The manipulation of meiotic recombination in crops is essential to develop new plant varieties rapidly, helping to produce more cultivars in a sustainable manner. One option is to control the formation and repair of the meiosis‐specific DNA double‐strand breaks (DSBs) that initiate recombination between the homologous chromosomes and ultimately lead to crossovers. These DSBs are introduced by the evolutionarily conserved topoisomerase‐like protein SPO11 and associated proteins. Here, we characterized the homoeologous copies of the SPO11‐1 protein in hexaploid bread wheat (Triticum aestivum). The genome contains three SPO11‐1 gene copies that exhibit 93–95% identity at the nucleotide level, and clearly the A and D copies originated from the diploid ancestors Triticum urartu and Aegilops tauschii, respectively. Furthermore, phylogenetic analysis of 105 plant genomes revealed a clear partitioning between monocots and dicots, with the seven main motifs being almost fully conserved, even between clades. The functional similarity of the proteins among monocots was confirmed through complementation analysis of the Oryza sativa (rice) spo11‐1 mutant by the wheat TaSPO11‐1‐5D coding sequence. Also, remarkably, although the wheat and Arabidopsis SPO11‐1 proteins share only 55% identity and the partner proteins also differ, the TaSPO11‐1‐5D cDNA significantly restored the fertility of the Arabidopsis spo11‐1 mutant, indicating a robust functional conservation of the SPO11‐1 protein activity across distant plants. These successful heterologous complementation assays, using both Arabidopsis and rice hosts, are good surrogates to validate the functionality of candidate genes and cDNA, as well as variant constructs, when the transformation and mutant production in wheat is much longer and more tedious.

中文翻译：

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面包小麦TaSPO11-1在远处植物物种的减数分裂重组中表现出进化的保守功能。

作物减数分裂重组的操纵对于快速开发新的植物品种至关重要，有助于以可持续的方式生产更多的品种。一种选择是控制减数分裂特异的DNA双链断裂（DSB）的形成和修复，该断裂会引发同源染色体之间的重组并最终导致交叉。这些DSB由进化上保守的拓扑异构酶样蛋白SPO11和相关蛋白引入。在这里，我们表征了六倍体面包小麦（小麦）中SPO11-1蛋白的同源拷贝。基因组包含三个SPO11-1基因拷贝，在核苷酸水平上具有93-95％的同一性，并且显然A和D拷贝起源于二倍体祖先普通小麦和乌节麦草。此外，对105个植物基因组的系统发育分析表明，单子叶植物和双子叶植物之间有明确的划分，七个主要基序几乎完全保守，甚至在进化枝之间也是如此。通过小麦TaSPO11-1-5D编码序列对水稻Oryza sativa（rice）spo11-1突变体的互补分析，证实了这些蛋白质在单子叶植物中的功能相似性。另外，值得注意的是，尽管小麦和拟南芥SPO11-1蛋白仅具有55％的同一性，并且伴侣蛋白也有所不同，但TaSPO11-1-5D cDNA显着恢复了拟南芥spo11-1的育性。突变体，表明远处植物中SPO11-1蛋白活性的功能保守性强。这些成功的利用拟南芥和水稻寄主的异源互补测定法是很好的替代品，可用于验证候选基因和cDNA以及变体构建体的功能，这时小麦的转化和突变体生产要长得多且乏味。