Abstract
BackgroundTriticum monococcum (2n = 2x = 14) is an ancient diploid wheat with many useful traits and is used as a model for wheat gene discovery. DArT (Diversity Arrays Technology) employs a hybridisation-based approach to type thousands of genomic loci in parallel. DArT markers were developed for T. monococcum to assess genetic diversity, compare relationships with hexaploid genomes, and construct a genetic linkage map integrating DArT and microsatellite markers.ResultsA DArT array, consisting of 2304 hexaploid wheat, 1536 tetraploid wheat, 1536 T. monococcum as well as 1536 T. boeoticum representative genomic clones, was used to fingerprint 16 T. monococcum accessions of diverse geographical origins. In total, 846 polymorphic DArT markers were identified, of which 317 were of T. monococcum origin, 246 of hexaploid, 157 of tetraploid, and 126 of T. boeoticum genomes. The fingerprinting data indicated that the geographic origin of T. monococcum accessions was partially correlated with their genetic variation. DArT markers could also well distinguish the genetic differences amongst a panel of 23 hexaploid wheat and nine T. monococcum genomes. For the first time, 274 DArT markers were integrated with 82 simple sequence repeat (SSR) and two morphological trait loci in a genetic map spanning 1062.72 cM in T. monococcum. Six chromosomes were represented by single linkage groups, and chromosome 4Am was formed by three linkage groups. The DArT and SSR genetic loci tended to form independent clusters along the chromosomes. Segregation distortion was observed for one third of the DArT loci. The Ba (black awn) locus was refined to a 23.2 cM region between the DArT marker locus wPt-2584 and the microsatellite locus Xgwmd33 on 1Am; and the Hl (hairy leaf) locus to a 4.0 cM region between DArT loci 376589 and 469591 on 5Am.ConclusionDArT is a rapid and efficient approach to develop many new molecular markers for genetic studies in T. monococcum. The constructed genetic linkage map will facilitate localisation and map-based cloning of genes of interest, comparative mapping as well as genome organisation and evolution studies between this ancient diploid species and other crops.
Highlights
Triticum monococcum (2n = 2x = 14) is an ancient diploid wheat with many useful traits and is used as a model for wheat gene discovery
We report here the results of a study aimed to (1) develop a T. monococcum diversity array (DArT) for high-throughput genome-wide genotyping, (2) assess the utility of the Diversity Arrays Technology (DArT) technology for analysis of genetic diversity in a representative collection of T. monococcum accessions, (3) compare the relationships between the Am-genome and other Triticum genomes using DArT markers, (4) produce a genetic linkage map for T. monococcum integrating DArT and simple sequence repeat (SSR) markers, and (5) refine the genome locations of two morphological trait loci
Array composition A total of 1536 DArT clones were developed from a PstI/ TaqI representation generated from a mixture of DNA of two T. monococcum accessions MDR002 and MDR308 [35]
Summary
Triticum monococcum (2n = 2x = 14) is an ancient diploid wheat with many useful traits and is used as a model for wheat gene discovery. Triticum monococcum (2n = 2x = 14), generally known as einkorn wheat, is an ancient diploid species domesticated in the Fertile Crescent ~10,000 years ago In modern times T. monococcum remains cultivated at low scale only in the mountainous areas of several Mediterranean countries This species has not been bred intensively and retained its genetic diversity [3]. T. monococcum has gradually been recognised as an attractive diploid model for exploitation of useful traits, discovery of novel genes and variant alleles, and functional genomics. In the foreseeable future T. monococcum is expected to play an important role in wheat genetic and genomic studies
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