Heavy-ion beam, a type of ionizing radiation, has been applied to plant breeding as a powerful mutagen and is a promising tool to induce large deletions and chromosomal rearrangements. The effectiveness of heavy-ion irradiation can be explained by linear energy transfer (LET; keV µm-1). Heavy-ion beams with different LET values induce different types and sizes of mutations. It has been suggested that deletion size increases with increasing LET value, and complex chromosomal rearrangements are induced in higher LET radiations. In this study, we mapped heavy-ion beam-induced deletions detected in Arabidopsis mutants to its genome. We revealed that deletion sizes were similar between different LETs (100 to 290 keV μm-1), that their upper limit was affected by the distribution of essential genes, and that the detected chromosomal rearrangements avoid disrupting the essential genes. We also focused on tandemly arrayed genes (TAGs), where two or more homologous genes are adjacent to one another in the genome. Our results suggested that 100 keV µm-1 of LET is enough to disrupt TAGs and that the distribution of essential genes strongly affects the heritability of mutations overlapping them. Our results provide a genomic view of large deletion inductions in the Arabidopsis genome.

中文翻译：

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与拟南芥必需基因分布相关的重离子诱导缺失的基因组学观点

重离子束是一种电离辐射，已作为一种强大的诱变剂应用于植物育种，是诱导大量缺失和染色体重排的有前途的工具。重离子辐照的有效性可以通过线性能量转移（LET；keV µm-1）。具有不同 LET 值的重离子束会诱发不同类型和大小的突变。有人提出，缺失大小随着 LET 值的增加而增加，并且在较高的 LET 辐射下会诱导复杂的染色体重排。在这项研究中，我们将在拟南芥突变体中检测到的重离子束诱导的缺失映射到其基因组。我们发现不同 LET（100 至 290 keV μm）之间的缺失大小相似-1），其上限受到必需基因分布的影响，并且检测到的染色体重排避免破坏必需基因。我们还关注串联排列基因（TAG），其中两个或多个同源基因在基因组中彼此相邻。我们的结果表明 100 keV µm-1LET 足以破坏 TAG，并且必需基因的分布强烈影响与它们重叠的突变的遗传力。我们的结果提供了拟南芥基因组中大缺失诱导的基因组视图。