Poulicard N. auteur aut IRD Galzi Agnès auteur aut IRD Fargette Denis auteur aut IRD Hébrard Eugénie auteur aut IRD text journalArticle eng text/pdf reformatted digital access 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. specialized 076 084 95 1 219-224 2014 0022-1317 https://www.documentation.ird.fr/hor/fdi:010062393 10.1099/vir.0.057810-0 0022-1317 [F B010062393] https://www.documentation.ird.fr/hor/fdi:010062393 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers15-10/010062393.pdf IRD - Base Horizon / Pleins textes 2014-09-09 2017-08-23 fdi:010062393 fre