PLANT PHYSIOLOGY , Vol 105, Issue 1 127-132, Copyright © 1994 by American Society of Plant Biologists
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MOLECULAR BIOLOGY AND GENE REGULATION |
Ethylene-Induced Increase in Glutamine Synthetase Activity and mRNA Levels in Hevea brasiliensis Latex Cells
V. Pujade-Renaud, A. Clement, C. Perrot-Rechenmann, J. C. Prevot, H. Chrestin, J. L. Jacob and J. Guern
Institut des Sciences Vegetales, Centre National de la Recherche Scientifique, bat 22, Avenue de la Terrasse, 91198 Gif-sur-Yvette, Cedex France (V.P.-R., C.P.-R., H.C., J.G.)
Ethylene, used as a stimulant of latex production in Hevea brasiliensis,
significantly activates the regenerating metabolism within the laticiferous
cells. In this context, attention was focused on glutamine synthetase (GS;
EC 6.3.1.2), a key enzyme in nitrogen metabolism. A specific and
significant activation of the cytosolic glutamine synthetase (GScyt) in the
laticiferous cells after ethylene treatment parallels the increase of latex
yield. A marked accumulation of the corresponding mRNA was found, but in
contrast, a slight and variable increase of the polypeptide level is at the
limit of detection by western blotting. The GS response to ethylene might
be mediated by ammonia that increases in latex cytosol following ethylene
treatment. The physiological significance for such a regulation by ethylene
of the GScyt is discussed in terms of the nitrogen requirement for protein
synthesis associated with latex regeneration.
