Revised Estimates of the Molecular Weights of dsRNA Segments in Hypovirulent Strains ofEndothia parasitica

Abstract

Multisegment ds[double-stranded]RNA were detected by polyacrylamide gel electrophoresis of preparations purified by CF-11 cellulose chromatography from 12 hypovirulent strains of E. parasitica isolated from France, Italy and North America. Ethidium bromide-stained dsRNA segments were identified by incubating individual gels with RNase, first in 0.3 NaCl and then in water. The MW of the dsRNA segments were 4.0-7.0 .times. 106. The types of dsRNA in European strains (type 1 in 1 strain, type 2 in 7 strains) were distinct from each other and from the dsRNA in North American strains (type 3 in 4 strains). Levels of pathogenicity or growth rate were not correlated with types of dsRNA. The concentration of dsRNA was lower in North American strains than in European strains.