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Membrane lipid remodeling is required for photosystem II function under low CO 2
Author(s) -
Jimbo Haruhiko,
Izuhara Taichi,
Hirashima Takashi,
Endo Kaichiro,
Nakamura Yuki,
Wada Hajime
Publication year - 2021
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.15054
Subject(s) - phosphatidic acid , biochemistry , photosynthesis , synechocystis , photosystem , photosystem i , phosphatidylglycerol , glycolipid , diacylglycerol kinase , cyanobacteria , membrane lipids , galactolipid , phospholipid , membrane , chemistry , biology , lipid metabolism , chloroplast , microbiology and biotechnology , photosystem ii , bacteria , phosphorylation , gene , phosphatidylcholine , mutant , genetics , protein kinase c
Summary Membrane lipid remodeling in plants and microalgae has a crucial role in their survival under nutrient‐deficient conditions. Aquatic microalgae have low access to CO 2 , an essential carbon source for photosynthetic assimilates; however, 70–90 mol% of their membrane lipids are sugar‐derived lipids (glycolipids) such as monogalactosyldiacylglycerol (MGDG). In this study, we discovered a new system of membrane lipid remodeling responding to CO 2 in Synechocystis sp. PCC 6803, a unicellular, freshwater cyanobacterium. As compared with higher CO 2 (HC; 1% CO 2 ), under ambient air (lower CO 2 : LC), phosphatidylglycerol (PG) content was increased at the expense of MGDG content. To explore the biological significance of this alteration in content, we generated a transformant of Synechocystis sp. PCC 6803 overexpressing sll0545 gene encoding a putative phosphatidic acid phosphate (oxPAP), which produces diacylglycerol that is used for the synthesis of glycolipids, and examined the effect on membrane lipid remodeling and phototrophic growth responding to LC. Photosystem II (PSII) activity and growth rate were inhibited under LC in oxPAP cells. PG content was substantially reduced, and MGDG and sulfoquinovosyldiacylglycerol contents were increased in oxPAP cells as compared with control cells. These phenotypes in oxPAP cells were recovered under the HC condition or PG supplementation. Increased PG content may be required for proper functioning of PSII under LC conditions.