Utilization of Miniature CRISPR-AsCas12f1 Nuclease for Efficient Genome Editing in Bacillus subtilis

To address the limitations of clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated (Cas)9 in Bacillus subtilis, such as low transformation efficiency and strong dependence on specific PAM sequences, this study developed a novel genome-editing tool based on AsCas12f1 nuclease derived from Acidibacillus sulfuroxidans. Using the CRISPR-AsCas12f1 system, we successfully achieved gene knockout and targeted insertion in B. subtilis with a knockout efficiency of up to 100%. We further demonstrated that the length of the donor DNA homology arms and the choice of PAM motifs significantly influenced the editing efficiency. To expand the applicability of this system, gene interference and activation experiments were performed using green fluorescent protein (GFP) as a reporter. The system achieved more than 90% gene knockdown efficiency and effectively activated the reported gene transcription, with a maximum activation fold of 3.20. In conclusion, the CRISPR-AsCas12f1 system established in this study provides an efficient and reliable genome editing tool for the functional gene research and industrial applications of B. subtilis.