Institute of Grassland, Flowers, and Ecology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
College of Plants and Technology, Beijing University of Agriculture, Beijing, China.
Planta. 2023 Jul 14;258(2):43. doi: 10.1007/s00425-023-04169-1.
The first complete mitochondrial genome of Carex (C. breviculmis) was sequenced and assembled, and its genomic signature was analyzed and the possible conformations of its mitochondrial genome were validated. Carex breviculmis is a very adaptable grass that is highly resistant to environmental stresses such as drought and low light. It is also admired as a landscape plant with high development prospects and scientific research value. In this study, the mitochondrial genome of C. breviculmis was assembled using Pacbio and Illumina sequencing data. We detected 267 pairs of repeats and found that three pairs of repeats could mediate the recombination of its mitochondrial genome and formed four possible conformations, of which we verified the two conformations mediated by the shortest pair of repeats using PCR amplification and Sanger sequencing. The major conformation of the C. breviculmis mitochondrial genome is a 1,414,795 bp long circular molecule with 33 annotated protein-coding genes, 15 tRNA genes, and three rRNA genes. We detected a total of 25 homologous sequences between the chloroplast and mitochondrial genomes, corresponding to 0.40% of the mitochondrial genome. Combined with the low GC content (41.24%), we conclude that the reduction in RNA editing sites in the C. breviculmis mitochondrial genome may be due to an accumulation of point mutations in C-to-T or retroprocessing events within the genome. The relatively low number of RNA editing sites in its mitochondrial genome could serve as important material for subsequent studies on the selection pressure of RNA editing in angiosperms. A maximum likelihood analysis based on 23 conserved mitochondrial genes from 28 species reflects an accurate evolutionary and taxonomic position of C. breviculmis. This research provided us with a comprehensive understanding of the mitochondrial genome of Carex and also provided important information for its molecular breeding.
首次完成了葎草属（C. breviculmis）的完整线粒体基因组测序和组装，并对其基因组特征进行了分析，验证了其线粒体基因组的可能构象。葎草是一种适应性很强的草，对干旱和低光照等环境压力具有很强的抵抗力。它也被视为一种具有很高发展前景和科学研究价值的景观植物。在本研究中，使用 Pacbio 和 Illumina 测序数据组装了 C. breviculmis 的线粒体基因组。我们检测到 267 对重复序列，并发现其中三对重复序列可以介导其线粒体基因组的重组，并形成四种可能的构象，我们通过 PCR 扩增和 Sanger 测序验证了由最短重复序列介导的两种构象。C. breviculmis 线粒体基因组的主要构象是一个 1,414,795bp 的圆形分子，包含 33 个注释的蛋白质编码基因、15 个 tRNA 基因和 3 个 rRNA 基因。我们总共检测到叶绿体和线粒体基因组之间的 25 个同源序列，占线粒体基因组的 0.40%。结合低 GC 含量（41.24%），我们推断 C. breviculmis 线粒体基因组中 RNA 编辑位点的减少可能是由于基因组内 C 到 T 的点突变积累或反向加工事件。其线粒体基因组中相对较少的 RNA 编辑位点可能为后续研究被子植物 RNA 编辑的选择压力提供重要材料。基于来自 28 个物种的 23 个保守线粒体基因的最大似然分析反映了 C. breviculmis 准确的进化和分类地位。本研究为我们提供了对葎草属线粒体基因组的全面了解，也为其分子育种提供了重要信息。
