Ultrastructural alteration of host plants infected with different cucumber mosaic virus isolates

The ultrastructural alterations caused by the infection of two cucumber mosaic virus isolates were investigated. Spherical virus particles of CMV M 22, an isolate originally from Salvia splendens , scattered throughout the cytoplasm and aggregated into crystals in the vacuoles of tobacco cells. The existence of virus particles inside the chloroplast was not detected for this isolate. But virus particles were found being aggregated through the plasmodesma, that indicated the way of cell to cell movement of this isolate. Virus particles of CMV 8 S1, an isolate with necrosis satellite RNA and originally from naturally infected tobacco, scattered throughout the cytoplasm and in the vacuoles of abnormal chloroplasts. In the tobacco leaf cells natural infected by CMV 8 in the field, numerous spherical particles and abnormal chloroplasts were observed. The results suggest that ultrastructural alterations induced by different CMV isolates are quite variable. This is a direct evidence of satellite RNA involveme