Linking the community structure of arbuscular mycorrhizal fungi and plants: a story of interdependence?

Abstract

Arbuscular mycorrhizal fungi (AMF) are crucial to plants and vice versa, but little is known about the factors linking the community structure of the two groups. We investigated the association between AMF and the plant community structure in the nearest neighborhood of Festuca brevipila in a semiarid grassland with steep environmental gradients, using high-throughput sequencing of the Glomeromycotina (former Glomeromycota). We focused on the Passenger, Driver and Habitat hypotheses: (i) plant communities drive AMF (passenger); (ii) AMF communities drive the plants (driver); (iii) the environment shapes both communities causing covariation. The null hypothesis is that the two assemblages are independent and this study offers a spatially explicit novel test of it in the field at multiple, small scales. The AMF community consisted of 71 operational taxonomic units, the plant community of 47 species. Spatial distance and spatial variation in the environment were the main determinants of the AMF community. The structure of the plant community around the focal plant was a poor predictor of AMF communities, also in terms of phylogenetic community structure. Some evidence supports the passenger hypothesis, but the relative roles of the factors structuring the two groups clearly differed, leading to an apparent decoupling of the two assemblages at the relatively small scale of this study. Community phylogenetic structure in AMF suggests an important role of within-assemblage interactions.

Plant geographic origin and phylogeny as potential drivers of community structure in root‐inhabiting fungi

“…P. recta and R. serotine , Figure ). Spatial distance can be a major factor in shaping AM fungal communities in roots in a similar spatial scale used in this study (Horn et al, ; Maherali & Klironomos, ), and dispersal limitation of AM fungi can be a dominant mechanism behind this observation (Vályi et al, ). This apparent dispersal inability can cause AM fungal community to structure at scales of <1 m (Mummey & Rillig, ).…”

The role of plant mycorrhizal type and status in modulating the relationship between plant and arbuscular mycorrhizal fungal communities

“…Findings from Horn et al . () and Hiiesalu et al . () indicate that plant–fungal interactions at least partly drive covariation of plant and AM fungal communities.…”

“…() and Horn et al . () recorded correlation between plant and AM fungal community composition in different ecosystems. Context‐dependent effects of AM fungi on plants (Hoeksema et al ., ) suggest that the relatedness of plant and AM fungal communities might change in response to shifts in the biotic or abiotic environment.…”

Temporal dynamics of mycorrhizal fungal communities and co‐associations with grassland plant communities following experimental manipulation of rainfall

“…Although these studies show that host plants influence AM fungal community assembly, the authors did not evaluate the influence of the plant community structure (but a few selected plant species), nor the role of the AM fungi in determining the plant community structure. Another study evaluating relationships between communities found that plant composition influenced AM fungal community composition in soil but not vice versa, and that this effect was weak after accounting for spatial effects (Horn, Hempel, Verbruggen, Rillig, & Caruso, ). However, this study used indirect approaches to estimate the strength and significance of relationships, which are accurate only if the major pattern of variation in the predictor community is also important for the response community (Ter Braak & Schaffers, ).…”