The seminar will be given by Yohann Daguerre in the LGEF meeting room at 1.30pm next Friday (13th). Yohann who is a post-doc in the ecogenomic team will present his last results about : « PtJAZ6 complex in Populus trichocarpa and its role in the ectomycorrhizal development »
Author Archives: eric
And the winner is…
![P1040928 [1600x1200]](http://mycor.nancy.inra.fr/IAM/wp-content/uploads/2016/04/P1040928-1600x1200.jpg)
Lien vers la vidéo de la remise des prix sur France3 Lorraine.
Lien vers la vidéo de la totalité de la cérémonie (pour la prestation de Thomas avancer à 1h 02min).
Lien vers l’article de l’Est Républicain.
Article: Plant Pathology
Influence of site and stand factors on Hymenoscyphus fraxineus induced basal lesion. B Marçais, C Husson, L Godart, O Caël. Plant Pathology
Summary
Hymenoscyphus fraxineus is an invasive fungus in Europe and causes a severe decline affecting ashes since the late nineties. One of the symptoms associated with the disease is lesions in the outer bark of the collar area. However, the etiology of these basal lesions and in particular the relative role of H. fraxineus and Armillaria species is still controversial; moreover, little is known on the influence of environmental factor on the disease epidemiology. We therefore surveyed 42 plots located in Northeastern France, in an area affected by ash decline since 2008 in order to determine which environmental factors condition the severity of lesions associated with H. fraxineus on ash collar. The spatial pattern that is the consequence of the invasive spread of the disease was taken into account in the analysis using a spatial hierarchical Bayesian model fitted by Integrated Nested Laplace Approximation (INLA). Results show that while basal lesions are tightly associated with H. fraxineus, their severity is not linked to the Armillaria species present in the plot. Sites with vegetation indicating moist condition or more humid topographical position were associated with more developed basal lesion.
Seminar: M. Grosdidier
The seminar of the week will be given by Marie Grosdidier who is currently doing her PhD in the team Ecology of Forest Pathogen. She will present her last results at 1.30pm in the seminar room of the main building at Champenoux.
Book: Genomics research on non-model plant pathogens
PhD Defense: C. Pellegrin
The defense will be held the 26th April at 9h00 in the conference room of the INRA campus at Champenoux.
Titre : Analyse d’effecteurs du champignon ectomycorhizien Laccaria bicolor : approches bio-informatiques et fonctionnelles
Résumé :
La symbiose ectomycorhizienne associe les racines d’un arbre aux hyphes d’un champignon, conduisant à un échange réciproque de nutriments entre les deux partenaires. La colonisation fongique massive du cortex racinaire est caractérisée par la formation d’une interface symbiotique, le réseau de Hartig. Le fonctionnement de cette interface symbiotique n’est pas parfaitement élucidé mais l’acquisition du génome du symbionte ectomycorhizien Laccaria bicolor a permis d’identifier des petites protéines prédites sécrétées, les MiSSPs (Mycorrhiza-induced Small Secreted Proteins). Mon projet de thèse avait pour objectifs la comparaison des sécrétomes, notamment les petites protéines sécrétées (SSPs), de champignons ectomycorhiziens et saprotrophes, la localisation subcellulaire in planta et l’analyse fonctionnelle de MiSSPs de L. bicolor. L’analyse bioinformatique a notamment permis de révéler des clusters de SSPs fortement conservées entre champignons ectomycorhiziens et saprotrophes ou spécifiques de champignons ectomycorhiziens, mettant en lumière que les champignons ectomycorhiziens partagent des SSPs avec leurs ancêtres saprotrophes mais possèdent aussi d’autres SSPs spécifiques à leur mode de vie.
Un jeu de MiSSPs de L. bicolor appartenant à un « core-regulon » ont été localisées in planta, montrant que trois d’entre eux sont capables de cibler spécifiquement des compartiments subcellulaires de la cellule végétale. La recherche d’interactant pour l’effecteur candidat MiSSP8 n’a pas permis l’identification d’un interactant, mais le motif répété DWRR présent dans la séquence de MiSSP8 est unique aux champignons et est partagé par une famille de protéine fongique de champignons majoritairement saprotrophes. Ces résultats suggèrent que l’utilisation de SSPs comme moyen de communication est générique chez les champignons et démontrent aussi qu’au moins une petite protéine sécrétée requise pour la symbiose de L. bicolor a évoluée à partir de protéines de champignons saprotrophes.
Abstract :
Roots of most trees form ectomycorrhizal (ECM) symbiosis with mutualistic soil-borne fungi, relying on a bi-directional exchange of nutrients between the two partners. Fungal colonization of cortical root cells form the Hartig net, a symbiotic interface. Functioning of this symbiotic interface is not well known. However, Laccaria bicolor genome sequencing sheds the light on upregulated small-secreted proteins, so-called MiSSPs (Mycorrhiza-Small Secreted Proteins). Several L. bicolor MiSSPs were demonstrated as symbiosis effectors. My PhD project aims to compare secretomes, in particular SSPs, of fungal with different lifestyles and pursue functional analysis of MiSSPs of L. bicolor.
Based on the clustering analysis, we identified clusters of SSPs shared between saprotrophic and ECM fungi and clusters of SSPs specific to ECM-fungi. This study highlights that ECM fungi share SSPs with their saprotrophic ancestors but also possess lifestyle specific SSPs.
In planta subcellular localization of a set of MiSSPs belonging to a core-regulon showed that three of them are able to target different plant subcellular compartments. Functional analysis of the symbiosis effector MiSSP8 does not lead to the identification of a putative interactor but the repetitive motif DWRR of MiSSP8 protein sequence is unique to fungi and is shared with SSPs from saprotrophic ancestors. Our results suggest the use of SSPs as mean of communication is common and generic and show at least one SSPs required for ectomycorhizal symbiosis of L. bicolor has evolved from SSPs found in saprotrophic fungi.
Article: Planta
Understanding plant cell-wall remodelling during the symbiotic interaction between Tuber melanosporum and Corylus avellana using a carbohydrate microarray. F Sillo, JU Fangel, B Henrissat, A Faccio, P Bonfante… – Planta
Abstract
Main conclusion
A combined approach, using a carbohydrate microarray as a support for genomic data, has revealed subtle plant cell-wall remodelling during Tuber melanosporum and Corylus avellanainteraction.
Cell walls are involved, to a great extent, in mediating plant–microbe interactions. An important feature of these interactions concerns changes in the cell-wall composition during interaction with other organisms. In ectomycorrhizae, plant and fungal cell walls come into direct contact, and represent the interface between the two partners. However, very little information is available on the re-arrangement that could occur within the plant and fungal cell walls during ectomycorrhizal symbiosis. Taking advantage of the Comprehensive Microarray Polymer Profiling (CoMPP) technology, the current study has had the aim of monitoring the changes that take place in the plant cell wall in Corylus avellana roots during colonization by the ascomycetous ectomycorrhizal fungus T. melanosporum. Additionally, genes encoding putative plant cell-wall degrading enzymes (PCWDEs) have been identified in the T. melanosporum genome, and RT-qPCRs have been performed to verify the expression of selected genes in fully developed C. avellana/T. melanosporum ectomycorrhizae. A localized degradation of pectin seems to occur during fungal colonization, in agreement with the growth of the ectomycorrhizal fungus through the middle lamella and with the fungal gene expression of genes acting on these polysaccharides.
Article: Bulletin of Mathematical Biology
Mate Finding, Sexual Spore Production, and the Spread of Fungal Plant Parasites FM Hamelin, F Castella, V Doli, B Marçais, V Ravigné, MA Lewis. Bulletin of Mathematical Biology, 1-18
Abstract
Sexual reproduction and dispersal are often coupled in organisms mixing sexual and asexual reproduction, such as fungi. The aim of this study is to evaluate the impact of mate limitation on the spreading speed of fungal plant parasites. Starting from a simple model with two coupled partial differential equations, we take advantage of the fact that we are interested in the dynamics over large spatial and temporal scales to reduce the model to a single equation. We obtain a simple expression for speed of spread, accounting for both sexual and asexual reproduction. Taking Black Sigatoka disease of banana plants as a case study, the model prediction is in close agreement with the actual spreading speed (100 km per year), whereas a similar model without mate limitation predicts a wave speed one order of magnitude greater. We discuss the implications of these results to control parasites in which sexual reproduction and dispersal are intrinsically coupled.
Seminar : F. Zhang
Vendredi 15 avril, 13h30, salle de réunion LGEF (INRA): Feng Zhang (IAM – Ecogénomique)
“Expression and purification of a symbiosis-induced GH5 endocellulase
in the ectomycorrhizal fungus Laccaria bicolor »
Article: Forest Pathology
Phytophthora× alni and Phytophthora lacustris associated with common alder decline in Central Portugal M Kanoun‐Boulé, T Vasconcelos, J Gaspar, S Vieira, C Dias‐Ferreira, …Forest Pathology
Summary
Since the early 1990s, an emerging disease induced by the highly aggressive oomycete Phytophthora ×alni has caused widespread alder decline across Europe. In parallel, P. lacustris, a recently described species associated with riparian habitats, has been subject of increasing interest. A field survey conducted in 2014 showed high mortality rates in alder stands located in the riparian gallery along two rivers in Central Portugal. The pathogens isolated from necrotic alder stem base during this study were identified as P. ×alni and P. lacustris. This paper is the first to report the occurrence of P. lacustris in Portugal and presents the first finding of P. ×alni affecting mature trees in natural ecosystems located in Central Portugal.
