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

JANOUSKOVÁ MARTINA; BUIL PAULA; MARRO NICOLÁS; GRILLI GABRIEL; ROZMOS MARTIN; BUKOVSKA PETRA; JAN JANSA

Congreso; III International symposium on mycorrhizal symbiosis in south america; 2023

Practices related to intensive agricultural production impose strong selection pressures onarbuscular mycorrhizal fungi (AMF), promoting fungal traits which enable to cope with highlevels of disturbance, readily available nutrients and other inputs. However, the impact of thisselection on the ability of the AMF communities to provide benefits to their host plants isunclear. While the theoretical framework suggests that intensive agriculture promotes lessmutualistic or even parasitic genotypes of AMF, experimental evidence for this isinconsistent.We therefore compared the functioning of mycorrhizas with AMF from arable soils andnearby undisturbed grasslands, and related them to AMF community composition. We foundAMF from arable soils to differ in the dominant taxa and several community-level traits fromthe grassland communities. They were not less efficient in providing nutrients to their hostplants 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 lessdisturbed land-use types are highly context-dependent, variable among plant species andprobably influenced by the relevance of mycorrhizal costs for the net mycorrhizal benefits ofplants. These findings enable to hypothesise about consequences, which the functionalshifts may have for crop production or in the extensification of agricultural systems.