Hydrophobin gene expression affects hyphal wall composition in Schizophyllum commune

Area of Science:

• Mycology
• Biochemistry
• Molecular Biology

Background:

• Hydrophobins are amphipathic proteins crucial for fungal development and interactions with hydrophobic surfaces.
• The SC3 hydrophobin gene in Schizophyllum commune has been previously implicated in fungal growth and development.

Purpose of the Study:

• To investigate the role of the SC3 hydrophobin gene in Schizophyllum commune cell wall composition.
• To determine if SC3 hydrophobins influence the synthesis or assembly of cell wall components.

Main Methods:

• Gene disruption of the SC3 hydrophobin gene in S. commune to create a DeltaSC3 strain.
• Analysis of cell wall composition, including mucilage and alkali-resistant glucan, in wild-type and DeltaSC3 strains.
• Complementation studies involving reintroduction of the SC3 gene or other hydrophobin genes.

Main Results:

• Disruption of the SC3 gene led to a significant increase in mucilage (water-soluble (1-3)beta-glucan) and a decrease in alkali-resistant glucan linked to chitin.
• Reintroducing the SC3 gene or other hydrophobins restored the wild-type cell wall composition.
• Adding purified SC3 protein or growing the mutant strain in wild-type spent medium did not alter cell wall composition, suggesting intracellular effects.

Conclusions:

• SC3 hydrophobins play a direct role in regulating fungal cell wall composition, affecting glucan and chitin interactions.
• Hydrophobins' functions extend beyond their known roles at hydrophilic/hydrophobic interfaces to influence intracellular processes governing cell wall synthesis.
• The SC3 gene is essential for maintaining the normal balance of cell wall components in Schizophyllum commune.