Regulation of fungal decomposition at single-cell level

Area of Science:

• Microbiology
• Environmental Science
• Biochemistry

Background:

• Filamentous fungi are vital decomposers in global nutrient cycles.
• Soil environments present heterogeneous microenvironments, leading to varied conditions for individual fungal hyphae.
• Understanding single-cell responses to environmental variation is key to fungal ecology.

Purpose of the Study:

• To investigate how fungi manage local environmental variations at the single-cell level.
• To chemically image the decomposition activity of individual hyphal tips in situ.
• To analyze the phenotypic heterogeneity of genetically identical hyphal tips.

Main Methods:

• Development of an infrared spectroscopy method for direct, in-situ chemical imaging.
• Culturing the ectomycorrhizal fungus Paxillus involutus on liquid media with lignin patches.
• Monitoring oxidative decomposition of lignin by individual hyphae over seven days.

Main Results:

• Identification of two hyphal tip subpopulations: low and high decomposition activity.
• Active hyphal tips showed increased extracellular polymeric substance secretion and stronger lignin oxidation.
• The ratio of active to inactive hyphae was influenced by local lignin patch conditions and overall mycelial activity.

Conclusions:

• Phenotypic heterogeneity in hyphal tips is a strategy for fungi to adapt to heterogeneous soil environments.
• Single-cell responses mediate the decomposition activity of entire fungal mycelia.
• This adaptability is crucial for filamentous fungi in dynamic ecosystems.