The antifungal peptide AnAFP from Aspergillus niger promotes nutrient mobilization through autophagic recycling...

Area of Science:

• Mycology
• Molecular Biology
• Biochemistry

Background:

• Antifungal peptides are potential therapeutics for fungal infections.
• Emerging evidence suggests these peptides also function internally for organism survival under nutrient limitation.
• The specific role of the antifungal AnAFP in Aspergillus niger during starvation remains largely uncharacterized.

Purpose of the Study:

• To elucidate the intracellular function of the antifungal AnAFP in Aspergillus niger.
• To investigate the effects of AnAFP on fungal growth, development, and cellular processes under nutrient-limiting conditions.
• To understand the molecular mechanisms underlying AnAFP's role in starvation survival.

Main Methods:

• Development of a Tet-on controlled anafp expression system in Aspergillus niger for inducible gene expression.
• Comparative transcriptome analysis of glucose-starving mycelium with normal and overexpressed anafp.
• Fluorescent microscopy using an AnAFP::eGFP fusion protein to determine subcellular localization.

Main Results:

• Overexpression of AnAFP led to reduced growth and premature autophagy in Aspergillus niger.
• Transcriptome analysis revealed significant impact on genes related to cell wall integrity, carbohydrate/protein/lipid metabolism, and transport.
• AnAFP::eGFP localized to cell walls and septa, with expression restricted to specific compartments, causing reduced hyphal diameter.

Conclusions:

• AnAFP plays a critical role in driving vegetative growth and sporulation in Aspergillus niger during nutrient limitation via autophagic recycling.
• AnAFP is predicted to facilitate nutrient mobilization through selective cell lysis, ensuring colony survival during starvation.
• The findings highlight a novel intracellular role for antifungal peptides in fungal stress response and survival strategies.