A Streamlined Protocol for Small-scale Protoplast Generation and CRISPR/Cpf1-mediated Genome Editing in Fusarium oxysporum

Abstract

Fusarium oxysporum is a significant threat to agriculture and One Health, requiring advanced molecular tools for functional genomics analyses and biological control agent development. Existing gene-editing methods are hampered by costly protoplast preparation protocols and by CRISPR/Cas9 limitations, such as restricted PAM sequences and complex guide RNA requirements. We engineered an efficient CRISPR/Cpf1 system that overcomes these issues through three main innovations: small-scale protoplast generation using novel filter columns that greatly reduces enzyme consumption while simplifying workflows, a CRISPR/Cpf1 system with flexible PAM recognition and staggered DNA cleavage to promote homologous recombination, and minimal homology arm strategies that significantly decrease cloning complexity. Extensive validation confirms successful gene targeting with molecular verification and functional analysis via standardized pathogenicity assays. This integrated platform offers affordable, accessible tools for systematic F. oxysporum research, enhancing fundamental understanding of plant-pathogen interactions and supporting high-throughput screening vital for agricultural biotechnology and biological agent development. MOTIVATIONFusarium oxysporum plays crucial roles as both a damaging plant pathogen and a model for studying host-pathogen interactions. It is well established that systematic functional genomics approaches are vital for advancing agricultural biotechnology and developing biological agents. Creating efficient gene-editing systems can help elucidate virulence mechanisms and enable rapid production of modified strains for practical use. However, current transformation methods face major challenges, such as high enzyme costs, and CRISPR/Cas9 systems are limited by PAM sequence availability and by blunt-end DNA cleavage, which hampers homologous recombination. Furthermore, complex guide RNA scaffolds complicate large-scale functional studies with traditional methods. To address these challenges, we have developed a streamlined CRISPR/Cpf1 (Cas12a) platform that combines small-scale protoplast preparation with significantly reduced enzyme use, exploiting Cpf1s unique features, such as flexible PAM recognition, staggered DNA cuts that promote recombination, improved target specificity, and simpler guide RNA design. This platform can also accelerate the development of biological agents and support high-throughput screening applications essential to the progress of agricultural biotechnology. HIGH LIGHTSO_LIReduced enzyme costs by 95% through small-scale protoplast preparation C_LIO_LICRISPR/Cpf1 system established for efficient gene editing in Fusarium oxysporum C_LIO_LIStreamlined workflow enables routine gene targeting and rapid mutant screening C_LIO_LIComplete workflow validated with EGFP-marked pathogenicity C_LI