Fungal endophytes, rhizobia and mycorrhiza in agroecosystems: interactive implications for the co-provision of ecosystem services.

GARCIA PARISI, P.A.; LANATI, MERCEDES; OMACINI, MARINA

Lyon

Congreso; 10th congress of the ISS/Holobiont; 2022

Grasses associated with asexual fungal endophytes and legumes associated with rhizo-bia form symbioses with arbuscular mycorrhizal fungi and co-occur in most agroecosystems.These symbionts can trigger dierent ecosystem functions and services through its impactson both host and neighbourhood traits. Our aim is to identify changes in processes linkedwith antagonist protection, nutrient provision and plant productivity within dierent agroe-cosystems, induced by the co-occurrence of multiple symbiosis. Here we present the results ofexperiments in which we manipulated the presence of the symbionts on the host in three agri-cultural systems: grass-legume pastures, grass weeds of wheat crops and cover crop/soybeancrop sequence. In particular, we explored how the interactive symbiont eects on their hostneighbourhood or their legacy in the soil aect the performance of other plants and theirencounter with other symbionts, insects, and pathogens. In grass-legume pastures, fungalendophytes conferred associational protection to legumes and non-endophytic grasses againstaphids, aphid-transmitted viruses and chewing insects and arbuscular mycorrhizal fungi in-creased the amount of xed-nitrogen transferred from the legume to the grass independentlyof its endophyte infection level. In wheat crop, high endophyte incidence in a winter weedprotected wheat plants from insect herbivory and increased its relative yield. Furthermore,in a cover crop - soybean crop rotation, high endophyte infection level of the grass usedas a cover crop decreased the incidence of pathogens and insect pests in a subsequent soy-bean crop through holobiont legacy in the soil. In conclusion, the multiple benets of thesymbionts to the host plant propagated to the ecosystem level increasing their contributionsto society. Although the physical, chemical or biological underlying mechanisms are stillunder research, our results suggest that these symbiosis benets could favour agroecosystemsustainability through practices that replace the use of fertilizers and pesticides.