Supporting Information Figs S1–S3
Fig. S1 Molecular identification and morphological characterization of ectomycorrhizal fungal
species found on beech roots. For morphotypes identified by ITS sequencing the GenBank
accession number (below the name), data of best alignment by BLAST in UNITE (accession
numbers starting with UDB) or NCBI (other accession numbers) are indicated. Bar 500 μm.
Identification
Tomentella badia
Best BLAST match(es)
(% similarity)
UDB000952
Tomentella badia
JF495174
(99%)
HM748639
Description
Monopodialdichotomously
branched, brown,
with only few
emanating hyphae.
Short distance
exploration type.
Uncultured Tomentella
(99%)
Cortinarius sp.
UDB000068
Cortinarius sertipes
(96%)
Irregularly pinnate
ramified, brownreddish, with
abundant white
emanating hyphae.
HQ204640
Medium-distance
exploration type.
FJ823395
Uncultured Cortinarius
(99%)
Boletus pruinatus
JF495173
Xerocomus pruinatus
(99%)
Monopodial
ramified, brown or
dark green silverywhite, rhizomorphs
present.
FM995548
Long-distance
exploration type.
UDB000018
Uncultured Boletaceae
(99%)
Humaria sp.
JF495172
Humaria hemisphaerica
(94%)
Single or
monopodial
branched, light
brown, rhizomorphs
absent.
EU024887
Short-distance
exploration type.
UDB000988
Humaria
Root tip dry weight:
12.5 µg
Root tip dry weight:
12.5 µg
Root tip dry weight*:
8.8 µg
Root tip dry weight*:
(99%)
Cenococcum
geophilum
UDB002301
Cenococcum geophilum
(98%)
FJ403485
EU668240
Uncultured
Cenococcum
8.8 µg
Single or rarely
dichotomously
branched, black,
compact mantle,
black rigid hyphae
emanating from
mantle.
Short-distance
exploration type.
Root tip dry weight:
5.6 µg
(99%)
Sebacina sp.
UDB000975
Sebacina epigaea
JF495175
(97%)
AY296259
Sebacinaceae
Monopodial
ramified, brown
yellowish, with
white, long
emanating hyphae.
Short-distance
exploration type.
Root tip dry weight:
7.8 µg
(98%)
Russula cuprea
UDB002420
Russula cuprea
JF495176
(98%)
AY061667
Monopodial
ramified, brown
yellowish, few
whitish emanating
hyphae.
Rhizomorphs absent.
Contact exploration
type.
Russula cuprea
Root tip dry weight:
9.7 µg
(99%)
Hysterangium
nephriticum
UDB001194
Hysterangium inflatum
(locked)
JQ281102
EU784366
Hysterangium
Monopodial
ramified, brown
yellowish, with
white, long,
abundant emanating
hyphae.
Root tip dry weight*:
nephriticum
8.8 µg
(99%)
Tonentella
viridula
UDB000261
Tomentella viridula
(99%)
JF495177
AF272914
Tomentella viridula
Monopodial
dichotomous
branched, brown,
with yellow tips,
with short, regular
emanating hyphae.
Short-medium
distance exploration
type.
Root tip dry weight:
10.8 µg
(99%)
Tomentella sp.
JF495178
UDB003320
Tomentella
subclavigera
(98%)
AM181395
Monopodialdichotomously
branched, dark
brown, rhizomorphs
absent, wrinkled
mantle surface.
Short-distance
exploration type.
Root tip dry weight:
9.9 µg
Uncultured
Thelephoraceae
(99%)
Tuber sp.
UDB000122
Tuber puberulum
JQ281103
(94%)
Monopodial
ramified, brown
reddish, with few,
long, abundant
emanating hyphae.
AY748861
Root tip dry weight:
7.8 µg
Uncultured
ectomycorrhiza (Tuber)
(99%)
MT 12
No sequence
information
Dichotomous
branched, browngrey-silver, fleeced
mantle, without long
emanating hyphae.
MT 13
No sequence
information
MT 15
No sequence
information
Single, unramified,
brown, compact
mantle, few hyphae
emanating from
mantle.
Monopodial
ramified, dark
brown, infrequent
emanating hyphae.
* = Root tip dry weight was approximated by using the mean value from all other EM root tip
categories. All masses were determined after drying of a known number of EM root tips.
Fig. S2
Validation of the freeze-drying method to measure soil microbial biomass N in forest soil from
the old-growth beech forest investigated here (Ah horizon, 0–10 cm soil depth). In this
experiment, homogenized soil was separated into four groups: untreated control, freeze-dried soil,
chloroform-fumigated soil (24 h), combination of freeze-drying and subsequent chloroformfumigation. For each treatment, six replicated soil samples of 30 g were extracted with 90 ml of 0.5
M K2SO4. The graph compares the increase in 0.5 M K2SO4-extractable soil N compared to control
samples due to (1) freeze-drying; (2) 24 h of chloroform-fumigation; (3) the combination of freezedrying and subsequent chloroform-fumigation of 24 h. No significant differences in N release were
found between these treatments, demonstrating that freeze-drying leads to the same release of N
from microbial cells as does chloroform-fumigation over 24 h.
-1
Increase in extractable soil N SE (mg N kg sdw)
35
30
25
20
15
10
5
0
freeze-drying
chloroform
freeze-drying + chloroform
Fig. S3
15
N signature after 18-months exposure to labeled leaf litter in relation to the N concentration in soil,
fine roots and root tips (A) and in relation to the estimated N content in the fungal mantel of root tips
(B). Mean N concentrations were determined for all measurements of soil, fine roots (Fr) and root tips
colonized with different fungi: Cg, Cenococcum geophilum; Se, Sebacina sp.; Hu, Humaria sp.; Bp, Boletus
pruinatus; Co, Cortinarias sp.; Rc, Russula cuprea.
A
600
R = 0.37, P = 0.41
500
Tb
300
15
 N (‰)
400
200
Co
100
0
5
10
Bp
Se
Cg
Fr
soil
0
Hu
15
20
25
Rc
30
35
-1
N (mg g D.wt.)
B
R = 0.37, P = 0.41
500
Tb
400
300
200
Co
Bp
Hu
100
15
 N (‰) in root tips after 18 months
600
Se
Cg
Rc
0
40
60
80
100
120
140
160
-1
Estimated N in fungal mantle (ng root tip )
180