20‐Hydroxyecdysone primary response gene <scp> <i>LmBlimp‐1</i> </scp> controls locust molt and survival by regulating chitin metabolism

Abstract BACKGROUND The Cys2‐His2‐type zinc finger transcription factor Blimp‐1 plays a crucial role in animal development; however, its function in insect molting remains poorly understood. In this study, we investigated the role of LmBlimp‐1 in the molting development of the migratory locust Locusta migratoria . RESULTS RNA interference (RNAi)‐mediated silencing of LmBlimp‐1 resulted in severe molting defects, developmental delay and ultimately 100% mortality. Furthermore, knockdown of LmBlimp‐1 significantly downregulated the expression of chitinase genes ( LmCht5‐1, LmCht5‐2 and LmCht10 ) and chitin synthesis‐related genes ( LmGfat , LmUAP1 and LmCHS1 ), leading to impaired degradation of the old cuticle and defective synthesis of the new cuticle. Mechanistic analyses further revealed that 20‐hydroxyecdysone (20E) induced the expression of LmBlimp‐1 , indicating that it functions as a primary response gene in the 20E signaling pathway. Knockdown of LmBlimp‐1 disrupted the expression of key 20E‐response genes, including LmE74 , LmHR3 and LmHR4 . Moreover, the 20E rescue experiment partially alleviated the lethal phenotype caused by LmBlimp‐1 RNAi. CONCLUSION These results demonstrate that LmBlimp‐1 acts as a critical regulator that integrates the 20E signal to modulate chitin metabolism and ensure successful molting. Our findings provide new insights into the molecular regulatory network underlying insect molting and offer a theoretical basis for the development of RNAi‐based pest management strategies. © 2026 Society of Chemical Industry.