Identification of resistance gene analogues (RGA) and development of E chromosome-specific RGA markers in wheat - Lophopyrum elongatum addition lines

Degenerate primers designed from the conserved regions of nucleotide-binding site domains of known plant resistance gene products were used to scan a complete set of wheat–Lophopyrum elongatum addition lines. Forty-six clones were isolated and they were grouped into seven families of resistance gene analogues (RGA). All families were characterised as the Toll–Interleukin receptor group of R-genes (plant disease resistance genes). The putative chromosome-specific SNP (single-nucleotide polymorphism) loci were identified by multiple sequence alignments. Furthermore, 20 E chromosome-specific RGA markers were used to identify polymorphic fragments in wheat–Lo. elongatum addition lines and amphidiploid. The results suggested that these chromosome-specific markers could be not only useful for marker-assisted selection and map-based cloning of R-genes in Lo. elongatum, but also feasible for investigating the evaluation process of the E genome.