Lepidopteran P450s of the CYP6B and CYP9A subfamilies are thought to play important roles in host plant adaptation and insecticide resistance. An increasing number of paralogs and orthologs with high levels of sequence identity have been found in these subfamilies by mining recent genome projects. However, the biochemical function of most of them remains unknown. A better understanding of the evolution of P450 genes and of the catalytic competence of the enzymes they encode is needed to facilitate studies of host plant use and insecticide resistance. Here, we focused on the full complement of CYP6B (4 genes) and CYP9A (7 genes) in the generalist herbivore, Helicoverpa armigera. These P450s were heterologously expressed in Sf9 cells and compared functionally. In vitro assays showed that all CYP6B and CYP9A P450s can metabolize esfenvalerate efficiently, except for the evolutionarily divergent CYP6B43. A new 2′-hydroxy-metabolite of esfenvalerate was identified and found to be the main metabolite produced by CYP9A12. All tested P450s showed only low induction responses to esfenvalerate. To put these results from H. armigera P450s in perspective, 158 complete CYP6B and 100 complete CYP9A genes from 34 ditrysian species were manually curated. The CYP9A subfamily was more widespread than the CYP6B subfamily and the latter showed dramatic gains and losses, with ten species lacking CYP6B genes. Two adjacent CYP6B loci were found on chromosome 21, with different fates during the evolution of Lepidoptera. The diversity and functional redundancy of CYP6B and CYP9A genes challenge resistance management and pest control strategies as many P450s are available to insects to cope with chemical stresses they encounter.

CYP6B 和 CYP9A 亚科的鳞翅目P450s 被认为在宿主植物适应和杀虫剂抗性中起重要作用。通过挖掘最近的基因组项目，在这些亚家族中发现了越来越多的具有高度序列同一性的旁系同源物和直向同源物。然而，它们中的大多数的生化功能仍然未知。需要更好地了解 P450 基因的进化及其编码的酶的催化能力，以促进宿主植物使用和杀虫剂抗性的研究。在这里，我们专注于全能草食动物Helicoverpa armigera中 CYP6B（4 个基因）和 CYP9A（7 个基因）的完整补充。这些 P450 在 Sf9 细胞中异源表达并进行功能比较。体外试验表明，除了进化上不同的 CYP6B43 外，所有 CYP6B 和 CYP9A P450 都可以有效地代谢艾芬戊酸。鉴定了一种新的 esfenvalerate 2'-羟基代谢物，发现它是 CYP9A12 产生的主要代谢物。所有测试的 P450 仅显示对 esfenvalate 的低诱导反应。把这些结果从棉铃虫从 P450s 的角度来看，来自 34 个 ditrysian 物种的 158 个完整的 CYP6B 和 100 个完整的 CYP9A 基因是手动策划的。CYP9A 亚科比 CYP6B 亚科分布更广，后者表现出显着的得失，有 10 个物种缺乏 CYP6B 基因。在 21 号染色体上发现了两个相邻的 CYP6B 位点，它们在鳞翅目进化过程中具有不同的命运。CYP6B 和 CYP9A 基因的多样性和功能冗余对抗性管理和害虫控制策略提出了挑战，因为昆虫可以利用许多 P450 来应对它们遇到的化学胁迫。