Cytopathic effects of oat sterile dwarf virus in enation cells of oat leaves.

: A Czechoslovak isolate of oat sterile dwarf virus caused thickening or distortion of cell walls and induced the formation of viroplasms containing incomplete virus particles in gall phloem. These effects were similar to those caused by other plant reoviruses but no tubular structures containing rows of virions were found. Dense bodies of a similar diameter to virions were occasionally seen inside mitochondria. Complete virions were distributed at random in the cytoplasm but clusters of virions were sometimes enclosed within a membrane. No crystalline arrays of virions were seen. Late in infection parenchyma cells contained membranous structures formed by membranes about 11 nm thick, close to viroplasms. As the cells degenerated further, there occurred scrolls of membranes, about 150 nm in diameter. Unbound masses of fine fibrous and tubular structures, strongly resembling P-protein, occurred in the cytoplasm. The fibrils were about 5 nm in diameter and the unbranched tubes 21 nm wide. Only complete virions were seen in these structures.