Development of an Efficient CRISPR/Cas9 System in and Its Application in Reducing Mycotoxin Contamination.

() is a globally recognized and highly impactful fungal pathogen of maize, causing yield losses and producing harmful mycotoxins that pose a threat to human and animal health. However, the genetic tools available for studying this crucial fungus are currently limited in comparison to other important fungal pathogens. To address this, an efficient CRISPR/Cas9 genome editing system based on an autonomously replicating plasmid with an AMA1 sequence was established in this study. First, gene disruption of and via nonhomologous end-joining (NHEJ) pathway was successfully achieved, with efficiency ranging from 66 to 100%. Second, precise gene deletions were achieved with remarkable efficiency using a dual sgRNA expression strategy. Third, the developed genome editing system can be applied to generate designer chromosomes in , as evidenced by the deletion of a crucial 38 kb fragment required for fumonisin biosynthesis. Fourth, the recycling system has been established and successfully applied in . Lastly, the developed Δ and Δ mutants can serve as biocontrol agents to reduce the fumonisin B (FB) contamination produced by the toxigenic strain. Taken together, these significant advancements in genetic manipulation and biocontrol strategies provide valuable tools for studying and mitigating the impact of on maize crops.