The establishment of C₄ photosynthesis requires considerable alterations in leaf architecture and biochemistry and evolves via intermediate states. The Brassicaceae family contains several species with a C₃-C₄ intermediate architecture and a limited CO₂ concentration in the bundle sheath via a photorespiratory glycine pump. In the Asteraceae intermediate forms can also be found close to C₄ species.       

C₃-C₄ species can be distinguished so far by their CO₂ compensation point and their bundle sheath anatomy. Within the Brassicaceae we investigate the diversity of such glycine pump mechanisms in by parallel analysis of the genome, the anatomy and physiology in a large panel of species. The gained knowledge will help us to introduce a C₃-C₄ like phenotype into the C₃ species Arabidopsis by a synthetic biology approach.

C3-C4 intermediates display C4-like leaf anatomical features thus differing from C3 leaf anatomy. To date, it is unknown how the characteristic leaf anatomy of C3-C4 intermediates is established and which gene-regulatory circuits govern this process. To unravel these intricate regulatory networks, the Brassicaceae family, with its five independent instances of the C3-C4 intermediate trait, will be used in conjunction with microscopy, cell biology, single-cell and computational biology approaches.

CAM plants can be found in warm and seasonally dry environments, where they can survive due to their efficient mode of photosynthesis regarding water-use efficiency. Some plants, such as Talinum fruticosum can switch between C₃ and CAM photosynthesis if conditions are (not) favorable. We are working on understanding this mechanism by using approaches in the fields of synthetic biology, proteomics, trancriptomics, metabolomics and genomics.