In order to survive and adapt to the environment, it is imperative for fungi to be able to sense
and respond to changes in extracellular pH conditions. In ascomycetes, sensing of
extracellular pH is mediated by the Pal pathway resulting in activation of the PacC
transcription factor at alkaline pH. The role of PacC in regulating fungal virulence and
pathogenicity has been described in several pathogenic fungi but to date not in a symbiotic
fungus. Epichloë festucae is a biotrophic fungal endophyte that forms a stable mutualistic …