title: Loss of CpSRP54 function leads to a truncated light-harvesting antenna size in Chlamydomonas reinhardtii.
abstract: The Chlamydomonas reinhardtii truncated light-harvesting antenna 4 (tla4) DNA transposon mutant has a pale green phenotype, a lower chlorophyll (Chl) per cell and a higher Chl a/b ratio in comparison with the wild type. It required a higher light intensity for the saturation of photosynthesis and displayed a greater per chlorophyll light-saturated rate of oxygen evolution than the wild type. The Chl antenna size of the photosystems in the tla4 mutant was only about 65% of that measured in the wild type. Molecular genetic analysis revealed that a single plasmid DNA insertion disrupted two genes on chromosome 11 of the mutant. A complementation study identified the "chloroplast signal recognition particle 54" gene (CpSRP54), as the lesion causing the tla4 phenotype. Disruption of this gene resulted in partial failure to assemble and, therefore, lower levels of light-harvesting Chl-binding proteins in the C. reinhardtii thylakoids. A comparative in silico 3-D structure-modeling analysis revealed that the M-domain of the CpSRP54 of C. reinhardtii possesses a more extended finger loop structure, due to different amino acid composition, as compared to that of the Arabidopsis CpSRP54. The work demonstrated that CpSRP54 deletion in microalgae can serve to generate tla mutants with a markedly smaller photosystem Chl antenna size, improved solar energy conversion efficiency, and photosynthetic productivity in high-density cultures under bright sunlight conditions.
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Jooyeon
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Kwangryul
authors.initials: K
authors.lastname: Baek
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA.
authors.forename: Henning
authors.initials: H
authors.lastname: Kirst
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA. Electronic address: melis@berkeley.edu.
authors.forename: Anastasios
authors.initials: A
authors.lastname: Melis
authors.affiliation: Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 133-791, Republic of Korea. Electronic address: esjin@hanyang.ac.kr.
authors.forename: EonSeon
authors.initials: E
authors.lastname: Jin
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000235:genetics / Q000378:metabolism; D000077194:Chlorophyll A; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism; D004251:DNA Transposable Elements / Q000235:genetics; D061125:Genes, Chloroplast / Q000235:genetics; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000235:genetics / Q000378:metabolism*; D058086:Microalgae / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D018271:Signal Recognition Particle / Q000235:genetics / Q000378:metabolism; D020524:Thylakoids / Q000235:genetics / Q000378:metabolism
chemical_list: D000596:Amino Acids; D029681:Arabidopsis Proteins; D004251:DNA Transposable Elements; D045342:Light-Harvesting Protein Complexes; D018271:Signal Recognition Particle; D002734:Chlorophyll; C037184:chlorophyll b; D000077194:Chlorophyll A
keywords: Chlorophyll antenna size; CpSRP54; LHC assembly; Photosynthesis; Productivity; TLA technology