Abstract
Since more than 10E9 years, nature operates endosymbiotic metabolic pathways in eukaryotic host cells. In plants, maintenance of the cells metabolism is compartmentalized. The metabolic stage of a family of plastid organelles defines the metabolic developmental stage of the plant. In this respect, the light driven electron transport processes in the chloroplast are essential to maintain the metabolism of the photoautotrophic developmental state of the plant. However, hardly anything is known about the biogenesis of photoautotrophy and of chloroplasts. We have therefore established an experimental system to characterize the biogenetic processes. Etioplasts isolated from dark-grown barley leaves have proven extremely valuable to study the development of chloroplasts. Upon illumination the onset of photoautotrophy development can be precisely controlled to study the processes in vivo and in vitro. We propose to study the identification and characterization of an electron transport chain (ETC) in etioplasts, and the structural and functional changes of the plastid and its membrane protein complexes during the biogenesis of photoautotrophy. Work includes characterization of chlorophyll assembly in protein complexes and chlorophyll transfer reactions associated with the biogenesis. We will characterize the Cytb6f/Pchl//Chl and Lil3/Chl complexes detected by us. We will resolve the type of electron transfer chains that plastids utilize in darkness, differentiate the function of pigmentation changes in the Cytb6f complex, and resolve the function of chlorophyll binding to the Lil3 protein. The lab has acquired a unique biochemical expertise to solve central issues in the biogenesis of photoautotrophy. To develop additional skills, four cooperation partners will join in characterizing the biogenesis of photoautrophy in the plant.
Norway