Cytomolecular discrimination of the Am chromosomes of Triticum monococcum and the A chromosomes of Triticum aestivum using microsatellite DNA repeats

Development of a New Am -Genome-Specific Single Nucleotide Polymorphism Marker Set for the Molecular Characterization of Wheat-Triticum monococcum Introgression Lines

We identified 1247 polymorphic single nucleotide polymorphisms between Triticum monococcum and wheat. We identified 191 markers validated across all seven chromosomes of T. monococcum. Detected a T. monococcum introgression in leaf-rust-resistant lines. Cultivated einkorn wheat (Triticum monococcum L. subsp. monococcum, 2n = 2x = 14, A^m A^m ) and its wild relative T. monococcum subsp. aegilopoides are important sources of economically useful genes that can be exploited for wheat (Triticum aestivum L.) breeding. Einkorn has excellent resistance to fungal diseases and gene transfer is relatively simple via standard breeding methods. To fulfill the growing demand by modern prebreeding programs for a cost-effective high-throughput procedure for accurately detecting introgressed chromosomes or chromosome segments from T. monococcum into wheat, we used the Axiom Wheat-Relative Genotyping Array and developed a set of A^m genome-specific exome-based single nucleotide polymorphism (SNP) markers suitable for rapid identification of T. monococcum chromatin in a wheat background. We identified 1247 polymorphic SNPs between T. monococcum and wheat. We identified 191 markers across all seven chromosomes of T. monococcum that are also present on an existing Triticum urartu Thum. ex Gandil. genetic map and potentially ordered them on the basis of the high macrocollinearity and conservation of marker order between T. monococcum and T. urartu. The marker set has been tested on leaf-rust-resistant BC₃ F₄ progenies of wheat-T. monococcum hybrids. Two markers (AX-94492165, AX-95073542) placed on the distal end of the chromosome arm 7AL detected a T. monococcum introgression into wheat. The SNP marker set thus proved highly effective in the identification of T. monococcum chromatin in a wheat background, offering a reliable method for screening and selecting wheat-T. monococcum introgression lines, a procedure that could significantly speed up prebreeding programs.