CLONING AND MAPPING OF RESISTANCE GENE HOMOLOGUES IN APRICOT (PRUNUS ARMENIACA L.)

Genomic DNA sequences, sharing homology with the NBS-LRR (Nucleotide Binding Site - Leucine Rich Repeat) resistance genes, were isolated and cloned from apricot using a PCR approach with degenerate primers designed from conserved regions of the NBS domain. RGA-specific primers were developed from the consensus sequences of each apricot RGA family and were used to develop AFLP-RGA markers by means of an AFLP-modified procedure, where one standard primer is substituted by an RGA-specific primer. Using this method, 27 polymorphic markers, six of which shared homology with the TIR class of the NBS-LRR R-genes, were obtained from 17 different primer combinations. Sixteen of the 27 mapped in an apricot genetic map previously constructed from the self-pollination of the cultivar ‘Lito’.