title: Cyanobacterial monogalactosyldiacylglycerol-synthesis pathway is involved in normal unsaturation of galactolipids and low-temperature adaptation of Synechocystis sp. PCC 6803.
abstract: We characterized certain physiological functions of cyanobacterial monoglucosyldiacylglycerol using a Synechocystis sp. PCC 6803 mutant in which the gene for monoglucosyldiacylglycerol synthase had been disrupted and its function complemented by inclusion of an Arabidopsis monogalactosyldiacylglycerol synthase gene. By using this method, we prepared the first viable monoglucosyldiacylglycerol-deficient mutant of cyanobacterium and found that monoglucosyldiacylglycerol is not essential for its growth and photosynthesis under a set of "normal growth conditions" when monogalactosyldiacylglycerol is adequately supplied by the Arabidopsis monogalactosyldiacylglycerol synthase. The mutant had healthy thylakoid membranes and normal pigment content. The membrane lipid composition of the mutant was similar with that of WT except lack of monoglucosyldiacylglycerol and a slight increase in the level of phosphatidylglycerol at both normal and low temperatures. However, the ratio of unsaturated fatty acids in monogalactosyldiacylglycerol and digalactosyldiacylglycerol was reduced in the mutant compared with WT. Although the growth of the mutant was indistinguishable with that of WT at normal growth temperature, it was markedly retarded at low temperature compared with that of WT. Our data indicated the possibility that cyanobacterial monogalactosyldiacylglycerol-synthesis pathway might be required for the adequate unsaturation level of fatty acids in galactolipids and affect the low-temperature sensitivity.
authors.affiliation: Department of Biological Sciences, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yuzawa
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan. Electronic address: shimojima.m.aa@m.titech.ac.jp.
authors.forename: Mie
authors.initials: M
authors.lastname: Shimojima
authors.affiliation: Department of Biological Sciences, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Sato
authors.affiliation: Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Mizusawa
authors.affiliation: Biomaterial Analysis Center, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Biomaterial Analysis Center, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Mamie
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Iwai
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Hori
authors.affiliation: Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo 163-8902, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Wada
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan; Earth-Life Science Institute, Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Masuda
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan; Earth-Life Science Institute, Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohta
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D038983:Galactolipids / Q000096:biosynthesis / Q000378:metabolism*; D005700:Galactosyltransferases / Q000235:genetics* / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics; D009154:Mutation; D010788:Photosynthesis; D046939:Synechocystis / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D013696:Temperature
chemical_list: D038983:Galactolipids; C009909:monogalactosyldiacylglycerol; D005700:Galactosyltransferases; C109990:1,2-diacylglycerol 3-beta-galactosyltransferase
keywords: Galactolipid; Low temperature; Monogalactosyldiacylglycerol; Monoglucosyldiacylglycerol; Synechocystis sp. PCC 6803