Silver nanoparticles and arbuscular mycorrhizal fungi influence Trifolium repen root-associated AMF community structure and its co-occurrence pattern

Abstract

Arbuscular mycorrhizal fungi (AMF) can form symbioses with most plants in terrestrial environments. In this study, we aimed to investigate root-associated AMF community of white clover in response to AMF inoculation and AgNPs addition in the multi-contaminated soil. Results demonstrated that mycorrhizal colonization was significantly increased by AMF inocultion in the 50 mg/kg AgNPs treatment. Compared with non-AMF inocultion group, AMF inoculation group exhibited higher shoot dry mass. In plants without AMF, root dry mass markedly declined when AgNPs addition level exceed 2000 mg/kg. The relative abundance of Glomus was above 70% both in rhizosphere and endosphere. The endosphere Glomus abundance was higher than rhizosphere in all groups. AMF inoculation and AgNPs addition did not influence AMF diversity in rhizosphere and endosphere. Shannon, simpson, chao and ace index in rhizosphere was higher than in endosphere. AMF community structures in endosphere were significantly affected by AMF inoculation and AgNPs additions. Soil Ca, Mg, Mn, P, Al, Mo, As, NH4+-N and pH levels had significant correlations with AMF community in rhizosphere and endosphere. In rhizosphere and endosphere, AgNPs addition (≥100 mg/kg) resulted in more complex networks and AMF inoculation decreased network complexity. We concluded that AgNPs and AMF could influence Trifolium repen root-associated AMF community structure only in endosphere, and co-occurrence networks in rhizosphere and endosphere, but have no effect on alpha diversity.