Fate of <i>Aegilops speltoides</i>-Derived, Repetitive DNA Sequences in Diploid <i>Aegilops</i> Species, Wheat-<i>Aegilops</i> Amphiploids and Derived Chromosome Addition Lines

Abstract

The present study reports the cloning and characterization of an Aegilopsspeltoides-derived subtelomeric repeat, designated as pSp1B16. Clone pSp1B16 has 98% sequence homology with the previously isolated Ae. speltoides repeat Spelt1. The distribution of pSp1B16 and another Ae. speltoides repeat, pGc1R1, was analyzed in diploid Aegilops species, tetra- and hexaploid wheats, wheat-Aegilops amphiploids and derived chromosome addition lines by fluorescence in situ hybridization (FISH). Clones pSp1B16 and pGc1R1 revealed FISH sites in Ae. speltoides, Ae. sharonensis and Triticumtimopheevii, whereas additional pGc1R1 FISH sites were observed in Ae. longissima and Ae. caudata. The pSp1B16 and pGc1R1 FISH patterns of the Aegilops chromosomes in the wheat-Aegilops amphiploids and chromosome addition lines are similar to those present in the Aegilops parent accession. We did not observe any evidence of pSp1B16 and pGc1R1 sequence elimination, which is in contrast to previous studies using similar hybrids and repeats. The presented data suggest that the genomic changes in synthetic amphiploids observed in previous studies might be caused by homoeologous recombination, which was suppressed in the amphiploid analyzed in this study.

Intrinsic karyotype stability and gene copy number variations may have laid the foundation for tetraploid wheat formation

“…Moreover, WGD alone could result in asynchronization of meiosis (32), resulting in structural chromosomal changes due to homeologous chromosome pairing and illegitimate (or nonhomologous) recombination. In this respect, the findings of Kumar et al (33) are illuminating. The authors showed that certain accessions of diploid Aegilops with the S genome carry suppressors of homeologous pairing with immediate effects on the chromosome pairing in the newly formed allopolyploids (33).…”

“…In this respect, the findings of Kumar et al (33) are illuminating. The authors showed that certain accessions of diploid Aegilops with the S genome carry suppressors of homeologous pairing with immediate effects on the chromosome pairing in the newly formed allopolyploids (33). In light of these findings, it is perhaps not surprising to see extremely low incidence of chromosome rearrangements in genotypes with S and Aegilops longissima carry suppressors of homeologous chromosome pairing.…”

Chromosome specific microsatellite analysis of common wheat lines resistant to powdery mildew

“…Одним із пояснень зникнення компонента (рис. 4, 5, 8) може слугувати досліджена тенденція до елімінації повторюваних тандемних послідовностей ДНК під час стабілізації геномів новосформованих гібридів [17]. Нульовий алель у спектрі за мікросателітним локусом може бути спричинений змінами в нуклеотидних послідовностях, фланкуючих мікросателітний повтор, на основі яких синтезуються праймери [18].…”

Molecular cytogenetic identification of a novel hexaploid wheat–Thinopyrum intermedium partial amphiploid with high protein content

“…The use of alien germplasm has increased intensively in cereal breeding programs for wheat improvement (Whitford et al, 2013). The alien species involved in the development of new amphiploids and wheat-alien chromosome addition, substitution, and translocation lines include the genera Aegilops (Schneider et al, 2005;Kumar et al, 2010;Farkas et al, 2014), Thinopyrum (Sepsi et al, 2008;Georgieva et al, 2011b;Zeng et al, 2013), Dasypyrum (Chen et al, 1995;Yang et al, 2005), Secale (Tang et al, 2008), Hordeum (Munns et al, 2011;Molnár-Láng et al, 2014), Psathyrostachys (Wang et al, 2011), etc. Despite major progress in plant production, the development of salt-and drought-tolerant crops remains elusive in the case of every important crop (Priya et al, 2015).…”