Mirzaghaderi Ghader, Abdolmalaki Zinat, Zohouri Mohsen, Moradi Zeinab, Mason Annaliese S
Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Kurdistan, P. O. Box 416, Sanandaj, Iran.
Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Plant Cell Rep. 2017 Aug;36(8):1277-1285. doi: 10.1007/s00299-017-2152-x. Epub 2017 Apr 29.
NOR loci of C-subgenome are dominant in wheat × Aegilops interspecific hybrids, which may have evolutionary implications for wheat group genome dynamics and evolution. After interspecific hybridisation, some genes are often expressed from only one of the progenitor species, shaping subsequent allopolyploid genome evolution processes. A well-known example is nucleolar dominance, i.e. the formation of cell nucleoli from chromosomes of only one parental species. We studied nucleolar organizing regions (NORs) in diploid Aegilops markgrafii (syn: Ae. caudata; CC), Ae. umbellulata (UU), allotetraploids Aegilops cylindrica (CCDD) and Ae. triuncialis (CCUU), synthetic interspecific F hybrids between these two allotetraploids and bread wheat (Triticum aestivum, AABBDD) and in F generation hybrids with genome composition AABBDDCCUU using silver staining and fluorescence in situ hybridization (FISH). In Ae. markgrafii (CC), NORs of both 1C and 5C or only 5C chromosome pairs were active in different individual cells, while only NORs on 1U chromosomes were active in Ae. umbellulata (UU). Although all 35S rDNA loci of the C subgenome (located on 1C and 5C) were active in Ae. triuncialis, only one pair (occupying either 1C or 5C) was active in Ae. cylindrica, depending on the genotype studied. These C-genome expression patterns were transmitted to the F and F generations. Wheat chromosome NOR activity was variable in Ae. triuncialis × T. aestivum F seeds, but silenced by the F generation. No effect of maternal or paternal cross direction was observed. These results indicate that C-subgenome NOR loci are dominant in wheat × Aegilops interspecific hybrids, which may have evolutionary implications for wheat group genome dynamics and allopolyploid evolution.
小麦与节节麦种间杂种中C基因组的核仁组织区（NOR）位点占主导地位，这可能对小麦组基因组动态和进化具有进化意义。种间杂交后，一些基因通常仅从一个亲本物种表达，从而塑造了随后的异源多倍体基因组进化过程。一个著名的例子是核仁显性，即仅由一个亲本物种的染色体形成细胞核仁。我们使用银染和荧光原位杂交（FISH）技术，研究了二倍体马克格拉夫山羊草（同义名：尾状山羊草；CC）、伞形山羊草（UU）、异源四倍体圆柱山羊草（CCDD）和三芒山羊草（CCUU）、这两个异源四倍体与普通小麦（普通小麦，AABBDD）之间的合成种间F杂种以及基因组组成为AABBDDCCUU的F代杂种中的核仁组织区（NOR）。在马克格拉夫山羊草（CC）中，1C和5C染色体对的NOR或仅5C染色体对的NOR在不同的单个细胞中是活跃的，而在伞形山羊草（UU）中只有1U染色体上的NOR是活跃的。尽管C基因组的所有35S rDNA位点（位于1C和5C上）在三芒山羊草中是活跃的，但在圆柱山羊草中只有一对（占据1C或5C）是活跃的，这取决于所研究的基因型。这些C基因组的表达模式传递到了F和F代。在三芒山羊草×普通小麦F种子中，小麦染色体NOR活性是可变的，但在F代中被沉默。未观察到母本或父本杂交方向的影响。这些结果表明，C基因组NOR位点在小麦与节节麦种间杂种中占主导地位，这可能对小麦组基因组动态和异源多倍体进化具有进化意义。
