Arbuscular mycorrhizal fungi in arable soils: Who is favoured, who is lost, and what does it mean for mycorrhiza functioning?

JANOUKOVÁ, MARTINA; BUIL, PAULA; MARRO, NICOLÁS; GRILLI, GABRIEL; MARTIN ROZMO; PETRA BUKOVSKÁ; JAN JANSA

Leticia, Amazonas

Simposio; III International Symposium on Mycorrhizal Symbiosis in South America; 2023

South America Micorrhizal Research Network

Practices related to intensive agricultural production impose strong selection pressures on arbuscular mycorrhizal fungi (AMF), promoting fungal traits which enable to cope with high levels of disturbance, readily available nutrients and other inputs. However, the impact of this selection on the ability of the AMF communities to provide benefits to their host plants is unclear. While the theoretical framework suggests that intensive agriculture promotes less mutualistic or even parasitic genotypes of AMF, experimental evidence for this is inconsistent.We therefore compared the functioning of mycorrhizas with AMF from arable soils and nearby undisturbed grasslands, and related them to AMF community composition. We found AMF from arable soils to differ in the dominant taxa and several community-level traits from the grassland communities. They were not less efficient in providing nutrients to their host plants than AMF from grasslands, but more "expensive" in terms of carbon and/or nitrogen. This explains why differences between AMF from intensively managed arable soils and less disturbed land-use types are highly context-dependent, variable among plant species and probably influenced by the relevance of mycorrhizal costs for the net mycorrhizal benefits of plants. These findings enable to hypothesise about consequences, which the functional shifts may have for crop production or in the extensification of agricultural systems.