Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100193, PR China.
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100193, PR China.
Gene. 2023 Jun 30;871:147427. doi: 10.1016/j.gene.2023.147427. Epub 2023 Apr 10.
Artemisia argyi L., also known as mugwort, is a perennial herb whose leaves are commonly used as a source of traditional medicines. However, the evolution and structure of the mitochondrial genome (mitogenome) in A. argyi remain unclear. In this study, the mitogenome of A. argyi was assembled and characterized for the first time.
The mitogenome of A. argyi was a circular molecule of 229,354 bp. It encodes 56 genes, including 33 protein-coding genes (PCGs), 20 tRNA genes, and three rRNA genes, and three pseudogenes. Five trans-spliced introns were observed in three PCGs namely, nad1, nad2 and nad5. Repeat analysis identified 65 SSRs, 14 tandem repeats, and 167 dispersed repeats. The A. argyi mitogenome contains 12 plastid transfer sequences from 79 bp to 2552 bp. Five conserved MTPTs were identified in all 18 Asteraceae species. Comparison of mitogenome between A. argyi and one Artemisia specie and two Chrysanthemum species showed 14 conserved gene clusters. Phylogenetic analysis with organelle genomes of A. argyi and 18 other Anthemideae plants showed inconsistent phylogenetic trees, which implied that the evolutionary rates of PCGs and rrna genes derived from mitochondrion and plastid were incongruent. The Ka/Ks ratio of the 27 shared protein-coding genes in the 18 Anthemideae species are all less than 1 indicating that these genes were under the effect of purifying selection. Lastly, a total of 568 RNA editing sites in PCGs were further identified. The average editing frequency of non-synonymous changes was significantly higher than that of synonymous changes (one-sample Student's t-test, p-values ≤ 0.05) in three tissues (root, leaf and stem).
In this study, the gene content, genome size, genome comparison, mitochondrial plastid sequences, dN/dS analysis of mitochondrial protein-coding genes, and RNA-editing events in A. argyi mitogenome were determined, providing insights into the phylogenetic relationships of Asteraceae plant.
艾草（Artemisia argyi L.），又称艾蒿，是一种多年生草本植物，其叶子常用于传统药物。然而，艾草的线粒体基因组（mitogenome）的进化和结构仍不清楚。在这项研究中，我们首次组装并分析了艾草的线粒体基因组。
艾草的线粒体基因组是一个圆形分子，大小为 229354 bp。它编码 56 个基因，包括 33 个蛋白编码基因（PCGs）、20 个 tRNA 基因和 3 个 rRNA 基因，以及 3 个假基因。在三个 PCGs（nad1、nad2 和 nad5）中观察到 5 个跨剪接内含子。重复分析鉴定出 65 个 SSRs、14 个串联重复和 167 个分散重复。艾草的线粒体基因组包含来自 79bp 到 2552bp 的 12 个质体转移序列。在所有 18 种菊科植物中都发现了 5 个保守的 MTPTs。艾草与 1 种蒿属物种和 2 种菊属物种的线粒体基因组比较显示了 14 个保守的基因簇。与 18 种其它春黄菊属植物的细胞器基因组进行系统发育分析显示，不一致的系统发育树表明线粒体和质体来源的 PCGs 和 rRNA 基因的进化速率不一致。18 种春黄菊属植物中 27 个共享蛋白编码基因的 Ka/Ks 比值均小于 1，表明这些基因受到纯化选择的影响。最后，在 PCGs 中进一步鉴定了 568 个 RNA 编辑位点。在三个组织（根、叶和茎）中，非同义突变的平均编辑频率显著高于同义突变（单样本学生 t 检验，p 值≤0.05）。
在这项研究中，我们确定了艾草线粒体基因组的基因组成、基因组大小、基因组比较、线粒体质体序列、线粒体蛋白编码基因的 dN/dS 分析以及 RNA 编辑事件，为菊科植物的系统发育关系提供了新的见解。
