Silkova Olga G, Loginova Dina B, Zhuravleva Anastasia A, Shumny Vladimir K
Department of Plant Genetics, Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia.
Plants (Basel). 2022 Jun 15;11(12):1582. doi: 10.3390/plants11121582.
Bouquet formation is believed to be involved in initiating homologous chromosome pairings in meiosis. A bouquet is also formed in the absence of chromosome pairing, such as in F wheat-rye hybrids. In some hybrids, meiosis is characterized by a single, mitotic-like division that leads to the formation of unreduced gametes. In this study, FISH with the telomere and centromere-specific probe, and immunoFISH with ASY1, CENH3 and rye subtelomere repeat pSc200 were employed to perform a comparative analysis of early meiotic prophase nuclei in four combinations of wheat-rye hybrids. One of these, with disomic rye chromosome 2R, is known to undergo normal meiosis, and here, 78.9% of the meiocytes formed a normal-appearing telomere bouquet and rye subtelomeres clustered in 83.2% of the meiocytes. In three combinations with disomic rye chromosomes 1R, 5R and 6R, known to undergo a single division of meiosis, telomeres clustered in 11.4%, 44.8% and 27.6% of the meiocytes, respectively. In hybrids with chromosome 1R, rye subtelomeres clustered in 12.19% of the meiocytes. In the remaining meiocytes, telomeres and subtelomeres were scattered along the nucleus circumference, forming large and small groups. We conclude that in wheat-rye hybrids with mitotic-like meiosis, chromosome behavior is altered already in the early prophase.
花束形成被认为与减数分裂中同源染色体配对的起始有关。在没有染色体配对的情况下也会形成花束，例如在F小麦-黑麦杂种中。在一些杂种中，减数分裂的特征是单一的、类似有丝分裂的分裂，导致形成未减数的配子。在本研究中，使用端粒和着丝粒特异性探针进行荧光原位杂交（FISH），以及使用ASY1、CENH3和黑麦亚端粒重复序列pSc200进行免疫荧光原位杂交（immunoFISH），对四种小麦-黑麦杂种组合的减数分裂前期早期细胞核进行了比较分析。其中一个组合含有二体黑麦染色体2R，已知其进行正常减数分裂，在此组合中，78.9%的减数分裂细胞形成了外观正常的端粒花束，83.2%的减数分裂细胞中黑麦亚端粒聚集。在含有二体黑麦染色体1R、5R和6R的三个组合中，已知其进行单次减数分裂，端粒分别在11.4%、44.8%和27.6%的减数分裂细胞中聚集。在含有染色体1R的杂种中，12.19%的减数分裂细胞中黑麦亚端粒聚集。在其余的减数分裂细胞中，端粒和亚端粒沿细胞核周边分散，形成大小不等的群体。我们得出结论，在具有类似有丝分裂减数分裂的小麦-黑麦杂种中，染色体行为在前期早期就已改变。
