Transgenic expression of mAChR-C dsRNA in maize confers efficient locust control

Plant-mediated RNA interference (RNAi), in which double-stranded RNAs (dsRNAs) targeting insect genes are expressed in plants for insect ingestion, has shown great potential for the control of herbivorous insect pests. Locusts, which are among the most destructive agricultural insect pests, appear to be resistant to orally delivered naked dsRNA. Moreover, the feasibility of using plant-mediated RNAi to suppress target gene expression in locusts remains unclear. Using the migratory locust Locusta migratoria, we report that the C-type muscarinic acetylcholine receptor (mAChR-C), a G protein-coupled receptor (GPCR) belonging to the bioamine receptor subfamily, plays a pivotal role in chitin metabolism by regulating genes responsible for chitin synthesis and degradation. Knockdown of locust mAChR-C via injection of dsRNA caused defective nymph molting and metamorphosis, accompanied by malformation, arrested development, and impaired motility. Notably, locusts fed transgenic maize expressing locust mAChR-C dsRNAs exhibited defective phenotypes similar to those subjected to mAChR-C dsRNA injection. In contrast, ingestion of transgenic maize expressing locust mAChR-C dsRNA had no significant effects on non-target insects, including the fall armyworm Spodoptera frugiperda, the cotton bollworm Helicoverpa armigera, the Asian corn borer Ostrinia furnacalis, and the oriental armyworm Mythimna separata. Our results suggest that transgenic expression of locust mAChR-C dsRNA is an effective RNAi approach for locust control and offers a promising eco-friendly strategy for locust management.