Résumé
Some forest tree species are able to carry out a process known as biological nitrification inhibition, BNI, i.e. they inhibit nitrifiers through the production of specific compounds. We tested the hypothesis that, by restricting N supply to NO2− - and N2O-reducers, BNI would decrease potential N2O production and consumption and in situ N2O emissions. as compared to soils under trees without BNI capacity. Soils were collected from long-term monocultures (>43 ys) of three tree species without BNI capacity (Fagus sylvatica, Pinus nigra and Pseudotsuga menziesii) and two tree species with BNI capacity (Abies nordmanniana and Picea abies). The level of limitation of denitrification by NO3− was high for species with BNI capacity and low for species without BNI capacity, and was correlated with potential nitrification rates and the abundances of genes specifically harboured by ammonia oxidizing archaea and Nitrobacter. However, potential denitrification and actual N2O emissions did not reflect the tree BNI status, and denitrification limitation by soil carbon was higher than limitation by N under three tree species. Structural equation modelling revealed that the ratio between the gene copy abundances of nitritereducers and N2O-reducers was the microbial variable that best explained N2O emissions, along with soil pH and moisture. In addition, the NO3− concentration in the soil solution at 60 cm depth increased with the potential nitrification-to-denitrification ratio, suggesting a higher risk of NO3− leaching under some tree species like Douglas fir.
Auteurs, date et publication :
Auteurs A. Florio , M. Marechal , A. Legout , C. Creuse des Chatelliers , J. Gervaix , S. Didier , B. Zeller , X. Le Roux
Publication : Soil Biology and Biochemistry
Date : 2025
Volume : 155
Pages : 108164
Catégorie(s)
#ANR-Citation #FORET Breuil #INRAE #M-POETERésumé
Keeping European temperate forests on acidic soils sustainable is challenging for forest management and wood production. Nutrient budgets are a diagnostic tool that assesses forest sustainability by adding up nutrient inputs (atmospheric dissolved deposition and soil weathering) and outputs (losses in drainage water and by wood harvesting). In these forests, nutrient budgets of essential nutrients are often unbalanced, especially for the base cations Ca, Mg and K, meaning that these nutrients deplete from the ecosystem, what threatens forest sustainability. Whereas Aeolian dust deposition (ADD) is recognized as a significant nutrient input in various ecosystems, particularly in oceans, it is not taken into account in usual nutrient budgets of European forests. ADD has been characterized in different places in the world, however, little is known in European forests and about ADD impacts on their biogeochemical cycles. To fill this gap, this review aims at (i) synthesizing data on ADD characteristics in European forests to put forward a deposition model over Europe and calculate nutrient fluxes, (ii) highlighting the contribution of ADD to plant tissues in two ecosystems with an isotopic approach, (iii) evaluating the contribution of ADD to the total nutrient inputs, and (iv) assessing the impacts of ADD on European nutrient budgets of forests concerning Ca, Mg and K. Aeolian dust in Europe is either long-distance transported from arid regions such as Sahara or short-distance from the erosion of local soils. It was estimated to deposit between 41 and 129 kg haÀ1 yearÀ1 throughout Europe. Its mineralogical composition reveals nutrient bearing minerals, silicates and nonsilicates (carbonates, oxides, hydroxides, sulphates, phosphates, halides). This suggests Aeolian dust may contribute as high as 30% of total nutrient inputs, so that it may significantly shift upwards nutrient budgets of European forests under latitude 52°N. Further investigations are therefore needed to inform about accurate ADD rates below the tree canopy and to take account of the total nutrient inputs.
Auteurs, date et publication :
Auteurs Émeline Lequy , Sébastien Conil , Marie-Pierre Turpault
Publication : Forest Ecology and Management
Date : 2025
Pages : 13
Catégorie(s)
#FORET Breuil #FORET Montiers #INRAERésumé
In forest ecosystems, fungi are the key actors in wood decay. They have the capability to degrade lignified substrates and the woody biomass of coniferous forests, with brown rot fungi being common colonizers. Brown rots are typically involved in the earliest phase of lignocellulose breakdown, which therefore influences colo nization by other microorganisms. However, few studies have focused on the impact of introducing decayed wood into forest environments to gauge successional colonization by natural bacterial and fungal communities following partial decay. This study aimed to address this issue by investigating the bacterial and fungal colo nization of Norway spruce (Picea abies) wood, after intermediate and advanced laboratory-based, pre-decay, by the brown rot fungus Gloeophyllum trabeum. Using Illumina metabarcoding, the in situ colonization of the wood blocks was monitored 70 days after the blocks were placed on the forest floor and covered with litter. We observed significant changes in the bacterial and fungal communities associated with the pre-decayed stage. Further, the wood substrate condition acted as a gatekeeper by reducing richness for both microbial communities and diversity of fungal communities. Our data also suggest that the growth of some fungal and bacterial species was driven by similar environmental conditions.
Auteurs, date et publication :
Auteurs Nicolas Valette , Arnaud Legout , Barry Goodell , Gry Alfredsen , Lucas Auer , Eric Gelhaye , Delphine Derrien
Publication : Fungal Ecology
Date : 2025
Volume : 61
Pages : 101188
Catégorie(s)
#ANR-Citation #FORET Breuil #INRAERésumé
Trees play a crucial role in nutrient cycling and ecosystem fertility, notably through rhizosphere processes. The aim of this study was to compare soil physicochemical properties between bulk soil and rhizosphere of several tree species, and to compare rhizosphere properties between fertilized and non-fertilized conditions. The soil sampling was performed in Breuil-Chenue forest (North-East of France) in seven stands: native forest (old beech (Fagus sylvatica L.) and oak (Quercus sessiliflora Smith) coppice with standards; CwS), beech, oak (Quercus petraea [Matt.] Liebl.), Douglas-fir and fertilised Douglas-fir, Norway spruce (Picea abies Karst.) and fertilised Norway spruce. Systematic soil sampling was performed at 0–3, 3–10, and 10–23 cm in 20 calibrated pits. The rhizosphere of the different species was generally enriched in C, N, Ca, Mg, and K. Interestingly, the same positive effect was observed in the fertilised plots. The rhizosphere effect varied between tree species for C, “base” cations, pHwater and cation exchange capacity. This study reveals that interactions between roots, microorganisms and soil can enrich the pool of nutrients in the rhizosphere compared to bulk soil whatever the soil fertility conditions, and that the magnitude of the rhizosphere effect depends on tree species.
Auteurs, date et publication :
Auteurs Christophe Calvaruso , Victor N’Dira , Marie-Pierre Turpault
Publication : Plant and Soil
Date : 2011
Volume : 342
Issue : 1
Pages : 469-480
Catégorie(s)
#FORET Breuil #INRAERésumé
Soil organic carbon is one of the largest surface pools of carbon that humans can manage in order to partially mitigate annual anthropogenic CO2 emissions. A significant element to assess soil sequestration potential is the carbon age, which is evaluated by modelling or experimentally using carbon isotopes. Results, however, are not consistent. The 14C derived approach seems to overestimate by a factor of 6–10 the average carbon age in soils estimated by modeling and 13C approaches and thus the sequestration potential. A fully independent method is needed. The cosmogenic chlorine nuclide, 36Cl, is a potential alternative. 36Cl is a naturally occurring cosmogenic radionuclide with a production that increased by three orders of magnitude during nuclear bomb tests. Part of this production is retained by soil organic matter in organochloride form and hence acts as a tracer of the fate of soil organic carbon. We here quantify the fraction and the duration of 36Cl retained in the soil and we show that retention time increases with depth from 20 to 322 years, in agreement with both modelling and 13C-derived estimates. This work demonstrates that 36Cl retention duration can be a proxy for the age of soil organic carbon.
Auteurs, date et publication :
Auteurs Cécile Grapeloup , Sophie Cornu , Xavier Giraud , Julie Pupier , Aster Team , Valery Guillou , Philippe Ciffroy , Beatriz Lourino Cabana , Cécile Couegnas , Christine Hatté , Lucilla Benedetti
Publication : Scientific Reports
Date : 2023
Volume : 13
Issue : 1
Pages : 15085
Catégorie(s)
#FORET Breuil #INRAERésumé
In forest ecosystems, the silicon (Si) mass-balance at the watershed scale can be strongly influenced by readily soluble Si components, such as dissolved Si, adsorbed Si, amorphous silica (biogenic and pedogenic opal) and short-range ordered aluminosilicates. The aim of the present study is to (a) identify the components of the readily soluble Si pool in the Cambisol found below three tree species, under homogeneous soil and climate conditions, and (b) study the impact of Si recycling by tree species on the Si pools. We therefore measured the concentrations of Si extracted by Na2CO3 (Si-alk), oxalate (Si-ox) and CaCl2. The Si-alk concentration decreased from the humus layer to 15 cm depth and then slightly increased until a depth of 75 cm. In the humus layer, the Si-alk concentration consisted mainly of phytoliths and differed significantly between tree species (expressed as mg SiO2 g(-1)): Douglas fir (14.5 +/- 0.65) > European beech (11.8 +/- 0.30) > Black pine (5.4 +/- 0.31). Below 7.5 cm, the Si-alk content did not differ significantly between tree species, and the Si-ox content, increasing significantly, was mainly comprised of Si adsorbed onto amorphous Fe oxides. These results suggest that (a) tree species can impact the readily soluble Si content in the topsoil, through different rates of Si uptake and phytolith restitution by the vegetation, and (b) the soil's readily soluble Si pool is mainly comprised of phytoliths and adsorbed Si. Here, the readily soluble Si pool is thus controlled by both the iron dynamics and Si biocycling.
Auteurs, date et publication :
Auteurs Jean-Thomas Cornelis , Hugues Titeux , Jacques Ranger , Bruno Delvaux
Publication : Plant and Soil
Date : 2011
Volume : 342
Issue : 1-2
Pages : 369-378
Catégorie(s)
#FORET Breuil #INRAERésumé
The exact molecular mechanisms as well as the genes involved in the mineral weathering (MW) process by bacteria remain poorly characterized. To date, a single type of glucose dehydrogenase (GDH) depending on a particular co-factor named pyrroloquinoline quinone (PQQ) is known. These enzymes allow the production of gluconic acid through the oxidation of glucose. However, it remains to be determined how bacteria missing PQQ-dependent GDH and/or the related pqq biogenesis genes weather minerals. In this study, we considered the very effective mineral weathering bacterial strain PMB3(1) of Collimonas pratensis. Genome analysis revealed that it does not possess the PQQ based system. The use of random mutagenesis, gene complementation and functional assays allowed us to identify mutants impacted in their ability to weather mineral. Among them, three mutants were strongly altered on their acidification and biotite weathering abilities (58 to 75% of reduction compared to WT) and did not produce gluconic acid. The characterization of the genomic regions allowed noticeably to the identification of a Glucose/Methanol/Choline oxidoreductase. This region appeared very conserved among collimonads and related genera. This study represents the first demonstration of the implication of a PQQ-independent GDH in the mineral weathering process and explains how Collimonas weather minerals.
Auteurs, date et publication :
Auteurs Laura Picard , Marie-Pierre Turpault , P. Oger , Stephane Uroz
Publication : FEMS Microbiology Ecology
Date : 2025
Catégorie(s)
#FORET Breuil #INRAERésumé
We evaluated whether and how rapidly temperate forest tree species able to stimulate or inhibit nitrification (through biological nitrification inhibition, BNI) also influence denitrifier activity and abundance in soil and identified the main determinants of changes in denitrification. A reciprocal soil core transfer approach was implemented at a long-term experimental site between Douglas fir, a species assumed to stimulate nitrification, and stands of tree species with (spruce and Nordmann fir) or without (Corsican pine and beech) BNI capacity. Sixteen months after soil transfer, potential denitrification decreased in soils transferred from Douglas fir to another tree species and increased in soil cores transferred from any species to Douglas fir. The change in denitrification was not related to the BNI capacity of the tree species ‘receiving’ the soil cores. Structural equation modelling revealed that in soil cores transferred between Douglas fir and BNI species, changes in denitrification were mainly correlated to nitrifier abundances, i.e. AOA and Nitrobacter, nitrification rates, and soil N O3− availability, whereas in soil cores transferred between Douglas fir and non-BNI species denitrification changes were well correlated to C availability and the abundance of nirK-harbouring denitrifiers. Overall, our results indicate that denitrification rates can change strongly and quickly following soil transfers between tree stands. Particularly, when Douglas fir replaces BNI tree species, this quickly results in both increased nitrification and denitrification rates, thus exacerbating the ensuing risk of increased NO3− leaching and N2O emission from soil.
Auteurs, date et publication :
Auteurs A. Florio , C. Bréfort , C. Creuze des Chatelliers , J. Gervaix , F. Poly , B. Zeller , X. Le Roux
Publication : Biology and Fertility of Soils
Date : 2025
Volume : 57
Issue : 8
Pages : 1089-1101
Catégorie(s)
#ANR-Citation #FORET Breuil #INRAE #M-POETERésumé
An ectomycorrhiza is a multitrophic association between a tree root, an ectomycorrhizal fungus, free-living fungi and the associated bacterial communities. Enzymatic activities of ectomycorrhizal root tips are therefore result of the contribution from different partners of the symbiotic organ. However, the functional potential of the fungus-associated bacterial communities remains unknown. In this study, a collection of 80 bacterial strains randomly selected and isolated from a soil-ectomycorrhiza continuum (oak-Scleroderma citrinum ectomycorrhizas, the ectomycorrhizosphere and the surrounding bulk soil) were characterized. All the bacterial isolates were identified by partial 16S rRNA gene sequences as members of the genera Burkholderia, Collimonas, Dyella, Mesorhizobium, Pseudomonas, Rhizobium and Sphingomonas. The bacterial strains were then assayed for beta-xylosidase, beta-glucosidase, N-acetyl-hexosaminidase, beta-glucuronidase, cellobiohydrolase, phosphomonoesterase, leucine-aminopeptidase and laccase activities, chitin solubilization and auxin production. Using these bioassays, we demonstrated significant differences in the functional distribution of the bacterial communities living in the different compartments of the soil-ectomycorrhiza continuum. The surrounding bulk soil was significantly enriched in bacterial isolates capable of hydrolysing cellobiose and N-acetylglucosamine. In contrast, the ectomycorrhizosphere appeared significantly enriched in bacterial isolates capable of hydrolysing glucopyranoside and chitin. Notably, chitinase and laccase activities were found only in bacterial isolates belonging to the Collimonas and Pseudomonas genera. Overall, the results suggest that the ectomycorrhizal fungi favour specific bacterial communities with contrasting functional characteristics from the surrounding soil.
Auteurs, date et publication :
Auteurs S. Uroz , P. E. Courty , J. C. Pierrat , M. Peter , M. Buee , M. P. Turpault , J. Garbaye , P. Frey-Klett
Publication : Microbial Ecology
Date : 2013
Volume : 66
Issue : 2
Pages : 404-415
Catégorie(s)
#FORET Breuil #INRAERésumé
In temperate ecosystems, acidic forest soils are among the most nutrient-poor terrestrial environments. In this context, the long-term differentiation of the forest soils into horizons may impact the assembly and the functions of the soil microbial communities. To gain a more comprehensive understanding of the ecology and functional potentials of these microbial communities, a suite of analyses including comparative metagenomics was applied on independent soil samples from a spruce plantation (Breuil-Chenue, France). The objectives were to assess whether the decreasing nutrient bioavailability and pH variations that naturally occurs between the organic and mineral horizons affects the soil microbial functional biodiversity. The 14 Gbp of pyrosequencing and Illumina sequences generated in this study revealed complex microbial communities dominated by bacteria. Detailed analyses showed that the organic soil horizon was significantly enriched in sequences related to Bacteria, Chordata, Arthropoda and Ascomycota. On the contrary the mineral horizon was significantly enriched in sequences related to Archaea. Our analyses also highlighted that the microbial communities inhabiting the two soil horizons differed significantly in their functional potentials according to functional assays and MG-RAST analyses, suggesting a functional specialisation of these microbial communities. Consistent with this specialisation, our shotgun metagenomic approach revealed a significant increase in the relative abundance of sequences related glycoside hydrolases in the organic horizon compared to the mineral horizon that was significantly enriched in glycoside transferases. This functional stratification according to the soil horizon was also confirmed by a significant correlation between the functional assays performed in this study and the functional metagenomic analyses. Together, our results suggest that the soil stratification and particularly the soil resource availability impact the functional diversity and to a lesser extent the taxonomic diversity of the bacterial communities.
Auteurs, date et publication :
Auteurs Stephane Uroz , Panos Ioannidis , Juliette Lengelle , Aurelie Cebron , Emmanuelle Morin , Marc Buee , Francis Martin
Publication : Plos One
Date : 2013
Volume : 8
Issue : 2