fCUT&Tag-Seq: An Optimized CUT&Tag-based Method for High-Resolution Profiling of Histone Modifications and Chromatin-Binding Proteins in Fungi

Abstract Histone modifications and chromatin-binding proteins play crucial roles in regulating gene expression in eukaryotes, with significant implications for fungal pathogenicity and development. However, profiling these modifications or proteins across the genome in fungi remains challenging due to the technical limitations of the traditional, widely used ChIP-Seq method. Here, we present an optimized CUT&Tag-Seq protocol (fCUT&Tag-Seq) specifically designed for filamentous fungi and dimorphic fungi. Our approach involves the preparation of protoplasts and nuclear extraction to enhance antibody accessibility, along with formaldehyde crosslinking to improve protein-DNA binding efficiency. We then successfully applied fCUT&Tag-Seq to accurately profile multiple histone modifications like H3K9me3, H3K27me3, H3K4me3, and H3K18ac, across different plant pathogenic or model fungal species, including Verticillium dahliae , Neurospora crassa , Fusarium graminearum , and Sporisorium scitamineum , showing good signal-to-noise ratios, reproducibility, and detection sensitivity. Furthermore, we extended this method to profile chromatin-binding proteins, such as the histone acetyltransferase Gcn5. This study establishes fCUT&Tag-Seq as a robust and useful tool for fungal epigenetic research, enabling detailed exploration of chromatin dynamics and advancing our understanding of fungal gene regulation, development, and pathogenicity. Impact Statement We developed a faster, lowLJinput method to study how genes are turned on and off in fungi, even in tough species that are difficult to analyze with standard methods. Our new approach, named fCUT&Tag-Seq, requires only 10,000 cells and can be completed in just two days. It delivers clearer, more reliable results and has already been successfully applied to multiple fungi, including crop pathogens. By revealing the molecular “control switches” that govern fungal development and virulence, we expect it will accelerate basic research and help identify new targets for controlling destructive plant diseases.