Abstract:
As a physical mutagen, carbon ion beam (CIB) irradiation can induce high-frequency mutation, which is user-friendly and environment-friendly in plant breeding. In this study, we resequenced eight mutant lines which were screened out from the progeny of the CIB-irradiated dehulled rice seeds. Among these mutants, CIB induced 135,535 variations, which include single base substitutions (SBSs), and small insertion and deletion (InDels). SBSs are the most abundant mutation, and account for 88% of all variations. Single base conversion is the main type of SBS, and the average ratio of transition and transversion is 1.29, and more than half of the InDels are short-segmented mutation (1-2 bp). A total of 69.2% of the SBSs and InDels induced by CIBs occurred in intergenic regions on the genome. Surprisingly, the average mutation frequency in our study is 9.8 × 10-5/bp and much higher than that of the previous studies, which may result from the relatively high irradiation dosage and the dehulling of seeds for irradiation. By analyzing the mutation of every 1 Mb in the genome of each mutant strain, we found some unusual high-frequency (HF) mutation regions, where SBSs and InDels colocalized. This study revealed the mutation mechanism of dehulled rice seeds by CIB irradiation on the genome level, which will enrich our understanding of the mutation mechanism of CIB radiation and improve mutagenesis efficiency.
摘要:
作为一种物理诱变剂,碳离子束(CIB)辐照可以诱发高频突变,在植物育种中是用户友好和环境友好的。在这项研究中,我们重新测序了8个突变系,这些突变系是从CIB辐照的去壳水稻种子的后代中筛选出来的。在这些突变体中,CIB诱导135,535个变异,其中包括单碱基取代(SBS),和小插入和删除(InDels)。SBS是最丰富的突变,占所有变化的88%。单碱基转换是SBS的主要类型,过渡和颠换的平均比率为1.29,超过一半的InDels是短片段突变(1-2bp)。由CIBs诱导的SBS和InDels总共有69.2%发生在基因组的基因间区域。令人惊讶的是,我们研究的平均突变频率为9.8×10-5/bp,比以前的研究高得多,这可能是由于相对较高的辐照剂量和种子的脱壳进行辐照所致。通过分析每个突变株基因组中每1Mb的突变,我们发现了一些不寻常的高频(HF)突变区域,SBSs和InDels共同定位。这项研究揭示了CIB辐照在基因组水平上对去壳水稻种子的诱变机理,这将丰富我们对CIB辐射突变机制的理解,提高诱变效率。