Missing links? — The connection between replication and movement of plant RNA viruses

Plant virus infection spreads from cell-to-cell within the host with the aid of viral movement proteins (MPs) that transport infectious genomes through intercellular pores called plasmodesmata (PD). MPs are able to accomplish RNA trafficking independent of virus infection. However, although dispensable for replication, they often associate with or assist in the formation of viral replication complexes. Quantitative analyses of genetic bottlenecks during infection, as well as considerations of transport specificity, suggest that intricate links between replication and movement may facilitate efficient delivery of plant viruses through PD during early infection, at a stage when viral genomes are still rare.

► Replication and movement of plant viruses are coordinated. ► Movement proteins may be recruited to or translated locally at replication sites. ► Replication can also occur localised at plasmodesmata. ► Coordination may increase transport efficiency or specificity. ► Movement protein–replication site interactions probably involve host factors.