Slr1670 from Synechocystis sp. PCC 6803 Is Required for the Re-assimilation of the Osmolyte Glucosylglycerol.
When subjected to mild salt stress, the cyanobacterium Synechocystis sp. PCC 6803 produces small amounts of glycerol through an as of yet unidentified pathway. Here, we show that this glycerol is a degradation product of the main osmolyte of this organism, glucosylglycerol (GG). Inactivation of ggpS, encoding the first step of GG-synthesis, abolished de novo synthesis of glycerol, while the ability to hydrolyze exogenously supplied glucoslylglycerol was unimpaired. Inactivation of glpK, encoding glycerol kinase, had no effect on glycerol synthesis. Inactivation of slr1670, encoding a GHL5-type putative glycoside hydrolase, abolished de novo synthesis of glycerol, as well as hydrolysis of GG, and led to increased intracellular concentrations of this osmolyte. Slr1670 therefore presumably displays GG hydrolase activity. A gene homologous to the one encoded by slr1670 occurs in a wide range of cyanobacteria, proteobacteria, and archaea. In cyanobacteria, it co-occurs with genes involved in GG-synthesis.
Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands.
Philipp
P
Savakis
Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology - Chinese Academy of Sciences Qingdao, China.
Xiaoming
X
Tan
Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology - Chinese Academy of Sciences Qingdao, China.
Cuncun
C
Qiao
Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology - Chinese Academy of Sciences Qingdao, China.
Kuo
K
Song
Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology - Chinese Academy of Sciences Qingdao, China.
Xuefeng
X
Lu
Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands.
Klaas J
KJ
Hellingwerf
Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands.
Filipe
F
Branco Dos Santos
Slr1670; Synechocystis; cyanobacteria; glucosylglycerol; osmolyte; salt stress