Table1_Assembly and comparative analysis of the first complete mitochondrial genome of zicaitai (Brassica rapa var. Purpuraria): insights into its genetic architecture and evolutionary relationships.xlsx

IntroductionZicaitai (Brassica rapa var. purpuraria) is a Brassica variety renowned for its distinctive taste and rich nutritional profile. In recent years, the mitochondrial genomes of several Brassica species have been documented, but the mitogenome of Zicaitai remains unreported.MethodsIn this study, we characterized the Zicaitai mitogenome achieved through the assembly of sequencing reads derived from both the Oxford Nanopore and Illumina platforms. A detailed comparative analysis was carried out with other Brassica species to draw comparisons and contrasts. In-depth analyses of codon usage patterns, instances of RNA editing, and the prevalence of sequence repeats within the mitogenome were also conducted to gain a more nuanced understanding of its genetic architecture. A phylogenetic analysis was performed, utilizing the coding sequences (CDS) from the mitochondrial genome of Zicaitai and that of 20 closely related species/varieties to trace evolutionary connections.ResultsThe Zicaitai mitogenome is characterized by a circular structure spanning 219,779 base pairs, and it encompasses a total of 59 genes. This gene set includes 33 protein-coding genes, 23 tRNA genes, and 3 rRNA genes, providing a rich foundation for further genomic study. An analysis of the Ka/Ks ratios for 30 protein-coding genes shared by the mitogenomes of Zicaitai and seven other Brassica species revealed that most of these genes had undergone purifying selection. Additionally, the study explored the migration of genes between the chloroplast and nuclear genomes and the mitogenome, offering insights into the dynamics of genetic exchange within the Brassica genus.DiscussionThe collective results in this study will serve as a foundational resource, aiding future evolutionary studies focused on B. rapa, and contributing to a broader understanding of the complexities of plant evolution.

引言紫菜苔（Brassica rapa var. purpuraria）是一种以其独特的风味和丰富的营养价值而闻名的芸苔属品种。近年来，已对多种芸苔属物种的线粒体基因组进行了记录，但紫菜苔的线粒体基因组尚未被报道。方法在本研究中，我们通过组装来自牛津纳米孔和Illumina平台的测序读数，对紫菜苔的线粒体基因组进行了特征描述。我们对其他芸苔属物种进行了详细的比较分析，以进行对比和对照。还对密码子使用模式、RNA编辑的实例以及线粒体基因组内序列重复的普遍性进行了深入分析，以获得对其遗传结构的更深入理解。通过使用紫菜苔线粒体基因组及其20个密切相关物种/品种的编码序列（CDS）进行了系统发育分析，以追溯进化联系。结果紫菜苔的线粒体基因组具有环状结构，跨度为219,779个碱基对，包含总共59个基因。这个基因集包括33个蛋白质编码基因、23个tRNA基因和3个rRNA基因，为进一步的基因组研究提供了丰富的基石。对紫菜苔和七个其他芸苔属物种共有的30个蛋白质编码基因的Ka/Ks比进行分析表明，其中大部分基因经历了净化选择。此外，本研究还探讨了叶绿体基因组、核基因组与线粒体基因组之间基因的迁移，为芸苔属中遗传交换的动态提供了见解。讨论本研究中的综合结果将成为一个基础性资源，有助于未来针对B. rapa的进化研究，并为更广泛地理解植物进化的复杂性做出贡献。