Laboratory of Cotton Genetics, Genomics and Breeding /Key Laboratory of Crop Heterosis and Utilization of Ministry of Education/Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.
Institute of Cash Crops, Hubei Academy of Agricultural Sciences, Wuhan, Hubei, 430064, China.
BMC Genomics. 2017 Nov 13;18(1):876. doi: 10.1186/s12864-017-4282-5.
Cotton (Gossypium spp.) is commonly grouped into eight diploid genomic groups and an allotetraploid genomic group, AD. The mitochondrial genomes supply new information to understand both the evolution process and the mechanism of cytoplasmic male sterility. Based on previously released mitochondrial genomes of G. hirsutum (AD), G. barbadense (AD), G. raimondii (D) and G. arboreum (A), together with data of six other mitochondrial genomes, to elucidate the evolution and diversity of mitochondrial genomes within Gossypium.
Six Gossypium mitochondrial genomes, including three diploid species from D and three allotetraploid species from AD genome groups (G. thurberi D, G. davidsonii D and G. trilobum D; G. tomentosum AD, G. mustelinum AD and G. darwinii AD), were assembled as the single circular molecules of lengths about 644 kb in diploid species and 677 kb in allotetraploid species, respectively. The genomic structures of mitochondrial in D group species were identical but differed from the mitogenome of G. arboreum (A), as well as from the mitogenomes of five species of the AD group. There mainly existed four or six large repeats in the mitogenomes of the A + AD or D group species, respectively. These variations in repeat sequences caused the major inversions and translocations within the mitochondrial genome. The mitochondrial genome complexity in Gossypium presented eight unique segments in D group species, three specific fragments in A + AD group species and a large segment (more than 11 kb) in diploid species. These insertions or deletions were most probably generated from crossovers between repetitive or homologous regions. Unlike the highly variable genome structure, evolutionary distance of mitochondrial genes was 1/6th the frequency of that in chloroplast genes of Gossypium. RNA editing events were conserved in cotton mitochondrial genes. We confirmed two near full length of the integration of the mitochondrial genome into chromosome 1 of G. raimondii and chromosome A03 of G. hirsutum, respectively, with insertion time less than 1.03 MYA.
Ten Gossypium mitochondrial sequences highlight the insights to the evolution of cotton mitogenomes.
棉花（Gossypium spp.）通常分为八个二倍体基因组群和一个异源四倍体基因组群 AD。线粒体基因组提供了新的信息，有助于理解细胞质雄性不育的进化过程和机制。本研究基于已发表的陆地棉（AD）、草棉（AD）、海岛棉（D）和亚洲棉（A）的线粒体基因组，以及其他六个线粒体基因组的数据，旨在阐明棉属内线粒体基因组的进化和多样性。
组装了六个棉属线粒体基因组，包括来自 D 基因组群的三个二倍体种和来自 AD 基因组群的三个异源四倍体种（二倍体种为 G.thurberi D、G.davidsonii D 和 G.trilobum D；异源四倍体种为 G.tomentosum AD、G.mustelinum AD 和 G.darwinii AD），它们分别为约 644 kb 和 677 kb 的单环状分子。D 组物种的基因组结构相同，但与亚洲棉（A）的线粒体基因组以及五个 AD 组物种的线粒体基因组不同。A + AD 或 D 组物种的线粒体基因组中主要存在四个或六个大重复序列，这些重复序列的变化导致了线粒体基因组内的主要倒位和易位。棉属线粒体基因组的复杂性在 D 组物种中表现为 8 个独特片段，在 A + AD 组物种中表现为 3 个特异片段，在二倍体物种中表现为一个大片段（超过 11 kb）。这些插入或缺失很可能是由重复或同源区域之间的交叉产生的。与高度可变的基因组结构不同，线粒体基因的进化距离是棉属叶绿体基因的 1/6。棉属线粒体基因的 RNA 编辑事件是保守的。我们分别证实了 G. raimondii 第 1 号染色体和 G. hirsutum A03 号染色体上的线粒体基因组的完整整合，插入时间不到 1.03 MYA。
十个棉属线粒体序列为棉属线粒体基因组的进化提供了新的见解。
