Trehalose-6-phosphate synthase 1, which catalyses the first step in trehalose synthesis, is essential for Arabidopsis embryo maturation
Article first published online: 21 JAN 2002
The Plant Journal
Volume 29, Issue 2, pages 225–235, January 2002
How to Cite
Eastmond, P. J., Van Dijken, A. J. H., Spielman, M., Kerr, A., Tissier, A. F., Dickinson, H. G., Jones, J. D. G., Smeekens, S. C. and Graham, I. A. (2002), Trehalose-6-phosphate synthase 1, which catalyses the first step in trehalose synthesis, is essential for Arabidopsis embryo maturation. The Plant Journal, 29: 225–235. doi: 10.1046/j.1365-313x.2002.01220.x
- Issue published online: 21 JAN 2002
- Article first published online: 21 JAN 2002
- Received 9 August 2001; revised 18 October 2001; accepted 31 October 2001.
- Trehalose-6-phosphate synthase;
- embryo maturation
Despite the recent discovery that trehalose synthesis is widespread in higher plants very little is known about its physiological significance. Here we report on an Arabidopsis mutant (tps1), disrupted in a gene encoding the first enzyme of trehalose biosynthesis (trehalose-6-phosphate synthase). The tps1 mutant is a recessive embryo lethal. Embryo morphogenesis is normal but development is retarded and stalls early in the phase of cell expansion and storage reserve accumulation. TPS1 is transiently up-regulated at this same developmental stage and is required for the full expression of seed maturation marker genes (2S2 and OLEOSN2). Sucrose levels also increase rapidly in seeds during the onset of cell expansion. In Saccharomyces cerevisiae trehalose-6-phosphate (T-6-P) is required to regulate sugar influx into glycolysis via the inhibition of hexokinase and a deficiency in TPS1 prevents growth on sugars (Thevelein and Hohmann, 1995). The growth of Arabidopsis tps1–1 embryos can be partially rescued in vitro by reducing the sucrose level. However, T-6-P is not an inhibitor of AtHXK1 or AtHXK2. Nor does reducing hexokinase activity rescue tps1–1 embryo growth. Our data establish for the first time that an enzyme of trehalose metabolism is essential in plants and is implicated in the regulation of sugar metabolism/embryo development via a different mechanism to that reported in S. cerevisiae.