title: Dispensability of a sulfolipid for photoautotrophic cell growth and photosynthesis in a marine cyanobacterium, Synechococcus sp. PCC 7002.
abstract: Sulfoquinovosyl diacylglycerol, which mainly comprises thylakoid membranes in oxygenic photosynthetic organisms, plays species-dependent roles in freshwater microbes. In this study, a sulfoquinovosyl-diacylglycerol deficient mutant was generated in a cyanobacterium, Synechococcus sp. PCC 7002, for the first time among marine microbes to gain more insight into its physiological significance. The mutation had little deleterious impact on photoautotrophic cell growth, and functional and structural properties of the photosystem II complex. These findings were similar to previous observations for a freshwater cyanobacterium, Synechococcus elongatus PCC 7942, but were distinct from those for another freshwater cyanobacterium, Synechocystis sp. PCC 6803, and a green alga, Chlamydomonas reinhardtii, both of which require sulfoquinovosyl diacylglycerol for cell growth and/or photosystem II. Therefore, the functionality of PSII to dispense with sulfoquinovosyl diacylglycerol in Synechococcus sp. PCC 7002, similar to that in Synechococcus elongatus PCC 7942, seemed to have been excluded from the evolution of the PSII complex from cyanobacteria to green algal chloroplasts. Meanwhile, sulfoquinovosyl diacylglycerol was found to contribute to photoheterotrophic growth of Synechococcus sp. PCC 7002, which revealed a novel species-dependent strategy for utilizing SQDG in physiological processes.
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi, Hachioji, Tokyo 192-0392, Japan; JST, Chiyoda-ku, Tokyo 102-0075, Japan. Electronic address: nsato@ls.toyaku.ac.jp.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sato
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Kamimura
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi, Hachioji, Tokyo 192-0392, Japan; JST, Chiyoda-ku, Tokyo 102-0075, Japan.
authors.forename: Mikio
authors.initials: M
authors.lastname: Tsuzuki
mesh_terms: D059001:Aquatic Organisms; D052818:Autotrophic Processes / Q000502:physiology* / Q000528:radiation effects; D049109:Cell Proliferation / Q000502:physiology* / Q000528:radiation effects; D005964:Glucosyltransferases / Q000378:metabolism; D006017:Glycolipids / Q000378:metabolism*; D008027:Light; D008055:Lipids / Q000502:physiology; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D013045:Species Specificity; D046940:Synechococcus / Q000145:classification / Q000502:physiology* / Q000528:radiation effects*
chemical_list: D006017:Glycolipids; D008055:Lipids; C015518:sulfolipids; C013694:sulfoquinovosyl diglyceride; D005964:Glucosyltransferases; C492484:UDP-sulfoquinovose synthase, Chlamydomonas reinhardtii
keywords: Photoautotrophic growth; Photoheterotrophic growth; Photosystem II; Sulfoquinovosyl diacylglycerol; Synechococcus sp. PCC 7002