Creating an effective gene-editing method using CRISPR-Cas9 in the lichen fungus Umbilicaria muhlenbergii

A high replacement efficiency of up to 65.0% was achieved in targeted gene disruption using a CRISPR-Cas9 system in Umbilicaria muhlenbergii.

• The established CRISPR-Cas9 system effectively disrupted six candidate transcription factors.
• No off-target mutations were found in any of the three independent mutants for each target gene.
• Disruption of the gene UmSOM1 significantly impaired fungal growth and altered colony characteristics.
• The CRISPR-Cas9 method outperformed conventional homologous recombination in gene disruption efficiency.
• This system may facilitate further functional genomic studies in lichen-forming fungi.

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