School of Agriculture and Aquaculture, Tra Vinh University, Tra Vinh City, Vietnam.
Department of Molecular Biology, Institute of Food and Biotechnology, Can Tho University, Can Tho City, Vietnam.
Genome Biol Evol. 2024 Sep 3;16(9). doi: 10.1093/gbe/evae184.
The mitochondrial plastid DNAs (MTPTs) in seed plants were reported more than 40 years ago and exhibited a high diversity regarding gene content, quantity, and size. However, the mechanism that resulted in the current diversity of MTPTs in angiosperms has not been fully discovered. In this study, we sequenced and characterized the complete organelle genomes of Limonia acidissima L., a monotypic species of Rutaceae. The newly generated and previously published organelle genomes of 42 species were used to explore the diversity of MTPTs regarding quantity, gene content, size, and coverage of chloroplast genome (cpDNA) regions. The results showed that the number of MTPTs ranged from three to 74, of which the lengths were from 100 to 53,731 bp. The highest coverage of MTPTs was found in the inverted repeat region, whereas the small single repeat region had the lowest coverage. Based on the previous data and current results, we propose a scenario for the diversity of MTPTs in angiosperms. In the first stage, the whole cpDNA might migrate to the mitogenome. Then, different genomic events, such as duplication, deletion, substitution, and inversion, have occurred continuously and independently and resulted in extremely variable profiles of mitogenomes among angiosperms. Our hypothesis provides a new and possibly reliable scenario for explaining the present circumstances of MTPTs in angiosperms. However, more genomic data should be mined, and more studies should be conducted to clarify this natural phenomenon in plants.
线粒体质体 DNA（MTPTs）在种子植物中被报道已有 40 多年，其在基因含量、数量和大小方面表现出高度多样性。然而，导致被子植物 MTPTs 目前多样性的机制尚未完全发现。在这项研究中，我们对芸香科唯一物种酸模柠檬 Limonia acidissima L. 的完整细胞器基因组进行了测序和特征描述。我们使用新生成的和之前发表的 42 个物种的细胞器基因组，探讨了 MTPTs 在数量、基因含量、大小和叶绿体基因组（cpDNA）区域覆盖度方面的多样性。结果表明，MTPTs 的数量从 3 到 74 不等，长度从 100 到 53731bp 不等。MTPTs 的最高覆盖率出现在反向重复区，而小单重复区的覆盖率最低。基于之前的数据和当前的结果，我们提出了被子植物 MTPTs 多样性的情景假设。在第一阶段，整个 cpDNA 可能迁移到线粒体基因组。然后，不同的基因组事件，如复制、缺失、替换和倒位，不断独立地发生，导致被子植物线粒体基因组呈现出极其多样的特征。我们的假设为解释被子植物 MTPTs 的现状提供了一个新的、可能可靠的情景，但需要挖掘更多的基因组数据，并进行更多的研究来阐明植物中的这种自然现象。
