A mitochondrial (mt) transcriptional unit, nad3-orf156, was studied in the nucleus-cytoplasm hybrids of wheat with D/D2 plasmons from Aegilops species and their parental lines. A comparative RFLP analysis and sequencing of the random PCR clones revealed the presence of seven sequence types and their polymorphic sites were mapped. All the hybrids possessed the paternal copies besides the maternal copies. More paternal copies were present in the D2 plasmon hybrids, whereas more maternal copies were present in the D plasmon hybrids. Two major copies were present with different stoichiometries in the maternal Aegilops parents. However, only a major D plasmon copy was detected in the hybrids, irrespective of their plasmon types. The hexaploid wheat parent (AABBDD genome) possessed the major D plasmon copy in approximately 5% stoichiometry, while no D plasmon-homologous copies were detected in the tetraploid wheat parent (AABB genome). The results suggest that the observed mtDNA heteroplasmy is due to paternal contribution of mtDNA. The different copy stoichiometry suggests differential amplification of the heteroplasmic copies among the hybrids and the parental lines. All editing sites and their editing frequencies were conserved among the lines, and only the maternal pattern of editing occurred in the hybrids.
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机译：研究了线粒体（mt）转录单位nad3-orf156在小麦与来自Aegilops物种及其亲本的D / D2等离子体激元的核-细胞质杂种中的研究。随机PCR克隆的比较RFLP分析和测序表明存在七种序列类型，并绘制了它们的多态位点。除母本外，所有杂种均具有父本。 D 2等离子体激元杂种中存在更多的父本副本，而D等离子体激元杂种中存在更多的母本副本。在母亲的Aegilops父母中，有两个主要副本具有不同的化学计量比。但是，杂种中仅检测到主要的D等离子体激元拷贝，而与它们的等离子体激元类型无关。六倍体小麦亲本（AABBDD基因组）具有约5％的化学计量比的主要D等离子体激元拷贝，而在四倍体小麦亲本（AABB基因组）中未检测到D等离子体激元同源拷贝。结果表明观察到的mtDNA异质性是由于mtDNA的父系贡献。不同的拷贝化学计量表明杂种和亲本系之间的异质拷贝差异扩增。各行之间的所有编辑位点及其编辑频率均得到保留，并且杂种中仅发生母本编辑模式。
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