Genetic classification of Aegilops columnaris Zhuk. (2n=4x=28, U^cU^cX^cX^c) chromosomes based on FISH analysis and substitution patterns in common wheat × Ae. columnaris introgressive lines

Abstract

Aegilops columnaris is a tetraploid species originated from Ae. umbellulata (2n=2x=14, UU) and a yet unknown diploid grass species. Although Ae. columnaris possesses some agronomically valuable traits, such as heat and drought tolerance and resistance to pests, it has never been used in wheat breeding because of difficulties in producing hybrids and a lack of information on the relationships between Ae. columnaris and common wheat chromosomes. In this paper, we report the development of 57 wheat - Ae. columnaris introgressive lines covering 8 of the14 chromosomes of Aegilops. Based on substitution spectra of hybrids and the results of FISH analysis of the parental Ae. columnaris line with seven DNA probes, we have developed the genetic nomenclature of the U and X chromosomes. Genetic groups and genome affinities were established for 11 of 14 chromosomes; the classification of the remaining three chromosomes remains unsolved. Each Ae. columnaris chromosome was characterized on the basis of C-banding pattern and the distribution of seven DNA sequences. Introgression processes were shown to depend on the parental wheat genotype and the level of divergence of homoeologous chromosomes. We found that lines carrying chromosome 5X are resistant to leaf rust; therefore, this chromosome could possess novel resistance genes that have never been utilized in wheat breeding.

DArTseq-based analysis of genomic relationships among species of tribe Triticeae

“…However, chromosome pairing is affected by diverse factors, and the reliability of failed chromosome pairing as an indicator of genome dissimilarity has been questioned 9 – 11 . Molecular cytogenetic methods such as C-banding, fluorescence in situ hybridization and genomic in situ hybridization have also helped to generate useful information on genome differences and phylogenetic relationships in the Triticeae 1 – 3 , 12 , 13 . Other molecular approaches, including isozyme analysis, variations in low-molecular-weight glutenin subunit and DNA marker systems have provided some explanations on Aegilops-Triticum relationships, the origin and differentiation of Aegilops species, and intra- and inter-specific variations in the D and U genome clusters of Aegilops species 14 – 17 .…”

Molecular identification of the stem rust resistance genes in the introgression lines of spring bread wheat

“…It should be noted that the substitution of 6Ag i (6D) from Ag. intermedium was previously identified in the cultivars Favorit and Voevoda, while the Lebyodushka cultivar had the genes Sr6Ag i + Lr19/Sr25 (combination of substitution 6Ag i (6D) and translocation 7DS-7DL-7Ae#1L) (Sibikeev et al, 2017a), and the translocation 7DS-7DL-7Ae#1L from tall wheatgrass with gene Sr25/ Lr19 was identified in the Dobrynya cultivar (Badaeva et al, 2018). The presence of the gene Sr25 in the Dobrynya and Lebyodushka cultivars is confirmed in this work (Table 1).…”

Chromosome and Molecular Analyses Reveal Significant Karyotype Diversity and Provide New Evidence on the Origin of Aegilops columnaris

“…neglecta [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ], but the origin of these two species was a subject of long debates and is still not clear. Analysis of meiotic chromosome pairing in intraspecific hybrids [ 15 , 16 , 17 , 18 ], comparison of karyotype structure [ 19 ] and C-banding patterns [ 13 , 20 ], molecular analysis on nuclear [ 11 , 12 ] and cytoplasmic DNAs [ 21 , 22 ] showed that one of the Ae. columnaris and Ae.…”

“…comosa exhibited low chromosome pairing [ 15 ]. Differences in the patterns of variation of the repetitive nucleotide sequences [ 11 , 26 ], RAPD-spectra [ 9 ], the results of DArTseq-based analysis [ 12 ], comparison of karyotype structures [ 19 ], C-banding, and Fluorescence in situ hybridization (FISH)-patterns [ 13 , 20 ] contradicted this hypothesis. Taking into consideration the distinctness of Ae.…”

“…The problem of chromosome classification was solved later when a set of wheat- Ae. columnaris (K−1193) introgression lines was developed and cytogenetically characterized [ 20 ].…”