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

Plant Physiol Biochem

Centro de Investigaciones Biológicas, Fundación para Investigaciones Biológicas Aplicadas, Vieytes 3103, C.C. 1348, 7600 Mar del Plata, Argentina.

Published: February 2005

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.

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http://dx.doi.org/10.1016/j.plaphy.2005.01.008DOI Listing

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