Bacillus subtilis expressing double‐stranded RNA induced RNA interference in Tribolium castaneum

BACKGROUND: RNA interference represents a promising and eco-friendly approach for pest management. As the core component of RNA biopesticides, the synthesis of double-stranded RNA (dsRNA) is the cornerstone for the further development and practical application of these biopesticides. Bacillus subtilis, with favorable characteristics (e.g., excellent safety, strong heterologous expression capability, and easy industrial fermentation), is an attractive dsRNA bio-factory for large-scale production of RNA biopesticides. RESULTS: An RNase-III-deficient B. subtilis strain was successfully constructed. Among the promoters screened from genes with high expression levels at each growth stage, pcotY, pcgeA, and phag exhibited high potential in driving dsRNA expression. Further optimization of the promoter phag significantly improved the yield of dsRNA. Using the mutant B. subtilis strain as the host, the optimized phag derivative phag-1 was utilized to express dsRNA targeting TcSpt5 and TcPolr2A of Tribolium castaneum. Larvae fed on an artificial diet containing these recombinant strains displayed significant reductions in survival and pupation rate, accompanied by reduced target gene expression. CONCLUSION: Collectively, B. subtilis serves as an efficient dsRNA production platform that can be employed to control pests. © 2026 Society of Chemical Industry.