Fungal Wound Healing through Instantaneous Protoplasmic Gelation.

Area of Science:

• Mycology
• Biochemistry
• Biomaterials Science

Background:

• Multicellular organisms require fluid transport systems, which are vulnerable to damage.
• While septate fungi use organelles to plug wounds, the response in aseptate Mucoromycota fungi was unknown.
• Wounding in filamentous fungi can lead to significant fluid loss.

Purpose of the Study:

• To investigate the wound response mechanism in aseptate hyphae of Mucoromycota.
• To identify the proteins responsible for regulating fluid loss upon wounding.
• To understand the molecular basis of protoplasmic gelation in fungi.

Main Methods:

• Inducing wounding in Mucorales fungi.
• Observing and analyzing protoplasmic discharge and gelation.
• Identifying and characterizing Mucoromycota-specific Gellin proteins using genetic and biochemical approaches.
• Conducting cell-free reconstitution experiments.

Main Results:

• Wounding in Mucorales triggers rapid protoplasmic discharge followed by gelation.
• Mucoromycota-specific Gellin proteins were identified as crucial for terminating this discharge.
• Loss of Gellin function results in uncontrolled protoplasmic bleeding.
• Gellin proteins, with multiple β-trefoil Gll domains, exhibit distinct gelation and membrane-binding properties.
• Reconstituted Gellin structures incorporated organelles, mimicking in vivo function.

Conclusions:

• A novel mechanism of regulated protoplasmic gelation has been defined in Mucoromycota.
• Gellin proteins are key regulators of wound-induced fluid loss in these fungi.
• The unique properties of Gellin proteins provide design principles for flow-responsive biomaterials.