CR26-ECODIV-3 - You will join the Tree-Microbe Interactions (IAM) Joint Research Unit (UMR) 1136, which has around 90 staff, including 46 permanent employees, divided into three teams (INRAE and University of Lorraine). The research conducted at IAM focuses on the biology and ecology of interactions between microorganisms and forest trees. It aims to improve our understanding of the interactions between trees, fungi (pathogenic, symbiotic and saprotrophic) and rhizosphere bacteria, which contribute to the functioning and sustainability of forest ecosystems. The host team (Ecology of Forest Pathogenic Fungi), composed of three researchers, two engineers, two assistant engineers, and three technicians, conducts research on the biology of forest pathogenic fungal populations.In this context, you will be responsible for developing an emerging theme within the unit, which will focus on the role of microbiota in the development of tree diseases. Trees host a collection of microorganisms (bacteria, archaea, fungi, oomycetes and viruses), commonly referred to as the microbiota. This microbiota colonises the tree's various ecological niches, such as the phyllosphere, rhizosphere, and endosphere and, together with the host plant, forms the plant holobiont. The regulatory role of tree microbiota in disease development has been demonstrated in certain cases and constitutes an innovative area of research. Recent work by the host team has highlighted the role of microbiota in regulating ash dieback. However, knowledge remains incomplete, particularly regarding the other pathosystems studied by the team. In the short term, your mission will be to study the role of microbiota in the development of one of the forest diseases studied by the team, Diplodia shoot blight of pine. In this pathosystem, the pathogen is present in trees in endophytic form long before symptoms appear. It has been shown that the wood microbiota plays a role in triggering the disease by modifying the composition of key metabolites in the tissues. You will be responsible for studies aimed at elucidating the role of endophytic microbiota in the epidemiological cycle of the pathogen. Initially, you will characterise the microbiota of symptomatic and non-symptomatic pine stems under natural conditions and its relationship with the onset of symptoms using metabarcoding and/or metagenomics approaches. In a second phase, you will develop innovative approaches for manipulating the microbiota (synthetic microbial consortia) in greenhouses in order to functionally validate its role. These experimental approaches may incorporate simulations of different climate change scenarios in order to study the interactions between plants, pathogens, microbiota, and climate. Furthermore, the study of the rhizosphere microbiota of trees, in particular ectomycorrhizal fungi and associated bacterial communities, is a topic that has been extensively studied within the unit, which will promote collective dynamics.You will thus benefit from the appropriate infrastructures and tools available locally and from the expertise in metabarcoding and metagenomics data analysis already present in the unit and, more widely, on the Lorraine site. More broadly, you will be involved in national (ECODIV Division, Holoflux Metaprogramme, RisqFor, SymbiPhyt and PhytoMic networks, Francophone Forest Pathology Group, PEPR Forestt) and international scientific networks (cross-border networks, European projects, IUFRO workgroups, Phytobiome Alliance) in the field of plant microbiota and forest health.

Armed conflicts profoundly disrupt forest landscapes and the communities that depend on them. Ecosystems are degraded, governance institutions weakened, and ...