DataSheet1_Effects of phytocompound Precocene 1 on the expression and functionality of the P450 gene in λ-cyhalothrin-resistant Spodoptera litura (Fab.).docx

Spodoptera litura (Fabricius) is an agriculturally significant polyphagous insect pest that has evolved a high level of resistance to conventional insecticides. A dietary assay was used in this work to assess the resilience of field populations of S. litura to λ-cyhalothrin. Analysis of the function and expression of the cytochrome P450 gene was used to test the sensitivity of S. litura larvae to sub-lethal concentrations of the insecticidal plant chemical Precocene 1, both by itself and in combination with λ-cyhalothrin. The activity of esterase enzymes (α and β) was found to decrease 48 h post treatment with Precocene 1. The activity of GST enzyme and cytochrome P450 increased with Precocene 1 treatment post 48 h, however. Expression studies revealed the modulation by Precocene 1 of cytochrome P450 genes, CYP4M16, CYP4M15, CYP4S8V4, CYP4G31, and CYP4L10. While CYP4M16 expression was stimulated the most by the synergistic Precocene 1 + λ–cyhalothrin treatment, expression of CYP4G31 was the most down-regulated by Precocene 1 exposure. Hence, it is evident that λ–cyhalothrin-resistant pest populations are still sensitive to Precocene 1 at a sublethal concentration that is nevertheless capable of hindering their development. Precocene 1 can therefore be considered a potent candidate for the effective management of insecticide-resilient S. litura.

斜纹夜蛾（Spodoptera litura (Fabricius)）是一种农业上具有重要经济价值的多食性害虫，已演化出对常规杀虫剂的高水平抗性。本研究采用饲喂生物测定法，评估了斜纹夜蛾田间种群对氯氟氰菊酯（λ-cyhalothrin）的抗性水平。此外，本研究通过对细胞色素P450（cytochrome P450）基因的功能与表达进行分析，探究了斜纹夜蛾幼虫对单独施用及与氯氟氰菊酯复配施用的杀虫植物源化合物早熟素1（Precocene 1）亚致死浓度的敏感性。研究发现，经早熟素1处理48小时后，α-酯酶与β-酯酶的活性均有所下降；然而，谷胱甘肽S-转移酶（GST）及细胞色素P450的活性则在处理48小时后出现升高。基因表达分析显示，早熟素1可调控多种细胞色素P450基因的表达，包括CYP4M16、CYP4M15、CYP4S8V4、CYP4G31及CYP4L10。其中，早熟素1与氯氟氰菊酯的协同处理对CYP4M16的表达诱导效果最为显著，而早熟素1单独处理则对CYP4G31的表达产生了最强的下调作用。由此可见，对氯氟氰菊酯具有抗性的害虫种群，在该亚致死浓度下仍对早熟素1敏感，且该浓度足以抑制其生长发育。因此，早熟素1可作为有效治理抗药性斜纹夜蛾的潜在高效候选药剂。