DNA N6-methylation orchestrates the pathogenicity of Mucorales fungi

The epigenetic modification N6-methyladenine (6mA), symmetrically distributed on both DNA strands, is highly abundant in Mucorales, opposed to other fungal pathogens, and regulates multiple biological processes. In contrast, symmetric 6mA and its associated enzymatic machinery are largely absent in mammals, highlighting a striking evolutionary divergence that suggests potential pathogen-specific therapeutic vulnerabilities.

Here, we develop a tetracycline-regulatable system in Rhizopus microsporus that enables repression of the essential methyltransferase Mta1 and consequent reduction of genomic 6mA levels. Induced depletion of 6mA profoundly attenuates fungal virulence in murine infection models, an effect associated with downregulation of key virulence determinants, including the mycotoxin mucoricin and the CotH3 invasin. Attenuated fungal pathogenicity was further accompanied by enhanced neutrophil swarming, resulting in efficient restriction of germinating fungi.