From Board Chair to guest researcher: Professor Anders Tunlid

Anders Tunlid pictured in his office at LINXS.

Professor Anders Tunlid acted as Chair for the LINXS Board between 2021– 2023. Now he returns to LINXS a guest researcher with the Environment and Climate theme, staying until summer 2026.

Why did you want to become a guest researcher at LINXS?

As I just retired from my role as Professor at the Department of Biology at Lund University, and still had some research going on, I felt that LINXS would be a good place to finalise my projects.

I think this is a good environment to sit in, and you always meet interesting people. It is nice to come here as many different researchers cross paths at LINXS. From day to day, you can discuss with people from as varied fields as environmental science, chemistry, physics and life sciences. In my experience, such interchange can stimulate new ideas.

In most other environments or departments, you tend to meet people from only your own field of research, which in my case is biology. LINXS really stand out in offering opportunity to mix across disciplines.

What are your research interests?

For the last 10-15 years, I have worked on fungi living in symbiosis with roots of forest trees. In the symbiosis, called ectomycorrhizae, the fungal partner obtains photosynthetic sugars from the host plant while, in return, the plant receives nitrogen from the fungus. Most of the nitrogen forms that are present in soils are embedded in complex organic matter and associated with mineral particles. This nitrogen cannot be assimilated by plants. In contrast the nitrogen can be accessed by many ectomycorrhizal fungi and translocated to the host plant roots. Little is known about the molecular mechanisms underlying these processes. This is the focus of my research.

Why is this research important?

Ectomycorrhizal symbioses are universal in boreal, temperate and montane forest ecosystems. For a long time, it has been known that the growth of important forest trees such as pine and spruce is dependent on nutrients provided by the fungal partner. Thus, identifying the factors that control and regulate the nutrient acquiring activities is of importance to fully explore the ecological potential of the symbiosis.

Soils contain over three times more carbon than the atmosphere or terrestrial vegetation, and the terrestrial carbon cycle plays a critical role in regulating the atmospheric CO2 level and thus Earth´s climate. Whether terrestrial ecosystems will capture, store or release carbon is highly dependent on the complex interactions between the organic matter, the physical and chemical conditions, and the activity of potential microbial degraders including ectomycorrhizal fungi. Understanding these interactions and predicting how they will respond to environmental change requires research approaches aimed at linking functional activities encoded in the genomes of microbes to biogeochemical processes operating at different spatial scales—from nanoscale minerals to forest-site soils. Advanced genomic, spectroscopic and chromatographic methods have a key role in this research.

What have you found so far?

We have characterized several mechanisms by which ectomycorrhizal fungi acquire nitrogen from soils. During nitrogen-mining, the fungi process the organic material to a material with increased adsorptive properties to mineral particles.

Two pathways contributed to these changes: Extracellular modifications of the organic matter and secretion of mineral surface reactive metabolites. Some of these metabolites have iron(III)-reducing activities and can participate in extracellular Fenton reactions and redox reactions at mineral surfaces. The activity through these complex networks of reactions is decisive for the overall effect of ectomycorrhizal fungal decomposition on nutrients and carbon-cycling in forest ecosystems. 

You used to be chair for LINXS – what hopes do you have for the institute?

I would like to see LINXS continue expanding. It is an interesting phase of development for LINXS, and the move has really boosted activity, which I am glad about.

I feel a lot for LINXS, and since I was chair, I have always believed in the need for such an organisation that can leverage and support research utilising X-rays and neutrons.

I also hope that LINXS will secure even larger funding in the future, to become an important national and international hub for researchers.

Read more about Anders Tunlid in Lund University Research Portal
Read more about the Environment and Climate theme