Differentiation of legume carlaviruses based on their biochemical properties

Nucleic acids of alfalfa latent virus (ALV), pea streak virus (PSV), and red clover vein mosaic virus (RCVMV) were hydrolyzed by pancreatic RNase but not by DNase. ALV and PSV each had one single-stranded RNA of 38.0 and 37.6 S, respectively, whereas two single-stranded RNAs of 39.1 and 12–15 S were found in the RCVMV preparations. The average apparent molecular weights obtained by sedimentation and electrophoresis of formalinized ALV-RNA, PSV-RNA, and the large RNA of RCVMV were 2.45, 2.55, and 2.59 × 10 6, respectively. The apparent molecular weight of the protein subunit of ALV was 27,000, whereas those of PSV and RCVMV were each 33,500, indicating that ALV is a distinct member of the carlavirus group. RCVMV and PSV are considered distinct viruses, since formalinized RCVMV-RNA, but not PSV-RNA, was resolved from formalinized tobacco mosaic virus RNA on gradients and since the capsid protein subunit of RCVMV resisted degradation on storage but that of PSV did not.