Vegetation, pH and Water Content as Main Factors for Shaping Fungal Richness, Community Composition and Functional Guilds Distribution in Soils of Western Greenland.

Fabiana Canini,Claudia Pacelli,Laura Zucconi,József Geml,Silvano Onofri,Laura Selbmann

doi:10.3389/fmicb.2019.02348

Fabiana Canini, Claudia Pacelli + Show 4 more

Open Access

https://doi.org/10.3389/fmicb.2019.02348

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Abstract

Fungi are the most abundant and one of the most diverse components of arctic soil ecosystems, where they are fundamental drivers of plant nutrient acquisition and recycling. Nevertheless, few studies have focused on the factors driving the diversity and functionality of fungal communities associated with these ecosystems, especially in the scope of global warming that is particularly affecting Greenland and is leading to shrub expansion, with expected profound changes of soil microbial communities. We used soil DNA metabarcoding to compare taxonomic and functional composition of fungal communities in three habitats [bare ground (BG), biological soil crusts (BSC), and vascular vegetation (VV) coverage] in Western Greenland. Fungal richness increased with the increasing complexity of the coverage, but BGs and BSCs samples showed the highest number of unique OTUs. Differences in both fungal community composition and distribution of functional guilds identified were correlated with edaphic factors (mainly pH and water content), in turn connected with the different type of coverage. These results suggest also possible losses of diversity connected to the expansion of VV and possible interactions among the members of different functional guilds, likely due to the nutrient limitation, with potential effects on elements recycling.

Highlights

The proportions of Operational Taxonomic Units (OTUs) found exclusively in vascular vegetation (VV) was the highest (23.6%) compared to biological soil crusts (BSC) and bare ground (BG) samples (7.8 and 16%, respectively), whereas the BG samples showed the highest number of indicator OTUs (266 OTUs, compared with 146 OTUs for VV and 215 for BSC samples, respectively; Supplementary Table S2)
ECM fungi showed an increase of richness in VV plots in respect to BSCs, but a not significant difference between VV and BG plots (Figure 1B)
The trends were the same for the relative abundance of the components of the guilds (Supplementary Figure S2), except for root-associated fungi that showed an increase from BG to VV and BSC plots (Supplementary Figure S2C)

Summary

Introduction

Almost all plants are highly dependent on mutualistic relationships with mycorrhizal fungi, including ectomycorrhizae, ericoid and arbuscular mycorrhizae (Väre et al, 1992; Michaelson et al, 2008; Newsham et al, 2009) that can allow more efficient nutrient and water uptake (Gardes and Dahlberg, 1996; Hobbie and Hobbie, 2006; Hobbie et al, 2009; Bjorbækmo et al, 2010).Soil Fungal Communities of GreenlandPlants release many root compounds that are fundamental in selecting microorganisms colonizing the rhizosphere (Mendes et al, 2013); in the main time, endophytic and mycorrhizal fungi may promote plant growth (Mucciarelli et al, 2003) and their resistance to abiotic and biotic stress factors (Rodriguez et al, 2008). The most relevant published studies indicated the importance of abiotic factors, such as climate at regional scale (Timling et al, 2012), edaphic factors and microclimate driven by micro- and mesotopography at landscape scale (Blaalid et al, 2014; Timling et al, 2014; Mundra et al, 2015; Geml et al, 2016; Grau et al, 2017) Among these mentioned works, Mundra et al (2015) observed that fungal communities associated with Bistorta vivipara were driven by different factors, such as periglacial processes, more than the above-ground vegetation, while in the other studies the total soil fungal community composition seems to correlate with vegetation (or habitat) types

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