Sucrose may play an additional role to that of an osmolyte in Synechocystis sp. PCC 6803 salt-shocked cells

Plant Physiol Biochem. 2005 Feb;43(2):133-8. doi: 10.1016/j.plaphy.2005.01.008.


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, 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Glucosyltransferases / metabolism
  • Osmotic Pressure
  • Sodium Chloride
  • Sucrose / metabolism*
  • Sucrose / pharmacology
  • Synechocystis / drug effects
  • Synechocystis / enzymology
  • Synechocystis / metabolism*


  • Sodium Chloride
  • Sucrose
  • Glucosyltransferases
  • sucrose-phosphate synthase