Caulimovirus Isolation and DNA Extraction

Members of the caulimovirus group (1 ) each have a circular double-stranded DNA genome of approx 8 kbp that is encapsidated in a spherical, naked nucleocapsid of approx 50 nm diameter (Fig. 1 ). Caulimoviruses characteristically produce subcellular inclusion bodies in infected tissues that contain most of the virions found in cells, embedded in an apparently random manner. The host ranges of individual caulimoviruses tend to be restricted to one or a few plant families, and group members are transmitted between plants by aphid vectors. Based on possession of all, or most, of these characteristics, 12 definite, and 3 possible, members of the group have been identified (2 ).