LAUSR

The model fungus Podospora anserina exhibits Crippled Growth (CG), a cell degeneration process linked to the spreading of a prion‐like hereditary element. Previous work has shown that the PaMpk1 MAP kinase and the PaNox1 NADPH oxidase are key player in setting up CG. Here, we identified PDC1, a new gene that negatively regulates the PaMpk1 pathway, by identifying the gene mutated in the PDC2205 mutant. This mutant exhibits strong CG in conditions where the wild‐type does not. PDC1 encodes a small protein conserved in other Pezizomycotina. The protein contains four evolutionary‐conserved cysteines, a tryptophan and a histidine; all six amino‐acid are essential for function. PDC1 is located in the cytosol and is present in lower amounts in stationary hyphae in accordance with its role as a repressor. Epistasis analyses place PDC1 between PaMpk1 and PaNox1.