Present work focuses on the influence of root architecture and N nutrition on the interaction between plants and soil microbial communities in response to drought stress. This is especially relevant in legumes as N fixation is highly sensitive to water stress. In a context of increased intensity and frequency of drought episodes, it is important to maintain N fixation and thus legume productivity throughout the plant growth cycle. Root architecture and its plasticity can provide higher drought resilience in pea. Features such as deep rooting, nodule location and the interaction between emerging roots and microbial communities contribute to this resilience, conspicuously through N cycling in the soil (Prudent et al., 2020). Yet, little is known on the effects of root architecture on microbial communities and its consequences on soil N cycling and plant resilience. The objective of this project is to tackle this pluri-component question with a holistic approach integrating whole plant ecophysiology and microbial ecology, with spatial patterns of exudation as a cornerstone of the plant-microbiome interaction (Tixier et al., 2023). Concise description of the work (materials & methods) Pea plants were compared for their response to water stress (WS) and different sources of N nutrition (symbiotic fixation N- and nitrate fertilization N+) in terms of water relations, plant productivity, root structure (architecture, C/N) and function (growth, exudation, water and nitrogen uptake). In order to assess root architecture, the plants were grown in the RhizoTubes© of the 4PMI (Plant Phenotyping Platform for Plant and Microorganism Interaction). This innovative equipment is fairly unique for root phenotyping, allowing a quantitative non-destructive assessment of root growth and development using image analysis. Main Results Here we showed that water and N shortage decrease plant productivity and modulate shoot and root traits with a bigger impact of water stress on pea root structure and function than N shortage. Indeed, smaller root area was associated with smaller root growth in WS plants. WS plants root system showed a sinking architecture when compared to WW plants with significantly higher Depth/Width ratio. These structural root changes were concomitant to functional changes such as a significant decreased in specific nitrogen uptake, a significant decrease in root specific water uptake only observed in N + treatment and a significant increase of amino acids exudation in response to water stress, regardless of root location. Significant decrease of sugar exudation in response to water stress was only observed in N- plants. Further, while sugar exudation was significantly affected by spatial position on root architecture, no significant effect of position was observed for amino acid exudation. Conclusions These results provide insights on the spatial regulation of exudation at the whole plant level, a first step to build a mechanistic understanding of exudation and its trade-off with productivity and resilience. Further, the correlation of these exudation patterns with microbial community structure and activity as well as soil C-N cycling will provide means to target and drive these communities in order to promote plant productivity and soil services such as C storage and N-cycling. Understanding these ecophysiological trade-offs and rhizosphere interactions is essential to develop ideotypes that are adapted to low-input agroecosystems facing climate change