DOI: 10.5061/dryad.34tmpg4s5
title: Rapid and chemically diverse C transfer from trees to mycorrhizal fruit bodies in the forest

description: Ectomycorrhizal fungi (EMF) are common belowground tree symbionts,
 supplying trees with water and nutrients. In return, large amounts of C
 assimilated by trees can be allocated into EMF. However, the chemical
 forms in which the C is transferred from trees to fungi under field
 conditions are mostly unknown. In this study, we aimed to unravel the fate
 of tree-derived C in EMF. We conducted 13CO2 pulse labeling of Pinus
 halepensis trees in two forest sites with adjacent EMF sporocarps,
 combined with a non-targeted metabolomics profiling of root and sporocarp
 tissues. 13C was measured in sporocarps of Tricholoma terreum and Suillus
 collinitus up to 3 m from pine stems. C was assimilated in the labeled
 trees’ needles and transferred to their roots. Starting from day 2 after
 labeling, the C was transferred to adjacent sporocarps, peaking on day 5.
 We identified more than 100 different labeled metabolites of different
 chemical groups present in roots and sporocarps. Of them, 17 were common
 to pine roots and both EMF species, and an additional 8 were common to
 roots and one of the two EMFs. The major labeled metabolites in the root
 tips were amino acids and tricarboxylic acid intermediates. The major
 labeled metabolites in sporocarps were amino acids, nucleotides, and fatty
 acids. We also identified labeled carbohydrates in all tissues. Labeling
 patterns diverged across different tissues, which can hint at how the C
 was transferred. Considering the young tree as a sole C source for these
 sporocarps, and with a diurnal assimilation of 5.4 g C, the total monthly
 C source is ~165 g C. On average, there were 10 sporocarps around each
 tree, each requiring ~1 g C. Therefore, a 10 g C investment would make 6%
 of total tree C allocation, and about 12% of net primary productivity.
 Overall, we found that this significant and ubiquitous transfer of
 metabolites from tree roots to EMF sporocarps is more rapid and chemically
 diverse than once thought.
description: # Rapid and chemically diverse C transfer from trees to mycorrhizal fruit
 bodies in the forest
 [https://doi.org/10.5061/dryad.34tmpg4s5](https://doi.org/10.5061/dryad.34tmpg4s5) ## Description of the data and file structure Ectomycorrhizal fungi (EMF) are common belowground tree symbionts, supplying trees with water and nutrients. In return, large amounts of C assimilated by trees can be allocated into EMF. However, the chemical forms in which the C is transferred from trees to fungi under field conditions are mostly unknown. In this study, we aimed to unravel the fate of tree-derived C in EMF. We conducted 13CO2 pulse labeling of *Pinus halepensis* trees in two forest sites with adjacent EMF sporocarps, combined with a non-targeted metabolomics profiling of root and sporocarp tissues. 13C was measured in sporocarps of *Tricholoma terreum* and *Suillus collinitus* up to 3 m from pine stems. Here we provide a table with soil properties (pH, salinity, and mineral composition) under the study trees at the two forest sites, and three tables showing P-values of isotopes of labeled semi-polar metabolites identified in *Pinus* roots, *Suillus* fruit bodies, and *Tricholoma* fruit bodies samples comparing before and after 13C labeling. Below is a description for each of the data tables. #### **Hosted via Dryad** **Rapaport_et_al_Soil_properties.xlsx** Soil properties (pH, salinity, and mineral composition) under the study trees at the two forest sites. Measurements were done on soil at 0-10 cm and 10-20 cm depths (excluding trees 24 and 29 in Charuvit forest, where soil was too shallow). EC, electric conductivity (dS m-1); SOC, soil organic carbon (%); All mineral values (Cl, Ca, Mg, N-NO3, N-NH4, Olsen P) are at mg kg-1. #### **Hosted via Zenodo** **Table S2** Soil properties (pH, salinity, and mineral composition) under the study trees at the two forest sites. Measurements were done on soil at 0-10 cm and 10-20 cm depths (excluding trees 24 and 29 in Charuvit forest, where soil was too shallow). EC, electric conductivity (dS m-1); SOC, soil organic carbon (%); mineral values are at mg kg-1. **Table S6** P-values of isotopes of labeled semi-polar metabolites of roots samples comparing before and after 13C labeling. The isotope shown is the most significant one from each metabolite. FDR correction was performed. TCA, tricarboxylic acid cycle cycle. **Table S7** P-values of isotopes of labeled semi-polar metabolites of samples from *Suillus* comparing before and after 13C labeling. The isotope shown is the most significant one from each metabolite. FDR correction was performed. TCA, tricarboxylic acid cycle cycle. **Table S8** P-values of isotopes of labeled semi-polar metabolites in *Tricholoma* samples comparing before and after 13C labeling. The isotope shown is the most significant one from each metabolite. FDR correction was performed. TCA, tricarboxylic acid cycle cycle. ## Sharing/Access information The data belong to an accepted paper in Functional Ecology. A DOI link will be added.