title: Alternative mutational pathways, outside the VPg, of rice yellow mottle virus to overcome eIF(iso)4G-mediated rice resistance under strong genetic constraints.
abstract: The adaptation of rice yellow mottle virus (RYMV) to rymv1-mediated resistance has been reported to involve mutations in the viral genome-linked protein (VPg). In this study, we analysed several cases of rymv1-2 resistance breakdown by an isolate with low adaptability. Surprisingly, in these rarely occurring resistance-breaking (RB) genotypes, mutations were detected outside the VPg, in the ORF2a/ORF2b overlapping region. The causal role of three mutations associated with rymv1-2 resistance breakdown was validated via directed mutagenesis of an infectious clone. In resistant plants, these mutations increased viral accumulation as efficiently as suboptimal RB mutations in the VPg. Interestingly, these mutations are located in a highly conserved, but unfolded, domain. Altogether, our results indicate that under strong genetic constraints, a priori unfit genotypes can follow alternative mutational pathways, i.e. outside the VPg, to overcome rymv1-2 resistance.
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France.
authors.forename: Nils
authors.initials: N
authors.lastname: Poulicard
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Pinel-Galzi
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Fargette
authors.affiliation: Institut de Recherche pour le Développement (IRD), UMR RPB, Montpellier, France.
authors.forename: Eugénie
authors.initials: E
authors.lastname: Hébrard
mesh_terms: D039603:Eukaryotic Initiation Factor-4G / Q000235:genetics / Q000276:immunology; D016679:Genome, Viral; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000276:immunology / Q000821:virology*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000821:virology*; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology; D012328:RNA Viruses / Q000235:genetics* / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics* / Q000276:immunology
chemical_list: D039603:Eukaryotic Initiation Factor-4G; D010940:Plant Proteins; D014764:Viral Proteins