Lin Mengjiao, Hu Na, Sun Jing, Zhou Wu
College of Eco-Environmental Engineering, Qinghai University, Xining 810016, China.
Qinghai Provincial Key Laboratory of Qinghai-Tibet Plateau Biological Resources, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China.
Plants (Basel). 2025 Aug 15;14(16):2547. doi: 10.3390/plants14162547.
ssp. Rousi a species of significant ecological and economic value that is native to the Qinghai-Tibet Plateau and arid/semi-arid regions. Investigating the mitochondrial genome can elucidate stress adaptation mechanisms, population genetic structure, and hybrid evolutionary history, offering molecular insights for ecological restoration and species conservation. However, the genetic information and evolutionary mechanisms of its mitochondrial genome remain poorly understood. This study aimed to assemble the complete mitochondrial genome of L. ssp. using Illumina sequencing, uncovering its structural features, evolutionary pressures, and environmental adaptability and addressing the research gap regarding mitochondrial genomes within the genus. The study assembled a 454,444 bp circular mitochondrial genome of ssp. , with a GC content of 44.86%. A total of 73 genes and 3 pseudogenes were annotated, with the notable absence of the gene, which is present in related species. The genome exhibits significant codon usage bias, particularly with high-frequency use of the alanine codon GCU and the isoleucine codon AUU. Additionally, 449 repetitive sequences, potentially driving genome recombination, were identified. Our evolutionary pressure analysis revealed that most genes are under purifying selection, while genes such as and exhibit positive selection. A nucleotide diversity analysis revealed that the gene exhibits the highest variation, whereas is the most conserved. Meanwhile, phylogenetic analysis showed that ssp. from China is most closely related to , with extensive homologous sequences (49.72% of the chloroplast genome) being identified between the chloroplast and mitochondrial genomes, indicating active inter-organellar gene transfer. Furthermore, 539 RNA editing sites, primarily involving hydrophilic-to-hydrophobic amino acid conversions, were predicted, potentially regulating mitochondrial protein function. Our findings establish a foundation for genetic improvement and research on adaptive evolutionary mechanisms in the genus, offering a novel case study for plant mitochondrial genome evolution theory.
鲁氏景天（ssp. Rousi）是一种具有重要生态和经济价值的物种，原产于青藏高原和干旱/半干旱地区。研究线粒体基因组可以阐明胁迫适应机制、种群遗传结构和杂交进化历史，为生态恢复和物种保护提供分子见解。然而，其线粒体基因组的遗传信息和进化机制仍知之甚少。本研究旨在利用Illumina测序组装鲁氏景天（L. ssp.）的完整线粒体基因组，揭示其结构特征、进化压力和环境适应性，并填补该属线粒体基因组研究的空白。该研究组装了一个454,444 bp的鲁氏景天（ssp.）环状线粒体基因组，GC含量为44.86%。共注释了73个基因和3个假基因，值得注意的是，相关物种中存在的某个基因在该基因组中缺失。该基因组表现出显著的密码子使用偏好，特别是丙氨酸密码子GCU和异亮氨酸密码子AUU的高频使用。此外，还鉴定出449个可能驱动基因组重组的重复序列。我们的进化压力分析表明，大多数基因处于纯化选择之下，而某些基因如某某和某某则表现出正选择。核苷酸多样性分析表明，某个基因表现出最高的变异，而某某是最保守的。同时，系统发育分析表明，来自中国的鲁氏景天（ssp.）与某某关系最为密切，叶绿体和线粒体基因组之间鉴定出广泛的同源序列（叶绿体基因组的49.72%），表明存在活跃的细胞器间基因转移。此外，预测了539个RNA编辑位点，主要涉及亲水到疏水氨基酸的转换，可能调节线粒体蛋白功能。我们的研究结果为该属的遗传改良和适应性进化机制研究奠定了基础，为植物线粒体基因组进化理论提供了一个新的案例研究。 （注：原文中部分基因名称未给出具体内容，翻译时用“某某”代替）
