The diamondback moth, Plutella xylostella (L.), is a highly mobile brassica crop pest with worldwide distribution and can rapidly evolve resistance to insecticides, including group 28 diamides. Reference genomes assembled using Illumina sequencing technology have provided valuable resources to advance our knowledge regarding the biology, origin and movement of diamondback moth, and more recently with its sister species, Plutella australiana. Here we apply a trio binning approach to sequence and annotate a chromosome level reference genome of P. xylostella using PacBio Sequel and Dovetail Hi-C sequencing technology and identify a point mutation that causes resistance to commercial diamides. A P. xylostella population collected from brassica crops in the Lockyer Valley, Australia (LV-R), was reselected for chlorantraniliprole resistance then a single male was crossed to a P. australiana female and a hybrid pupa sequenced. A chromosome level 328 Mb P. xylostella genome was assembled with 98.1% assigned to 30 autosomes and the Z chromosome. The genome was highly complete with 98.4% of BUSCO Insecta genes identified and RNAseq informed protein prediction annotated 19,002 coding genes. The LV-R strain survived recommended field application doses of chlorantraniliprole, flubendiamide and cyclaniliprole. Some hybrids also survived these doses, indicating significant departure from recessivity, which has not been previously documented for diamides. Diamide chemicals modulate insect Ryanodine Receptors (RyR), disrupting calcium homeostasis, and we identified an amino acid substitution (I4790K) recently reported to cause diamide resistance in a strain from Japan. This chromosome level assembly provides a new resource for insect comparative genomics and highlights the emergence of diamide resistance in Australia. Resistance management plans need to account for the fact that resistance is not completely recessive.

小菜蛾Plutella xylostella (L.) 是一种高度流动的芸苔属作物害虫，在世界范围内均有分布，可快速进化出对杀虫剂（包括第 28 组二酰胺）的抗性。使用Illumina 测序技术组装的参考基因组提供了宝贵的资源，以提高我们对小菜蛾的生物学、起源和运动的了解，以及最近对其姊妹物种Plutella australiana 的了解。在这里，我们使用 PacBio Sequel 和 Dovetail Hi-C 测序技术应用三重合并方法对小菜蛾的染色体水平参考基因组进行测序和注释，并确定导致对商业二酰胺抗性的点突变。一个小菜蛾从澳大利亚洛克耶谷 (LV-R) 的芸苔属作物中收集的种群被重新选择用于氯虫苯甲酰胺抗性，然后将单个雄性与澳大利亚 P. australiana雌性杂交，并对杂交蛹进行测序。一个染色体水平为 328 Mb 的小菜蛾基因组被组装，其中 98.1% 分配给 30 个常染色体和 Z 染色体。基因组高度完整，确定了 98.4% 的 BUSCO Insecta 基因，RNAseq 通知蛋白质预测注释了 19,002 个编码基因。LV-R 菌株在推荐的现场施用剂量的氯虫苯甲酰胺、氟虫酰胺和环虫酰胺中存活下来。一些杂交种也能在这些剂量下存活下来，表明与隐性，以前没有记录到二酰胺。二酰胺化学物质调节昆虫Ryanodine 受体(RyR)，破坏钙稳态，我们发现最近报道的氨基酸替代 (I4790K) 会导致日本菌株对二酰胺产生抗性。这种染色体水平组装为昆虫比较基因组学提供了新的资源，并突出了澳大利亚对二酰胺抗性的出现。抗性管理计划需要考虑到抗性并非完全隐性的事实。