Research topics

Currently being drafted

The IRHS SMS team aims to identify the metabolic determinants of plant performance in the context of agroecological transition and under environmental constraints. It employs integrative, multi-scale approaches, combining stable isotopes, gas exchange, metabolomics and imaging, across a continuum ranging from ecophysiology to functional genomics. Our work is situated within the framework of source–sink relationships, whose dynamics and resilience—strongly modulated by the environment and genotype—emerge from the integration of photosynthetic processes, nutrient assimilation and phloem function, including its energy and redox metabolism. A major challenge lies in gaining an integrated understanding of the metabolic regulations that control resource allocation between organs. The team focuses in particular on two key stages of the life cycle that determine plant yield: the seedling establishment phase and the source leaf of the seed-bearing plant.

• Determinism of source metabolism

The source leaf of the seed-bearing plant constitutes the point of entry for carbon into the system and a central regulatory node. Photosynthesis is closely coupled with the assimilation of nitrogen and sulphur, notably via photorespiration and C1 metabolism. However, the mechanisms linking photosynthetic activity, diurnal respiration and phloem loading to the composition of the sap remain only partially understood. 
We aim to overcome this obstacle by analysing how these processes determine the intensity and quality of fluxes to sink organs, and how they are modulated by the environment to control carbon allocation and the quality of reproductive organs

• Functional determinism of seed and seedling vigour

Plant establishment relies on a continuum of key stages, ranging from seed germination to post-emergence seedling growth, and on a continuum of processes that are highly sensitive to environmental variations. We are interested in identifying the functional mechanisms associated with seedling plasticity in response to the environment and with genotype*environment and genotype*environment*management interactions during key stages of plant establishment, and more specifically during the heterotrophic–autotrophic transition phase, a phase requiring fine coordination between the mobilisation of reserves and the initiation of photosynthesis.

The main physiological factors and metabolic determinants of successful weaning and the acquisition of physiological autonomy are being investigated through the exploration of genetic diversity and from transcriptomics to fluxomics, with a focus on the role of nitrogen nutrition (Ben Hdech et al., 2020, Barrit et al., 2024, Morère-Le Paven et al., 2024), thermal stress (SOJASUR Regional Pre-competitive Research Project_2025–2028; Réthoré et al., 2024) and innovative molecules; on the impact of the seed microbiota (ANR-PPR SucSeed Project_2021–2026); on the determinants of seedling response to water deficit tolerance (H2020 EUCLEG project, 2017–2021), and on the role of the phloem in the integration and redistribution of fluxes and nutrients during the establishment and regulation of source–sink relationships in the heterotrophic–autotrophic transition phase.