Graduate Students Mini Symposium II - 2026

13:15 h Franziska Otto - AG Erb

Improving Rubisco through allosteric modulation

The intrinsic oxygenase activity of Rubisco imposes a major limitation on photosynthetic efficiency. Direct active-site engineering to improve CO₂ specificity is evolutionarily constrained by a trade-off with catalytic efficiency. We want to circumvent this by targeting allosteric regulation: engineering synthetic binders to modulate the catalytic large subunit (LSU) via its interface, bypassing the natural small subunit (SSU). This approach enables precise tuning of Rubisco function through designed surface interactions. Our modular strategy demonstrates that Rubisco's activity can be reprogrammed externally, offering a promising path to enhance CO₂ fixation in plants, bacteria and algae for improved photosynthetic yield.

13:45 h Lucy Saueressig - AG Junker

Functional relevance of canopy stratum-specific leaf microbiota for tree performance

Environmental heterogeneity in tree canopies correlates with intra-individual variation in leaf microbiota. To investigate whether this variation has a functional relevance for the host plant or reflects (a)biotic variability, we transferred microbiota from two canopy strata of Quercus robur to germ-reduced clones of the same species. We used UV radiation to simulate conditions that either matched or mismatched the origin of the microbial inoculum (environmental matching). Our results demonstrate advantageous effects of a matching microbiota as plants of these treatments increased in host performance. We highlight that leaf microbiota of different canopy positions not only varies in diversity and composition but that this intra-individual variation is functionally relevant for the plant host.