Abstract
Turnip cells infected with radish mosaic virus contain characteristic large vesiculated cytoplasmic inclusion bodies, visible by light and electron microscopy. They consist of spherical aggregates of virus particles, sometimes in a crystalline array, embedded in a membranous mass. The presence of active dictyosomes and abundant endoplasmic reticulum in the outer zone of young inclusions suggests that these organelles are involved in the formation of inclusion bodies.