Modularity Reveals the Tendency of Arbuscular Mycorrhizal Fungi To Interact Differently with Generalist and Specialist Plant Species in Gypsum Soils

Abstract

Patterns in plant-soil biota interactions could be influenced by the spatial distribution of species due to soil conditions or by the functional traits of species. Gypsum environments usually constitute a mosaic of heterogeneous soils where gypsum and nongypsum soils are imbricated at a local scale. A case study of the interactions of plants with arbuscular mycorrhizal fungi (AMF) in gypsum environments can be illustrative of patterns in biotic interactions. We hypothesized that (i) soil characteristics might affect the AMF community and (ii) there are differences between the AMF communities (modules) associated with plants exclusive to gypsum soils (gypsophytes) and those associated with plants that show facultative behavior on gypsum and/or marlylimestone soils (gypsovags). We used indicator species and network analyses to test for differences between the AMF communities harbored in gypsophyte and gypsovag plants. We recorded 46 operational taxonomic units (OTUs) belonging to nine genera of Glomeromycota. The indicator species analysis showed two OTUs preferentially associating with gypsum soils and three OTUs preferentially associating with marly-limestone soils. Modularity analysis revealed that soil type can be a major factor shaping AMF communities, and some AMF groups showed a tendency to interact differently with plants that had distinct ecological strategies (gypsophytes and gypsovags). Characterization of ecological networks can be a valuable tool for ascertaining the potential influence of above-and below-ground biotic interactions (plant-AMF) on plant community composition.

The interactions between plant life form and fungal traits of arbuscular mycorrhizal fungi determine the symbiotic community

“…However, the AM fungal community composition by plant life form found in the present study is in agreement with previous findings (see the meta-analysis by Yang et al 2012). Another interesting line of research has pointed out the relation of generalist and specialist AM fungal species with similar ecological plant groups (Öpik et al 2009;Davison et al 2011;Torrecillas et al 2014). Unfortunately, quantifying the role of plant traits in these studies is difficult since they focus on single plant life forms.…”

Soil Characteristics Driving Arbuscular Mycorrhizal Fungal Communities in Semiarid Mediterranean Soils

“…In this sense, we considered the AMF communities as the sum of both soil and root populations, to establish their relationships with the edaphic characteristics tested. There is evidence of several biotic factors with strong influences in regulating AMF community composition, with the best studied being the host plant (29,30,(72)(73)(74) and host functional traits (6,37). Among the abiotic factors that can have relevant roles in driving AMF communities are soil moisture (75), rainfall patterns, and geographical distance (40,76).…”

“…Despite their importance in semiarid regions, few studies have investigated AMF diversity and community composition, e.g., in plants from gypsum soils (6,29,36), in semiarid prairies (30), in degraded areas (37), and in a shrub community (38).…”

“…As a consequence, the number of ecological studies concerning AMF has increased considerably in recent years (1)(2)(3)(4)(5)(6)(7)(8)(9). Those studies considered AMF communities associated with different host plants in many different ecosystems.…”

“…There is clear evidence that AMF community composition and distribution at different sites or in different habitats are affected mainly by host plant species and environmental factors such as soil type (6,7,10,29,31,33,(39)(40)(41). If soil type determines the composition and species richness of AMF communities, what are the key soil parameters defining such communities?…”