Replication of positive-strand RNA viruses in plants:: contact points between plant and virus components

Positive-strand RNA viruses constitute the largest group of plant viruses and have an important impact on world agriculture. These viruses have small genomes that encode a limited number of proteins and depend on their hosts to complete the various steps of their replication cycle. In this review, the contact points between positive-strand RNA plant viruses and their hosts, which are necessary for the translation and replication of the viral genomes, are discussed. Special emphasis is placed on the description of viral replication complexes that are associated with specific membranous compartments derived from plant intracellular membranes and contain viral RNAs and proteins as well as a variety of host proteins. These complexes are assembled via an intricate network of protein-protein, protein-membrane, and protein-RNA interactions. The role of host factors in regulating the assembly, stability, and activity of viral replication complexes are also discussed.