Tree and Matrix - Comparative analyses of mitochondrial genomes bring new evolutionary insights for stink bugs (Hemiptera: Pentatomidae)

Stink bugs (Pentatomidae) are a speciose group of insects that feed mostly on plants. Many species are considered agricultural pests of economically important crops around the globe. Mitochondrial genomes are valuable for evolutionary and phylogenetic studies, but have been little explored for Pentatomidae. Here, we assembled and annotated the mitochondrial genomes of four pentatomid species (Diceraeus melacanthus, Euschistus heros, Piezodorus guildinii, and Stiretrus anchorago) and performed a comparative analysis for this family and its subfamilies. Stink bug mitogenomes disclosed a conserved gene order and content, although we detected two uncommon armless tRNAs in E. heros and D. melacanthus. Phylogenetic results indicate that Pentatominae is polyphyletic, showing that internal relationships of Pentatomidae should be further investigated. Stink bug mitochondrial genes are under strong purifying selection, except for ATP8 which showed signs of positive selection.

蝽科（Pentatomidae）是一类物种丰富的昆虫类群，多数以植物为食。全球范围内诸多物种均为危害经济作物的农业害虫。线粒体基因组（mitochondrial genome）在进化与系统发育研究中极具应用价值，但目前针对蝽科的相关研究仍较为匮乏。本研究组装并注释了4种蝽科昆虫的线粒体基因组，分别为黑斑双角蝽（Diceraeus melacanthus）、褐翅蝽（Euschistus heros）、豆荚绿蝽（Piezodorus guildinii）以及锚纹蝽（Stiretrus anchorago），并针对该科及其亚科开展了比较基因组分析。蝽科线粒体基因组展现出保守的基因排列与基因组成，但本研究在褐翅蝽与黑斑双角蝽中发现了2种罕见的无臂转运RNA（transfer RNA, tRNA）。系统发育分析结果显示，蝽亚科（Pentatominae）为多系群，表明蝽科内部的系统发育关系仍有待进一步探究。蝽科线粒体基因整体处于强烈的纯化选择压力之下，仅ATP8基因呈现出正向选择的信号。