Goatgrasses with U- and M-genomes are important sources of new alleles for wheat breeding to maintain yield and quality under extreme conditions. However, the introgression of beneficial traits from wild Aegilops species into wheat has been limited by poor knowledge of their genomes and scarcity of molecular tools. Here, we present the first linkage map of allotetraploid Aegilops biuncialis Vis., developed using 224 F2 individuals derived from a cross between MvGB382 and MvGB642 accessions. The map comprises 5663 DArTseq markers assigned to 15 linkage groups corresponding to 13 chromosomes. Chromosome 1Mb could not be constructed due to a lack of recombination caused by rearrangements in the MvGB382 accession. The genetic map spans 2518 cM with an average marker density of 2.79 cM. The skeleton map contains 920 segregating markers, divided between the Mb sub-genome (425 markers) and the Ub sub-genome (495 markers). Chromosomes of the Mb sub-genome, originating from Aegilops comosa Sm. in Sibth. et Sm., show well-preserved collinearity with Triticum aestivum L. chromosomes. In contrast, chromosomes of the Ub sub-genome, originating from Aegilops umbellulata Zhuk., exhibit a varying degree of collinearity, with 1Ub, 3Ub, and 5Ub retaining a substantial level of collinearity with Triticum aestivum, while 2Ub, 4Ub, 6Ub, and 7Ub show significant rearrangements. A quantitative trait locus affecting fertility was identified near the centromere on the long arm of chromosome 3Mb, explaining 23.5% of the variance. The genome structure of Aegilops biuncialis, highlighted by the genetic map, provides insights into the speciation within the species and will support alien gene transfer into wheat.

• MeSH
• Aegilops * genetika   MeSH
• chromozomy rostlin genetika   MeSH
• genetická vazba MeSH
• genetické markery MeSH
• genom rostlinný * MeSH
• mapování chromozomů MeSH
• pšenice * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• genetické markery MeSH

Wild wheat relative Aegilops biuncialis offers valuable traits for crop improvement through interspecific hybridization. However, gene transfer from Aegilops has been hampered by difficulties in detecting introgressed Ub- and Mb-genome chromatin in the wheat background at high resolution. The present study applied DArTseq technology to genotype two backcrossed populations (BC382, BC642) derived from crosses of wheat line Mv9kr1 with Ae. biuncialis accession, MvGB382 (early flowering and drought-tolerant) and MvGB642 (leaf rust-resistant). A total of 11,952 Aegilops-specific Silico-DArT markers and 8,998 wheat-specific markers were identified. Of these, 7,686 markers were assigned to Ub-genome chromosomes and 4,266 to Mb-genome chromosomes and were ordered using chromosome scale reference assemblies of hexaploid wheat and Ae. umbellulata. Ub-genome chromatin was detected in 5.7% of BC382 and 22.7% of BC642 lines, while 88.5% of BC382 and 84% of BC642 lines contained Mb-genome chromatin, predominantly the chromosomes 4Mb and 5Mb. The presence of alien chromatin was confirmed by microscopic analysis of mitotic metaphase cells using GISH and FISH, which allowed precise determination of the size and position of the introgression events. New Mv9kr1-Ae. biuncialis MvGB382 4Mb and 5Mb disomic addition lines together with a 5DS.5DL-5MbL recombination were identified. A possible effect of the 5MbL distal region on seed length has also been observed. Moreover, previously developed Mv9kr1-MvGB642 introgression lines were more precisely characterized. The newly developed cytogenetic stocks represent valuable genetic resources for wheat improvement, highlighting the importance of utilizing diverse genetic materials to enhance wheat breeding strategies.

• Klíčová slova
• Aegilops biuncialis, Chromosome addition lines, DArTseq analysis, Thousand-grain weight, Wheat-Aegilops introgressions,
• MeSH
• Aegilops * genetika   MeSH
• chromatin * genetika   metabolismus   MeSH
• chromozomy rostlin * genetika   MeSH
• genetické markery MeSH
• genom rostlinný * MeSH
• genotyp MeSH
• genotypizační techniky MeSH
• genová introgrese MeSH
• mapování chromozomů MeSH
• pšenice * genetika   MeSH
• šlechtění rostlin metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chromatin * MeSH
• genetické markery MeSH

The annual goatgrass, Aegilops biuncialis is a rich source of genes with considerable agronomic value. This genetic potential can be exploited for wheat improvement through interspecific hybridization to increase stress resistance, grain quality and adaptability. However, the low throughput of cytogenetic selection hampers the development of alien introgressions. Using the sequence of flow-sorted chromosomes of diploid progenitors, the present study enabled the development of chromosome-specific markers. In total, 482 PCR markers were validated on wheat (Mv9kr1) and Ae. biuncialis (MvGB642) crossing partners, and 126 on wheat-Aegilops additions. Thirty-two markers specific for U- or M-chromosomes were used in combination with GISH and FISH for the screening of 44 Mv9kr1 × Ae. biuncialis BC3F3 genotypes. The predominance of chromosomes 4M and 5M, as well as the presence of chromosomal aberrations, may indicate that these chromosomes have a gametocidal effect. A new wheat-Ae. biuncialis disomic 4U addition, 4M(4D) and 5M(5D) substitutions, as well as several introgression lines were selected. Spike morphology and fertility indicated that the Aegilops 4M or 5M compensated well for the loss of 4D and 5D, respectively. The new cytogenetic stocks represent valuable genetic resources for the introgression of key genes alleles into wheat.

• MeSH
• Aegilops * genetika   MeSH
• chromozomy rostlin genetika   MeSH
• genetické markery MeSH
• genomika MeSH
• hybridizace in situ fluorescenční MeSH
• pšenice * genetika   MeSH
• translokace genetická MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• genetické markery MeSH

Breeding of wheat adapted to new climatic conditions and resistant to diseases and pests is hindered by a limited gene pool due to domestication and thousands of years of human selection. Annual goatgrasses (Aegilops spp.) with M and U genomes are potential sources of the missing genes and alleles. Development of alien introgression lines of wheat may be facilitated by the knowledge of DNA sequences of Aegilops chromosomes. As the Aegilops genomes are complex, sequencing relevant Aegilops chromosomes purified by flow cytometric sorting offers an attractive route forward. The present study extends the potential of chromosome genomics to allotetraploid Ae. biuncialis and Ae. geniculata by dissecting their M and U genomes into individual chromosomes. Hybridization of FITC-conjugated GAA oligonucleotide probe to chromosomes suspensions of the two species allowed the application of bivariate flow karyotyping and sorting some individual chromosomes. Bivariate flow karyotype FITC vs. DAPI of Ae. biuncialis consisted of nine chromosome-populations, but their chromosome content determined by microscopic analysis of flow sorted chromosomes indicated that only 7Mb and 1Ub could be sorted at high purity. In the case of Ae. geniculata, fourteen chromosome-populations were discriminated, allowing the separation of nine individual chromosomes (1Mg, 3Mg, 5Mg, 6Mg, 7Mg, 1Ug, 3Ug, 6Ug, and 7Ug) out of the 14. To sort the remaining chromosomes, a partial set of wheat-Ae. biuncialis and a whole set of wheat-Ae. geniculata chromosome addition lines were also flow karyotyped, revealing clear separation of the GAA-rich Aegilops chromosomes from the GAA-poor A- and D-genome chromosomes of wheat. All of the alien chromosomes represented by individual addition lines could be isolated at purities ranging from 74.5% to 96.6% and from 87.8% to 97.7%, respectively. Differences in flow karyotypes between Ae. biuncialis and Ae. geniculata were analyzed and discussed. Chromosome-specific genomic resources will facilitate gene cloning and the development of molecular tools to support alien introgression breeding of wheat.

• Klíčová slova
• Aegilops biuncialis, Aegilops geniculata, chromosome flow sorting, flow karyotyping, genome dissecting,
• Publikační typ
• časopisecké články MeSH

Effective utilization of genetic diversity in wild relatives to improve wheat requires recombination between wheat and alien chromosomes. However, this is suppressed by the Pairing homoeologous gene, Ph1, on the long arm of wheat chromosome 5B. A deletion mutant of the Ph1 locus (ph1b) has been used widely to induce homoeologous recombination in wheat × alien hybrids. However, the original ph1b mutation, developed in Chinese Spring (CS) background has poor agronomic performance. Hence, alien introgression lines are first backcrossed with adapted wheat genotypes and after this step, alien chromosome segments are introduced into breeding lines. In this work, the ph1b mutation was transferred from two CSph1b mutants into winter wheat line Mv9kr1. Homozygous genotypes Mv9kr1 ph1b/ph1b exhibited improved plant and spike morphology compared to Chinese Spring. Flow cytometric chromosome analysis confirmed reduced DNA content of the mutant 5B chromosome in both wheat genotype relative to the wild type chromosome. The ph1b mutation in the Mv9kr1 genotype allowed wheat-alien chromosome pairing in meiosis of Mv9kr1ph1b_K × Aegilops biuncialis F1 hybrids, predominantly with the Mb-genome chromosomes of Aegilops relative to those of the Ub genome. High frequency of wheat-Aegilops chromosome interactions resulted in rearranged chromosomes identified in the new Mv9kr1ph1b × Ae. Biuncialis amphiploids, making these lines valuable sources for alien introgressions. The new Mv9kr1ph1b mutant genotype is a unique resource to support alien introgression breeding of hexaploid wheat.

• Klíčová slova
• Aegilops biuncialis, bread wheat, chromosome flow sorting, homoeologous recombination, in situ hybridization, meiotic chromosome pairing, ph1b mutant,
• Publikační typ
• časopisecké články MeSH

Grain dietary fiber content is an important health-promoting trait of bread wheat. A dominant dietary fiber component of wheat is the cell wall polysaccharide arabinoxylan and the goatgrass Aegilops biuncialis has high β-glucan content, which makes it an attractive gene source to develop wheat lines with modified fiber composition. In order to support introgression breeding, this work examined genetic variability in grain β-glucan, pentosan, and protein content in a collection of Ae. biuncialis. A large variation in grain protein and edible fiber content was revealed, reflecting the origin of Ae. biuncialis accessions from different eco-geographical habitats. Association analysis using DArTseq-derived SNPs identified 34 QTLs associated with β-glucan, pentosan, water-extractable pentosan, and protein content. Mapping the markers to draft chromosome assemblies of diploid progenitors of Ae. biuncialis underlined the role of genes on chromosomes 1Mb, 4Mb, and 5Mb in the formation of grain β-glucan content, while other QTLs on chromosome groups 3, 6, and 1 identified genes responsible for total- and water-extractable pentosan content. Functional annotation of the associated marker sequences identified fourteen genes, nine of which were identified in other monocots. The QTLs and genes identified in the present work are attractive targets for chromosome-mediated gene transfer to improve the health-promoting properties of wheat-derived foods.

• Klíčová slova
• Aegilops biuncialis, DArTseq analysis, dietary fiber, genome-wide association study (GWAS), β-glucan,
• MeSH
• Aegilops * genetika   MeSH
• beta-glukany * MeSH
• lokus kvantitativního znaku MeSH
• potravní vláknina MeSH
• pšenice genetika   MeSH
• rostlinné geny MeSH
• šlechtění rostlin MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta-glukany * MeSH
• potravní vláknina MeSH
• voda MeSH