Cytogenetic characterization and molecular marker development for a wheat-T. boeoticum 4Ab (4B) disomic substitution line with stripe rust resistance.

Abstract

Triticum boeoticum (2n = 2x = 14, AbAb) is an important relative of wheat. This species tolerates many different types of environmental stresses, including drought, salt, and pathogenic infection, and is lower in dietary fiber and higher in antioxidants, protein (15-18%), lipids, and trace elements than common wheat. However, the gene transfer rate from this species to common wheat is low, and few species-specific molecular markers are available. In this study, the wheat-T. boeoticum substitution line Z1889, derived from a cross between the common wheat cultivar Crocus and Triticum boeoticum line G52, was identified using multicolor fluorescence in situ hybridization (mc-FISH), multicolor genomic in situ hybridization (mc-GISH) and a 55K single nucleotide polymorphism (SNP) array. Z1889 was revealed to be a 4Ab (4B) substitution line with a high degree of resistance to stripe rust pathogen strains prevalent in China. In addition, 22 4Ab chromosome-specific molecular markers and 11 T. boeoticum genome-specific molecular markers were developed from 1145 4Ab chromosome-specific fragments by comparing the sequences generated by specific-length amplified fragment sequencing (SLAF-seq), with an efficiency of up to 55.0%. Furthermore, the specificity of these markers was verified in four species containing the Ab genome. These markers can not only be used for the detection of the 4Ab chromosome but also provide a basis for molecular marker-assisted selection-based breeding in wheat.