Chloroplast Gene Expression and Reverse Genetics in Chlamydomonas Reinhardtii

It is well established that the biosynthesis of the photosynthetic apparatus in higher plants and eukaryotic algae is achieved through the concerted action of the chloroplast and nucleo-cytosolic genetic systems. Although numerous studies have appeared on this subject the molecular mechanisms underlying this interaction are still poorly understood. The green unicellular alga Chlamydomonas reinhardtii is particularly well suited for studies of this sort. First, photosynthetic function is dispensable provided a reduced carbon source, e.g. acetate, is added to the growth medium. Thus mutants deficient in photosynthesis can be generated and maintained with ease. Since the photosynthetic apparatus of C. reinhardtii is very similar to that of higher plants, this alga provides an excellent model system for studying the biosynthesis and function of the various components of the photosynthetic machinery. Second, standard genetic analysis is feasible in C. reinhardti. Third, reliable transformation procedures have been established recently both for the chloroplast and nuclear compartments of C. reinhardtii (1, 2, 3, 4).