Figure S1
Response curves of individual AMF taxa fitted against the first DCA axis: the most complex significant
model is shown for each AMF taxon, fitting the different models in the following order: no response,
linear response, unimodal response. Results for AMF taxa in soil (a) and in the leek roots from the soil
biotest (b) are shown. In the first graph, responses of five taxa were unimodal, the response of
Rhizophagus irregularis as assessed by mitochondrial qPCR marker (Rhiz mtLSU) was linear and the
response of Diversispora (Div) was not significant. In the second graph, the response of Cetraspora
(Cetr), Gigaspora (Gig) and Diversispora (Div) was linear, whereas the response of other four taxa
was unimodal.
Figure S2
Visualization of four significant spatial predictors of the soil AMF community profiles within the given
geographical space. Colors encode values from the lowest (light green) through the highest (deep
blue). Contour map of Switzerland is provided in the background.
Figure S3
Visualisation of the CCA results by ordination diagrams showing the effects of selected spatial
predictors (a), soil properties (b) and application of mineral fertilizer (fert_min, c) on the AMF
community profiles in the field soils, as assessed by quantitative real-time PCR. Abundance of
individual AMF taxa was assessed by nuclear large ribosomal subunit (LSU) markers (Gig: Gigaspora
margarita , Cetr: Cetraspora pellucida, Div: Diversispora celata, Rhiz: Rhizophagus irregularis, Clar:
Claroideoglomus claroideum, Funn: Funneliformis mosseae) or by a mitochondrial LSU marker (Rhiz
mtLSU, Rhizophagus irregularis). Selected soil properties were: concentration of humus (Humus%),
carbonate concentration (CaCO3%), silt content (silt%), available K concentration in the soil (Kavail)
and dry weight of the leek aboveground biomass in the biotest (leekDW), the last being a proxy for
soil fertility. In the diagrams (a) and (b), where both displayed axes are canonical, 14% and 13% of
the total variation is explained, respectively. In the diagram (c), only the horizontal axis is canonical,
explaining 3% of the total variation.
Figure S4
CCA ordination diagrams showing the effect of selected spatial predictors (a), soil properties (b) and
application of mineral fertilizer (fert_min, c) on the AMF community profiles in the leek roots from
the soil biotest. Abbreviations as in Figure S3. “micr_massSIR” represents microbial biomass assessed
by substrate-induced respiration. In the diagrams (a) and (b), where both displayed axes are
canonical, 7% and 21% of the total inertia is explained, respectively. In the diagram (c), only the
horizontal axis is canonical, explaining 2% of the total variation.
Figure S5
Comparison of the abundance of Claroideoglomus claroideum in the field soil (x-axis) and in the
corresponding biotest root samples (y-axis). Both axes are shown with logarithmic scaling. The data
indicate random dispersion (i.e. no obvious correlation) for sites, where the fungal taxa was
positively detected in both datasets, as well as a number of cases where the fungus was not detected
in the field soil but was positively detected in the biotest leek roots.
Figure S6
Generalized additive model response curves of statistically significant relationships between the
abundance of individual AMF taxa in the soil (log-transformed) and the underlying soil properties.
The effects are visualized with the partial residuals of the particular predictor variable and estimated
95% confidence regions.
Figure S7
Generalized additive models response curves of statistically significant relationships between the
abundance of individual AMF taxa in the leek roots (log-transformed) and the underlying soil
properties. The effects are visualized with the partial residuals of the particular predictor variable and
estimated 95% confidence regions.
Figure S8
Relationship between soil pH measured in aqueous suspension (pH(H2O)) and carbonate
concentration as assessed by a volume of CO2 released after addition of HCl to the soil in a closed
vessel (CaCO3(%)). Each dot represents one soil, the plotted regression line refers to 2-parameter
exponential model (f = a × bx), R2=0.38, p˂0.001.
40
CaCO3 (%)
30
20
10
0
5
6
pH (H2O)
7
8
Figure S9
Venn diagrams illustrating the partitioning of variance of the sums of genomic DNA concentration of
the six AMF taxa per sample as quantified by real-time PCR with taxon-specific markers targeting
nuclear ribosomal large subunit gene, among the different predictor groups in the field soil (a) and in
the leek roots from the biotest (b). The size of circles is proportional to the variability across sites in
the sums of genomic DNA concentration of the six AMF taxa explained by a particular predictor
group, and the overlap of the circles represents the variation shared among predictor groups.
a
b
Figure S10
Visualization of the significant spatial predictor of the sum of abundances of the six AMF taxa in the
leek roots. Colors encode values from the lowest (light green) through the highest (deep blue).
Contour map of Switzerland is provided in the background.