Chen Rong, Rao Rui, Wang Chun, Zhu Dongbo, Yuan Fen, Yue Liangliang
Yunnan Key Laboratory of Plateau Wetland Conservation, Restoration and Ecological Services, Southwest Forestry University, Kunming, China.
National Plateau Wetlands Research Center, Southwest Forestry University, Kunming, China.
Front Plant Sci. 2025 Jan 20;15:1509669. doi: 10.3389/fpls.2024.1509669. eCollection 2024.
W. W. Sm. is a tree species of the Burseraceae family, endemic to China, found in hot/warm-dry valleys. This species plays a crucial role in maintaining biodiversity in these ecosystems.
We performed assembly of the mitochondrial genome using PMAT (v.1.5.4), resulting in a typical circular molecule of 606,853 bp. The genome consists of 31 tRNA genes, 3 rRNA genes, 35 protein-coding genes, and 1 pseudogene. The study also investigates RNA editing sites and evolutionary patterns.
The mitochondrial genome exhibits a low proportion of repetitive sequences (3.30%), suggesting a highly conserved structure. A high copy number of the gene (4 copies) is noted, which may contribute to genomic rearrangement and adaptive evolution. Among the 476 RNA editing sites, hydrophilic-hydrophobic and hydrophobic-hydrophobic editing events are most common, accounting for 77.10%. Negative selection predominates among most genes (Ka/Ks < 1), while a few genes (e.g., , , , , and ) show signs of positive selection (Ka/Ks > 1), potentially conferring evolutionary advantages. Additionally, a significant A/T bias is observed at the third codon position. Phylogenomic analysis supports the APG IV classification, with no evidence of horizontal gene transfer.
This mitochondrial genome offers valuable insights into the adaptive mechanisms and evolutionary processes of . It enhances our understanding of the species' biogeography in tropical Southeast Asia and Southwest China, providing key information on the evolutionary history of this genus.
W. W. Sm. 是橄榄科的一种树种，为中国特有，生长于炎热/温暖干燥的山谷。该物种在维持这些生态系统的生物多样性方面发挥着关键作用。
我们使用PMAT（v.1.5.4）对线粒体基因组进行组装，得到了一个典型的606,853 bp环状分子。该基因组由31个tRNA基因、3个rRNA基因、35个蛋白质编码基因和1个假基因组成。该研究还调查了RNA编辑位点和进化模式。
线粒体基因组的重复序列比例较低（3.30%），表明其结构高度保守。注意到某基因的高拷贝数（4个拷贝），这可能有助于基因组重排和适应性进化。在476个RNA编辑位点中，亲水-疏水和疏水-疏水编辑事件最为常见，占77.10%。大多数基因以负选择为主（Ka/Ks < 1），而少数基因（如 、 、 、 和 ）显示出正选择迹象（Ka/Ks > 1），可能赋予进化优势。此外，在第三密码子位置观察到显著的A/T偏好。系统基因组分析支持APG IV分类，没有水平基因转移的证据。
该线粒体基因组为W. W. Sm. 的适应性机制和进化过程提供了有价值的见解。它增进了我们对该物种在热带东南亚和中国西南部生物地理学的理解，为该属的进化历史提供了关键信息。
