Introduction

Ongoing interactions between host and herbivorous insect trigger a co-evolutionary arms race. Genetic diversity within insects facilitates their adaptation to phytochemicals and their derivatives, including plant-derived insecticides. Cytochrome P450s play important roles in metabolizing phytochemicals and insecticides, due to their diversity and almost perfect evolution.

Objectives

This study aims to uncover a common molecular mechanism in herbivorous insects by investigating the role of kinase-transcription factor regulation of P450s in conferring tolerance to both insecticides and phytochemicals.

Methods

RNA interference, transcriptome sequencing, insecticide, and phytochemical bioassays were conducted to validate the functions of Akt, FoxO, and candidate P450s. Dual-luciferase activity assays were employed to identify the regulation of P450s by the Akt-FoxO signaling pathway. Recombinant P450 enzymes were utilized to investigate the metabolism of insecticides and phytochemicals.

Results

We identified an Akt-FoxO signaling cascade, a representative of kinase-transcription factor pathways. This cascade mediates the expression of eight P450 enzymes involved in the metabolism of insecticides and phytochemicals in Nilaparvata lugens. These P450s are from different families and with different substrate selectivity, enabling them to respectively metabolize insecticides and phytochemicals with structure diversity. Nevertheless, the eight P450 genes were up-regulated by FoxO, which was inhibited in a higher cascade by Akt through phosphorylation. The discovery of the Akt-FoxO signaling pathway regulating a series of P450 genes elucidates the finely tuned regulatory mechanism in insects for adapting to phytochemicals and insecticides.

Conclusion

These finding sheds light on the physiological balance maintained by these regulatory processes. The work provides the experimental evidence of co-adaptation to the stresses imposed by host plant and insecticide within the model of the kinase-TF involving various P450s. This model provides a comprehensive view of how pests adapt to multiple environmental stresses.

中文翻译：

---

Akt-FoxO 信号转导驱动食草昆虫对杀虫剂和寄主植物胁迫的共同适应

 介绍

宿主和食草昆虫之间持续的互动引发了一场共同进化的军备竞赛。昆虫内部的遗传多样性有助于它们适应植物化学物质及其衍生物，包括植物来源的杀虫剂。细胞色素 P450 在代谢植物化学物质和杀虫剂方面起着重要作用，因为它们具有多样性和近乎完美的进化。

 目标

本研究旨在通过研究 P450s 的激酶转录因子调节在赋予杀虫剂和植物化学物质耐受性中的作用，揭示食草昆虫中的常见分子机制。

 方法

进行 RNA 干扰、转录组测序、杀虫剂和植物化学生物测定以验证 Akt、FoxO 和候选 P450 的功能。采用双荧光素酶活性测定来鉴定 Akt-FoxO 信号通路对 P450 的调节。利用重组 P450 酶研究杀虫剂和植物化学物质的代谢。

 结果

我们鉴定了一个 Akt-FoxO 信号级联反应，它是激酶转录因子通路的代表。该级联反应介导 Nilaparvata lugens 中参与杀虫剂和植物化学物质代谢的 8 种 P450 酶的表达。这些 P450 来自不同的家族，具有不同的底物选择性，使它们能够分别代谢结构多样的杀虫剂和植物化学物质。然而，8 个 P450 基因被 FoxO 上调，FoxO 通过磷酸化在更高的级联反应中被 Akt 抑制。调节一系列 P450 基因的 Akt-FoxO 信号通路的发现阐明了昆虫适应植物化学物质和杀虫剂的精细调节机制。

 结论

这些发现揭示了这些调节过程维持的生理平衡。这项工作提供了在涉及各种 P450 的激酶 TF 模型中对寄主植物和杀虫剂施加的胁迫共同适应的实验证据。该模型提供了害虫如何适应多种环境压力的全面视图。