The Complete Mitochondrial Genome Sequence of Bactericera cockerelli and Comparison with Three Other Psylloidea Species

Potato psyllid (Bactericera cockerelli) is an important pest of potato, tomato and pepper. Not only could a toxin secreted by nymphs results in serious phytotoxemia in some host plants, but also over the past few years B. cockerelli was shown to transmit “Candidatus Liberibacter solanacearum”, the putative bacterial pathogen of potato zebra chip (ZC) disease, to potato and tomato. ZC has caused devastating losses to potato production in the western U.S., Mexico, and elsewhere. New knowledge of the genetic diversity of the B. cockerelli is needed to develop improved strategies to manage pest populations. Mitochondrial genome (mitogenome) sequencing provides important knowledge about insect evolution and diversity in and among populations. This report provides the first complete B. cockerelli mitogenome sequence as determined by next generation sequencing technology (Illumina MiSeq). The circular B. cockerelli mitogenome had a size of 15,220 bp with 13 protein-coding gene (PCGs), 2 ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and a non-coding region of 975 bp. The overall gene order of the B. cockerelli mitogenome is identical to three other published Psylloidea mitogenomes: one species from the Triozidae, Paratrioza sinica; and two species from the Psyllidae, Cacopsylla coccinea and Pachypsylla venusta. This suggests all of these species share a common ancestral mitogenome. However, sequence analyses revealed differences between and among the insect families, in particular a unique region that can be folded into three stem-loop secondary structures present only within the B. cockerelli mitogenome. A phylogenetic tree based on the 13 PCGs matched an existing taxonomy scheme that was based on morphological characteristics. The available complete mitogenome sequence makes it accessible to all genes for future population diversity evaluation of B. cockerelli.马铃薯木虱（Bactericera cockerelli）是危害马铃薯、番茄及辣椒的重要农业害虫。若虫分泌的毒素可引发部分寄主植物出现严重的植物毒血症；且在过去数年间，研究证实B. cockerelli可传播“候选韧皮部杆菌属茄科专化型”（Candidatus Liberibacter solanacearum）——该病菌为马铃薯斑马片病（zebra chip, ZC）的推定病原细菌——至马铃薯和番茄植株。斑马片病已给美国西部、墨西哥及其他地区的马铃薯生产造成了毁灭性损失。为优化害虫种群治理方案，亟需解析B. cockerelli的遗传多样性。线粒体基因组（mitogenome）测序可为解析昆虫种群内部及种群间的演化与多样性提供关键数据支撑。本研究首次报道了基于下一代测序技术（Illumina MiSeq）测得的B. cockerelli完整线粒体基因组序列。该环状B. cockerelli线粒体基因组全长15220 bp，包含13个蛋白质编码基因（protein-coding genes, PCGs）、2个核糖体RNA基因（ribosomal RNAs, rRNAs）、22个转运RNA基因（transfer RNAs, tRNAs）以及一段长975 bp的非编码区。B. cockerelli线粒体基因组的整体基因排列与另外3个已发表的木虱总科（Psylloidea）线粒体基因组完全一致，分别为个木虱科（Triozidae）的中国拟个木虱（Paratrioza sinica），以及木虱科（Psyllidae）的Cacopsylla coccinea与Pachypsylla venusta。这表明上述物种共享同一套祖先线粒体基因组。但序列分析结果显示，不同木虱科间存在序列差异，其中尤为独特的是一段仅存在于B. cockerelli线粒体基因组中的区域，该区域可折叠形成3个茎环二级结构。基于13个蛋白质编码基因构建的系统发育树，与基于形态特征建立的现有分类学框架完全吻合。本次获得的完整线粒体基因组序列，可为未来开展B. cockerelli的种群多样性评估提供全部相关基因的研究基础。