Knockout BR‐C induces premature expression of E93 thus triggering adult differentiation under larval morphology

Abstract BACKGROUND Holometabolan pupal‐specifier broad‐complex ( BR‐C ) and adult specifier ecdysone‐induced protein 93F ( E93 ) are essential for metamorphosis; however, their interaction and effects on programmed cell death and cell differentiation during pupation remain unclear. RESULTS Here, multiple single‐guide RNA (sgRNA)‐mediated mosaic knockout of BR‐C induced a deformed larva/pupa intermediate phenotype in Spodoptera frugiperda . Quantitative real‐time polymerase chain reaction (qPCR) analysis showed that the adult specifier E93 was prematurely expressed in the BR‐C mutants during the penultimate and last instar larval stages. Additionally, histological observation and TUNEL assay showed that apoptosis in the fat body and midgut was activated in the larval tissues; astonishingly, the adult midgut appeared in the pupae of BR‐C mutants. CONCLUSION Overall, the results demonstrated that the premature expression of E93 induced by lack of BR‐C triggers adult differentiation during the larval stages, which revealed the inhibitory effect of BR‐C on E93 during metamorphosis in S. frugiperda . © 2024 Society of Chemical Industry.