"Increased frequency and intensity of extreme climatic events are predicted in Europe, including severe droughts and intense precipitation events. Such changes will influence plant physiology, soil microbial activity and nutrient cycling, inducing changes in ecosystem functioning, with expected consequences on productivity, soil functions and carbon balance. Thus, an improved mechanistic comprehension of ecosystem responses to altered precipitation patterns is required to adequately assess responses to future climatic conditions, within a research framework that can address couplings between biogeochemical cycles by integrating all players associated in plant-soil microbial-nitrogen cycling interactions. The effects of contrasting precipitation patterns will be addressed in an integrated, multidisciplinary approach combining state-of-the-art molecular microbiology techniques with stable isotopes approaches and biogeochemical methods. The overall goal is to understand the temporal and spatial couplings between i) precipitation patterns, ii) the structure and activity of the soil microbial community and soil nitrogen fluxes, and iii) plant water and nitrogen uptake, and how these couplings affect the stability of ecosystems functions. The proposed work will i) investigate which active microbial groups are most involved in the response of the plant-microbial system to precipitation patterns, ii) carry out temporally resolved investigations of precipitation patterns impacts on the outcome of plant-microbial competition for nitrogen and the coupling between plant water uptake depth and soil microbial activity, iii) assess the coupling between the stability of soil microbial community and of major functions that it performs, in response to altered precipitation patterns, enabling valuable insight into the future implications of changes in European summer climate for soil nitrogen availability, and providing crucial information for the development of mitigation strategies."