Improved purification procedure and some serological and physical properties of cassava common mosaic virus from South America

Abstract

Large quantities of cassava common mosaic virus (CCMV) were purified from systemically infected Nicotiana benthamiana plants. A polyclonal antiserum, with a titre of 1/128 in the tube precipitin test, was produced by immunising rabbits with purified virus. Viral antigens were detected in cassava, using both the double-antibody sandwich or plate-trapped antigen forms of enzyme-linked immunosorbent assay (ELISA). The virus reacted with antisera to the potexviruses potato virus X and tulip virus X in F(ab`)2 ELISA. As determined by ELISA, isolates of CCMV from cassava and chaya are closely serologically related to each other. Leaf extracts from infected N. benthamiana plants were infective to a dilution of 10(- 4) but not 10(-5); after heating for 10 min at 65 degrees C but not 70 degrees C; and after storage at room temperature for 14 days. The virus has a sedimentation coefficient of 126 S20,w, a single coat protein molecule of c. mol. wt 21 000, and a single-stranded RNA genome of c. mol. wt of 2.0 x 10(6). Several dsRNA species, including the putative viral replicative form of c. mol. wt 4.1 x 10(6), were isolated from virus-infected cassava and N. benthamiana. (AS)