Caulimoviruses are spherical or bacilliform plant viruses containing a circular double-stranded (ds) DNA genome of 7.1 to 8.2 kb. Depending on the gene arrangement, the following six genera in the family Caulimoviridae are distinguished (Pringle. 1999; see Chapter 1 of this book; see Figure 14.1). Viruses with icosahedral panicles are classified in genera Caulimovirus (type species. Cauliflower mosaic virus, CaMV).