"Despite the importance of senescence in world food production and safety, the proteases responsible for the massive protein degradation during senescence have not been identified. Strong candidates for senescence-associated proteases are members of various cysteine protease families that localize in lytic vacuoles that presumably engulf the chloroplast during senescence. This project aims at identifying the proteases that degrade chloroplasts in the model plant Arabidopsis thaliana. To detect and identify the active proteases during senescence the Activity-based Protease Profiling (ABPP) will be applied. ABPP is a novel functional proteomics technology based on the use of labeled small molecule inhibitors that label proteases in an activity-dependent manner. This technology can be used to show where, when and which proteases are active during senescence, and will reveal proteases that act redundantly. The role of these proteases in senescence will be further studied using reverse genetics and cell biological approaches. This project extends on the expertise and interest of the applicant in senescence and provides an excellent interdisciplinary training in cell biology, molecular cloning and state-of-the-art chemical biology. By performing this work in the Plant Chemetics lab at the Max Planck institute for Plant Breeding Research in Cologne, the applicant will have access to one of the best research and training facilities in Europe and leave at the end of the project with the knowledge and materials to establish an independent scientific career."