Mutational analysis of plant cap-binding protein eIF4E reveals key amino acids involved in biochemical functions and potyvirus infection.

The eukaryotic translation initiation factor 4E (eIF4E) (the cap-binding protein) is involved in natural resistance against several potyviruses in plants. In lettuce, the recessive resistance genes mo1(1) and mo1(2) against Lettuce mosaic virus (LMV) are alleles coding for forms of eIF4E unable, or less effective, to support virus accumulation. A recombinant LMV expressing the eIF4E of a susceptible lettuce variety from its genome was able to produce symptoms in mo1(1) or mo1(2) varieties.

Interaction between potyvirus helper component-proteinase and capsid protein in infected plants.

Monoclonal antibodies were raised against helper component-proteinase (HcPro) purified from plants infected with the potyvirus Lettuce mosaic virus (LMV). These antibodies were used in a two-site triple antibody sandwich ELISA assay together with polyclonal antibodies directed against purified virions. An interaction between HcPro and the viral coat protein (CP) was demonstrated in extracts of LMV-infected leaves, as well as for two other potyviruses, Plum pox virus and Potato virus Y.