Plant Physiol, April 2003, Vol. 131, pp. 1628-1637
Glucosylglycerol, a Compatible Solute, Sustains Cell Division
under Salt Stress1
Ali
Ferjani,
Laszlo
Mustardy,
Ronan
Sulpice,
Kay
Marin,
Iwane
Suzuki,
Martin
Hagemann, and
Norio
Murata*
Department of Regulation Biology, National Institute for Basic
Biology, Okazaki 444-8585, Japan (A.F., L.M., R.S., I.S., N.M.);
Department of Molecular Biomechanics, School of Life Science, The
Graduate School for Advanced Studies, Okazaki 444-8585, Japan (A.F.,
I.S., N.M.); Biological Research Center of the Hungarian Academy of
Sciences, Szeged, Hungary (L.M.); and Universität Rostock, FB
Biowissenschaften, Pflanzenphysiologie, Albert Einsteinstrasse 3a,
18051 Rostock, Germany (K.M., M.H.).
The cyanobacterium Synechocystis sp. PCC 6803 accumulates the compatible solute glucosylglycerol (GG) and sucrose
under salt stress. Although the molecular mechanisms for GG synthesis
including regulation of the GG-phosphate synthase (ggpS)
gene, which encodes GgpS, has been intensively investigated, the role
of GG in protection against salt stress remains poorly understood. In
our study of the role of GG in the tolerance to salt stress, we found
that salt stress due to 450 mM NaCl inhibited cell division
and significantly increased cell size in 
ggpS mutant
cells, whereas the inhibition of cell division and increase in cell
size were observed in wild-type cells at high concentrations of NaCl,
such as 800 mM. Electron microscopy revealed that, in
ggpS cells, separation of daughter cells was
incomplete, and aborted division could be recognized by the presence of
a structure that resembled a division ring. The addition of GG to the
culture medium protected ggpS cells against salt
stress and reversed the adverse effects of NaCl on cell division and
cell size. These observations suggest that GG is important for salt
tolerance and thus for the proper division of cells under salt stress conditions.
1
This work was supported in part by the Ministry
of Education, Science and Culture, Japan (Grants-in-Aid for Scientific
Research [S] nos. 13854002 to N.M. and I.S. and for Scientific
Research on Priority Area no. 14086207 to N.M.) and by the Cooperative Research Program of the National Institute for Basic Biology on the
Stress Tolerance of Plants. R.S. was the recipient of a postdoctoral fellowship for foreign researchers from the Japanese Society for the
Promotion of Science (no. P-01108).
*
Corresponding author; e-mail murata{at}nibb.ac.jp; fax
81-564-54-4866.
© 2003 American Society of Plant Biologists
