Department of Entomology, Texas A&M University, College Station, TX, USA.
Puerto Rico, Science, Technology & Research Trust, San Juan, PR, USA; Know Your Bee, Inc, San Juan, PR, USA.
Insect Biochem Mol Biol. 2019 Oct;113:103208. doi: 10.1016/j.ibmb.2019.103208. Epub 2019 Aug 15.
The complete mitochondrial genome of the soybean aphid (Aphis glycines Matsumura), a major agricultural pest in the world, is described for the first time, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, as well as a large repeat region between tRNA-Glu and tRNA-Phe, and an AT-rich control region. The 17,954 bp mtgenome is the largest reported from the family Aphididae, and its gene order follows the ancestral insect mtgenome except for the repeat region, which contains a 195 bp unit repeated 11.9 times, representing the highest reported repeats among the known aphid mtgenomes to date. A new molecular phylogeny of Aphidae is reconstructed based on all available aphid mtgenomes, and it is shown that the mtgenome data can robustly resolve relationships at the subfamily level, but do not have sufficient phylogenetic information to resolve deep relationships. A phylogeny-based comparative analysis of mtgenomes has been performed to investigate the evolution of the repeat region between tRNA-Glu and tRNA-Phe. So far, among aphids, 13 species are known to have this repeat region of variable lengths, and a phylogenetic analysis of the repeat region shows that a large proportion of the sequences are conserved across the phylogeny, suggesting that the repeat region evolved in the most recent common ancestor of Aphidinae and Eriosomatinae, and that it has gone through numerous episodes of lineage-specific losses and expansions. Combined together, this study provides novel insights into how the repeat regions have evolved within aphids.
大豆蚜（Aphis glycines Matsumura）的完整线粒体基因组首次被描述，这是一种世界范围内的主要农业害虫。该基因组由 13 个蛋白编码基因、22 个 tRNA 基因、2 个 rRNA 基因以及 tRNA-Glu 和 tRNA-Phe 之间的一个大重复区和一个富含 AT 的调控区组成。这个 17954bp 的 mtgenome 是报道的蚜科中最大的，其基因顺序遵循昆虫的祖先 mtgenome，除了重复区，其中包含一个重复 11.9 次的 195bp 单元，这是迄今为止已知的蚜虫 mtgenome 中报道的最高重复次数。基于所有可用的蚜虫 mtgenome 重建了蚜科的新分子系统发育，结果表明 mtgenome 数据可以稳健地解析亚科水平的关系，但没有足够的系统发育信息来解析深层关系。基于系统发育的 mtgenome 比较分析已经被用来研究 tRNA-Glu 和 tRNA-Phe 之间重复区的进化。到目前为止，已知有 13 种蚜虫具有这种可变长度的重复区，对重复区的系统发育分析表明，大部分序列在系统发育中是保守的，这表明重复区是在蚜亚科和根瘤蚜亚科的最近共同祖先中进化的，并且经历了多次谱系特异性的丢失和扩张。综合起来，这项研究为重复区在蚜虫中的进化方式提供了新的见解。
