Loss-of-Susceptibility Mutants of Arabidopsis thaliana Reveal an Essential Role for elF(iso)4E during Potyvirus Infection

• Published in: Current biology 2002-06, Vol.12 (12), p.1046-1051
• Main Authors: Lellis, AD, Kasschau, K D, Whitham, SA, Carrington, J C
• Format: Article
• Language: English
• ISSN: 0960-9822
• DOI: 10.1016/S0960-9822(02)00898-9

The Arabidopsis thaliana-potyvirus system was developed to identify compatibility and incompatibility factors involved during infection and disease caused by positive-strand RNA viruses. Several Arabidopsis mutants with increased susceptibility to Tobacco etch potyvirus (TEV) were isolated previously, revealing a virus-specific resistance system in the phloem. In this study, Arabidopsis mutants with decreased susceptibility to Turnip mosaic potyvirus (TuMV) were isolated. Three independent mutants that conferred immunity to TuMV were isolated and assigned to the same complementation group. These mutants were also immune or near-immune to TEV but were susceptible to an unrelated virus. The locus associated with decreased susceptibility was named loss-of-susceptibility to potyviruses 1 (lsp1). The LSP1 locus was isolated by map-based cloning and was identified as the gene encoding translation factor elF(iso)4E, one of several known Arabidopsis isoforms that has cap binding activity. elF4E and elF(iso)4E from different plant species were shown previously to interact with the genome-linked protein (VPg) of TEV and TuMV, respectively. Models to explain the roles of elF(iso)4E during virus infection are presented.