College of Plant Protection, Henan Agricultural University, Zhengzhou 450046, China.
Center for Human Genetics, KU Leuven, 3000 Leuven, Belgium.
Int J Mol Sci. 2023 Feb 16;24(4):3976. doi: 10.3390/ijms24043976.
Orchidaceae is one of the largest families of angiosperms. Considering the large number of species in this family and its symbiotic relationship with fungi, Orchidaceae provide an ideal model to study the evolution of plant mitogenomes. However, to date, there is only one draft mitochondrial genome of this family available. Here, we present a fully assembled and annotated sequence of the mitochondrial genome (mitogenome) of , a species with high economic and ornamental value. The mitogenome of was 447,368 bp in length and comprised 26 circular subgenomes ranging in size from 5973 bp to 32,281 bp. The genome encoded for 39 mitochondrial-origin, protein-coding genes; 16 tRNAs (three of plastome origin); three rRNAs; and 16 ORFs, while and were lost from the mitogenome. Moreover, interorganellar DNA transfer was identified in 14 of the 26 chromosomes. These plastid-derived DNA fragments represented 28.32% (46,273 bp) of the plastome, including 12 intact plastome origin genes. Remarkably, the mitogenome of and shared 18% (about 81 kb) of their mitochondrial DNA sequences. Additionally, we found a positive correlation between repeat length and recombination frequency. The mitogenome of had more compact and fragmented chromosomes compared to other species with multichromosomal structures. We suggest that repeat-mediated homologous recombination enables the dynamic structure of mitochondrial genomes in Orchidaceae.
兰科是被子植物中最大的科之一。考虑到该科物种数量众多，且与真菌共生，兰科为研究植物线粒体基因组的进化提供了理想的模型。然而，迄今为止，该科仅有一个线粒体基因组草案。在这里，我们呈现了一个具有高经济和观赏价值的物种，的线粒体基因组（mitogenome）的完全组装和注释序列。的线粒体基因组大小为 447,368 bp，由 26 个大小在 5973 bp 到 32,281 bp 之间的环状亚基因组组成。该基因组编码了 39 个线粒体起源的蛋白质编码基因、16 个 tRNA（3 个源于质体）、3 个 rRNA 和 16 个 ORFs，而和丢失了。此外，在 26 条染色体中的 14 条中发现了细胞器间的 DNA 转移。这些来自质体的 DNA 片段代表了 质体的 28.32%（46,273 bp），包括 12 个完整的质体起源基因。值得注意的是，和的线粒体基因组共享了 18%（约 81 kb）的线粒体 DNA 序列。此外，我们发现重复长度与重组频率之间存在正相关。与具有多染色体结构的其他物种相比，的线粒体基因组具有更紧凑和碎片化的染色体。我们认为重复介导的同源重组使兰科植物线粒体基因组具有动态结构。
