生物入侵是造成巨大环境和经济损失的原因。红松节油甲虫(RTB),DendroctonusvalensLeConte,是一种来自北美的重要入侵树皮甲虫,在中国造成了大量树木死亡。缺乏高质量的参考基因组严重限制了基因适应导致次生害虫在其入侵区域变得如此破坏性的程度。
这里,我们提出了一个322.41Mb染色体尺度的RTB参考基因组,其中98%的组装序列锚定在14个连锁基团上,包括X染色体,N50大小为24.36Mb,明显高于其他鞘翅目物种。重复序列占基因组的45.22%,高于其他四种鞘翅目,即,山松甲虫Dendroctonusponderosae,红面粉甲虫Triboliumcastaneum,水泡甲虫Hycleuscichorii,和科罗拉多马铃薯甲虫Leptinotarsadecemlineata。我们在RTB中鉴定了快速扩展的基因家族和阳性选择的基因,这可能是其快速适应环境的原因。通过对本地和入侵地区的地理种群进行基因组重测序,揭示了RTB的种群遗传结构。这表明了北美人口的巨大差异,并说明了中国可能的入侵和传播途径。选择性扫描分析强调了中国人群环境适应能力的增强。
总的来说,我们的高质量参考基因组是侵袭性树皮甲虫基因组学研究的重要资源,通过整合油松基因组,这将促进RTB入侵成功的功能研究和破译机制。
Biological invasions are responsible for substantial environmental and economic losses. The red
turpentine beetle (RTB), Dendroctonus valens LeConte, is an important invasive bark beetle from North America that has caused substantial tree mortality in
China. The lack of a high-quality reference genome seriously limits deciphering the extent to which genetic adaptions resulted in a secondary pest becoming so destructive in its invaded area.
Here, we present a 322.41 Mb chromosome-scale reference genome of RTB, of which 98% of assembled sequences are anchored onto fourteen linkage groups including the X chromosome with a N50 size of 24.36 Mb, which is significantly greater than other Coleoptera species. Repetitive sequences make up 45.22% of the genome, which is higher than four other Coleoptera species, i.e., Mountain pine beetle Dendroctonus ponderosae, red flour beetle Tribolium castaneum, blister beetle Hycleus cichorii, and Colorado potato beetle Leptinotarsa decemlineata. We identify rapidly expanded gene families and positively selected genes in RTB, which may be responsible for its rapid environmental adaptation. Population genetic structure of RTB was revealed by genome resequencing of geographic populations in native and invaded regions, suggesting substantial divergence of the North American population and illustrates the possible invasion and spread route in
China. Selective sweep analysis highlighted the enhanced ability of Chinese populations in environmental adaptation.
Overall, our high-quality reference genome represents an important resource for genomics study of invasive bark beetles, which will facilitate the functional study and decipher mechanism underlying invasion success of RTB by integrating the Pinus tabuliformis genome.