Cooccurring Gentiana verna and Gentiana acaulis and Their Neighboring Plants in Two Swiss Upper Montane Meadows Harbor Distinct Arbuscular Mycorrhizal Fungal Communities

Abstract

The community composition of arbuscular mycorrhizal fungi (AMF) was analyzed in roots of Gentiana verna, Gentiana acaulis, and accompanying plant species from two species-rich Swiss alpine meadows located in the same area. The aim of the study was to elucidate the impact of host preference or host specificity on the AMF community in the roots. The roots were analyzed by nested PCR, restriction fragment length polymorphism screening, and sequencing of ribosomal DNA small-subunit and internal transcribed spacer regions. The AMF sequences were analyzed phylogenetically and used to define monophyletic sequence types. The AMF community composition was strongly influenced by the host plant species, but compositions did not significantly differ between the two sites. Detailed analyses of the two cooccurring gentian species G. verna and G. acaulis, as well as of neighboring Trifolium spp., revealed that their AMF communities differed significantly. All three host plant taxa harbored AMF communities comprising multiple phylotypes from different fungal lineages. A frequent fungal phylotype from Glomus group B was almost exclusively found in Trifolium spp., suggesting some degree of host preference for this fungus in this habitat. In conclusion, the results indicate that within a relatively small area with similar soil and climatic conditions, the host plant species can have a major influence on the AMF communities within the roots. No evidence was found for a narrowing of the mycosymbiont spectrum in the two green gentians, in contrast to previous findings with their achlorophyllous relatives.Arbuscular mycorrhiza is an ancient symbiosis (26) between the majority of land plants and fungi from the phylum Glomeromycota (30). Arbuscular mycorrhizal fungi (AMF) colonize plant roots and contribute to the mineral nutrient uptake of the hosts in exchange for carbohydrates (32).The diversity of AMF can be evaluated using microscopic analysis of spore morphology or molecular methods. The production of spores is highly dependent on environmental conditions and the physiological status and life strategy of the particular mycorrhizal fungus. Molecular methods allow the identification of the symbiotic community currently colonizing the roots of an individual plant at any given time. The majority of recent molecular studies have used AMFspecific primers for nuclearly encoded rRNA genes (rDNA). However, identification of AMF on the species or even isolate level is complicated by the heterogeneity of rDNA within glomeromycotan spores and isolates. Several authors have shown that different variants of rDNA genes coexist within single AMF spores (15, 27). Hence, a conservative approach in the evaluation of phylogenetic analyses is advisable by, e.g., defining a well-supported monophyletic sequence cluster as an AMF phylotype.On the basis of the morphological features of their spores, only about 200 species of AMF have been described so far (http://www.lrz-muenchen.de/ϳschuessler/amphylo/). This small number of species was originally though...

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

“…Oehl et al (9), in an extensive study, found that soil type is a key factor determining the composition of the AMF community. Recent AMF diversity studies have revealed that the AMF community composition is host plant dependent (16,17,21,22,(59)(60)(61)(62)(63)(64). Interestingly, when we focused on the plant and AMF communities inhabiting gypsum soils, we also found differences between the AMF harbored in gypsophyte and gypsovag plants.…”

A conserved arbuscular mycorrhizal fungal core-species community colonizes potato roots in the Andes

“…Zangaro et al (2008Zangaro et al ( , 2013 showed that root colonization and spore density decreased among successional stages from grasslands to mature forests and different stages in plant age and succession also influence the AMF communities (Husband et al 2002;Aldrich-Wolfe 2007). Other studies indicate host preferences (Scheublin et al 2004;Sýkorová et al 2007;Torrecillas et al 2012;Yang et al 2012). In general, standardized analyses, possibly based on the methods presented here, may allow a more robust interpretation and comparison of such data in the future.…”

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).…”