Dr. Claire Seydoux, European Synchrotron Radiation Facility, presents subcellular metabolite mapping in Arabidopsis seeds and ongoing research on metabolic compartmentalization and the evolution of C4 photosynthesis.
The efficiency of living organisms relies on a highly organized multiscale compartmentalization of metabolic pathways across tissues, cell types, and organelles. In plants, this spatial organization is central to photosynthetic performance and metabolic integration. Resolving chemical heterogeneity at the subcellular level, however, remains a major analytical challenge. Advanced chemical imaging techniques such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and synchrotron-based X-ray fluorescence (s-XRF) offer powerful solutions to visualize ions and metabolites within their native spatial context. By combining high spatial resolution with molecular and elemental specificity, these approaches enable direct mapping of plant chemistry across cells and organelles.
Photosynthesis is intrinsically limited by the competition between O₂ and CO₂ for the active site of RuBisCO, leading to the energetically costly process of photorespiration. Some plant lineages have partially overcome this limitation through the spatial separation of CO₂ fixation into distinct cell types, giving rise to C4 photosynthesis. Because photosynthesis is tightly interconnected with nutrient assimilation and broader metabolic networks, understanding its evolution requires a spatially resolved view of plant chemistry.