在橡胶树物种中,橡胶树(巴西橡胶树)是最重要的天然橡胶来源。在以往的研究中,我们对橡胶树的完整核和叶绿体基因组进行了测序,为研究它们的系统发育提供了宝贵的资源,抗病性,和繁殖。然而,考虑到植物线粒体基因组比其他细胞器更复杂,更难组装,对它们的线粒体基因组知之甚少,这限制了对橡胶树基因组进化的全面理解。在这项研究中,我们对四种橡胶树的线粒体基因组进行了测序和组装。4个线粒体基因组的GC含量一致,密码子用法和AT偏差。然而,基因组长度和序列重复存在显着差异。具体来说,四种橡胶树的环状线粒体基因组范围从935,732到1,402,206bp,有34-35个独特的蛋白质编码基因,35-38个tRNA基因,和6-13个rRNA基因。此外,叶绿体和线粒体基因组之间有17,294-46,552bp的基因组间转移片段,由八个完整的基因组成(psaA,rrn16S,tRNA-Val,rrn5S,rrn4.5S,tRNA-Arg,tRNA-Asp,和tRNA-Asn),基因间间隔区和部分基因序列。橡胶树物种的进化位置,对于理解其适应性策略和与其他物种的关系至关重要,通过基于21种Malpighiales物种线粒体基因组中蛋白质编码基因的系统发育分析进行了验证。这项研究的发现不仅为橡胶树线粒体基因组的结构和进化提供了有价值的见解,而且为进一步的分子生物学奠定了基础。进化研究,以及对橡胶树和其他橡胶树物种的基因组育种研究,从而可能为保护和利用策略提供信息。
Among the
Hevea species, rubber tree (
Hevea brasiliensis) is the most important source of natural rubber. In previous studies, we sequenced the complete nuclear and chloroplast genomes of
Hevea species, providing an invaluable resource for studying their phylogeny, disease resistance, and breeding. However, given that plant mitochondrial genomes are more complex and more difficult to assemble than that of the other organelles, little is known about their mitochondrial genome, which limits the comprehensive understanding of
Hevea genomic evolution. In this study, we sequenced and assembled the mitochondrial genomes of four
Hevea species. The four mitochondrial genomes had consistent GC contents, codon usages and AT skews. However, there were significant differences in the genome lengths and sequence repeats. Specifically, the circular mitochondrial genomes of the four
Hevea species ranged from 935,732 to 1,402,206 bp, with 34-35 unique protein-coding genes, 35-38 tRNA genes, and 6-13 rRNA genes. In addition, there were 17,294-46,552 bp intergenomic transfer fragments between the chloroplast and mitochondrial genomes, consisting of eight intact genes (psaA, rrn16S, tRNA-Val, rrn5S, rrn4.5S, tRNA-Arg, tRNA-Asp, and tRNA-Asn), intergenic spacer regions and partial gene sequences. The evolutionary position of Hevea species, crucial for understanding its adaptive strategies and relation to other species, was verified by phylogenetic analysis based on the protein-coding genes in the mitochondrial genomes of 21 Malpighiales species. The findings from this study not only provide valuable insights into the structure and evolution of the Hevea mitochondrial genome but also lay the foundation for further molecular, evolutionary studies, and genomic breeding studies on rubber tree and other Hevea species, thereby potentially informing conservation and utilization strategies.