Search

Background: The push-pull strategy is considered as a promising eco-friendly method for pest management. Plant volatile organic compounds (PVOCs) act as semiochemicals constitute the key factor in implementing this strategy. Benzyl alcohol and geraniol, as functional PVOCs, were reported to regulate insect behavior, showing the potential application in pest control. Using geraniol as lead, a geraniol derivative 5i with fine repellent activity was discovered in our previous work. In order to explore novel, eco-friendly aphid control agents, a series of benzyl geranate derivatives was designed and synthesized using 5i as the lead and benzyl alcohol as the active fragment., Results: Benzyl alcohol was firstly evaluated to have repellent activity to Acyrthosiphon pisum. Based on this repellent fragment, a series of novel benzyl geranate derivatives was rationally designed and synthesized using a scaffold-hopping strategy. Among them, compound T9, with a binding affinity (K d  = 0.43 μm) and a substantial repellency of 64.7% against A. pisum, is the most promising compound. Molecule docking showed that hydrophobic and hydrogen-bonding interactions substantially influenced the binding affinity of compounds with ApisOBP9. Additionally, T9 exhibited low-toxicity to honeybees and ladybugs., Conclusion: Using a simple scaffold-hopping strategy combined with active fragment benzyl alcohol, a new derivative T9, with high aphid-repellency and low-toxicity to nontarget organisms, can be considered as a novel potential eco-friendly aphid control agent for sustainable agriculture. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: As one of the most abundant and destructive pests in agriculture, aphids cause significant damage to crops due to their sap-taking and as virus vectors. Chemical insecticides are the most effective method to control aphids, but they bring insecticide resistance problems and harm nontarget organisms, especially bees, therefore the search for novel eco-friendly aphid control agents with low bee toxicity is urgent. Insect kinins are a class of small neuropeptides that control important functions in insects. In our previous study, we found insect kinin analog IV-3 has good aphicidal activity and the location of the aromatic ring on the side chain of Phe 2 is the key to the formation of the β-turn resulting in the biological activity of insect kinin analogs. However, there are few studies on insect kinin Phe 2 substitution and modification, and its structure-activity relationship is still unclear., Results: In this project, 44 insect kinin analogs with the Phe 2 modification, replacing it with different natural or unnatural amino acids, were designed and synthesized based on the lead IV-3 to explore the role of the Phe 2 residues. Bioassays with soybean aphids of Aphis glycines indicated that nine analogs have better aphicidal activity than the lead IV-3. In particular, compound L 25 exhibits excellent aphicidal activity (LC 50  = 0.0047 mmol L -1 ) and has low toxicity to bees. Furthermore, a reliable three-dimensional quantitative structure-activity relationship (3D-QSAR) was established to produce a helpful clue that introducing hydrophobic groups away from the backbone chain is beneficial to improve aphicidal activity., Conclusion: The residue Phe 2 of insect kinin analogs is the key position and has a significant impact on the activity. L 25 has a high toxicity for aphids, while a low toxicity to bees, and therefore can be considered as a lead compound to develop new biosafe aphid control agents. Finally, we provide a useful 3D-QSAR model as theoretical guidance for further structural optimization. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Background: Fall armyworm (FAW, Spodoptera frugiperda) is one of the most destructive and invasive pests worldwide and causes significant economic losses. Intensive and frequent use of insecticides has led to the development of resistance in FAW. Adipokinetic hormone (AKH) have been proven to be involved in insecticide resistance in insects. However, the molecular mechanism underlying chlorantraniliprole resistance mediated by AKH signaling in FAW remains unclear., Results: The expression of SpfAKHR was highest in male adults and lowest in 1st instar larvae. SpfAKH was expressed the highest in eggs and the lowest in 6th instar larvae. AKH signaling was involved in the sensitivity of FAW to chlorantraniliprole through a toxicological bioassay, and the combination of chlorantraniliprole and bithionol (an inhibitor of key enzymes in the AKH pathway) significantly increased the mortality of FAW. Chlorantraniliprole significantly induced the expression of ten P450s, SpfAKH and SpfAKHR in FAW. RNA interference against SpfAKHR significantly decreased the P450 content, downregulated the expression of three P450 genes (SpfCYP6B50, SpfCYP321A9 and SpfCYP9A58) and inhibited the resistance of FAW to chlorantraniliprole. The topical application of AKH peptide significantly increased the P450 content, upregulated the expression of five P450 genes (SpfCYP321A9, SpfCY321A8, SpfCYP321A10, SpfCYP321A7 and SpfCYP6AB12), and enhanced the survival of FAW against chlorantraniliprole., Conclusions: AKH plays an important role in enhancing chlorantraniliprole resistance in FAW by exerting a positive influence on P450 gene expression and P450 content. These results provide valuable insights into insecticide resistance regulation and FAW control strategies. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)