A novel allatostatin-A analog, III-2 may particularly regulates juvenile hormone III to influence Spodoptera frugiperda metamorphosis and development

Abstract

Allatostatin (AST) is a class of insect neuropeptides that affects insect growth and development by inhibiting the synthesis of juvenile hormones (JH) in different insects. Ⅲ-2 is a novel allatostatin-A（AST-A）analog derived from a class of nitroaromatic groups connected by different amino acids. In this study, we found that Ⅲ-2 showed high insecticidal activity against S. frugiperda larvae with a LC50 of 18.7 mg L-1. As demonstrated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), III-2 particularly encouraged JH III and hindered 20E synthesis in S. frugiperda. The results of RNA-Seq and quantitative real-time polymerase chain reaction (qPCR) showed that Ⅲ-2 treatment promoted the expression of JH terminal synthetases SfCYP15C1 and SfJHAMT and inhibited the expression of SfJHE and SfJHEH in the metabolic pathway of JH. Significant differences were observed in the expression of the genes related to cuticle formation. We report for the first time that AST compounds specifically interfere with the synthesis and secretion of a certain JH in insects, thus affecting the ecdysis and growth of insects, and leading to death. This study may provide a new plant conservation concept for us to seek the targeted control of certain insects based on specific interference with different JH.