The Joint Research Unit Tree/Microbe Interactions (IAM) Université de Lorraine / INRAE was created on January 1st 2001, as the result of a merger between the INRA Laboratory of Forest Microbiology and the Laboratory of Forest Biology of the University Henri Poincaré, to which the INRA Laboratory of Forest Pathology was later attached in January 2005. Since its creation, the unit is located on two distinct geographical sites: the INRA campus in Champenoux and the Faculty of Science and Technology in Vandoeuvre-lès-Nancy. In 2020, following the merger of the INRA and IRSTEA research institutes, the UMR is under the dual supervision of the University of Lorraine and INRAE. Since 2020, the unit has been headed by a director (S. Duplessis, DR INRAE) assisted by two deputy directors (P. Frey, DR INRAE & N. Rouhier, PR UL). It is composed of 44 permanent staff (31 INRAE, 13 UL) and welcomes about 50 non-permanent staff per year.

Since 2001, the primary goal of the IAM research unit has been to increase knowledge of the biology and ecology of interactions between microorganisms and forest trees with the aim of improving understanding of the functioning of forest ecosystems and ultimately being able to propose sustainable management of these ecosystems in the current context of increased human activity and global change. This thematic continuity, mainly based on the understanding of interactions between trees and the cohort of micro-organisms (bacteria and fungi) associated with them within forest ecosystems, is structured around two axes: integrative biology and ecology of these interactions.

These structuring axes make it possible to approach the study of these interactions through multidisciplinary and complementary approaches at different spatio-temporal scales, to meet the three main scientific objectives that we have set, namely:

• Understanding the molecular, ecological and environmental mechanisms governing the interactions between trees and microorganisms
• Understanding the functional role of interactions between trees and microorganisms in forest ecosystems
• Understanding the processes governing the evolution and adaptation of tree/microorganism associations to enable better anticipation of potential impacts related to global changes.

The IAM unit is structured into three research teams:

• Ecogenomics of interactions (team manager: Stephane Uroz, DR INRAE):

The team project aims to decipher the molecular mechanisms governing the continuum of interactions between trees, fungi, bacteria and soil in order to improve the understanding of the structure and function of forest microbial communities, through three interconnected lines of research, (i) evolutionary genomics of fungal lifestyles, (ii) molecular mechanisms of tree-fungi-bacteria-soil interactions, and (iii) diversity and function of microbial communities

• Ecology of forest pathogenic fungi (team manager: Pascal Frey, DR INRAE):

This team is working on the study of the ecology, epidemiology and evolutionary biology of emerging diseases of forest trees, including some major forest diseases (poplar rust, ash blight, alder dieback, oak powdery mildew)

• Stress response and redox regulation (team manager: Melanie Morel-Rouhier, PR UL):

With its expertise in protein structure/function analysis, this team is developing two lines of research, (i) the response to environmental constraints of trees and plants in general, and (ii) the degradation of organic matter by saprophytic fungi in forest ecosystems.