Research Institute, Sichuan Agricultural University, Wenjiang, China.
Key Laboratory of Crop Genetic Resources and Improvement, Ministry of Education, Sichuan Agricultural University, Wenjiang, China.
Cytogenet Genome Res. 2021;161(3-4):213-222. doi: 10.1159/000515623. Epub 2021 Jul 7.
The genera of the tribe Triticeae (family Poaceae), constituting many economically important plants with abundant genetic resources, carry genomes such as St, H, P, and Y. The genome symbol of Roegneria C. Koch (Triticeae) is StY. The St and Y genomes are crucial in Triticeae, and tetraploid StY species participate extensively in polyploid speciation. Characterization of St and Y nonhomologous chromosomes in StY-genome species could help understand variation in the chromosome structure and differentiation of StY-containing species. However, the high genetic affinity between St and Y genome and the deficiency of a complete set of StY nonhomologous probes limit the identification of St and Y genomes and variation of chromosome structures among Roegneria species. We aimed to identify St- and Y-enhanced repeat clusters and to study whether homoeologous chromosomes between St and Y genomes could be accurately identified due to high affinity. We employed comparative genome analyses to identify St- and Y-enhanced repeat clusters and generated a FISH-based karyotype of R. grandis (Keng), one of the taxonomically controversial StY species, for the first time. We explored 4 novel repeat clusters (StY_34, StY_107, StY_90, and StY_93), which could specifically identify individual St and Y nonhomologous chromosomes. The clusters StY_107 and StY_90 could identify St and Y addition/substitution chromosomes against common wheat genetic backgrounds. The chromosomes V_St, VII_St, I_Y, V_Y, and VII_Y displayed similar probe distribution patterns in the proximal region, indicating that the high affinity between St and Y genome might result from chromosome rearrangements or transposable element insertion among V_St/Y, VII_St/Y, and I_Y chromosomes during allopolyploidization. Our results can be used to employ FISH further to uncover the precise karyotype based on colinearity of Triticeae species by using the wheat karyotype as reference, to analyze diverse populations of the same species to understand the intraspecific structural changes, and to generate the karyotype of different StY-containing species to understand the interspecific chromosome variation.
该族的冰草族（禾本科），构成了许多具有丰富遗传资源的经济上重要的植物，携带基因组如 St、H、P 和 Y。冰草属（Triticeae）的基因组符号是 StY。St 和 Y 基因组在冰草族中至关重要，四倍体 StY 物种广泛参与了多倍体物种形成。在 StY-基因组物种中，St 和 Y 非同源染色体的特征可以帮助理解 StY 包含物种的染色体结构和分化的变化。然而，St 和 Y 基因组之间的高度遗传亲和力以及缺乏完整的 StY 非同源探针集限制了 St 和 Y 基因组的鉴定以及冰草属物种之间的染色体结构变化。我们的目标是识别 St-和 Y-增强的重复簇，并研究由于高亲和力，St 和 Y 基因组之间的同源染色体是否可以准确识别。我们采用比较基因组分析来识别 St-和 Y-增强的重复簇，并首次为分类学上有争议的 StY 物种之一大赖草（Keng）生成了基于 FISH 的核型。我们探索了 4 个新的重复簇（StY_34、StY_107、StY_90 和 StY_93），它们可以特异性地识别单个 St 和 Y 非同源染色体。簇 StY_107 和 StY_90 可以在普通小麦遗传背景下识别 St 和 Y 添加/替代染色体。染色体 V_St、VII_St、I_Y、V_Y 和 VII_Y 在近端区域显示出相似的探针分布模式，表明 St 和 Y 基因组之间的高亲和力可能是由于在异源多倍化过程中 V_St/Y、VII_St/Y 和 I_Y 染色体之间的染色体重排或转座元件插入所致。我们的结果可用于进一步采用 FISH，根据小麦核型作为参考，揭示基于冰草族物种的同线性的精确核型，分析同一物种的不同群体，以了解种内结构变化，并生成不同 StY 包含物种的核型，以了解种间染色体变化。
