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You are very welcome 15:15-16:00 November 6 to Sigmasalen in the Mathematics Centre where Carl Troein will talk about Modeling degradation of soil organic matter by a mycorrhizal fungus
Boreal trees rely on their ectomycorrhizal fungal symbionts to acquire
growth-limiting nutrients, such as nitrogen, which mainly occurs as proteins
complexed in soil organic matter (SOM). The mechanisms for liberating this
nitrogen are unclear since ectomycorrhizal fungi have lost many genes
encoding lignocellulose-degrading enzymes present in their saprotrophic
ancestors. We hypothesized that hydroxyl radicals (•OH), produced by the
ectomycorrhizal fungus Paxillus involutus during growth on SOM, are involved
in liberating organic nitrogen.
P. involutus was grown for 7 days on nitrogen-containing or nitrogen-free
substrates that represent major organic compounds of SOM. •OH production was
strongly induced when P. involutus switched from ammonium to protein as main
nitrogen source. Dynamic modeling predicted that •OH production occurs in a
burst regulated mainly by ammonium and ferric iron concentrations.
We propose that the production of •OH and extracellular proteolytic enzymes
are regulated by similar nutritional signals. Oxidation works in concert with
proteolysis, improving nitrogen liberation from proteins in SOM. Organic
nitrogen mining by ectomycorrhizal fungi has until now only been attributed
The Bio-Modelling Seminar Series (BMSS) is shared between the Departments of Mathematics, Physics, and Biology at Lund University. Our aim is to encourage collaborations and to bridge the gap between the disciplines by focusing on key concepts.