Ayme Valérie, Petit-Pierre Julien, Souche Sylvie, Palloix Alain, Moury Benoît
INRA, UR1052 Génétique et Amélioration des Fruits et Légumes, F-84143 Montfavet, France.
INRA, UR407 Pathologie Végétale, F-84143 Montfavet, France.
J Gen Virol. 2007 May;88(Pt 5):1594-1601. doi: 10.1099/vir.0.82702-0.
The virulence properties of potato virus Y (PVY) towards an allelic series at the pvr2 locus in pepper genotypes are related to variations in the genome-linked viral protein (VPg). Eleven amino acid substitutions in the central part of the VPg were identified in strains differing by their virulence properties and were introduced, either singly or in combination, in an infectious PVY clone to get an in-depth genetic analysis of the virulence determinant. The virulence spectrum of these mutants was evaluated by inoculation of four pepper genotypes carrying different alleles at the pvr2 locus. The mutations introduced had complex effects on virulence, including antagonistic epistasis and trade-offs for virulence towards different pvr2 alleles. In addition, several mutants showed new virulence properties that were unknown in the natural environment. Such complex effects of mutations on plant virus virulence are unprecedented. They provide a better understanding of the variable levels of durability of the resistance conferred by the different pvr2 alleles, and have important consequences for a durable management of the resistances.
马铃薯Y病毒（PVY）对辣椒基因型中pvr2基因座上等位基因系列的毒力特性与基因组连接病毒蛋白（VPg）的变异有关。在具有不同毒力特性的菌株中，VPg中部鉴定出11个氨基酸替换，并将其单独或组合引入感染性PVY克隆中，以深入分析毒力决定因素的遗传学。通过接种在pvr2基因座携带不同等位基因的四种辣椒基因型，评估了这些突变体的毒力谱。引入的突变对毒力有复杂影响，包括拮抗上位性和对不同pvr2等位基因毒力的权衡。此外，几个突变体表现出自然环境中未知的新毒力特性。突变对植物病毒毒力的这种复杂影响是前所未有的。它们有助于更好地理解不同pvr2等位基因赋予的抗性的不同持久水平，并对持久抗性管理具有重要意义。
