RNAi of 20S proteasome β subunit 3 inhibits midgut homeostasis and the survival of the migratory locust, Locusta migratoria

Abstract BACKGROUND Tissue homeostasis is essential for both morphogenesis and maintaining function. In insects, intestinal homeostasis is critical for growth and development. The midgut is key in food digestion, nutrient absorption, and immune response. Locusta migratoria is among the most damaging agricultural pests worldwide. Identifying a suitable target gene is important for RNA interference (RNAi)‐based pest control. RESULTS In this study, RNAi‐mediated knockdown of the 20S proteasome β subunit 3 of L. migratoria ( LmProsβ3 ) caused atrophy of the midgut and gastric caecum in fourth‐ and fifth‐instar nymphs as well as adult locusts. This deficiency also led to a decrease in body length and weight, eventually resulting in mortality. Histological analysis using haematoxylin and eosin (H&E) staining and transmission electron microscopy (TEM) showed that LmProsβ3 knockdown damaged columnar epithelial cells and regenerative cells, with the nucleus disappearing due to cell cycle inhibition. Additionally, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in the ds LmProsβ3 group were higher than those in the double‐stranded green fluorescent protein (ds GFP ) group. Moreover, the activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) in the double‐stranded LmProsβ3 (ds LmProsβ3 ) group were reduced. CONCLUSION LmProsβ3 is essential for midgut homeostasis and survival, influencing the growth and development of locusts. These findings help clarify the functions of LmProsβ3 in maintaining midgut health. LmProsβ3 could be a potential target gene for RNAi‐based locust control. © 2025 Society of Chemical Industry.