title: Characterization of Chlamydomonas reinhardtii phosphatidylglycerophosphate synthase in Synechocystis sp. PCC 6803.
abstract: Phosphatidylglycerol (PG) is an indispensable phospholipid class with photosynthetic function in plants and cyanobacteria. However, its biosynthesis in eukaryotic green microalgae is poorly studied. Here, we report the isolation and characterization of two homologs (CrPGP1 and CrPGP2) of phosphatidylglycerophosphate synthase (PGPS), the rate-limiting enzyme in PG biosynthesis, in Chlamydomonas reinhardtii. Heterologous complementation of Synechocystis sp. PCC 6803 pgsA mutant by CrPGP1 and CrPGP2 rescued the PG-dependent growth phenotype, but the PG level and its fatty acid composition were not fully rescued in the complemented strains. As well, oxygen evolution activity was not fully recovered, although electron transport activity of photosystem II was restored to the wild-type level. Gene expression study of CrPGP1 and CrPGP2 in nutrient-starved C. reinhardtii showed differential response to phosphorus and nitrogen deficiency. Taken together, these results highlight the distinct and overlapping function of PGPS in cyanobacteria and eukaryotic algae.
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica Taipei, Taiwan.
authors.forename: Chun-Hsien
authors.initials: CH
authors.lastname: Hung
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan.
authors.forename: Kaichiro
authors.initials: K
authors.lastname: Endo
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica Taipei, Taiwan ; PRESTO, Japan Science and Technology Agency Saitama, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan ; CREST, Japan Science and Technology Agency Saitama, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Wada
keywords: Chlamydomonas reinhardtii; chloroplast; glycerolipid; phosphatidylglycerol; photosynthesis