An unexpected plethora of trehalose biosynthesis genes in Arabidopsis thaliana

Trehalose accumulation has been documented in many organisms, such as bacte ria and fungi, where it serves a storage and stress-protection role. Althou gh conspicuously absent in most plants, trehalose biosynthesis genes were d iscovered recently in higher plants. We have uncovered a family of 11 TPS g enes in Arabidopsis thaliana, one of which encodes a trehalose-6-phosphate (Tre6P) synthase, and a subfamily of which might encode the still elusive T re6P phosphatases. A regulatory role in carbon metabolism is likely but mig ht not be restricted to the TPS control of hexokinase activity as documente d for yeast. Incompatibility between high trehalose levels and chaperone-as sisted protein folding might be a reason why plants have evolved to accumul ate some alternative stress-protection compounds to trehalose.