Authors
Grégoire Marandel¹, Jaroslav Salava², Albert Abbott³, Thierry Candresse¹, Véronique Decroocq^1
1UMR Génomique, Diversité, Pouvoir Pathogène, INRA et Université Bordeaux II Victor Ségalen, IBVM, 71 avenue Edouard Bourleaux, 33883 Villenave d’Ornon, France
²Division of Plant Medicine, Crop Research Institute, Drnovská 507, 161 06 Prague 6, Czech Republic
³Department of Genetics, Biochemistry, and Life Science Studies, Clemson University, 100 Jordan Hall, Clemson, SC 29634, USA

Abstract
Plum pox virus (PPV) is responsible for sharka disease, one of the most detrimental stone fruit diseases affecting Prunus trees worldwide. Only a few apricot cultivars have been described as resistant, most originating from North American breeding programmes. Several PPV resistance quantitative trait loci (QTLs) have been mapped in various progenies, consistently highlighting the contribution to the resistance of the upper part of linkage group 1 (LG1). However, to date, no consensus has been reached on the precise number of QTLs linked to the resistance to PPV in apricot and P. davidiana or on their accurate position on the genetic linkage map. In the present study, the quantitative resistance of cultivar ‘Harlayne’ was analysed over five growth periods in a large F1 population. Four QTLs were identified, three mapping on LG1, explaining between 5% and 39% of the observed phenotypic variance. In an effort to further this analysis of PPV resistance in apricot, these results were merged in a single QTL meta-analysis with those of five other PPV resistance analyses available in the literature. Three consensus QTL regions were identified on LG1 and a putative fourth region on LG3. QTL meta-analysis also revealed the contribution of each resistant cultivar to metaQTLs, providing interesting comparative data on the resistance factors shared between the resistance sources used in the various studies. Finally, it was shown that one of the metaQTLs co-localizes with the eukaryotic translation initiation factor eIF4E, thus providing new hypotheses on the mechanisms of PPV resistance in apricot.

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