Dai Zhijun, Sun Bangyong, Wang Yun, Zhang Ze, Sun Wei
School of Life Sciences, Chongqing University, Chongqing 401331, China.
Insects. 2022 Mar 17;13(3):297. doi: 10.3390/insects13030297.
To prevent their ingestion by phytophagous insects, plants produce secondary metabolites as defensive weapons. Conversely, insects need to counter these metabolites to survive. Different species, though they are closely related, can evolve distinct strategies to resist plant-derived factors. However, the mechanism under this high divergence resistance is still unclear at a molecular level. In this study, we focus on how (Lepidoptera; Noctuidae) detoxifies phytoecdysteroids, a class of metabolites capable of disrupting the normal development of insects. Firstly, we find that the show resistance to artificial foods containing a high level of 20-hydroxyecdysone (20E), the major form of phytoecdysteroids, without any adverse effects on growth and development. Furthermore, a comparative transcriptomic analysis between and another noctuid insect () was performed. Almost all known ecdysteroid degradation pathways including 3-epimerization, 22-phosphorylation, 22-esterification, and 26-hydroxylation were upregulated in the midgut of 20E treated larvae, whereas only 22-esterification and 26-hydroxylation were enhanced in larvae. In summary, though both species belong to the Noctuidae family, they evolved two different strategies to tolerate a high dosage of ingested 20E.
为防止被植食性昆虫摄取，植物会产生次生代谢产物作为防御武器。相反，昆虫需要对抗这些代谢产物才能生存。不同物种，尽管它们亲缘关系密切，但可能会进化出不同的策略来抵抗植物衍生的因子。然而，这种高度分化抗性背后的分子机制在分子水平上仍不清楚。在本研究中，我们聚焦于棉铃虫（鳞翅目；夜蛾科）如何解毒植物蜕皮甾体，这是一类能够干扰昆虫正常发育的代谢产物。首先，我们发现棉铃虫对含有高水平20-羟基蜕皮酮（20E）的人工饲料具有抗性，20E是植物蜕皮甾体的主要形式，且对其生长发育没有任何不利影响。此外，我们对棉铃虫和另一种夜蛾科昆虫（烟芽夜蛾）进行了比较转录组分析。在经20E处理的棉铃虫幼虫中肠中，几乎所有已知的蜕皮甾体降解途径，包括3-差向异构化、22-磷酸化、22-酯化和26-羟基化，均上调，而在烟芽夜蛾幼虫中仅22-酯化和26-羟基化增强。总之，尽管这两个物种都属于夜蛾科，但它们进化出了两种不同的策略来耐受高剂量摄入的20E。
