[The struggle for translation: how RNA phytoviruses use eukaryotic Initiation Factor 4E]

Potyvirus are one of the largest groups of phytopathogenic virus and are responsible for significant agronomic loss. Host proteins belonging to the eukaryotic translation initiation complex, and particularly eIF4E (eukaryotic Initiation Factor 4E, which binds to the mRNA cap), play an important role in the success of a productive potyvirus infection. Plant eIF4E interacts with the viral VPg protein, which binds to the 5' end of the viral genome. In several plant species eIF4E isoforms have amino acid changes that prevent the interaction with VPg, leading to recessive resistance to potyviruses. Analysis of the natural variability of eIF4E and VPg proteins suggests that their diversity is structured by coevolution between the host and the pathogen. The role of the eIF4E and VPg interaction in the viral life cycle remains largely unknown: It could be involved in translation, replication or cell to cell trafficking of the viral genome. Genetic analysis shows that, besides eIF4E, other proteins of the translation initiation complex are likely to be involved in viral production. Furthermore, other groups of RNA virus require proteins of the translation initiation complex for completing their life cycle. This pinpoints the importance of translation initiation, a key target used by viruses to subvert the cell's machinery.