Shu Benshui, Huang Yuting, Xie Xinyi, Liu Cuiting, Lin Jintian, Xiao Ying, Zhang Jingjing
Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
Pestic Biochem Physiol. 2025 Nov;214:106567. doi: 10.1016/j.pestbp.2025.106567. Epub 2025 Jul 11.
Azadirachtin, a highly effective botanical pesticide, demonstrated notable biological activities against Spodoptera frugiperda, including mortality induction, growth and development inhibition, and antifeedant effects. Neuropeptide F (NPF) has been shown to play a role in various physiological processes in insects. Nonetheless, the functions of Sf-NPF1 in regulating food intake and antifeedant induction by azadirachtin in S. frugiperda larvae are yet to be elucidated. In this study, the antifeedant effects induced by 0.5 and 1.0 μg/g azadirachtin treatments in S. frugiperda larvae were evaluated. The sequence of Sf-NPF1 was identified with two transcript variants, and the proteins exhibit high identity with NPFs found in lepidopteran insects. Spatiotemporal expression analysis indicated that Sf-NPF1 exhibited high expression levels in first instar larvae and male adults, while the lowest expression was observed in non-feeding stages (egg and pupa stages). Besides, Sf-NPF1 also demonstrated notable expression in the midgut tissue of larvae. Azadirachtin treatments inhibited the expression of Sf-NPF1 in the larval midgut. The injection of the Sf-NPF1a mature peptide resulted in increased larval food intake and weight gain during a two-day treatment period. The antifeedant effect induced by 1.0 μg/g azadirachtin was also mitigated by the injection of Sf-NPF1a mature peptide. Our results indicated that Sf-NPF1 may serve as a positive regulator of food intake in S. frugiperda larvae, while azadirachtin could exert an antifeedant effect in larvae via inhibiting the expression of Sf-NPF1. These findings establish a foundation for comprehending the mechanism behind the antifeedant effect induced by azadirachtin in insect larvae and provide a potential target for developing novel insecticides.
印楝素是一种高效的植物源杀虫剂，对草地贪夜蛾表现出显著的生物活性，包括诱导死亡、抑制生长发育以及拒食作用。神经肽F（NPF）已被证明在昆虫的各种生理过程中发挥作用。然而，草地贪夜蛾NPF1（Sf-NPF1）在调节草地贪夜蛾幼虫食物摄取以及印楝素诱导拒食方面的功能尚未阐明。在本研究中，评估了0.5和1.0μg/g印楝素处理对草地贪夜蛾幼虫的拒食作用。鉴定出Sf-NPF1的序列有两个转录变体，其蛋白质与鳞翅目昆虫中的NPF具有高度同源性。时空表达分析表明，Sf-NPF1在一龄幼虫和雄性成虫中表达水平较高，而在非取食阶段（卵和蛹期）表达最低。此外，Sf-NPF1在幼虫中肠组织中也有显著表达。印楝素处理抑制了幼虫中肠中Sf-NPF1的表达。注射Sf-NPF1a成熟肽导致在为期两天的处理期内幼虫食物摄入量增加和体重增加。注射Sf-NPF1a成熟肽也减轻了1.0μg/g印楝素诱导的拒食作用。我们的结果表明，Sf-NPF1可能作为草地贪夜蛾幼虫食物摄取的正调节因子，而印楝素可能通过抑制Sf-NPF1的表达在幼虫中发挥拒食作用。这些发现为理解印楝素在昆虫幼虫中诱导拒食作用的机制奠定了基础，并为开发新型杀虫剂提供了潜在靶点。
