Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India.
Int J Radiat Biol. 2024;100(12):1665-1682. doi: 10.1080/09553002.2024.2409666. Epub 2024 Oct 7.
Black gram ( [L.] Hepper) is an important annual legume with great economic, nutritional and ecological significance. Novel variations through induced mutagenesis can accelerate narrow genetic base-impeded black gram improvement. This is a first study on characterization of genome-wide mutation spectrum induced by electron beam (EB).
Black gram genotype 'Pant U-31' was irradiated with 400 Gy EB generated in a 10 MeV LINAC. A stable mutant PM-32 (M) was re-sequenced by combining Illumina (BIOO Scientific, Inc., Austin, TX) and Nanopore Technologies (Oxford, UK). Variants were predicted in reference to the available whole genome scaffold level draft assembly of parent 'Pant U-31'.
Genome analysis predicted a total of 76,893 genes of which 58,517 were annotated. The identified variants totaling 728,161, largely comprised (91.56%) of single base substitutions (SBSs) with a transition (Ti) to transversion (Tv) ratio of 1.95. Of the indels constituting 8.44% of total induced variants, insertions accounted for 4.29%, with preponderance of multiple bases (53.63%) and 2-5 bp insertions as the major class (33.71%). Multiple-base deletions (2-5 bases) formed the bulk (31.14%) of the total deletions. The genic variants (2438) with estimated high and moderate effects were located within 1271 predicted genes. A higher number of mutations were observed on chromosomes Vm1 (588) and Vm3 (428) with the highest frequency on chromosome Vm3 (every 0.07 Mb).
Our study reiterated the mutagenic utility of EB for inducing SBSs and small indels genome-wide. The knowledge gained from SNP-level profiling of EB-induced mutations can expedite comparative mutation breeding studies in legumes.
黑绿豆（[L.] Hepper）是一种重要的一年生豆科植物，具有巨大的经济、营养和生态意义。通过诱导突变产生的新变异可以加速因遗传基础狭窄而受阻的黑绿豆改良。这是首次研究电子束（EB）诱导的全基因组突变谱。
用 10MeV 直线加速器产生的 400Gy EB 辐照黑绿豆基因型'Pant U-31'。将突变体 PM-32（M）与 Illumina（BIOO Scientific，Inc.，Austin，TX）和 Nanopore Technologies（Oxford，UK）相结合进行重新测序。在参考可用的亲本'Pant U-31'全基因组支架水平草案组装的情况下，对变体进行预测。
基因组分析共预测了 76893 个基因，其中 58517 个被注释。总共鉴定出 728161 个变体，主要由单碱基替换（SBS）组成（91.56%），其中转换（Ti）到颠换（Tv）的比例为 1.95。在构成总诱导变体的 8.44%的插入缺失中，插入占 4.29%，多数为多个碱基（53.63%）和 2-5bp 插入，主要类别（33.71%）。总缺失中以多个碱基（2-5 个碱基）的缺失居多（31.14%）。估计具有高和中度效应的基因变异（2438 个）位于 1271 个预测基因内。在 Vm1（588）和 Vm3（428）染色体上观察到更多的突变，在 Vm3 染色体上的频率最高（每 0.07 Mb）。
本研究重申了 EB 诱导全基因组 SBS 和小插入缺失的诱变效用。从 EB 诱导突变的 SNP 水平分析中获得的知识可以加速豆科植物的比较突变育种研究。
