Portail HAL Institut Agro Montpellier
Not a member yet
54878 research outputs found
Sort by
Early root-root interactions weaken foliar defense responses against Septoria tritici blotch in a durum wheat varietal mixture
No full textInternational audienceThe interactions between co-cultivated plant cultivars are increasingly recognized as influencing their susceptibility to pathogens in mixtures. However, the underlying mechanisms remain largely unexplored. Using a model of durum wheat cultivar mixtures where susceptibility to Septoria foliar disease is increased, we combined aerial and root phenotyping with transcriptional analyses and untargeted metabolomics to elucidate the potential signaling cascade driving this modulation of susceptibility. We observed contrasting root architectures between cultivars in mixture. Molecular analysis showed a delayed induction of defense-related genes and metabolites following pathogen inoculation in plants grown in mixture compared to pure stand. The findings suggest that root architecture potentially triggers a competitive response that could delay the induction of defense responses following pathogen inoculation. Altogether, these results point to a possible interplay between root architecture, resource competition, plant metabolism, and defense modulation in shaping plant–pathogen interactions within varietal mixtures
First-ever data on space use by breeding Whiskered Terns Chlidonias hybrida using bio-logging
No full textInternational audienceWetlands are critical ecosystems for many species of conservation concern, including migratory birds. These species face resource depletion and unpredictability in the context of global change and are expected to adjust their space use accordingly. Understanding how waterbirds use space and identifying their foraging needs are essential for guiding conservation efforts. Here, we present preliminary results on the fine-scale space use of a wetland flagship species, the Whiskered Tern Chlidonias hybrida, in La Brenne, a historical French breeding stronghold. The species is listed as 'Vulnerable' in France and breeds in only a few large wetlands. For the first time, we equipped four adult terns with miniature GPS tracking devices, providing unique, high-resolution data on their daily movements throughout the breeding season (i.e. pre-incubation, incubation, rearing, and post-breeding). Our results showed that most daily foraging trips did not exceed 2-3 km, resulting in relatively small home ranges (ranging from 2.00 km2 to 14.95 km2). Values were higher during the post-breeding period (up to 8 km from the nest and home range size up to 74.45 km2). Furthermore, we found that Whiskered Terns remained faithful to their foraging areas throughout the season and preferentially foraged in ponds - especially those near their colony - compared with other potential foraging habitats. On average, 91% of foraging positions occurred in ponds and 9% in grasslands. We also provide practical details on bird capture and device attachment methods. Finally, this pioneering bio-logging study offers promising prospects for future research on the movement ecology of Whiskered Terns, which could be invaluable for their conservation
A Super-Pangenome for Cultivated Citrus Reveals Evolutive Features During the Allopatric Phase of Their Reticulate Evolution
No full textData availability: Raw data from long-read sequencing and genome assemblies of C. micrantha, C. medica and C. reticulata were deposited at EBI under the following accession numbers: - CITMI (C. micrantha): Raw data: PRJEB78372 - Assemblage: PRJEB78515 - Umbrella: PRJEB78526 - CITME (C. medica): Raw data: PRJEB78445 - Assemblage: PRJEB78498 - Umbrella: PRJEB78525- CITRE (C. reticulata): Raw data: PRJEB78477 - Assemblage: PRJEB78537 - Umbrella: PRJEB78524Resequencing raw reads derived from 58 citrus accessions were deposited in the EBI database under AC experiment accessions ERX12760151, ERX12780957, ERX12791201 and ERX12817346 to ERX12817400 (supporting information, Table 1).The raw RNA-seq data for C. medica, C. reticulata, C. maxima and C. micrantha were deposited in the European Nucleotide Archive under accession code PRJEB77075. The pseudochromosome and chloroplast genome assemblies of C. medica, C. reticulata and C. micrantha and their annotations are available on: https://citrus-genome-hub.southgreen.fr.International audienceThe main genetic diversity observed in cultivated citrus results from a reticulate evolution involving four ancestral taxa whose radiation occurred in allopatry. In such context, GWAS analysis, genome diversity and transcriptomic studies will be significantly enhanced through pangenome approaches. We report the implementation of a super-pangenome for cultivated citrus, established with de novo assemblies of C. medica, C. reticulata and C. micrantha, released for the first time alongside a published chromosome-scale assembly of C. maxima. Repetitive element annotation revealed that half of each genome consisted of transposable elements or DNA-satellites. The new genome assemblies display strong synteny and collinearity, while discrepancies are observed with the C. maxima assembly. Resequencing information from 55 accessions helped to explore the intra- and interspecific diversity of the ancestral taxa and their relationships with horticultural groups. Diagnostic SNPs of the ancestral taxa revealed interspecific introgressions in several representative accessions of C. reticulata, C. maxima and C. medica as well as insights into the origin and phylogenomic structures of horticultural groups. PAV analysis revealed a gene whose absence or presence was specific to one of the ancestral taxa. Diagnostic PAV analysis uncovered a large chloroplastic introgression in C. medica chromosome 4. The analysis of the functional enrichment and species-specific adaptations in the citrus super-pangenome revealed distinct functional specialisations. This highlights the evolutionary paths that have shaped species, contributing to the diversity in the citrus super-pangenome while maintaining a shared foundation of essential biological processes. We established a Genome Hub, offering a platform for continuous genomic research
Doping feruloylated arabinoxylan covalent hydrogels with cellulose nanocrystals
No full textInternational audienceTo improve the viscoelastic properties of Feruloylated Water Extractable Arabinoxylan (F-WEAX) gels, F-WEAX was crosslinked using a laccase in the presence of cellulose nanocrystals (CNC). The CNC/F-WEAX weight ratio ranged from 0 to 1.5, with a constant F-WEAX concentration of 1% (w/v). The addition of CNC increased gel stiffness and the elastic modulus scales as [CNC]³. CNC also affects the relaxation behaviour, enhancing significantly the loss factor at low frequencies. QCM-D measurements shows that F-WEAX adsorbed irreversibly onto CNC with the same affinity as non-feruloylated ones. In the presence of CNC, the action of laccase produces double the quantity of elastically active oxidation products, which are the dimer and trimer forms of ferulic acid (FA). As a consequence, the swelling capacity of the F-WEAX-CNC gels decreases, however less than anticipated from the increase in shear modulus. The synergistic enhancement of elasticity, while maintaining swelling capacity, is tentatively attributed to the formation of high-functionality junctions through the irreversible adsorption of F-WEAX onto CNC
About identifiability and observability for a class of dynamical systems
No full textInternational audienceWe present novel results and constructive methods on the observability, identifiability and joined observability-identifiability analysis of autonomous dynamical systems, with a special focus on nonlinear systems. While most existing works treat rational systems, the study of general nonlinearities remains less developed, up to our knowledge. Moreover, even in rational systems, a rigorous and unified theoretical argument ensuring the identifiability of parameters from input-output equations is still lacking. To address these gaps, we extend existing results in the literature. The key ingredient of our methods is a test of the linear independence of some functions of the observations and their derivatives. We furthermore describe constructive procedures to retrieve the unknowns based on the resolution of linear systems of equations. Finally, we apply our approach to several illustrative cases, including two non-rational cases that highlight its relevance. In particular, we show how our results allow the treatment of general nonlinearities and may complement existing techniques
Nature-based solutions for water management: Pluridisciplinary state-of-the-art and research needs
No full textInternational audienceNature-based Solutions (NbS) offer a way to preserve, manage and restore ecosystems so as to better meet today's societal challenges, by combining benefits for society and the environment, including biodiversity. They are a response to current climate change-related challenges for water management. However, various barriers exist to the implementation of NbS, such as a lack of appropriation of the concept, as well as needs for knowledge and know-how. Focusing on societal challenges linked to water, we highlight the importance of implementing pluridisciplinary and transdisciplinary projects when trying to implement NbS projects. This requires new approaches in research, practice, and governance. This discussion allows identifying levers for a widespread use of NbS for water management
New planthoppers (Hemiptera: Cixiidae) from Madagascar support the establishment of a new genus, the revised status of Eumyndus perinetensis, and an updated molecular phylogeny of Malagasy Oecleini
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/616204/) * Autres projets (id;sigle;titre): 2018/30/E/ NZ8/00880;;(USA) The evolutionary dynamics of the symbioses of Auchenorrhyncha// ;Epibio-OI II;(FRA) EPIdémiosurveillance et BIOcontrôle dans l'Océan Indien//International audienceRecent survey efforts in Madagascar have focused on the tribe Oecleini in the planthopper family Cixiidae due to an interest in identifying vectors of palm lethal decline phytoplasmas. During these surveys, planthoppers were collected on palms in natural habitats that were determined to represent a new genus, Geminimyndus gen. nov. Herein, two new species are described, G. spinaparum sp. nov. and G. spinamagnus sp. nov. Eumyndus perinetensis Synave is transferred to Geminimyndus gen. nov. as Geminimyndus perinetensis, comb. nov. Supplemental molecular data for the cytochrome c oxidase subunit I, histone 3, 18S rRNA and 28S rRNA are provided to support the establishment of the new genus and the transfer of E. perinetensis to the new genus.Les efforts récents de prospection à Madagascar se sont concentrés sur la tribu Oecleini de la famille des fulgoromorphes Cixiidae en raison de l'intérêt porté à l'identification des vecteurs du phytoplasme du dépérissement létal des palmiers possible par les espèces de ce groupe taxonomique. Au cours de ces prospections, des cixiides ont été collectées sur des palmiers dans des habitats naturels et il a été déterminé qu'elles représentaient un nouveau genre, Geminimyndus gen. nov. Deux nouvelles espèces sont décrites ici, G. spinaparum sp. nov. et G. spinamagnus sp. nov. et Eumyndus perinetensis est transféré dans ce nouveau genre. Des données moléculaires supplémentaires pour la sous-unité I de la cytochrome c oxydase, l'histone 3, l'ARNr 18S et l'ARNr 28S sont fournies pour étayer l'établissement du nouveau genre et le transfert d'E. perinetensis vers le nouveau genre
Citizen science contributions to soil biodiversity research and conservation: insights from European studies
No full textInternational audienceCitizen science (CS) has emerged as a valuable approach for bridging knowledge gaps in biodiversity studies by expanding spatial and temporal coverage, yet remains underused in soil biodiversity monitoring. We conducted the first Europe-wide synthesis of CS initiatives dedicated to soil biodiversity, systematically reviewing published and unpublished projects to assess their contributions and limitations. A total of 126 papers and projects were analyzed across 36 countries, with Western European countries leading in study volume. National-scale studies dominated, with urban areas being the most studied land use type. Taxonomic coverage was broad but uneven, dominated by soil macrofauna (ants, gastropods and earthworms) and fungi. Methodologies ranged from opportunistic sampling to structured surveys, reflecting diverse scientific objectives and producing data of variable quality. Citizens contributed substantially to species identification, although verification practices varied widely, from expert validation to self-reported identifications without verification. Overall, our synthesis reveals a fragmented but dynamic CS landscape that, while providing valuable contributions, remains far from realizing its full scientific potential. Strengthening the role of CS in soil biodiversity research will require greater emphasis on taxonomic accuracy, with error rates systematically assessed. Emerging image-based identification tools, including community-based identification features and automated species recognition, offer promising avenues to enhance both taxonomic accuracy and participant engagement. Equally important is fostering inclusive participation to broaden spatial coverage and co-develop conservation-relevant indicators with stakeholders. Finally, dataset interoperability and metadata standardization are essential to integrate heterogeneous initiatives and unlock the full potential of CS for researchers and soil biodiversity monitoring frameworks
L’histoire de l’aménagement foncier rural du Languedoc, entre nature et agriculture. L’exemple des Espaces naturels sensibles (ENS) de l’Hérault
No full textNational audienc
Package R Startbox
No full textLe package startbox est dédié à la gestion et à l’analyse des données d’essais en protection phytosanitaire, en particulier pour la vigne. Les données sont stockées dans un fichier Excel standard. Le package startbox regroupe des fonctions utiles pour le traitement des données selon les étapes suivantes :1. Chargement des données dans R2. Préparation des données (agrégation, filtre…)3. Réalisation des analyses statistiques4. Visualisation graphique des résultats (barplot, heatmap