Different extracellular proteins are
synthesized at different pHs. In addition, at the transcriptional
level, several proteases, glucanases, cell-wall proteins and a
glucose transporter are pH-controlled, which suggests a pHdependent
transcriptionally controlled response of different
enzymes. External pH is also important to pathogens because
their pathogenicity factors are produced only within a very
narrow range of pHs [46] (Fig. 4A), so that pH modification
determines the pathogen’s ability to successfully colonize
and invade the targeted host