Trees benefit from symbiosis with two fungi

(CONNECT) Researchers from the University of Zurich (UZH) and Agroscope, the federal government's competence center for agricultural research, have shown that trees benefit more from a symbiosis with two different fungi than with just one. So-called mycorrhizal fungi envelop tree roots or penetrate the cells of the root system. They receive part of the sugar produced by plant photosynthesis from the trees as a source of energy. In exchange, the trees receive nutrients such as phosphate and nitrate as well as water from the fungi, "a kind of unromantic marriage of convenience", according to a report by both institutes.

The simultaneous relationship with two different mycorrhizal fungi allows the trees a more diverse nutrient supply, as their roots cover a more extensive soil profile and can cope with different soil properties. For example, the scientists found that the distribution of trees with double symbioses is more pronounced in drier areas than in locations with more rainfall. "Our results suggest that polygamy with two fungal variants served as a strategy for the trees to adapt to harsher environmental conditions, i.e. to colonize niches with fewer nutrients and to endure harsher climates," summarizes UZH professor Marcel van der Heijden.

"In forestry, this knowledge could help to select tree species that are specialised in polygamous fungal relationships in the future," van der Heijden continues. "These trees should be able to cope better with the ongoing global warming and could be used to colonise dry climate zones." ce/mm