Meta-scale mountain grassland observatories uncover commonalities as well as specific interactions among plant and non-rhizosphere soil bacterial communities

Abstract

Interactions between plants and bacteria in the non-rhizosphere soil are rarely assessed, because they are less direct and easily masked by confounding environmental factors. By studying plant vegetation alliances and soil bacterial community co-patterning in grassland soils in 100 sites across a heterogeneous mountain landscape in the western Swiss Alps, we obtained sufficient statistical power to disentangle common co-occurrences and weaker specific interactions. Plant alliances and soil bacterial communities tended to be synchronized in community turnover across the landscape, largely driven by common underlying environmental factors, such as soil pH or elevation. Certain alliances occurring in distinct, local, environmental conditions were characterized by co-occurring specialist plant and bacterial species, such as the Nardus stricta and Thermogemmatisporaceae. In contrast, some generalist taxa, like Anthoxanthum odoratum and 19 Acidobacteria species, spanned across multiple vegetation alliances. Meta-scale analyses of soil bacterial community composition and vegetation surveys, complemented with local edaphic measurements, can thus prove useful to identify the various types of plant-bacteria interactions and the environments in which they occur.

Greater topoclimatic control of above‐ versus below‐ground communities

“…Incongruent reactivity to environmental changes between biologically dependent taxa and groups (e.g. plants and bacteria; Yashiro et al., 2018) can lead to shuffled species interactions and disruptions in biotic networks (Alexander, Diez, & Levine, 2015; Araújo & Luoto, 2007; Walther, 2010). Furthermore, land use changes, such as expansion of forest cover (Gago‐Silva et al., 2017), influence both directly and indirectly (though altering the abiotic conditions) the re‐distribution of taxa (Guo, Lenoir, et al, 2018).…”

Bacterial communities associated to Chilean altiplanic native plants from the Andean grasslands soils

“…5; gray dots). This might be explained by the presence of generalists, which are well-adapted bacteria to diverse habitats by their capability to metabolize a large diversity of substrates 86,87 . It could also be explained by bacteria-bacteria interactions, and for the fact that the co-occurrence of certain types of bacteria might guarantee their success in all types of compartments 62 .…”

“…For instance, differences in the stages of plant development or plant age are factors that could affect the rhizosphere microbiome assemblage 14,18,24,89–91 and could be the cause of some of the observed variability. Also, in the rhizosphere, the intraspecific variability could be a consequence of weak or non-stable relationships 87 .…”

Archaeorhizomycetes Spatial Distribution in Soils Along Wide Elevational and Environmental Gradients Reveal Co-abundance Patterns With Other Fungal Saprobes and Potential Weathering Capacities

“…Although not formally corresponding to Hutchinson’s definition, the latter case can inform on the environmental requirements of an entire fungal group or clade (e.g., genus, family, order, or class). Advancing our understanding of the ecological requirements and spatial distributions of soil fungi at multiple taxonomic depth will require sampling soils across large regions spanning wide elevation and other abiotic and biotic gradients (e.g., Pellissier et al, 2014; Tedersoo et al, 2014 for soil fungi, Yashiro et al, 2016, 2018 for soil bacteria).…”

“…The advance we bring here is to use a large soil metagenomics dataset sampled across wide environmental gradients in the Western Swiss Alps (Yashiro et al, 2016, 2018). The area was sampled in a random-stratified strategy aiming to cover a gradual change in abiotic (i.e., edaphic and climatic variables) and potentially biotic conditions.…”