ABSTRACT
Technological advances in molecular biology should make possible the resolution of the important structural features which control viral gene expression and hence viral phenotype. This chapter reviews gene expression of RNA plant viruses using established viral classification groupings. It discusses each virus group by briefly describing the structural organization of the virion and of the viral genomic RNA(s). The chapter discusses the nine virus groups that have a single-stranded, ribonucleic acid component which is infectious. The initial five virus groups have members possessing a particle morphology which is spherical. The remaining four virus groups have members which are anisometric in morphology. The chapter presents the expression of the viral RNA in cell-free systems and in the host cells. It integrates in vivo and in vitro observations and overviews the genomic expression of each virus group.
