In eukaryotes, ei F4E translation initiation factors are essential proteins encoded by a small multigene family. In plants, they are a major source of host plant resistance to potyviruses that require specific 4E factors to infect cells. Combining mutations in different eiF4E genes could be a way of broadening the spectrum of plant resistance to viruses. We attempted to combine null mutations affecting the two main Arabidopsis thaliana 4E factors eiF4E1 and eiFiso4E but discovered that this combination is lethal. Transmission through the male gametophyte is completely abolished in the eif4e1 and eifiso4e double mutant. This shows that eIF4E1 and eIFiso4E are essential for male gametophyte development and act redundantly. These results may have implications for ei F4E-based pyramiding strategies to improve crop resistance