MicroRNA miR-7-5p|-1|0| regulates wing development in brown planthoppers, Nilaparvata lugens

MicroRNAs (miRNAs) regulate insect development; however, their roles in non-Drosophila wing polyphenism, such as the brown planthopper (BPH, Nilaparvata lugens), remain unclear. Although Nlmad1 downstream of IIS-FoxO has been shown to regulate wing morphs, its upstream control is poorly understood.

Here, we showed that the functional role of the evolutionarily conserved miR-7-5p|-1|0|, miR-7-5p and miR-71-5p in N. lugens wing development and its mechanistic link to Nlmad1. Through computational prediction, dual-luciferase assays, and phenotypic analyses, we demonstrated that Nlu-miR-7-5p|-1|0| directly targets the 3'UTR of Nlmad1 to suppress its expression. Overexpression of Nlu-miR-7-5p|-1|0| in macropterous nymphs induced significant wing development defects, whereas inhibition of endogenous Nlu-miR-7-5p|-1|0| in the brachypterous strain only resulted in a subtle phenotype in wing development. Notably, Nlu-miR-7-5p influenced Nlmad1 transcript levels but requires further validation for direct interaction, whereas Nlu-miR-71-5p modulated wing development independently of Nlmad1, suggesting distinct regulatory pathways.

This study is the first to establish miR-7-5p|-1|0| as a post-transcriptional regulator of Mad-family proteins in insects, expanding our understanding of miRNA-driven developmental plasticity. By linking conserved miRNAs to species-specific polyphenic traits, our findings provide a framework for targeting miR-7-5p|-1|0|-Nlmad1 interactions in novel pest management strategies aimed at disrupting wing development and population dispersal. © 2025 Society of Chemical Industry.