Molecular cytogenetic study on the plants of Elymus nutans with varying fertility on the Qinghai-Tibet Plateau

Liu, Bo; Tao, Xiaoyan; Dou, Quanwen

doi:10.1016/j.pld.2021.12.003

Cited by 7 publications

(9 citation statements)

References 31 publications

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“…The St and H genomes presented distinctly higher pairing aberrations than the Y genome. These results are in accordance with the cytological investigation of E. nutans with varying fertility, suggesting that the St and H genomes may contain more chromosomal structural variations than the Y genome ( Liu et al, 2021 ).…”

Section: Discussionsupporting

confidence: 89%

“…Low to high frequencies of heterozygotes have been revealed in domesticated and wild populations of E. nutans by molecular karyotyping ( Dou et al, 2009 , 2017 ). The association between karyotype heterozygosity and low seed fertility has also been demonstrated, reflecting the involvement of chromosome rearrangements in the heterozygotes of E. nutans ( Liu et al, 2021 ). In this study, an individual of E. nutans with a heterozygous karyotype and low fertility was used, and detailed cytological observations were carried out at different meiosis stages with each chromosome clearly identified by FISH.…”

Section: Introductionmentioning

confidence: 94%

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Meiotic Chromosomal Abnormality Detected in a Heterozygote of Elymus nutans

2022

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Elymus nutans is an allopolyploid with a genome constitution of StStYYHH (2n = 6x = 42). Highly frequent intergenomic translocations and chromosomal variations with repeat amplification and deletions in E. nutans have been identified in the previous studies. However, more complicated structural variations such as chromosomal inversions or intra-genomic translocations are still unknown in this species, so does the reason for the origin of the chromosomal variations. Heterozygotes with rearranged chromosomes always present irregular meiosis behaviors, which subsequently cause the secondary chromosome rearrangements. Investigation on the meiosis of heterozygotes, especially on the individual chromosome level, may provide the important clues to identify the more complicated chromosome structural variations in the populations, and clarify the origin of the chromosome variations. In this study, meiotic analysis was conducted on a heterozygote plant of Elymus nutans, which showed high intra- and inter-genome chromosomal variations, by sequential fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH), with each chromosome clearly recognized. The results showed chromosomal abnormalities at every meiotic stage and abnormalities in frequency variations between different sub-genomes and different individual chromosomes. The abnormalities were revealed as univalent, fragment, rod, or Y shape bivalent in diakinesis; univalent and rod bivalent in metaphase I; lagged and segregated chromatid, bridge, fragment of the sister chromatid, fragment, bridge accompanied with fragment, and unequal segregated chromosome in anaphase I; bridge and lagged chromatid in ana-telophase II; and micronucleus at uninucleate stage. Generally, the St and H genomes harbor more abnormalities than the Y genome. Moreover, a paracentric inversion in 2St was exclusively determined, and another paracentric inversion in 6Y was tentatively identified. In addition, novel deletions were clearly detected in 3H, 4H, 1Y, and 3Y homologous chromosomes; in particular, de novo pericentric inversion in 3H was repeatedly identified in metaphase I. The study revealed the chromosomal inversions pre-existed in parents or populations, as well as de novo inversions and deletions originated in the meiosis of the heterozygote in E. nutans. Moreover, it indicated wide range of meiosis abnormalities on different stages and different chromosomes, and suggests that secondary rearrangements contribute much to the chromosome variations in E. nutans.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 94%

Meiotic Chromosomal Abnormality Detected in a Heterozygote of Elymus nutans

2022

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“…Our previous study suggested that the St and H genomes may contain more chromosomal structural variations than the Y genome in E. nutans [22,23]. However, the H genome contained a high number of polymorphic CRs, and the St and Y genomes had low and similar frequencies of those in the present study.…”

Section: Association Between Stability Of Sub-genomes and Crs In E Nu...supporting

confidence: 44%

“…The FISH patterns of E. nutans were far variated in domesticated or natural populations, those of which exhibited as high frequencies of inter-genomic translocations, amplification, and deletion of repeats [20,21]. On the other hand, chromosomal variations in E. nutans can be indicated by pollen meiosis abnormalities observed in low-fertility plants [22,23]. Although chromosomal variations were revealed in both E. sibiricus and E. nutans, chromosomal structural variations, such as intra-genome translocations and inversions, are still not recognized due to the cytological limitations of previous studies.…”

Section: Introductionmentioning

confidence: 99%

Single-gene FISH maps and major chromosomal rearrangements in Elymus sibiricus and E. nutans

et al. 2023

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Background Chromosomal variations have been revealed in both E. sibiricus and E. nutans, but chromosomal structural variations, such as intra-genome translocations and inversions, are still not recognized due to the cytological limitations of previous studies. Furthermore, the syntenic relationship between both species and wheat chromosomes remains unknown. Results Fifty-nine single-gene fluorescence in situ hybridization (FISH) probes, including 22 single-gene probes previously mapped on wheat chromosomes and other newly developed probes from the cDNA of Elymus species, were used to characterize the chromosome homoeologous relationship and collinearity of both E. sibiricus and E. nutans with those of wheat. Eight species-specific chromosomal rearrangements (CRs) were exclusively identified in E. sibiricus, including five pericentric inversions in 1H, 2H, 3H, 6H and 2St; one possible pericentric inversion in 5St; one paracentric inversion in 4St; and one reciprocal 4H/6H translocation. Five species-specific CRs were identified in E. nutans, including one possible pericentric inversion in 2Y, three possible pericentric multiple-inversions in 1H, 2H and 4Y, and one reciprocal 4Y/5Y translocation. Polymorphic CRs were detected in three of the six materials in E. sibiricus, which were mainly represented by inter-genomic translocations. More polymorphic CRs were identified in E. nutans, including duplication and insertion, deletion, pericentric inversion, paracentric inversion, and intra- or inter-genomic translocation in different chromosomes. Conclusions The study first identified the cross-species homoeology and the syntenic relationship between E. sibiricus, E. nutans and wheat chromosomes. There are distinct different species-specific CRs between E. sibiricus and E. nutans, which may be due to their different polyploidy processes. The frequencies of intra-species polymorphic CRs in E. nutans were higher than that in E. sibiricus. To conclude, the results provide new insights into genome structure and evolution and will facilitate the utilization of germplasm diversity in both E. sibiricus and E. nutans.

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“…SCVs include deletions, duplications, inversions, translocations, and more complex rearrangements (Alkan et al, 2011;Lei et al, 2021). The above SCVs in E. nutans have been reported in previous studies (Dou et al, 2009(Dou et al, , 2017Liu et al, 2022aLiu et al, , 2022bLu, 1993), but these studies only focused on the individual or small population level of E. nutans.…”

Section: Introductionmentioning

confidence: 85%

Evaluation of chromosome diversity of Elymus nutans on the Qinghai‐Tibet plateau by FISH

Liu,

Jiang,

Liu

et al. 2023

Grass and Forage Science

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Elymus nutans Griseb. is an important herbage for forage and ecological restoration in the Qinghai‐Tibet Plateau (QTP). It is widely distributed in different habitats of the QTP and has been reported to have high genetic diversity in protein, morphology and DNA sequence. The main objective of our investigation has been to obtain some knowledge of E. nutans chromosome genetic diversity. In this study, the TE probe S5 and tandem repeat probe AAG combined with sequential GISH were able to successfully distinguish different subgenomes and chromosomes in 7 E. nutans accessions from major global distribution sites. On this basis, a total of 123 individuals from four representative populations of E. nutans in the QTP were hybridised. The results of the experiment showed that four types of reciprocal translocations between subgenomes were observed in the four wild populations, and the translocation chromosomes, frequency, and heterozygosis were different in each population. The distribution and quantity of S5 and AAG signals also varied within and among the four populations. The results indicated that E. nutans had high genetic diversity at the chromosome level both within and among populations, and it was speculated that non‐homologous recombination was one of the reasons for the high genetic diversity. These results provide important theoretical guidance for the collection, protection, and evaluation of E. nutans.

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Molecular cytogenetic study on the plants of Elymus nutans with varying fertility on the Qinghai-Tibet Plateau

Cited by 7 publications

References 31 publications

Meiotic Chromosomal Abnormality Detected in a Heterozygote of Elymus nutans

Meiotic Chromosomal Abnormality Detected in a Heterozygote of Elymus nutans

Single-gene FISH maps and major chromosomal rearrangements in Elymus sibiricus and E. nutans

Evaluation of chromosome diversity of Elymus nutans on the Qinghai‐Tibet plateau by FISH

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