A genome?s-eye view of the light-harvesting polypeptides of Chlamydomonas reinhardtii

Abstract

Chlamydomonas reinhardtii is a valuable model system for defining the structure and function of polypeptides of the photosynthetic apparatus and the dynamic aspects of photosynthesis. Recently, a genome-wide analysis of cDNAs and a draft genome sequence that covers approximately 90% of the genome were made available, providing a clear picture of the composition of specific gene families, the relationships among the gene family members, and the location of each member on the genome. We used the available sequence information to analyze the extensive family of light-harvesting genes in C. reinhardtii. There are nine genes encoding polypeptides of the major light-harvesting complex of photosystem II, two genes encoding the minor light-harvesting polypeptides of photosystem II, and nine genes encoding polypeptides predicted to comprise the photosystem I light-harvesting complex. Furthermore, there are five genes encoding early light-induced proteins and two genes encoding LI818 polypeptides. A candidate for the PsbS gene has also been found in the raw genome sequence data (Niyogi, personal communication), although no genes encoding homologues of the Sep, or Hli polypeptides have been identified. In this manuscript, we identify and classify the family of light-harvesting polypeptides encoded on the C. reinhardtii genome. This is an important first step in designing specific genetic, biochemical, and physiological studies aimed at characterizing the composition, function, and regulation of the light-harvesting complexes.

Zeaxanthin Binds to Light-Harvesting Complex Stress-Related Protein to Enhance Nonphotochemical Quenching in Physcomitrella patens

“…Consistent with this, NPQ in P. patens depends on both PSBS and LHCSR (Alboresi et al, 2010;Gerotto et al, 2011) and presents an active xanthophyll cycle (Alboresi et al, 2008). The analysis of the P. patens genome (Koziol et al, 2007;Alboresi et al, 2008Alboresi et al, , 2011Rensing et al, 2008) revealed that the composition of its antenna system is more similar to that of vascular plants than to unicellular green algae due to the presence of genes encoding LHCb3 and LHCb6, which are not found in Chlamydomonas reinhardtii (Elrad and Grossman, 2004). Both carotenoid accumulation and NPQ are enhanced by abiotic stress Azzabi et al, 2012).…”

Chlamydomonas reinhardtii PsbS Protein Is Functional and Accumulates Rapidly and Transiently under High Light

“…3) suggests that the mechanism of PsbS, which is still debated, is at least partially conserved between plants and the green algae despite some differences in photosystem II organization between the organisms. In particular, LHCII proteins in Chlamydomonas have biochemical/spectroscopic properties similar to those of plants (Natali and Croce, 2015), but they cannot be classified in the Lhcb1-3 isoforms as in plants (Jansson, 1999;Elrad and Grossman, 2004). In Chlamydomonas, the CP24 subunit, which is next to the LHCII-M trimer (Dekker and Boekema, 2005) and that has been suggested to detach from PSII during NPQ induction in a PsbS-dependent phenomenon (Betterle et al, 2009), is lacking and at its place a third LHCII trimer is bound to PSII (Tokutsu et al, 2012;Drop et al, 2014).…”

Light-harvesting antenna complexes in the moss Physcomitrella patens: implications for the evolutionary transition from green algae to land plants

“…It appears that none of the P. patens Lhcb4 (PpLhcb4; "Pp" for P. patens, hereafter) isoforms are related to AtLhcb4.3 [6], which is found only in dicots and is now classified as Lhcb8 due to its distinct function from AtLhcb4.1 and AtLhcb4.2 [22]. Further, as the ortholog of AtLhcb6 has not been found in green algae so far [11,12], the presence of an AtLhcb6 ortholog in P. patens suggests its uniqueness to land plants, although it is absent in Pinaceae and Gnetales, similar to the case of Lhcb3 [21]. In addition to major and minor LHCIIs, the ortholog of AtLhcb7, which is rarely expressed [22], is present in P. patens [6].…”

“…In A. thaliana, Lhcb1, Lhcb2, and Lhcb3 encode major LHCIIs, and Lhcb4, Lhcb5, and Lhcb6 encode minor LHCIIs [10]. In green algae, the genes encoding major LHCIIs are designated as Lhcbm ("m" for major) and have relatively low amino acid sequence similarity to A. thaliana Lhcb1 (AtLhcb1; "At" for A. thaliana, hereafter), AtLhcb2, and AtLhcb3 [11,12].…”