, DNase, by EDTA regressive staining and by quantitative electron microscopic autoradiography. The results indicate that BYSMV is an RNA virus which apparently replicates only in the cytoplasm. The viral envelope and viroplasms are made mainly of proteins. The suggested sequence of events in BYSMV synthesis is as follows: (1) soon after inoculation cell RNA synthesis is depressed and viral RNA synthesis begins in the cytoplasm; (2) virions and associated viroplasms become visible after viral RNA synthesis has reached its peak; (3) a sort of equilibrium is then established between host and pathogen-RNA synthesis.