Huang Yahui, Zhu Bingyue, Hu Siqi, Shi Wenbo, Liu Yuxue, Lin Qianhui, Wang Shuo, Yang Jing, Shi Chao
College of Biological Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
BMC Plant Biol. 2025 Jun 7;25(1):774. doi: 10.1186/s12870-025-06801-6.
Houttuynia cordata is a well-known medicinal and edible plant with important economic value. It belongs to the magnoliid clade, a basal lineage of angiosperms. Currently, the limited number of reported mitochondrial genomes from magnoliids severely restricts our understanding of early mitochondrial genome evolution. To address this gap, we present the complete mitochondrial genome of H. cordata.
The H. cordata mitochondrial genome spans 534,194 bp, and predominantly adopts a bicyclic structure among four possible configurations. It encodes 45 protein-coding genes (PCGs) (40 unique), 29 transfer RNAs (21 unique), and 3 ribosomal RNAs. Repeat analysis revealed significant differences in tandem repeats, dispersed repeats, and simple sequence repeat (SSR) types and densities between the two chromosomes, with Chromosome 1 exhibiting higher repeat density and diversity. Additionally, the H. cordata mitochondrial genome harbors 18 potential mitochondrial plastid DNAs (MTPTs), most of which originate from the inverted repeats (IR) regions of the plastid genome. Variant detection at the individual-level revealed significant heteroplasmy across most regions, while large repeat regions and MTPTs regions exhibited relative conservation. Phylogenetic and collinearity analyses further indicated substantial differences between the mitochondrial genome structure of H. cordata and 15 other magnoliid species, while conserved regions were maintained.
This study elucidates the unique evolutionary characteristics of the H. cordata mitochondrial genome and provides valuable insights into its genetics and evolution. Comparative analysis with other magnoliid species reveals both dynamic evolutionary changes and the conservation of mitochondrial genome structure and gene content in early angiosperms.
鱼腥草是一种著名的药食两用植物，具有重要的经济价值。它属于木兰类植物，是被子植物的一个基部谱系。目前，已报道的木兰类植物线粒体基因组数量有限，严重限制了我们对早期线粒体基因组进化的理解。为了填补这一空白，我们公布了鱼腥草的完整线粒体基因组。
鱼腥草线粒体基因组跨度为534,194 bp，在四种可能的构型中主要采用双环结构。它编码45个蛋白质编码基因（PCG）（40个独特基因）、29个转运RNA（21个独特基因）和3个核糖体RNA。重复序列分析显示，两条染色体在串联重复、分散重复和简单序列重复（SSR）类型及密度上存在显著差异，其中染色体1表现出更高的重复密度和多样性。此外，鱼腥草线粒体基因组含有18个潜在的线粒体质体DNA（MTPT），其中大部分起源于质体基因组的反向重复（IR）区域。个体水平的变异检测显示，大多数区域存在显著的异质性，而大的重复区域和MTPT区域表现出相对保守性。系统发育和共线性分析进一步表明，鱼腥草线粒体基因组结构与其他15种木兰类植物存在显著差异，同时也保留了保守区域。
本研究阐明了鱼腥草线粒体基因组独特的进化特征，为其遗传学和进化提供了有价值的见解。与其他木兰类植物的比较分析揭示了早期被子植物线粒体基因组结构和基因含量的动态进化变化及保守性。
