Résumé
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
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Major historical landscape changes have left significant signatures on species diversification. However, how these changes have affected the build-up and maintenance of Amazonia's megadiversity continues to be debated. Here, we addressed this issue by focusing on the evolutionary history of a pan-Amazonian toad genus that has diversified throughout the Neogene (Amazophrynella). Based on a comprehensive spatial and taxonomic sampling (286 samples, all nominal species), we delimited operational taxonomic units (OTUs) from mitochondrial DNA sequences. We delimited 35 OTUs, among which 13 correspond to nominal species, suggesting a vast underestimation of species richness. Next, we inferred time-calibrated phylogenetic relationships among OTUs based on complete mitogenomic data, which confirmed an ancient divergence between two major clades distributed in eastern and western Amazonia, respectively. Ancestral area reconstruction analyses suggest that the Andean foothills and the Brazilian Shield region represent the ancient core areas for their diversification. These two clades, probably isolated from one other by lacustrine ecosystems in western Amazonia during the Miocene, display a pattern of northward and eastward dispersals throughout the Miocene-Pliocene. Given the ecological association of Amazophrynella with non-flooded forests, our results reinforce the perception that ancient Amazonian landscape changes had a major impact on the diversification of terrestrial vertebrates.
Auteurs, date et publication :
Auteurs Leandro J. C. L. Moraes , Fernanda P. Werneck , Alexandre Rejaud , Miguel T. Rodrigues , Ivan Prates , Frank Glaw , Philippe J. R. Kok , Santiago R. Ron , Juan C. Chaparro , Mariela Osorno-Munoz , Francisco Dal Vechio , Renato S. Recoder , Sergio Marques-Souza , Rommel R. Rojas , Lea Demay , Tomas Hrbek , Antoine Fouquet
Publication : BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY
Date : 2022
Volume : 136
Issue : 1
Pages : 75-91
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Isabelle Braud , Chloé Martin , Isabelle Charpentier , Jean-François Le Gaillard
Date : 2022
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
The occurrence and distribution of the various species of the genus Pelecocera Meigen, 1822 (Diptera: Syrphidae) occurring in France are revised and a new species, Pelecocera garrigae Lair & Nève, 2022 sp. nov., is described from Mediterranean France. Distribution and ecological data of the six French species of Pelecocera are provided and an identification key is given to all these species. Sequences of the cytochrome c oxidase subunit I (COI) from all European Pelecocera species support the morphological species concept, except for Pelecocera scaevoides (Fallén, 1817). The binomen Pelecocera lugubris Perris, 1839 is recovered to name the Pelecocera lusitanica (Mik, 1898) of authors in France.
Auteurs, date et publication :
Auteurs Xavier Lair , Lise Ropars , Jeffrey H. Skevington , Scott Kelso , Benoît Geslin , Elise Minssieux , Gabriel Nève
Publication : Zootaxa
Date : 2022
Volume : 5141
Issue : 1
Pages : 1-24
Catégorie(s)
#CNRS #FORET O3HPRésumé
An animal’s behavioral phenotype comprises several traits, which are hierarchically structured in functional units. This is manifested in measured behaviors often being correlated, partly reflecting the need of a coordinated functional response. Unfortunately, we still have limited understanding whether consistent differences in animal behaviors are due to underlying physiological constraints or a result of plastic adaptation to their current environment. Therefore, characterizing the spatial distribution of behaviors can provide important insights into causes and consequences of behavioral variation. In the present study, we quantified behaviors in a wild, free-ranging population of the Neotropical frog Allobates femoralis. We investigated how these behaviors were linked to the frogs’ natural and social environment and quantified the extent to which these behaviors consistently differed among individuals (i.e., animal personality). We assessed levels of aggressiveness, exploration, and boldness by measuring several underlying behaviors expressed in a set of experimental assays, and found evidence for consistent among-individual differences along these axes. Contrary to our expectation, there was no relationship between individual behaviors and their natural environment, but we found a plastic response of males to changes in female density, which might reflect how individuals cope with their socio-ecological environment.
Auteurs, date et publication :
Auteurs Mélissa Peignier , Yimen G. Araya-Ajoy , Lauriane Bégué , Sarah Chaloupka , Katharina Dellefont , Christoph Leeb , Patrick Walsh , Max Ringler , Eva Ringler
Publication : Behavioral Ecology and Sociobiology
Date : 2022
Volume : 76
Issue : 7
Pages : 93
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Two new species of Tovomita Aubl. (Clusiaceae) from the Guiana Shield are described and illustrated. Tovomita maxima Molino & J.Engel, sp. nov., known from French Guiana, Guyana and Brazil, stands out by its large size (up to 30 m high), large leaves with eucamptodromous venation, calyptrate bracteoles and an unusual variation in the number of stamens (74-145). Tovomita saulensis J.Engel & Molino, sp. nov., probably endemic to central French Guiana, is an understory tree with small leaves with brochidodromous venation and flowers with few stamens (9-15). Illustrations, descriptions, photographs in vivo, a preliminary conservation status, distribution map and comments on the morphology of related species are provided.
Auteurs, date et publication :
Auteurs Julien Engel , Jean-François Molino , Lucas C. Marinho
Publication : Adansonia
Date : 2022
Volume : 44
Issue : 16
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Lianas are self-supporting systems that are increasing their dominance in tropical forests due to climate change. As lianas increase tree mortality and reduce tree growth, one key challenge in ecological remote sensing is the separation of a liana and its host tree using remote sensing techniques. This separation can provide essential insights into how tropical forests respond, from the point of view of ecosystem structure to climate and environmental change. Here, we propose a new machine learning method, derived from Random Forest (RF) and eXtreme Gradient Boosting (XGBoosting) algorithms, to separate lianas and trees using Terrestrial Laser Scanning (TLS) point clouds. We test our method on five tropical dry forest trees with different levels of liana infestation. First, we use a multiple radius search method to define the optimal radius of six geometric features. Second, we compare the performance of RF and XGBoosting algorithms on the classification of lianas and trees. Finally, we evaluate our model against independent data collected by other projects. Our results show that the XGBoosting algorithm achieves an overall accuracy of 0.88 (recall of 0.66), and the RF algorithm has an accuracy of 0.85 (recall of 0.56). Our results also show that the optimal radius method is as accurate as the multiple radius method, with F1 scores of 0.49 and 0.48, respectively. The RF algorithm shows the highest recall of 0.88 on the independent data. Our method provides a new flexible approach to extracting lianas from 3D point clouds, facilitating TLS to support new studies aimed to evaluate the impact of lianas on tree and forest structures using point clouds.
Auteurs, date et publication :
Auteurs Tao Han , Gerardo Arturo Sánchez-Azofeifa
Publication : Remote Sensing
Date : 2022
Volume : 14
Issue : 16
Pages : 4039
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Background and aims – The genus Carapichea (Rubiaceae), recently resurrected and separated from Psychotria, currently includes 24 Neotropical species and is morphologically heterogeneous. A revision of the genus in the Guianas is presented here, as part of the authors’ work on the Rubiaceae treatment in the Flora of the Guianas series.
Auteurs, date et publication :
Auteurs Olivier Lachenaud , Piero Delprete
Publication : Plant Ecology and Evolution
Date : 2022
Volume : 155
Issue : 2
Pages : 275-300
Catégorie(s)
#CNRS #FORET NouraguesRésumé
The hologenome concept considers the entity formed by a host and its microbiota, the holobiont, as new level of hierarchical organization subject to neutral and selective forces. We used grafted plants to formally evaluate the hologenome concept. We analyzed the root-endosphere microbiota of two independent watermelon and grapevine plant systems, including ungrafted and reciprocalgrafting combinations. Grafted and ungrafted hosts harbor markedly different microbiota compositions. Furthermore, the results indicate a non-random assembly of bacterial communities inhabiting the root endosphere of chimeric plants with interactive effect of both the rootstock and scion on the recruitment of microorganisms. Because chimeric plants did not have a random microbiota, the null hypothesis that holobionts assemble randomly and hologenome concept is an intellectual construction only can be rejected. The study supports the relevance of hologenome as biological level of organization and opens new avenues for a better fundamental understanding of plants as holobionts.
Auteurs, date et publication :
Auteurs Marine Biget , Tingting Wang , Cendrine Mony , Qicheng Xu , Lucie Lecoq , Véronique Chable , Kevin R. Theis , Ning Ling , Philippe Vandenkoornhuyse
Publication : iScience
Date : 2025
Volume : 26
Issue : 2
Pages : 106031
Catégorie(s)
#CNRS #EcoGenO #Université de RennesRésumé
Plants are widely recognized as chemical factories, with each species producing dozens to hundreds of unique secondary metabolites. These compounds shape the interactions between plants and their natural enemies. We explore the evolutionary patterns and processes by which plants generate chemical diversity, from evolving novel compounds to unique chemical profiles.
Auteurs, date et publication :
Auteurs Dale L. Forrister , María‐José Endara , Abrianna J. Soule , Gordon C. Younkin , Anthony G. Mills , John Lokvam , Kyle G. Dexter , R. Toby Pennington , Catherine A. Kidner , James A. Nicholls , Oriane Loiseau , Thomas A. Kursar , Phyllis D. Coley
Publication : New Phytologist
Date : 2025
Volume : 237
Issue : 2
Pages : 631-642