To elucidate the deltamethrin resistance mechanism in Helicoverpa armigera, we explored mutations at the deltamethrin target site, genomic level variations between insecticide-susceptible and -resistant strains, and differences in gene expression patterns between the strains. Known pyrethroid resistance-associated point mutations within the voltage-gated sodium channel were undetected in the cDNA and gDNA of resistant strains or field populations. The whole-genome de novo assembly of a Korean-resistant strain was performed (GCA_026262555.1), and 13 genomes of susceptible and resistant individuals were re-sequenced using field populations. Approximately 3,369,837 variants (SNPs and indels) were compared with our reference H. armigera genome, and 1,032,689 variants were identified from open reading frames. A resistance-specific CYP3 subfamily gene with five variants (CYP321A1v1–v5) was identified in the resistant strains, indicating the potential role of these variants in resistance. RNA-seq analysis identified 36,720 transcripts from 45 Illumina RNA-seq datasets of the fatbody, gut, and the rest of the body. Differential gene expression analysis revealed some differently overexpressed detoxification enzyme genes in the resistant strains, particularly cytochrome P450 genes. This finding was consistent with the results of bioassay tests using PBO-based synergists that inhibit enzymes belong to cytochrome P450 family, further supporting the role of detoxification enzymes in resistance. Therefore, H. armigera may acquire deltamethrin resistance through a combination of actions, including the overexpression of various detoxification enzymes, such as CYP321A5 identified in this study may serve as a basis for understanding insecticide resistance at the molecular level and can be applied as diagnostic markers for resistance.

为了阐明棉铃虫的溴氰菊酯抗性机制，我们探索了溴氰菊酯靶位点的突变、杀虫剂敏感菌株和抗药菌株之间的基因组水平变异以及菌株之间基因表达模式的差异。在抗性菌株或田间群体的 cDNA 和 gDNA 中，未检测到电压门控钠通道内已知的与拟除虫菊酯抗性相关的点突变。对韩国抗性菌株进行了全基因组从头组装（GCA_026262555.1），并使用现场群体对易感和抗性个体的 13 个基因组进行了重新测序。将大约 3,369,837 个变异（SNP 和插入缺失）与我们的参考棉铃虫基因组进行了比较，并从开放阅读框中鉴定了 1,032,689 个变异。在抗性菌株中鉴定出具有五个变体（CYP321A1v1-v5）的抗性特异性 CYP3 亚家族基因，表明这些变体在抗性中的潜在作用。 RNA-seq 分析从脂肪体、肠道和身体其他部位的 45 个 Illumina RNA-seq 数据集中识别出 36,720 个转录本。差异基因表达分析揭示了耐药菌株中一些不同程度过度表达的解毒酶基因，特别是细胞色素P450基因。这一发现与使用基于 PBO 的增效剂抑制细胞色素 P450 家族酶的生物测定结果一致，进一步支持了解毒酶在耐药性中的作用。因此，H. 棉铃虫可能通过多种作用的组合获得溴氰菊酯抗性，包括各种解毒酶的过度表达，例如本研究中鉴定的CYP321A5，可以作为在分子水平上了解杀虫剂抗性的基础，并可用作抗性的诊断标记。