Abstract
Twenty-nine isolates of cucumber mosaic virus (CMV) obtained from 29 plants of 20 species in 11 families collected from Japan were compared serologically with CMV-Y (the yellow strain of CMV) in double diffusion test. Twenty-five isolates out of 29 were serologically identical to CMV-Y, while an isolate from Zinnia elegans (designated as CMV-Z), two isolates from Petasites japonicus (respectively designated as CMV-P1 and CMV-P2) and an isolate from Farfugium japonicum were not identical to CMV-Y serologically because they produced distinct spurs in agar gel.
Antisera Y-F-IV and Z-F-IV respectively prepared by injecting formaldehyde-fixed CMV-Y and CMV-Z in rabbits intravenously reacted sufficiently with virus particles of both strains CMV-Y and CMV-Z, while they did not react with D-proteins of these strains. The precipitin bands produced between CMV-Y and CMV-Z, CMV-P1 or CMV-P2 showed distinct spurs when they were tested against antiserum Y-F-IV. However, the precipitin bands of these 4 isolates against Z-F-IV were fused with each other without spur. No precipitin bands developed against antiserum Y-F-IV or Z-F-IV if CMV D-proteins were used as antigens. Antiserum Y-IM obtained by intramuscular injection of unfixed CMV-Y contained antibodies specific for both CMV particles and D-proteins. When antiserum Y-IM was used, spur was formed between precipitin bands of CMV-Y and CMV-Z. However, antiserum Y-IM reacted with D-proteins of these strains resulting in fusion of precipitin bands. Antiserum Y-Dp-IM raised against D-protein prepared from CMV-Y by CaCl2 treatment reacted with D-proteins of both CMV-Y and CMV-Z with spur formation, but did not react with intact virus particles.
