Sucrose may play an additional role to that of an osmolyte in Synechocystis sp. PCC 6803 salt-shocked cells.
The role of sucrose in cyanobacteria is still not fully understood. It is generally considered a salt-response molecule, and particularly, in Synechocystis sp. strain PCC 6803, it is referred as a secondary osmolyte. We showed that sucrose accumulates transiently in Synechocystis cells at early stages of a salt shock, which could be ascribed to salt activation of sucrose-phosphate synthase (SPS, UDP-glucose: D-fructose-6-phosphate 2-alpha-D-glucosyltransferase; EC 2.4.1.14), the key enzyme in sucrose synthesis pathway, and to an increase of the expression of the SPS encoding gene. Experiments with a mutant strain impaired in sucrose biosynthesis showed that sucrose is essential in stationary phase cells to overcome a later salt stress. Taken together, these results led us to suggest a more intricate function for sucrose than to be an osmoprotectant compound.
Desplats
Paula
P
Centro de Investigaciones Biológicas, Fundación para Investigaciones Biológicas Aplicadas, Vieytes 3103, C.C. 1348, 7600 Mar del Plata, Argentina.
Folco
Eduardo
E
Salerno
Graciela L
GL
D005964:Glucosyltransferases / Q000378:metabolism; D009997:Osmotic Pressure; D012965:Sodium Chloride; D013395:Sucrose / Q000378:metabolism* / Q000494:pharmacology; D046939:Synechocystis / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*
D012965:Sodium Chloride; D013395:Sucrose; D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase