OZMYC : « Impact des stress abiotiques (OZone, sécheresse) sur la symbiose ectoMYCorhizienne et rôle de l’ectomycorhization sur les réponses des arbres »

PI : Marie-Noëlle Vaultier (UMR 1434 SILVA), co-PI: Claire Veneault-Fourrey (UMR 1136 IAM), 

Co-applicants : Marie-Béatrice Bogeat-Triboulot, Irène Hummel, Pierrick Priault, David Cohen, Cyril Buré (UMR 1434 Silva); Annegret Kohler (UMR 1136 Interactions Arbres/Micro-organismes – IAM)

Collaborations : Martina Peter (Swiss federal institute for Forest, Snow and Landscape Research-WSL, Suisse); Tim Tschaplinsky (Oak Ridge National Laboratory, USA); Ondrej Novak (Laboratory of Growth Regulators, Palacky University & Institute of Experimental Botany, République Tchèque)


Context — In temperate and boreal forest ecosystems, ectomycorrhiza are the most predominant plant-fungal mutualistic interactions established between roots and soil-born fungi. Nowadays, climate change (recurrent droughts, atmospheric pollutant such as tropospheric ozone) is on-going and both trees and soil microorganisms are highly sensitive to the consequences of global change. Tree-associated microorganisms also directly affect plant performance through regulating biomass production, carbon gain and allocation as well as nutrient acquisition. Abiotic stresses negatively impact trees productivity, e.g. by decreasing carbon assimilation and allocation to stems and roots. Still poor data exist on how these abiotic stresses can impact the functioning (bi-directional exchanges of nutrients) of ectomycorrhizal associations and the long-lasting positive effect of this symbiosis on tree productivity. It is thus crucial to address the challenging question of how trees interact with and respond to their biotic and abiotic environment at the same time.

Objectives — We propose to better link the influence of above-ground stress (drought or ozone) responses of plants on below ground processes, and doing so, performing an integrative study on plant-soil-stress interactions.

Approaches — We plan to compare three levels of cell organization (metabolites, hormonal and gene-expression profiling) in below- and above-ground organs (roots and leaves) in stress (drought or O3) and control conditions, in order to evaluate whether (and how) abiotic stresses might impair ectomycorrhization function and determine the importance of ectomycorrhization in stress resilience for trees.

Expected results and impacts — The advances anticipated here will set the stage for detailed understanding of trees adaptation to abiotic stresses without disturbing mutualistic biotic interactions such as ectomycorrhiza. The knowledge acquired on the molecular plasticity of poplar trees under different environmental cues will likely help to reveal genes that cross regulated resistance to multiple stresses and consequently contribute to the development of trees tolerant to a wide range of abiotic stresses without impacting beneficial ectomycorrhizal interaction.