Zhong Tailin, Huang Shijie, Liu Rongxiu, Zhuo Juan, Lu Haifei, Gan Chunlin, Fu Jun, Qian Qixia
College of Urban Construction of Zhejiang Shuren University, Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Zhejiang Shuren University, Shaoxing, Zhejiang, People's Republic of China.
National Key Laboratory for Development and Utilization of Forest Food Resources, Zhejiang A&F University, Hangzhou, 311300, China.
BMC Genomics. 2025 May 6;26(1):446. doi: 10.1186/s12864-025-11633-7.
As a dicotyledonous plant within the Styracaceae family, Sinojackia microcarpa (S. microcarpa) is notable for its library-shaped fruit and sparse distribution, serving as a model system for studying the entire tree family. However, the scarcity of genomic data, particularly concerning the mitochondrial and nuclear sequences of S. microcarpa, has substantially impeded our understanding of its evolutionary traits and fundamental biological mechanisms.
This study presents the first complete mitochondrial genome sequence of S. microcarpa and conducts a comparative analysis of its protein-encoding genes across eight plant species. Our analysis revealed that the mitochondrial genome of S. microcarpa spans 687,378 base pairs and contains a total of 59 genes, which include 37 protein-coding genes (PCGs), 20 transfer RNA (tRNA) genes, and 2 ribosomal RNA (rRNA) genes. Sixteen plastid-derived fragments strongly linked with mitochondrial genes, including one intact plastid-related gene (rps7), were identified. Additionally, Ka/Ks ratio analysis revealed that most mitochondrial genes are under purifying selection, with a few genes, such as nad9 and ccmB, showing signs of relaxed or adaptive evolution. An analysis of twenty-nine protein-coding genes from twenty-four plant species reveals that S. microcarpa exhibits a closer evolutionary relationship with species belonging to the genus Camellia. The findings of this study provide new genomic data that enhance our understanding of S. microcarpa, and reveal its mitochondrial genome's evolutionary proximity to other dicotyledonous species.
Overall, this research enhances our understanding of the evolutionary and comparative genomics of S. microcarpa and other plants in the Styracaceae family and lays the foundation for future genetic studies and evolutionary analyses in the Styracaceae family.
小果秤锤树作为安息香科的一种双子叶植物，以其果实形状如秤砣且分布稀疏而闻名，是研究整个安息香科的模式系统。然而，基因组数据的匮乏，尤其是关于小果秤锤树线粒体和核序列的数据，极大地阻碍了我们对其进化特征和基本生物学机制的理解。
本研究首次公布了小果秤锤树完整的线粒体基因组序列，并对其与其他八个植物物种的蛋白质编码基因进行了比较分析。我们的分析表明，小果秤锤树的线粒体基因组跨度为687,378个碱基对，共包含59个基因，其中包括37个蛋白质编码基因（PCG）、20个转运RNA（tRNA）基因和2个核糖体RNA（rRNA）基因。鉴定出16个与线粒体基因紧密相连的质体衍生片段，其中包括一个完整的质体相关基因（rps7）。此外，Ka/Ks比值分析表明，大多数线粒体基因受到纯化选择，少数基因，如nad9和ccmB，显示出放松或适应性进化的迹象。对来自24个植物物种的29个蛋白质编码基因的分析表明，小果秤锤树与山茶属物种的进化关系更为密切。本研究结果提供了新的基因组数据，加深了我们对小果秤锤树的理解，并揭示了其线粒体基因组与其他双子叶植物物种的进化亲缘关系。
总体而言，本研究增进了我们对小果秤锤树以及安息香科其他植物的进化和比较基因组学的理解，为安息香科未来的遗传研究和进化分析奠定了基础。
