PROPERTIES OF MAIZE CHLOROTIC DWARF VIRUS AND ITS RIBONUCLEIC-ACID

Maize chlorotic dwarf virus (MCDV) was purified by a procedure in which virus was precipitated at low ionic strength. MCDV contained 36.2% single-stranded RNA. An RNA MW of 3.2 .times. 106 was found by sedimentation of formaldehyde-treated RNA in linear-log sucrose gradients containing formaldehyde and by electrophoresis of formaldehyde-treated RNA in formaldehyde-containing polyacrylamide gels. The relationship between distance sedimented and RNA molecular weight for the sedimentation analysis is described. The nucleotide composition of the RNA was 29.8% Ap, 28.6% Up, 24.4% Gp and 17.2% Cp. MCDV appears to be unique among small, single-stranded RNA plant viruses. A large genome and high virion MW (8.8 .times. 106) probably account for its fast sedimentation rate and high buoyant density.