Chlamydomonas reinhardtii in the Landscape of Pigments

Abstract

This review focuses on the biosynthesis of pigments in the unicellular alga Chlamydomonas reinhardtii and their physiological and regulatory functions in the context of information gathered from studies of other photosynthetic organisms. C. reinhardtii is serving as an important model organism for studies of photosynthesis and the pigments associated with the photosynthetic apparatus. Despite extensive information pertaining to the biosynthetic pathways critical for making chlorophylls and carotenoids, we are just beginning to understand the control of these pathways, the coordination between pigment and apoprotein synthesis, and the interactions between the activities of these pathways and those for other important cellular metabolites branching from these pathways. Other exciting areas relating to pigment function are also emerging: the role of intermediates of pigment biosynthesis as messengers that coordinate metabolism in the chloroplast with nuclear gene activity, and the identification of photoreceptors and their participation in critical cellular processes including phototaxis, gametogenesis, and the biogenesis of the photosynthetic machinery. These areas of research have become especially attractive for intensive development with the application of potent molecular and genomic tools currently being applied to studies of C. reinhardtii.

Retrograde bilin signaling enables Chlamydomonas greening and phototrophic survival

“…Our results raise the possibility that chlorophyte species lacking phytochromes possess complementary regulatory systems responsible for mediating the light-dependent increase in chlorophyll accumulation seen in C. reinhardtii. It is even conceivable that undiscovered bilin-based light sensors might be responsible for this response or for near UV-and blue-dependent responses of C. reinhardtii not ascribed to flavin-based sensors (26,60), because PCB-based sensors can detect any wavelength of light from the near UV to the near IR (61,62). Alternatively, bilin-based retrograde signaling may be the sole reason for retention of the bilin biosynthetic pathway in chlorophytes lacking phytochromes.…”

“…They thus might be expected to share similar mechanisms for light sensing and retrograde signaling. However, many chlorophyte genomes lack phytochromes (21-24), a deficiency offset by a larger complement of flavin-and retinal-based sensors (25)(26)(27)(28)(29)(30).…”

Quantitative Genetic Analysis of Chlorophyll during Dark-induced Senescence at Seedling Stage in Recombinant Inbred Line Population of Maize

“…Chlorophyll metabolism has been clearly elucidated in the plant model Arabidopsis and most of the key genes involved in this pathway have been cloned and characterized (Hörtensteiner and Krautler, 2011;Hörtensteiner, 2013). Chlorophyll metabolism involves three major processes, namely, chlorophyll synthesis (Willows, 2003;Grossman et al, 2004) chlorophyll cycle (Rüdiger, 2002) and chlorophyll degradation (also called PAO pathway) (Takamiya et al, 2000;Eckhardt et al, 2004). The free form of chlorophyll from excessive chlorophyll synthesis produces reactive oxygen species, which in turn results in cell death (Op den Camp et al, 2003).…”

Isolation and characterization of pigment deficient insertional mutants in the chlorophyte Chlamydomonas reinhardtii

“…Its role as a model system is particularly important to study photosynthesis and responses to light [3][4][5] due to the possibility of Chlamydomonas to grow either photoautotrophically in mineral media and light or heterotrophically in acetate and dark. The study of Chlamydomonas pigment-less mutants generated by traditional mutagenesis has offered interesting information about photoprotective mechanisms in microalgae and plants [4], but the identification of the gene affected in these kinds of mutants is not easy.…”