Genome assembly of the Chinese maize elite inbred line RP125 and its EMS mutant collection provide new resources for maize genetics research and crop improvement.

作者：Shujun Nie, Bo Wang, H. Ding, Haijian Lin, L. Zhang, Qi-Gang Li, Yujiao Wang, Bin Zhang, Anping Liang, Q. Zheng, Hui Wang, Huayang Lv, K. Zhu, Minghui Jia, Xiao-Tong Wang, Jiyuan Du, Runtai Zhao, Zhenzhen Jiang, Caina Xia, Z. Qiao, Xiaohu Li, Bo-Ling Liu, Hongbo Zhu, R. An, Yucui Li, Q. Jiang, Benfang Chen, Hongkai Zhang, De-liang Wang, Changxiao Tang, Yang Yuan, Jie-Fan Dai, J. Zhan, Weiqiang He, Xuebo Wang, Jian-Hua Shi, Bin Wang, Min Gong, Xiujing He, Peng Li, Li Huang, Hui Li, Chao Pan, Hong Huang, G. Yuan, H. Lan, Yongxin Nie, Xinzheng Li, Xiangyu Zhao, Xian-sheng Zhang, G. Pan, Qingyu Wu, Fang Xu, Zhiming Zhang · 发表于：The Plant Journal · 年份：2021 · DOI：10.1111/tpj.15421 · 研究领域：Medicine

Maize is an important crop worldwide, as well as a valuable model with vast genetic diversity. Accurate genome and annotation information for a wide range of inbred lines would provide valuable resources for crop improvement and pan-genome characterization. In this study, we generated a high-quality de novo genome assembly (contig N50 of 15.43 megabases) of the Chinese elite inbred line RP125 using Nanopore long-read sequencing and Hi-C scaffolding, which yield highly contiguous, chromosome-length scaffolds. Global comparison of the RP125 genome with those of B73, W22, and Mo17 revealed a large number of structural variations. To create new germplasm for maize research and crop improvement, we carried out an EMS mutagenesis screen on RP125. We obtained a total of 5,818 independent M2 families, with 946 mutants showing heritable phenotypes. Taking advantage of the high-quality RP125 genome, we successfully cloned 10 mutants from the EMS library, including the novel kernel mutant qk1 (quekou: 'missing a small part' in Chinese), which exhibited partial loss of endosperm and a starch accumulation defect. QK1 encodes a predicted metal tolerance protein that is specifically required for iron transport. Increased accumulation of iron and ROS as well as ferroptosis-like cell death were detected in endosperm of qk1. Our study provides the community with a high-quality genome sequence and a large collection of mutant germplasm.