SUPPLEMENTARY MATERIALS

Structural elucidation of compounds 1 and 4.

The molecular formula of compound 4 was determined to be C14H12O6 on the basis of its positive-mode electrospray ionization-high resolution mass spectrometry(ESI-HRMS) (m z-1 277.0709 [M+H]+, calcd. for C14H13O6 277.0707). The1H-NMR spectrum (Supplementary Table 1) showed a typical pattern for a disubstitutedtrans-double bond in a stilbene-related structure (JH-H 16.5 Hz). However, both signals were shifted to lower field (6.99 and 7.05 ppm, respectively) compared to the parent structure, astringin, indicating a major change in the substitution of the aromatic rings. Missing carbohydrate signals and aspin system consisting of a multiplet at  6.28 (1H equivalent, H-10) and a doublet signal at  6.53 (JH-H2.1 Hz, 2H equivalents, H-8 and H12) revealed the loss of the -D-glucose moiety, resulting in a symmetrical 3,5-dihydroxy-substituted phenyl ring. The heteronuclear multiple bond correlation(HMBC)spectrum showed the attachment of this ring to one carbon atom of the trans-double bond system (C141.0, H 7.05;C-6, H-6). HMBC correlations of the second trans-double bond proton at 6.99 (H-5) with an unsaturated methine (C115.5, H 6.12; H-2, C-2) and a saturated methine (C81.6/H 5.73; C-4, H-4), as well as with a quaternary carbon at 168.1(C-3) indicated structural changes in the formero-dihydroxyphenyl ring system. 1H-1H-correlation spectroscopy (COSY) correlations of the saturated methine proton at 5.73 (dd, JH-H9.0, 3.0 Hz) with a methylene group at 2.44 (dd, JH-H 16.0, 9.0 Hz, H-13b) and 2.99 (dd, JH-H 16.0, 3.0 Hz, H-13a), respectively, together with HMBC correlations between H-4 and carbonyl functions at 175.5 and 174.8 led to the conclusion that the structure of the former o-dihydroxyphenyl ring system was changedto a but-2-en-4-olide, an α,β-unsaturated-γ-lactone with a CH2COOH substituent (Supplementary Fig. 1). All other spectral data were consistent with the structure of 4. Structures with a similar but-2-en-4-olide ring systemhave been reported as synthetic products of stilbene oxidation (Bezuidenhoudt et al., 1990), as metabolites isolated from peanut kernels (Sobolev et al., 2006), as degradation products of the reaction of 3,4-dimethoxybenzyl alcohol (veratryl alcohol) with lignin peroxidase(Leisola et al., 1985; Shimada et al., 1987; Schmidt et al., 1989) and as a reaction product of the biotransformation of 4-methylcatechol by Pseudomonas desmolyticum(Catelani et al., 1971).

Compound 1 had a molecular composition of C20H22O11 based on negative mode ESI-HRMS (m/z 437.1094 [M-H]-, calcd. for C20H21O11 437.1084). Comparison of the 1H NMR data with those of astringin showed an intact 3,5-disubstituted phenyl ring with the -D-glucose substituent, but the absence of signals for the o-dihydroxy substituted phenyl ring. The signal pattern closely resembled that of compound 4. A doubling of signals at  7.12/7.13 (H-6) and 4.80/4.82 (H-1’), pointed to the presence of two diastereoisomers. Thus,1 was determined to be -D-glucosylated derivative of 4. The compound had an optical rotation value close to zero.

Supplementary Table 1 |1H NMR (500 MHz) and 13C NMR data (125 MHz) of compounds 1 in DMSO-d6and 4 in MeOH-d4

Positiona / 1 / 4
H (multiplicityJ in Hz) / c / H (multiplicityJ in Hz) / c
1 / 172.4 / 175.5
2 / 6.27 (s) / 114.6 / 6.12 (s) / 115.5
3 / 165.4 / 168.1
4 / 5.58 (d, 8.8) / 78.5 / 5.73 (dd, 9.0, 3.0) / 81.6
5 / 7.04 (d, 16.5) / 118.2 / 6.99 (d, 16.5) / 118.8
6 / 7.13(d, 16.5)/7.12 (d, 16.5)b / 138.6 / 7.05 (d, 16.5) / 141.0
7 / 137.0 / 138.7
8 / 6.83 (br s) / 105.8 / 6.53 (d, 2.1) / 107.2
9 / 159.1 / 160.1
10 / 6.46 (t, 1.9) / 105.1 / 6.28 (t, 2.1) / 105.5
11 / 158.6 / 160.1
12 / 6.65 (br s) / 108.9 / 6.53 (d, 2.1) / 107.2
13a / 3.10 (m) / 38.1 / 2.99 (dd, 16.0, 3.0) / 41.6
13b / 2.45 (m) / 2.44 (dd, 16.0, 9.0)
14 / 170.9 / 174.8
1' / 4.82 (d, 7.5)/4.80 (d, 7.5)b / 100.5
2' / 3.20 (overlap) / 73.1
3' / 3.24 (overlap) / 76.5
4' / 3.14 (overlap) / 69.5
5' / 3.30 (overlap) / 76.9
6'a / 3.45 (m) / 60.4
6'b / 3.70 (m)
2'-OH
3'-OH
4'-OH
11-OH / 5.30 (d, 4.5)
5.10 (d, 4.0)
5.04 (d, 5.1)
9.66 (s)

a) Numbering scheme for compounds is given with structure in Suppl. Fig. 2.

b) Signal doubling due to epimerization at position 4

1

Supplementary Table 2 |Mass spectrometry data for astringin and identified astringin metabolites

Experiment title: / Stilbene biotransformation
Organism/Plant species: / Picea abies
Organ/tissue: / Bark / Cell free fungal enzyme extracts
Analytical tool: / Brucker Daltronics Esquire 6000 ESI ion-trap mass spectrometer
Metabolite / HPLC Ret. Time / Metabolite Class / Mol formula / ES(-) Theor.
m/z / ES(-) Found m/z / m/z error (Da) / MS/MS ES(-) fragments / MS/MS/MS ES(-) fragments / Source of commercial standard / Maximum UV absorbance / Species detected in previously / References (Mass fragmentation spectra) / References (Compound reported)
Astringin / 11.2 12.0 / Stilbene glycoside / C20H22O9 / 405.1264 / 405.1 / 0.026 / 243.1, 322.1, 201.2 / 243.1: 241.1, 225.1, 201.2, 185.1, 159.2 / 331 / Picea abies / Hammerbacher et al., 2011 / Hammerbacher et al., 2011
Astringin lactone (1) / 10.5 / C20H22O11 / 437.1162 / 437.1 / 0.016 / 275.2, 231.1, 189.1 / 231.2: 187.1, 172.1, 145.1 / 331
Piceatannol (2) / 13.5 14.1 / Stilbene / C14H12O4 / 243.0736 / 243.1 / 0.026 / 225.1, 201.0, 175.1, 159.0, 132.0 / 200.7: 184.7, 174.6, 158.7, 140.8 / Alexis (ALX-270-202-M001) / 331 / Picea abies / Hammerbacher et al., 2011 / Hammerbacher et al., 2011
Astringin dimer (3) / 12.1 13.8 14.3 15.7 / Stilbene glycoside / C40H42O18 / 809.2371 / 809.9 / 0.663 / 647.3, 485.3, 405.1, 243.1, 322.0 / 647.3: 485.3, 405.1, 243.1, 322.0 / 331
Piceatannol lactone (4) / 12.3 / C14H12O6 / 275.0634 / 275.1 / 0.037 / 231.2, 187.1, 172.1, 145.1 / 231.2: 187.1, 172.1, 145.1 / 331
Piceatannol dimer (5) / 19.3 19.9 / Stilbene / C28H22O8 / 485.1315 / 485.3 / 0.169 / 243.1, 322.1, 201.1 / 243.1: 241.1, 225.1, 201.0, / 331
Astringin Piceatannol dimer (6) / 16.8 18.4 19.2 19.6 / Stilbene / C34H32O13 / 647.1843 / 647.3 / 0.116 / 485.3, 405.1, 243.1, 322.0 / 485.1: 243.1, 241.1, 225.1 / 331

1

Substance 1

Substance 4

Supplementary Figure 1 |Ring-opened lactone products derived from C. polonica transformation of astringin.

Supplementary Figure2| NMR spectrum of one set of dimeric products (3a) derived from C. polonica biotransformation of astringin in this study. These compounds (lower trace) were identified as a ~1:1 mixture of piceasides A and B as reported in a previous study (Li et al., 2008). The spectrum of the authentic mixture is shown in the upper trace.

Supplementary Figure 3 |NMR spectrum of another set of dimeric products (3b) derived from C. polonica biotransformation of astringin in this study. These compounds (lower trace) were identified as a ~1:1 mixture of piceasides G and H as reported in a previous study. The spectrum of the authentic mixture is shown in the upper trace.

Supplementary Figure 4 | Diagnostic mass spectral fragments of astringin and its biotransformation products.(A): Astringin (m z-1 405)was fragmented into the piceatannol isomers(2a and 2b) and glucose. Further fragmentation of piceatannol (m z-1 243.3) yielded diagnostic fragments reported earlier6. (B): The ring-opened lactone 1was fragmented into its aglucone 4and glucose. (C) Theastingin-piceatannol dimers (6a and 6b)were fragmented into the corresponding piceatannol dimers (5a and 5b) and glucose.(D): The astringin dimers (3a and 3b) were fragmented into 6a and 6band glucose, and subsequently 5a and 5b.

Supplementary Figure 5 | Relative virulence of six C. polonica isolates first described in is correlated with their ability to grow on caffeic acid as the sole carbon source. Growth on minimal medium with caffeic acid was measured relative to medium amended with glucose (n=5). Relative virulence as shown below is taken from Krokene and Solheim (2002).catabolism

1