Abstract
The host range of satsuma dwarf virus was studied by means of mechanical inoculations. Among the tested plants, including 27 species of 10 families, 22 species of 8 families were found to be susceptible to the virus. The virus was purified, after clarification of homogenized petunia leaf tissues with Mg-bentonite, by precipitation with ammonium sulfate, treatment with carbon tetrachloride, differential centrifugation, and sucrose density-gradient centrifugation. Three zones appeared after sucrose density-gradient centrifugation for six hours. The middle and the bottom zone were separated from each other by three cycles of sucrose density-gradient centrifugation. Spherical particles, 26nm in diameter, were observed in the three zones. However, particles in the top zone were empty or incomplete. Sedimentation coefficients of the middle and the bottom zone were 119S and 129S, respectively. The bottom zone had a higher ratio of absorbance at 260:280nm than did the middle zone. An enhancement of infectivity over the infectivity of each zone alone at the same concentration was obtained after mixing of the middle and the bottom zones. The infectivity dilution curve of the purified virus was of the double hit type. After isopycnic density-gradient centrifugation in cesium chloride, two components with different buoyant densities (1.43 and 1.46g/cm3) were found in the purified virus. The lighter component coincided with the middle zone and the denser component coincided with the bottom zone. Virus antisera were prepared in rabbits by giving two intravenous and two intramuscular injections of the purified preparation. The antisera titers were 1/640 in complement fixation tests. In agar double-diffusion tests, the virus did not react with antisera against tomato blackring, tomato ringspot, cherry leaf roll, tobacco ringspot, strawberry latent ringspot, raspberry ringspot, bean pod mottle, cowpea mosaic, cucumber mosaic, and citrus leaf rugose viruses.
