Analysis of meiotic genome stabilization in the rye-wheat amphidiploid secalotriticum (×Secalotriticum, S/RRAABB, 2n = 42)

Lyusikov, O. M.; Gordei, I. A.

doi:10.1134/s1022795414070126

Cited by 1 publication

(5 citation statements)

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“…The formation of the secalotriticum genome takes place in F1BC1 on the basis of partially unreduced 21-chromosome gametes of F1 pentaploids with balanced chromosome sets of the original species haplogenomes (7(R), 7(A), 7(B)). Equation division (division into chromatids) of asynaptic univalents in anaphase I (AI) is the main source of chromosomal abnormalities during the second meiosis division (MII): individual chromatids are not included in the metaphase plate in MII; in anaphase II they often lag behind other chromosomes in division, segregate randomly, undergo fragmentation, and form micronuclei in the microspore tetrads, which leads to the elimination of genetic material and aneuploidy and the genomic instability [3, 23, 24]. Stability of the secalotriticum genome and its genetic diversity are determined by the cytoplasm type and some factors, apparently related to the structural and functional state of centromeres in its genome.…”

Section: Resultsmentioning

confidence: 99%

“…Stability of the secalotriticum genome and its genetic diversity are determined by the cytoplasm type and some factors, apparently related to the structural and functional state of centromeres in its genome. Analyzing meiosis in hybrids, we observed the formation of (pseudo)univalents mainly as a result of desynapsis [23, 24]. Desynapsis here means the early decomposition of bivalents into univalents of desynaptic origin (pseudounivalents) that occur in the late prophase (prometaphase I) of meiosis.…”

Section: Resultsmentioning

confidence: 99%

“…Unlike the asynaptic univalents characteristic of triticale, the pseudounivalents maintain their unipolar centromere orientation in the reductional (I) division of meiosis. The equational (II) division of meiosis was characterized by regular polar segregation and a low level of chromosome elimination [23, 24].…”

Section: Resultsmentioning

confidence: 99%

“…Stabilization was due to the narrowing of the spectrum and a rapid decrease in the frequency of the chromosome abnormalities in the second meiotic division (by 15-50%) in F1-F3, including the level of chromosome elimination (from 30% to 6% tetrads with micronuclei). In F3-5 and subsequent secalotriticum generations, the normalization of the first division of meiosis was more pronounced: the average level of anomalies in MI metaphase decreased from 57.3% in F3 to 16.9% in F5 and also from 25-30% up to 8-10% in AI-AII anaphases and reached less than 5% at the tetrad stage [3, 23, 24]. The fact that the chromosomal changes mentioned above tend to occur quickly and most intensively in the first generations, up to the fifth, inclusive, and especially in F1 before the chromosome doubling, is probably a general trend in remote hybridization of cereals [3, 21, 23, 24].…”

Section: Resultsmentioning

confidence: 99%

“…In F3-5 and subsequent secalotriticum generations, the normalization of the first division of meiosis was more pronounced: the average level of anomalies in MI metaphase decreased from 57.3% in F3 to 16.9% in F5 and also from 25-30% up to 8-10% in AI-AII anaphases and reached less than 5% at the tetrad stage [3, 23, 24]. The fact that the chromosomal changes mentioned above tend to occur quickly and most intensively in the first generations, up to the fifth, inclusive, and especially in F1 before the chromosome doubling, is probably a general trend in remote hybridization of cereals [3, 21, 23, 24]. Thus, continuous cycles of crosses in the secalotriticum production played a significant role in stabilizing the hybrid karyotype and replacing possible lost parts of the parental genomes in the first generations after hybridization.…”

Section: Resultsmentioning

confidence: 99%

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Dynamics of the Centromeric Histone CENH3 Structure in Rye-Wheat Amphidiploids (Secalotriticum)

Lipikhina

Евтушенко

Lyusikov

et al. 2018

BioMed Research International

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The centromeres perform integral control of the cell division process and proper distribution of chromosomes into daughter cells. The correct course of this process is often disrupted in case of remote hybridization, which is a stress factor. The combination of parental genomes of different species in a hybrid cell leads to a “genomic shock” followed by loss of genes, changes in gene expression, deletions, inversions, and translocations of chromosome regions. The created rye-wheat allopolyploid hybrids, which were collectively called secalotriticum, represent a new interesting model for studying the effect of remote hybridization on the centromere and its components. The main feature of an active centromere is the presence of a specific histone H3 modification in the centromeric nucleosomes, which is referred to as CENH3 in plants. In this paper the results of cytogenetic analysis of the secalotriticum hybrid karyotypes and the comparison of the CENH3 N-terminal domain structure of parent and hybrid forms are presented. It is shown that the karyotypes of the created secalotriticum forms are stable balanced hexaploids not containing minichromosomes with deleted arms, in full or in part. A high level of homology between rye and wheat enables to express both parental forms of CENH3 gene in the hybrid genomes of secalotriticum cultivars. The CENH3 structure in hybrids in each crossing combination has some specific features. The percentage of polymorphisms at several amino acid positions is much higher in one of the secalotriticum hybrids, STr VD, than in parental forms, whereas the other hybrid, STr VM, inherits a high level of amino acid substitutions at the position 25 from the maternal parent.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%