Résumé
The biogeography of neotropical fungi remains poorly understood. Here, we reconstruct the origins and diversification of neotropical lineages in one of the largest clades of ectomycorrhizal fungi in the globally widespread family Russulaceae.
Auteurs, date et publication :
Auteurs Jan Hackel , Terry W. Henkel , Pierre‐Arthur Moreau , Eske De Crop , Annemieke Verbeken , Mariana Sà , Bart Buyck , Maria‐Alice Neves , Aída Vasco‐Palacios , Felipe Wartchow , Heidy Schimann , Fabian Carriconde , Sigisfredo Garnica , Régis Courtecuisse , Monique Gardes , Sophie Manzi , Eliane Louisanna , Mélanie Roy
Publication : New Phytologist
Date : 2025
Volume : 236
Issue : 2
Pages : 698-713
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Organic matter management is key to sustain ecosystem services provided by soils. However, it is rarely considered in a holistic view, considering local resources, agro-environmental effects and harmonization with farmers’ needs. Organic inputs, like compost and biochar, could represent a sustainable solution to massive current challenges associated to the intensification of agriculture, in particular for tropical regions. Here we assess the potential of agricultural residues as a resource for farmer communities in southwestern India to reduce their dependency on external inputs and sustain ecosystem services. We propose a novel joint evaluation of farmers’ aspirations together with agro-environmental effects of organic inputs on soils. Our soil quality evaluation showed that biochar alone or with compost did not improve unilaterally soils in the tropics (Anthroposol, Ferralsol and Vertisol). Many organic inputs led to an initial decrease in water-holding capacities of control soils (-27.3%: coconut shell biochar with compost on Anthroposol). Responses to organic matter inputs for carbon were strongest for Ferralsols (+33.4% with rice husk biochar), and mostly positive for Anthroposols and Vertisols (+12.5% to +13.8% respectively). Soil pH responses were surprisingly negative for Ferralsols and only positive if biochar was applied alone (between -5.6% to +1.9%). For Anthroposols and Vertisols, highest increases were achieved with rice husk biochar + vermicomposts (+7.2% and +5.2% respectively). Our socio-economic evaluation showed that farmers with a stronger economical position showed greater interest towards technology like biochar (factor 1.3 to 1.6 higher for farmers cultivating Anthroposols and/or Vertisols compared to Ferralsols), while poorer farmers more skepticism, which may lead to an increased economical gap within rural communities if technologies are not implemented with long-term guidance. These results advocate for an interdisciplinary evaluation of agricultural technology prior to its implementation as a development tool in the field.
Auteurs, date et publication :
Auteurs Severin-Luca Bellè , Jean Riotte , Norman Backhaus , Muddu Sekhar , Pascal Jouquet , Samuel Abiven
Publication : PLOS ONE
Date : 2022
Volume : 17
Issue : 1
Pages : e0263302
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
Abstract. Terrestrial biosphere models typically use the biochemical model of Farquhar, von Caemmerer, and Berry (1980) to simulate photosynthesis, which requires accurate values of photosynthetic capacity of different biomes. However, data on tropical forests are sparse and highly variable due to the high species diversity, and it is still highly uncertain how these tropical forests respond to nutrient limitation in terms of C uptake. Tropical forests often grow on soils low in phosphorus (P) and are, in general, assumed to be P rather than nitrogen (N) limited. However, the relevance of P as a control of photosynthetic capacity is still debated. Here, we provide a comprehensive dataset of vertical profiles of photosynthetic capacity and important leaf traits, including leaf N and P concentrations, from two 3-year, large-scale nutrient addition experiments conducted in two tropical rainforests in French Guiana. These data present a unique source of information to further improve model representations of the roles of N, P, and other leaf nutrients in photosynthesis in tropical forests. To further facilitate the use of our data in syntheses and model studies, we provide an elaborate list of ancillary data, including important soil properties and nutrients, along with the leaf data. As environmental drivers are key to improve our understanding of carbon (C) and nutrient cycle interactions, this comprehensive dataset will aid to further enhance our understanding of how nutrient availability interacts with C uptake in tropical forests. The data are available at https://doi.org/10.5281/zenodo.5638236 (Verryckt, 2021).
Auteurs, date et publication :
Auteurs Lore T. Verryckt , Sara Vicca , Leandro Van Langenhove , Clément Stahl , Dolores Asensio , Ifigenia Urbina , Romà Ogaya , Joan Llusià , Oriol Grau , Guille Peguero , Albert Gargallo-Garriga , Elodie A. Courtois , Olga Margalef , Miguel Portillo-Estrada , Philippe Ciais , Michael Obersteiner , Lucia Fuchslueger , Laynara F. Lugli , Pere-Roc Fernandez-Garberí , Helena Vallicrosa
Publication : Earth System Science Data
Date : 2022
Volume : 14
Issue : 1
Pages : 5-18
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Production, emission, and absorption of biogenic volatile organic compounds (BVOCs) in ecosystem soils and associated impacts of nutrient availability are unclear; thus, predictions of effects of global change on source-sink dynamic under increased atmospheric N deposition and nutrition imbalances are limited. Here, we report the dynamics of soil BVOCs under field conditions from two undisturbed tropical rainforests from French Guiana. We analyzed effects of experimental soil applications of nitrogen (N), phosphorus (P), and N + P on soil BVOC exchanges (in particular of total terpenes, monoterpenes, and sesquiterpenes), to determine source and sink dynamics between seasons (dry and wet) and elevations (upper and lower elevations corresponding to top of the hills (30 m high) and bottom of the valley). We identified 45 soil terpenoids compounds emitted to the atmosphere, comprising 26 monoterpenes and 19 sesquiterpenes; of these, it was possible to identify 13 and 7 compounds, respectively. Under ambient conditions, soils acted as sinks of these BVOCs, with greatest soil uptake recorded for sesquiterpenes at upper elevations during the wet season (-282 μg m-2 h-1). Fertilization shifted soils from a sink to source, with greatest levels of terpene emissions recorded at upper elevations during the wet season, following the addition of N (monoterpenes: 406 μg m-2 h-1) and P (sesquiterpenes: 210 μg m-2 h-1). Total soil terpene emission rates were negatively correlated with total atmospheric terpene concentrations. These results indicate likely shifts in tropical soils from sink to source of atmospheric terpenes under projected increases in N deposition under global change, with potential impacts on regional-scale atmospheric chemistry balance and ecosystem function.
Auteurs, date et publication :
Auteurs Joan Llusià , Dolores Asensio , Jordi Sardans , Iolanda Filella , Guille Peguero , Oriol Grau , Romà Ogaya , Albert Gargallo-Garriga , Lore T. Verryckt , Leandro Van Langenhove , Laëtitia M. Brechet , Elodie Courtois , Clément Stahl , Ivan A. Janssens , Josep Peñuelas
Publication : Science of The Total Environment
Date : 2022
Volume : 802
Pages : 149769
Catégorie(s)
#ANR-Citation #CIRAD #CNRS #FORET NouraguesRésumé
Individual-based forest models (IBMs) are useful to investigate the effect of environment on forest structure and dynamics, but they are often restricted to site-specific applications. To build confidence for spatially distributed simulations, model transferability, i.e. the ability of the same model to provide reliable predictions at contrasting sites, has to be thoroughly tested. We tested the transferability of a spatially explicit forest IBM, TROLL, with a trait-based species parameterization and global gridded climate forcing, by applying it to two sites with sharply contrasting climate and floristic compositions across the tropics, one in South America and one in Southeast Asia. We identified which parameters are most influential for model calibration and assessed the model sensitivity to climatic conditions for a given calibration. TROLL produced realistic predictions of forest structure and dynamics at both sites and this necessitates the recalibration of only three parameters, namely photosynthesis efficiency, crown allometry and mortality rate. All three relate to key processes that constrain model transferability and warrant further model development and data acquisition, with mortality being a particular priority of improvement for the current generation of vegetation models. Varying the climatic conditions at both sites demonstrate similar, and expected, model responses: GPP increased with temperature and irradiance, while stem density and aboveground biomass declined as temperature increased. The climate dependence of productivity and biomass was mediated by plant respiration, carbon allocation and mortality, which has implications both on model development and on forecasting of future carbon dynamics. Our detailed examination of forest IBM transferability unveils key processes that need to improve in genericity before reliable large-scale implementations can be envisioned.
Auteurs, date et publication :
Auteurs E-Ping Rau , Fabian Fischer , Émilie Joetzjer , Isabelle Maréchaux , I Fang Sun , Jérôme Chave
Publication : Ecological Modelling
Date : 2022
Volume : 463
Pages : 109801
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Soil organic carbon is regulated by a dynamic interaction of vegetation inputs, organic matter degradation and stabilization processes in soils, and its redistribution in the landscape. Tropical ecosystems are highly important in terms of carbon stored in vegetation and soil, but many processes of the soil carbon cycle in the tropics are yet to be fully understood. Here, we studied soil organic carbon stocks and quality in small-scale tropical, sub-humid and semi-arid watersheds along a climate gradient in southwestern India with varying vegetation and geology to identify major drivers of soil organic carbon dynamics in three prevalent soil types (Lixisol, Vertisol and Ferralsol) under shrubland and dry deciduous forest. We used a combination of organic carbon analysis (total organic carbon content, 13C, C:N), mid-infrared spectroscopy and soil property information (bulk density, texture, oxides, pH, cation-exchange capacity). Soil organic carbon stocks in these watersheds showed a substantial range from 58.2 to 169.4 MgCha−1 in the first 60 cm, and the differences depended on local- to watershed-scale variations in vegetation type and history, geology, soil physio-chemical (clay, oxides) and biological (bioturbation) properties. Considerable parts of the organic carbon stored in these soils was found below 30 cm (up to 40%), stressing the importance of tropical subsoils. From our analysis of the soil organic carbon quality and literature data on paleoclimate and vegetation, we could identify land-use changes in these watersheds, from tropical moist evergreen forests, forest-savannah transitions and plantations to secondary regrowth forest over time. Our study provides new data and insights into the local-scale drivers of soil organic carbon quantity and quality of tropical, sub-humid and semi-arid watersheds under shrubland and dry deciduous forest with varying geology and soil types.
Auteurs, date et publication :
Auteurs Severin-Luca Bellè , Jean Riotte , Muddu Sekhar , Laurent Ruiz , Marcus Schiedung , Samuel Abiven
Publication : Geoderma
Date : 2022
Volume : 409
Pages : 115606
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
The intestines of wild Caenorhabditis nematodes are inhabited by a variety of microorganisms, including gut microbiome bacteria and pathogens, such as microsporidia and viruses. Because of the similarities between Caenorhabditis elegans and mammalian intestinal cells, as well as the power of the C. elegans system, this host has emerged as a model system to study host intestinemicrobe interactions in vivo. While it is possible to observe some aspects of these interactions with bright-field microscopy, it is difficult to accurately classify microbes and characterize the extent of colonization or infection without more precise tools.
Auteurs, date et publication :
Auteurs Dalaena E Rivera , Vladimir Lažetić , Emily R Troemel , Robert J Luallen
Publication : Journal of Visualized Experiments
Date : 2022
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Although irrigation water is frequently assessed for the presence of plant pathogens, large spatial and temporal surveys that provide clues on the diversity and circulation of pathogens is missing. We evaluate the diversity of soft rot Pectobacteriaceae (SRP) of the genera Dickeya and Pectobacterium over two years in a temperate, mixed use watershed. The abundance of isolated strains correlates with the agricultural gradient along the watershed with a positive correlation found with temperature, nitrate and dissolved organic carbon water concentration. We characterized 582 strains by amplification and sequencing of the gapA gene. MLSA analysis performed with 3 housekeeping genes for 99 strains and core genome analysis of 38 sequenced strains confirmed for all the strains but one the taxonomic assignation obtained with the sole gapA sequence. Pectobacterium spp. (549 isolates) were far more abundant than Dickeya spp. (33 isolates). Dickeya spp. were only observed in the lower part of the river when water temperature was above 19°C and we experimentally confirmed a decreased fitness of several Dickeya spp. at 8°C in river water. D. oryzae dominates the Dickeya spp. P. versatile and P. aquaticum dominate the Pectobacterium spp. but their repartition along the watershed was different, P. versatile being the only species regularly recovered all along the watershed. Excepting P. versatile, Dickeya and Pectobacterium spp. responsible for disease outbreak on crops were less abundant or rarely detected. This work sheds light on the various ecological behaviours of different SRP in stream water and indicates that SRP occupation is geographically structured.
Auteurs, date et publication :
Auteurs Hajar Ben Moussa , Claire Bertrand , Emma Rochelle-Newall , Sarah Fiorini , Jacques Pédron , Marie-Anne Barny
Publication : Phytopathology
Date : 2022
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENS #PLANAQUARésumé
The genus Pipa is a species-poor clade of Neotropical frogs and one of the most bizarre-looking due to many highly derived anatomical traits related to their fully aquatic lifestyle. With their African relatives, they form the Pipidae family, which has attracted much attention, especially regarding its anatomy, reproductive biology, paleontology and biogeography. However, the actual diversity and phylogenetic relationships within Pipa remain poorly understood, and thus so do their historical biogeography and the evolution of striking features, such as the absence of teeth and endotrophy in some species. Using short mtDNA sequences across the distribution of the genus, we identified 15 main lineages (Operational Taxonomic Units - OTUs). This more than doubles the number of the currently seven valid nominal species. Several closely related OTUs do not share nuDNA alleles, confirming species divergence. Time-calibrated phylogenies obtained from mitogenomes and from 10 nuclear loci provide highly similar topologies but strikingly distinct node ages for Pipa. High dN/dS ratios and the variation of substitution rates across the trees suggest a strong effect of saturation on fast evolving positions of mtDNA, producing a substantially shorter stem branch of Pipa. Focusing on the nuDNA topology, we inferred an early Neogene Amazonian origin of the diversification of Pipa, with an initial split between the Guiana-Brazilian Shields and Western Amazonia, a pattern observed in many other co-distributed groups. All the western species are edentate, suggesting a single loss in the genus. Each of these groups diversified further out of Amazonia, toward the Atlantic Forest and toward trans-Andean forests, respectively. These events are concomitant with paleogeographic changes and match patterns observed in other co-distributed taxonomic groups. The two Amazonian lineages have probably independently acquired endotrophic larval development.
Auteurs, date et publication :
Auteurs Antoine Fouquet , Josselin Cornuault , Miguel T. Rodrigues , Fernanda P. Werneck , Tomas Hrbek , Andres R. Acosta-Galvis , David Massemin , Philippe J. R. Kok , Raffael Ernst
Publication : MOLECULAR PHYLOGENETICS AND EVOLUTION
Date : 2022
Volume : 170
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Wolbachia are maternally transmitted intracellular bacteria that are not only restricted to the reproductive organs but also found in various somatic tissues of their native hosts. The abundance of the endosymbiont in the soma, usually a dead end for vertically transmitted bacteria, causes a multitude of effects on life history traits of their hosts, which are still not well understood. Thus, deciphering the host-symbiont interactions on a cellular level throughout a host’s life cycle is of great importance to understand their homeostatic nature, persistence, and spreading success. Using fluorescent and transmission electron microscopy, we conducted a comprehensive analysis of Wolbachia tropism in soma and germ line of six Drosophila species at the intracellular level during host development. Our data uncovered diagnostic patterns of infections to embryonic primordial germ cells and to particular cells of the soma in three different neotropical Drosophila species that have apparently evolved independently. We further found that restricted patterns of Wolbachia tropism are determined in early embryogenesis via selective autophagy, and their spatially restricted infection patterns are preserved in adult flies. We observed tight interactions of Wolbachia with membranes of the endoplasmic reticulum, which might play a scaffolding role for autophagosome formation and subsequent elimination of the endosymbiont. Finally, by analyzing D. simulans lines transinfected with nonnative Wolbachia, we uncovered that the host genetic background regulates tissue tropism of infection. Our data demonstrate a novel and peculiar mechanism to limit and spatially restrict bacterial infection in the soma during a very early stage of host development.
Auteurs, date et publication :
Auteurs Anton Strunov , Katy Schmidt , Martin Kapun , Wolfgang J. Miller , Bruno Lemaitre
Publication : mBio
Date : 2022
Volume : 13
Issue : 2
Pages : e03863-21