Development and application of EST-based markers specific for chromosome arms of rye (Secale cereale L.)

To develop a set of molecular markers specific for the chromosome arms of rye, a total of 1,098 and 93 primer pairs derived from the expressed sequence tag (EST) sequences distributed on all 21 wheat chromosomes and 7 rye chromosomes, respectively, were initially screened on common wheat 'Chinese Spring' and rye cultivar 'Imperial'. Four hundred and fourteen EST-based markers were specific for the rye genome. Seven disomic chromosome addition lines, 10 telosomic addition lines and 1 translocation line of 'Chinese Spring-Imperial' were confirmed by genomic in situ hybridization and fluorescencein situ hybridization, and used to screen the rye-specific markers. Thirty-one of the 414 markers produced stable specific amplicons in 'Imperial', as well as individual addition lines and were assigned to 13 chromosome arms of rye except for 6RS. Six rye cultivars, wheat cultivar 'Xiaoyan 6' and accessions of 4 wheat relatives were then used to test the specificity of the 31 EST-based markers. To confirm the specificity, 4 wheat-rye derivatives of 'Xiaoyan 6 × German White', with chromosomes 1RS, 2R and 4R, were amplified by some of the EST-based markers. The results indicated that they can effectively be used to detect corresponding rye chromosomes or chromosome arms introgressed into a wheat background, and hence to accelerate the utilization of rye genes in wheat breeding.