Elsa Maria Vera Ruiz, José Miguel Soriano, Carlos Romero, Javier Terol, Elena Zuriaga, Gerard Llacer, Maria Luisa Badenes
Instituto Valenciano de Investigaciones Agrarias (IVIA), Apartado Oficial, 46113 Moncada, Valencia, Spain
Tetyana Zhebentyayeva, Albert Glenn Abbott
Department of Genetics and Biochemistry, Clemson University, 100 Jordan Hall, Clemson, SC 29634, USA
Sharka disease, caused by the Plum pox virus (PPV), is one of the main limiting factors for stone fruit crops worldwide. Only a few resistance sources have been found in apricot (Prunus armeniaca L.), and most studies have located a major PPV resistance locus (PPVres) on linkage group 1 (LG1). However, the mapping accuracy was not sufficiently reliable and PPVres was predicted within a low confidence interval. In this study, we have constructed two high-density simple sequence repeat (SSR) improved maps with 0.70 and 0.68 markers/cm, corresponding to LG1 of ‘Lito’ and ‘Goldrich’ PPV-resistant cultivars, respectively. Using these maps, and excluding genotype– phenotype incongruent individuals, a new binary trait locus (BTL) analysis for PPV resistance was performed, narrowing down the PPVres support intervals to 7.3 and 5.9 cm in ‘Lito’ and ‘Goldrich’, respectively. Subsequently, 71 overlapping oligonucleotides (overgo) probes were hybridized against an apricot bacterial artificial chromosome (BAC) library, identifying 870 single BACs from which 340 were anchored onto a map region of approximately 30–40 cm encompassing PPVres. Partial BAC contigs assigned to the two allelic haplotypes (resistant/susceptible) of the PPVres locus were built by highinformation content fingerprinting (HICF). In addition, a total of 300 BAC-derived sequences were obtained, and 257 showed significant homology with the peach genome scaffold_1 corresponding to LG1. According to the peach syntenic genome sequence, PPVres was predicted within a region of 2.16 Mb in which a few candidate resistance genes were identified.
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