ABSTRACT
Tymoviruses derive their name from the type member, turnip yellow mosaic virus (TYMV), one of the most extensively studied of plant viruses. Members of the group have small isometric particles about 29 nm in diameter. Other characteristics common to all the viruses in the group are the high cytidine contents of their RNAs and some of the cytopathological effects they induce. The homogeneity of the group is also evident from serological data, which indicate that each member is related to at least one other. Nearly all people's knowledge of Tymovirus structure and composition is based on TYMV, which has been more thoroughly investigated than any other plant virus except tobacco mosaic. The stability of empty protein shells indicates that Tymovirus particles depend largely on protein-protein interactions for their integrity. A series of subgenomic TYMV RNAs isolated from virus preparations have been translated in a rabbit-reticulocyte in vitro system.
