Membrane Association for Plant Virus Replication and Movement

Plant viral genomes encode a limited number of proteins. These viral proteins are required for viral RNA (vRNA) replication, movement and encapsidation. At least one of these viral proteins invariably associates with cellular membranes. These membrane-associated viral proteins have multifunctional domains, notably trans-membrane domains (TMDs) and/or amphipathic helices for membrane insertion or association. Expression of these membrane-associated viral proteins induces extensive intracellular membrane remodeling that leads to the formation of viral factories. These viral factories are either static spherules within organelle membranes (e.g. mitochondrion, chloroplast), or endoplasmic reticulum (ER) – derived motile vesicles. These membranous viral factories, especially the ER-derived vesicles, not only support vRNA synthesis, but also deliver their viral infectious content to the neighboring non-infected cells, and establish the virus systemic infection. Biogenesis of these vesicles very often involves the hijacking of components of the cellular secretory pathway, and association with ER/actin network.