Function of pH-dependent transcription factor PacC in regulating development, pathogenicity, and mycotoxin biosynthesis of phytopathogenic fungi.

pH, as one of the most important environmental factors, affects various biological processes in pathogenic fungi. Sensing and responding to fluctuations in ambient pH are essential for these fungi to complete their life cycle. Fungi have evolved a complicated and conserved system, the so-called Pal-pH pathway, to regulate genes and adapt to alterations in ambient pH. PacC is the dominant transcription factor in the Pal-pH pathway and regulates various biological processes. The regulatory mode of PacC has been extensively studied in Aspergillus nidulans and is generally conserved in other fungal species, including numerous phytopathogenic fungi. However, species-specific alterations have been reported. This review summarizes recent advances in the regulatory mechanisms of PacC and its role in controlling development, pathogenicity, and mycotoxin biosynthesis in phytopathogenic fungi. Potential applications of these findings and some unresolved questions are also discussed.