Development of Botanical Pesticides: Exploration on the Phenotype of Vestigial Wings of Insect Pests Induced by Plant Natural Products or Their Derivatives by Blocking Tyrosine Phosphorylation of Insulin Receptor 1

Abstract

Unlike faster-acting conventional insecticides, some botanical insecticides exhibit growth inhibitory activity against some insect pests. One of the distinguishing features of growth inhibitory activity appears to be in malformed moths with vestigial wings. However, the molecular mechanism underlying vestigial wings of insect pests induced by plant natural products or their derivatives is still elusive. In this work, based upon the phenotype of the vestigial wings of Mythimna separata Walker (as a model pest) induced by a podophyllotoxin derivative 2a (as a model compound), we found that compound 2a not only resulted in 22.1% of malformed moths with vestigial wings but also significantly decreased the fecundity of vestigial-winged female moths in the P generation; the trait of vestigial wings caused by 2a in the P generation can be inherited by the F1 generation; compound 2a may target insulin receptor 1 (InR1), suppress the InR1 mRNA level, and block InR1-pY1229 and InR1-pY1233/1234 phosphorylation levels in a tissue-specific manner "head/thorax/wing tissues". Notably, compound 2a can also induce the vestigial wings of Spodoptera frugiperda (another seriously harmful migratory lepidoptera pest). It is noteworthy that this insect insulin receptor can be used as a new kind of target receptors for the design of novel green insecticides.