Lee Sang Woo, Kwon Yu-Jeong, Baek Inwoo, Choi Hong-Il, Ahn Joon-Woo, Kim Jin-Baek, Kang Si-Yong, Kim Sang Hoon, Jo Yeong Deuk
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea.
Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea.
Front Plant Sci. 2021 Oct 28;12:752108. doi: 10.3389/fpls.2021.752108. eCollection 2021.
Protons may have contributed to the evolution of plants as a major component of cosmic-rays and also have been used for mutagenesis in plants. Although the mutagenic effect of protons has been well-characterized in animals, no comprehensive phenotypic and genomic analyses has been reported in plants. Here, we investigated the phenotypes and whole genome sequences of Arabidopsis M lines derived by irradiation with proton beams and gamma-rays, to determine unique characteristics of proton beams in mutagenesis. We found that mutation frequency was dependent on the irradiation doses of both proton beams and gamma-rays. On the basis of the relationship between survival and mutation rates, we hypothesized that there may be a mutation rate threshold for survived individuals after irradiation. There were no significant differences between the total mutation rates in groups derived using proton beam or gamma-ray irradiation at doses that had similar impacts on survival rate. However, proton beam irradiation resulted in a broader mutant phenotype spectrum than gamma-ray irradiation, and proton beams generated more DNA structural variations (SVs) than gamma-rays. The most frequent SV was inversion. Most of the inversion junctions contained sequences with microhomology and were associated with the deletion of only a few nucleotides, which implies that preferential use of microhomology in non-homologous end joining was likely to be responsible for the SVs. These results show that protons, as particles with low linear energy transfer (LET), have unique characteristics in mutagenesis that partially overlap with those of low-LET gamma-rays and high-LET heavy ions in different respects.
质子作为宇宙射线的主要成分，可能对植物进化有贡献，并且已被用于植物诱变。尽管质子的诱变效应在动物中已得到充分表征，但在植物中尚未有全面的表型和基因组分析报道。在此，我们研究了经质子束和γ射线辐照产生的拟南芥M系的表型和全基因组序列，以确定质子束在诱变中的独特特性。我们发现突变频率取决于质子束和γ射线的辐照剂量。基于存活率和突变率之间的关系，我们推测辐照后存活个体可能存在一个突变率阈值。在对存活率有相似影响的剂量下，使用质子束或γ射线辐照产生的组间总突变率没有显著差异。然而，质子束辐照产生的突变体表型谱比γ射线辐照更宽，并且质子束比γ射线产生更多的DNA结构变异（SVs）。最常见的SV是倒位。大多数倒位连接点包含具有微同源性的序列，并且仅与少数核苷酸的缺失相关，这意味着在非同源末端连接中优先使用微同源性可能是SVs产生的原因。这些结果表明，质子作为低传能线密度（LET）的粒子，在诱变中具有独特特性，在不同方面与低LET的γ射线和高LET的重离子部分重叠。
