重离子束(HIB)是一种有效的物理诱变剂,已广泛应用于植物突变育种中。在发育和基因组水平上由不同HIB剂量引起的效应的系统知识将促进作物的有效育种。在这里,我们系统地研究了HIB的作用。用十种剂量的碳离子束(CIB,25-300Gy),这是使用最广泛的HIB。我们最初检查了增长,M1种群的发育和光合参数,发现超过125Gy的剂量会对水稻造成明显的生理损害。随后,我们通过全基因组测序(WGS)分析了来自6种治疗方法(25-150Gy)的179例M2个体的基因组变异.突变率峰值在100Gy(2.66×10-7/bp)。重要的是,我们发现同一M1个体的不同穗之间共有的突变比例较低,验证了不同的穗可能来自不同的祖细胞这一假设。此外,我们分离了129个具有不同表型变异的突变体,包括农艺性状的变化,来自11,720平方米的工厂,占1.1%的突变率。其中,M3中约有50%具有稳定的遗传。11个稳定M4突变体的WGS数据,包括三条收益率较高的线,揭示他们的基因组突变谱和候选基因。我们的结果表明,HIB是促进育种的有效工具,水稻的最佳剂量范围是67-90%的中位致死剂量(LD50),这里分离的突变体可以进一步用于功能基因组研究,遗传分析,和繁殖。
Heavy ion beam (HIB) is an effective physical mutagen that has been widely used in plant mutational breeding. Systemic knowledge of the effects caused by different HIB doses at developmental and genomic levels will facilitate efficient breeding for crops. Here we examined the effects of HIB systematically. Kitaake rice seeds were irradiated by ten doses of carbon ion beams (CIB, 25 - 300 Gy), which is the most widely used HIB. We initially examined the growth, development and photosynthetic parameters of the M1 population and found that doses exceeding 125 Gy caused significant physiological damages to rice. Subsequently, we analyzed the genomic variations in 179 M2 individuals from six treatments (25 - 150 Gy) via whole-genome sequencing (WGS). The mutation rate peaks at 100 Gy (2.66×10-7/bp). Importantly, we found that mutations shared among different panicles of the same M1 individual are at low ratios, validating the hypothesis that different panicles may be derived from different progenitor cells. Furthermore, we isolated 129 mutants with distinct phenotypic variations, including changes in agronomic traits, from 11,720 M2 plants, accounting for a 1.1% mutation rate. Among them, about 50% possess stable inheritance in M3. WGS data of 11 stable M4 mutants, including three lines with higher yields, reveal their genomic mutational profiles and candidate genes. Our results demonstrate that HIB is an effective tool that facilitates breeding, that the optimal dose range for rice is 67 - 90% median lethal dose (LD50), and that the mutants isolated here can be further used for functional genomic research, genetic analysis, and breeding.