Abstract：
Taxus plants are the exclusive source of paclitaxel, an anticancer drug with significant medicinal and economic value. Interspecies hybridization and gene introgression during evolution have obscured distinctions among Taxus species, complicating their phylogenetic classification. While the chloroplast genome of Taxus wallichiana, a widely distributed species in China, has been sequenced, its mitochondrial genome (mitogenome) remains uncharacterized.We sequenced and assembled the T. wallichiana mitogenome using BGI short reads and Nanopore long reads, facilitating comparisons with other gymnosperm mitogenomes. The T. wallichiana mitogenome spanning 469,949 bp, predominantly forms a circular configuration with a GC content of 50.51%, supplemented by 3 minor configurations mediated by one pair of LRs and two pairs of IntRs. It includes 32 protein-coding genes, 7 tRNA genes, and 3 rRNA genes, several of which exist in multiple copies.We detailed the mitogenome\'s structure, codon usage, RNA editing, and sequence migration between organelles, constructing a phylogenetic tree to elucidate evolutionary relationships. Unlike typical gymnosperm mitochondria, T. wallichiana shows no evidence of mitochondrial-plastid DNA transfer (MTPT), highlighting its unique genomic architecture. Synteny analysis indicated extensive genomic rearrangements in T. wallichiana, likely driven by recombination among abundant repetitive sequences. This study offers a high-quality T. wallichiana mitogenome, enhancing our understanding of gymnosperm mitochondrial evolution and supporting further cultivation and utilization of Taxus species.
摘要：
紫杉属植物是紫杉醇的独家来源，具有重要药用和经济价值的抗癌药物。进化过程中的种间杂交和基因渗入掩盖了紫杉属物种之间的区别，使它们的系统发育分类复杂化。而红豆杉的叶绿体基因组，在中国分布广泛的物种，已经测序了，其线粒体基因组（有丝分裂基因组）仍未表征。我们使用BGI短读数和纳米孔长读数对T.wallichiana有丝分裂基因组进行了测序和组装，促进与其他裸子植物有丝分裂基因组的比较。T.Wallichiana有丝分裂基因组跨越469,949bp，主要形成GC含量为50.51%的圆形结构，由一对LR和两对IntR介导的3个次要构型补充。它包括32个蛋白质编码基因，7个tRNA基因，和3个rRNA基因，其中几个存在多个副本。我们详细说明了有丝分裂基因组的结构，密码子使用,RNA编辑,和细胞器之间的序列迁移，构建系统发育树以阐明进化关系。不像典型的裸子植物线粒体,T.Wallichiana没有显示线粒体-质体DNA转移（MTPT）的证据，突出其独特的基因组结构。合成分析表明T.wallichiana广泛的基因组重排，可能是由丰富的重复序列之间的重组驱动的。这项研究提供了一个高质量的T.wallichiana有丝分裂基因组，增强我们对裸子植物线粒体进化的理解，并支持紫杉属物种的进一步培养和利用。
