Lay summary
During leaf senescence, chlorophyll is broken down to colorless catabolites, which are deposited in the vacuole. The process of chlorophyll degradation is comprised of a complex series of enzymatic reaction and involves transport of breakdown products from the chloroplast to the vacuole. Although several reactions of this pathway have biochemically and/or molecularly been identified, some enzymatic reactions and in particular the membtane transport systems have not been elucidated. Furthermore, so far only one single factor has been identified which seems to be involved in regulating the pathway. The aim of this study is to identify some of the unknown/additional factors required in chlorophyll breakdown. This will be performed by identifying and characterizing new candidate genes/proteins for specific reactions. In order to address regulatory aspects of the pathway, a cell death mutant is used, which is defective in a key step of the pathway. Second-site mutagenesis will identify new genes, which might involved in the regulation of the pathway.