高粱A1型细胞质雄性不育系与保持系线粒体基因组分析比较

Comparison of Mitochondrial Genome Between A1 Cytoplasmic Male Sterile Line and Maintainer Line of Sorghum bicolor

线粒体基因组易位是导致作物细胞质雄性不育(Cytoplasmic male sterility,CMS)性状产生的重要遗传机制。比较高粱A1型细胞质雄性不育系与保持系线粒体基因组,寻找易位区为克隆高粱A1型细胞质雄性不育相关基因奠定基础。以高粱A1型细胞质雄性不育系Tx623A和其保持系Tx623B为试验材料,采用二代Illumina Hiseq结合三代PacBio测序技术,对2个样品的线粒体基因组进行组装,比较和分析不育系和保持系基因组结构和基因差异。高粱Tx623A和Tx623B线粒体基因组大小分别为449 727 bp和452 772 bp,预测编码开放阅读框(Open reading frame,ORFs)分别为147和145个,且两基因组特有基因分别为8个和6个。两线粒体基因组共线性比较分析,发现存在一个57 kb的基因组片段易位的结构变异(Structural variation,SV)区域,该易位区可能与A1型细胞质雄性不育有关。Tx623A和Tx623B线粒体基因组中易位区为高粱A1型细胞质雄性不育基因克隆提供了基因组信息。

Mitochondrial genomic translocation is an important genetic mechanism for cytoplasmic male sterility(CMS)in crops. The main purpose of this study is to explore the translocation region of mitochondrial genomes by comparing the mitochondrial genome between A1 cytoplasmic male sterile line and maintainer line of Sorghum bicolor,and to lay a foundation for cloning related genes of sorghum A1 cytoplasmic male sterility. A1 cytoplasmic male sterile line Tx623 A and its maintainer line Tx623 B of sorghum were used in this experiment.Their mitochondrial genome sequencing data from Illumina Hiseq(next generation sequencing)and PacBio seq(third generation sequencing)were assembled,and then,the differences of genome structures and genes between the two lines were compared and analyzed. The results showed that the mitochondrial genome sizes of Tx623 A and Tx623 B were 449 727 bp and 452 772 bp,respectively. The predicted open reading frames(ORFs)were 147 and 145,among which the number of the specific genes for Tx623 A were 8 and 6 for Tx623 B. Importantly,a57 kb genome structural variation(SV)region was found after comparing the two mitochondrial genomes,and which may be related to A1 cytoplasmic male sterility. Collectively,our results provide genomic information for cloning related genes of sorghum A1 cytoplasmic male sterility.