PARENT SESSION

Symposium S4B Sugar signalling: Photosynthesis, hormones and development
Tuesday August 31st, 2004 2:40 PM-4:40 PM Room 210A
Chair: Dan Bush
Co-Chair: Mathew Paul

Trehalose-6-phosphate in Arabidopsis. Henriette Schluepmann^*,1, Anja van Dijken¹, Till Pelny², Mahnaz Aghdasi¹, Matthew Paul², Sjef Smeekens¹, ¹ Molecular Plant Physiology, Utrecht University, Utrecht, The Netherlands² Crop Performance and Improvement, IACR-Rothamstead, Harpenden, Herts, United Kingdom

ABSTRACT- Trehalose is the alpha-1,1-linked glucose disaccharide; it is found in microbes, lower animals, insects and plants. In some desiccation resistant plant species this sugar accumulates quantitatively and is thought to contribute to desiccation tolerance; but in Arabidopsis as in most other plants, it is only present in near detection limit quantities. Arabidopsis contains 11 homologues with a trehalose-phosphate synthase domain, 18 homologues with trehalose phosphate phosphatase domains and only one gene encoding a trehalase. The Arabidopsis genome therefore reflects radiation in metabolism of the precursor, trehalose-6-phosphate (T6P), but no radiation in catabolism of trehalose suggestive of an important role for trehalose-6-phosphate in this plant. Attps1, trehalose-phosphate synthase 1 mutants are embryo-lethal and can be complemented by expression of the small single domain E.coli enzyme. Inducible complementation experiments further show that T6P synthesis is also required for root growth and transition to floral development. On medium supplemented with sugar, seedlings depleted in T6P are unable to grow, whilst seedlings accumulating T6P acquire more weight than wild type. T6P is therefore required for carbon utilization and this could underlie its important role in development. In addition, altering T6P levels in the plants alters leaf color and photosynthetic capacity per leaf area. It also alters resistance to abiotic and biotic stresses. We wonder what the target of T6P might be and have used genetic, metabolomic and transcriptomic approaches to gain new insights on this.

KEY WORDS: metabolism, trehalose, regulation, development