Auteurs, date et publication :
Auteurs A. Depince , L. Marandel , L. Goardon , P.-Y. Le Bail , C. Labbe
Publication : Theriogenology
Date : 2011
Volume : 75
Issue : 9
Pages : 1755-1761
Catégorie(s)
#INRAE #PEARLRésumé
Bacterial communities play an essential role in the sustainability of forest ecosystems by releasing from soil minerals the nutritive cations required not only for their own nutrition but also for that of trees. If it is admitted that the nutritional needs of trees vary during seasons, the seasonal dynamics of the mineral weathering bacterial communities colonizing the tree rhizosphere remain unknown. In this study, we characterized the mineral weathering efficacy of bacterial strains, from the rhizosphere and the adjacent bulk soil at four different seasons under two different tree species, the evergreen spruce and the deciduous beech, using a microplate assay that measures the quantity of iron released from biotite. We showed that the functional and taxonomic structures of the mineral weathering bacterial communities varied significantly with the tree species as well as with the season. Notably, the Burkholderia strains from the beech stand appeared more efficient to weather biotite that the one from the spruce stand. The mineral weathering efficacy of the bulk soil isolates did not vary during seasons under the beech stand whereas it was significantly higher for the spring and summer isolates from the spruce stand. The weathering efficacy of the rhizosphere isolates was significantly higher for the autumn isolates compared to the isolates sampled in the other seasons under the beech stand and in summer compared to the other seasons under spruce. These results suggest that seasonal differences do occur in forest soil bacterial communities and that evergreen and deciduous trees do not follow the same dynamic. (C) 2011 Elsevier Ltd. All rights reserved.
Auteurs, date et publication :
Auteurs C. Collignon , S. Uroz , M-P. Turpault , P. Frey-Klett
Publication : Soil Biology and Biochemistry
Date : 2011
Volume : 43
Issue : 10
Pages : 2012-2022
Catégorie(s)
#FORET Breuil #INRAERésumé
Fungi constitute an important group in soil biological diversity and functioning. However, characterization and knowledge of fungal communities is hampered because few primer sets are available to quantify fungal abundance by real-time quantitative PCR (real-time Q-PCR). The aim in this study was to quantify fungal abundance in soils by incorporating, into a real-time Q-PCR using the SYBRGreen® method, a primer set already used to study the genetic structure of soil fungal communities. To satisfy the real-time Q-PCR requirements to enhance the accuracy and reproducibility of the detection technique, this study focused on the 18S rRNA gene conserved regions. These regions are little affected by length polymorphism and may provide sufficiently small targets, a crucial criterion for enhancing accuracy and reproducibility of the detection technique. An in silico analysis of 33 primer sets targeting the 18S rRNA gene was performed to select the primer set with the best potential for real-time Q-PCR: short amplicon length; good fungal specificity and coverage. The best consensus between specificity, coverage and amplicon length among the 33 sets tested was the primer set FR1 / FF390. This in silico analysis of the specificity of FR1 / FF390 also provided additional information to the previously published analysis on this primer set. The specificity of the primer set FR1 / FF390 for Fungi was validated in vitro by cloning - sequencing the amplicons obtained from a real time Q-PCR assay performed on five independent soil samples. This assay was also used to evaluate the sensitivity and reproducibility of the method. Finally, fungal abundance in samples from 24 soils with contrasting physico-chemical and environmental characteristics was examined and ranked to determine the importance of soil texture, organic carbon content, C∶N ratio and land use in determining fungal abundance in soils.
Auteurs, date et publication :
Auteurs Nicolas Chemidlin Prévost-Bouré , Richard Christen , Samuel Dequiedt , Christophe Mougel , Mélanie Lelièvre , Claudy Jolivet , Hamid Reza Shahbazkia , Laure Guillou , Dominique Arrouays , Lionel Ranjard
Publication : Plos One
Date : 2011
Volume : 6
Issue : 9
Pages : e24166
Catégorie(s)
#Genosol #INRAEAuteurs, date et publication :
Auteurs Laurent Lagadic , Thierry Caquet , B. Réal , I. Dubus , N. Surdyk , Anne Togola , Marc Roucaute , Arnaud Auber , Caroline Gorzerino , Ana Roucaute , Marie-Agnes Coutellec , Virginie Ducrot
Date : 2011
Catégorie(s)
#INRAE #PEARLRésumé
Unlike farmland, forests growing on acidic soils are among the terrestrial ecosystems that are the least influenced or amended by man. Forests which developed on acidic soils are characterized by an important stock of inorganic nutrients entrapped in poorly weatherable soil minerals. In this context, the mineral-weathering process is of great importance, since such minerals are not easily accessible to tree roots. To date, several bacterial genera have been noted for their ability to weather minerals and, in the case of some of them, to improve tree nutrition. Nevertheless, few studies have focused their analyses on mineral-weathering bacterial communities in relation to geochemical cycles and soil characteristics, their ecological origin, associated tree species and forest management practices. Here we discuss the heterogeneity of the mineral-weathering process in forest soils and present what is known concerning the taxonomic and functional characteristics of mineral-weathering bacteria, as well as the different locations where they have been isolated in forest soils. We also discuss the biotic and abiotic factors that may influence the distribution of these bacteria, such as the effect of tree species or forest management practices. (C) 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Auteurs, date et publication :
Auteurs Stephane Uroz , Phil Oger , Cendrella Lepleux , Christelle Collignon , Pascale Frey-Klett , Marie-Pierre Turpault
Publication : Research in Microbiology
Date : 2011
Volume : 162
Issue : 9, SI
Pages : 820-831
Catégorie(s)
#FORET Breuil #INRAERésumé
Aims The aim of this study was to assess the seasonal influence on the dynamics of exchangeable nutrients (K, Ca and Mg) in acidic and nutrient-poor forest soils, where nutrients can become limiting for tree growth. Methods The amounts of exchangeable base cations (K(+)+Ca(2+)+Mg(2+)) were measured in soil samples collected in three soil compartments (Bulk, Outer Rhizosphere, and Inner Rhizosphere) and in 4 months (November, February, May and August) under two stands of 31-year-old Norway spruce and beech in an acidic temperate forest. Results In all season, both rhizosphere compartments were enriched in exchangeable nutrients compared to bulk soil. This suggests that tree roots and root-associated microorganisms (bacteria and mycorrhizal fungi) increased nutrient availability through mineral weathering or mineralization processes, and thus could contribute to forest sustainability in nutrient-poor conditions. Interestingly, in contrast to beech, a drastic decrease of exchangeable base cations was observed in bulk soil of spruce between November and February (higher than 80% for K and Mg, and 100% for Ca). The relation between this decrease, Al solubility, and nitrate concentration are evoked in the discussion. Conclusion This study reveals that processes resulting from interactions between trees, microorganisms and soil influence not only the seasonal dynamics of nutrients in the root vicinity but also the bulk soil function.
Auteurs, date et publication :
Auteurs Christelle Collignon , Christophe Calvaruso , Marie-Pierre Turpault
Publication : Plant and Soil
Date : 2011
Volume : 349
Issue : 1-2, SI
Pages : 355-366
Catégorie(s)
#FORET Breuil #INRAERésumé
The present work aimed to evaluate the seasonal increment in diameter of Eucalyptus grandis trees for 24 months and its relationship with the climatic variables and fertilization with nitrogen and with sewer mud. The trees were planted in the spacing of 3 x 2 m and fertilized with nitrogen (planting, 6, 12, 18 months) and sewer mud (planting and 8 months). 20 trees were selected by treatment according witch the distribution of basal area and installed dendrometer bands at a 1.3 meter. The results showed a clear effect of the climatic variables on the seasonal increment in diameter of trees, being observed a delay period (lag) of 28 days for the answer of the trees in relation to the climatic variables. Regading to the fertilization effect, it was observed that the increment of trunk diameter was higher in the eucalyptus trees with organic in relation to mineral fertilization with nitrogen. (Résumé d'auteur)
Auteurs, date et publication :
Auteurs Carlos Roberto Sette Junior , Mario Tomazello Filho , José Luis Lousada , Jean-Paul Laclau
Publication : Ciência Florestal
Date : 2025
Volume : 22
Issue : 4
Pages : 771-783
Catégorie(s)
#CIRAD #FORET Itatinga #INRAEAuteurs, date et publication :
Auteurs C.-R. Sette Jr , M.-T. Filho , J.-L. Lousada , J.-P. Laclau
Publication : Ciencias Florestal, Santa Maria
Date : 2025
Volume : 22
Pages : 771-783
Catégorie(s)
#CIRAD #FORET Itatinga #INRAEAuteurs, date et publication :
Auteurs O.-C. Campoe , J.-L. Stape , J.-P. Laclau , C. Marsden , Y. Nouvellon
Publication : Tree Physiology Advance Access
Date : 2025
Volume : 00
Pages : 1-11
Catégorie(s)
#CIRAD #FORET Itatinga #INRAEAuteurs, date et publication :
Auteurs Clément Peltre , Bent T. Christensen , Sophie Dragon , Christian Icard , Thomas Kätterer , Sabine Houot
Publication : Soil Biology and Biochemistry
Date : 2025
Volume : 52
Pages : 49-60