36^th BioSC Lecture

Claudia Knief, INRES - Molecular Biology of the Rhizosphere, University of Bonn

"Spatial patterns in the maize rhizosphere microbiota: related to root structure and defined by photosynthate allocation"

February 25, 2026 | 16:00 h - 17:30 h | Building 15.1, Room 249, Forschungszentrum Jülich

Photo: iStock

Plants transport substantial amounts of assimilated carbon into the root system and beyond into the rhizosphere, where rhizodeposition promotes microbial life. Our recent work shows that the rhizosphere microbiota shows spatial heterogeneities, in part related to root architecture. We expect that photosynthate allocation contributes to the formation of such spatial patterns. Thus, we studied the spatial distribution of photosynthates in the root system, how distributional patterns within the root system relate to rhizodeposition and how this relates to the establishment of rhizosphere microbial communities. To assess photosynthate distribution in roots, we apply the short-lived tracer ¹¹C in form of ¹¹CO₂ and visualize tracer allocation by positron emission tomography (PET) in combination with magnetic resonance imaging (MRI). To trace the path of photosynthates further into the rhizosphere and its microbiota, we apply in addition the stable isotope ¹³C to quantify ¹³C abundance by isotope ratio mass spectrometry (IRMS) and perform DNA-based stable isotope probing. Data will be presented that visualize the distribution of the ¹¹C in the root system and how this is linked to spatial patterns of the rhizosphere microbiota. Our data suggest local support of specific microbial taxa by rhizodeposits and therewith habitat differentiation for rhizosphere colonizers within the plant root system.