Pharmacological Properties and Function of the PxOctβ3 Octopamine Receptor in Plutella xylostella (L.)

Simple Summary The diamondback moth (Plutella xylostella) is a global migratory pest that primarily destroys cruciferous vegetables. Due to the extensive application of insecticides, P. xylostella has developed resistance to more than 90 types of active insecticidal ingredients, and this has exacerbated its control. Octopamine plays a key role in the neural activity of invertebrates because it regulates various physiological functions and behaviors in insects. The actions of octopamine have been shown to be mediated via the activation of octopamine receptors (OARs). In this study, we identified an OAR gene (PxOct beta 3) in P. xylostella, analyzed its molecular characteristics and patterns of expression, and expressed it in HEK-293 cells to not only analyze the pharmacological properties of the encoded PxOct beta 3 receptor but also identify its specific agonists and antagonists. RNA interference-mediated inhibition of the expression of PxOct beta 3 resulted in shorter durations of pupation in the diamondback moth. These results indicate that PxOct beta 3 plays an important role in the physiology of P. xylostella. The diamondback moth (Plutella xylostella) is one of the most destructive lepidopteran pests of cruciferous vegetables, and insights into regulation of its physiological processes contribute towards the development of new pesticides against it. Thus, we investigated the regulatory functions of its beta-adrenergic-like octopamine receptor (PxOct beta 3). The open reading frame (ORF) of PxOct beta 3 was phylogenetically analyzed, and the levels of expression of the receptor mRNA were determined. This ORF was also cloned and expressed in HEK-293 cells. A series of octopamine receptor agonists and antagonists were tested against PxOct beta 3. We showed that the receptor is a member of the Oct beta 3 protein family, and an analysis using quantitative PCR showed that it was expressed at all developmental stages of P. xylostella. Octopamine activated PxOct beta 3, resulting in increased levels of intracellular cAMP. Furthermore, the agonists naphazoline, clonidine, 2-phenethylamine, and amitraz activated the PxOct beta 3 receptor, and naphazoline was the most effective. Only metoclopramide and mianserin had significant antagonistic effects on PxOct beta 3, whereas yohimbine, phentolamine, and chlorpromazine lacked obvious antagonistic effects. The injection of double-stranded RNA in an RNA interference assay indicated that PxOct beta 3 regulates development in P. xylostella. This study demonstrated the pharmacological properties and functions of PxOct beta 3 in P. xylostella, thus, providing a theoretical basis for the design of pesticides that target octopamine receptors.

Automated summary

In this study, researchers identified and analyzed the molecular characteristics and expression patterns of an octopamine receptor gene PxOct beta 3 in the diamondback moth. They found that PxOct beta 3 plays an important role in the physiological processes of the moth and demonstrated its pharmacological properties. This study provides a theoretical basis for the development of new pesticides targeting octopamine receptors.