Ectomycorrhizal fungi form symbiotic relationships with trees, playing a pivotal role in forest ecosystems by enhancing plant nutrient uptake in exchange for carbon from photosynthesis. Unlike most mycorrhizal fungi that transfer inorganic nutrients to their host plants, ectomycorrhizal fungi have the unique ability to acquire nutrients—particularly nitrogen—directly from soil organic matter. This process allows them to bypass the typical nutrient mineralization pathways in soils.
In boreal forests, where nutrients predominantly exist in organic forms, the capacity of ectomycorrhizal fungi to access organic nitrogen is especially critical. However, despite their ecological importance, there is limited understanding of the efficiency and mechanisms of organic nitrogen acquisition among the diverse species of ectomycorrhizal fungi. This knowledge gap stems from their high diversity; ectomycorrhizal symbiosis has evolved independently over 80 times, resulting in up to 20,000 different species.
Objectives
The project aims to phenotype a diverse collection of ectomycorrhizal fungi in vitro, encompassing over 50 different genera. By assessing their growth performance on various organic nitrogen sources, quantifying enzyme production that facilitates nutrient acquisition, and analyzing modifications of organic matter induced by fungal activity, this project seeks to evaluate the efficiencies and mechanisms used by ectomycorrhizal fungi for organic nitrogen acquisition. Ultimately, this work will connect the functional diversity of ectomycorrhizal fungi with soil biogeochemical cycles.
Methodology
- Cultivation of fungi: Grow cultures on media containing different organic nitrogen sources.
- Biomass measurement: Quantify fungal growth and nitrogen uptake.
- Enzyme assays: Use fluorometric and colorimetric methods to measure enzyme activity.
- Spectroscopy analysis: Employ Fourier-transform infrared spectroscopy (FTIR) to characterize
changes in organic matter. - Data interpretation: Analyze results to determine nutrient acquisition strategies among
various fungal taxa.
Skills and techniques acquired
- Fungal microbiology: Sterile techniques, media preparation, and high-throughput in vitro
phenotyping. - Enzymology: Performing and interpreting enzyme assays.
- Spectroscopy: Utilizing FTIR spectroscopy for organic matter characterization.
- Data Analysis: Statistical analysis and scientific interpretation of experimental data.
Application process
- Flexible starting date,
- 45-60 cr
- Interested candidates should contact Dr. François Maillard at francois.maillard@biol.lu.se.