Biophysical and biochemical properties of tomato aspermy virus

A virus isolated from tomato in British Columbia was identified as tomato aspermy virus (TAV). The virus was purified and compared with an isolate of TAV from chrysanthemum (CV-L) and with an isolate of cucumber mosaic virus (CMV). TAV and CV-L were serologically identical but CMV was only distantly related. The amino acid composition of TAV was similar to that of CV-L, showing only four amino acid exchanges, whereas there were 18 amino acid exchanges between TAV and CMV. TAV had a sedimentation coefficient of 98 S, a diffusion coefficient of 1.49 × 10^?7 cm²/sec and a molecular weight of 5.3 million. The molecular weight of the viral protein subunit, determined on polyacrylamide gel, was 26,300. The base percentage composition of the viral RNA was G = 23.1, A = 26.2, C = 21.6, and U = 29.0. Phosphorus analysis of the RNA indicated that the nucleic acid content of the virus was 17.7%.