Purification of the trehalase GMTRE1 from soybean nodules and cloning of its cDNA. GMTRE1 is expressed at a low level in multiple tissues

Trehalose (alpha-D-glucopyranosyl-1,1-alpha-D-glucopyranoside), a disacchar ide widespread among microbes and lower invertebrates, is generally believe d to be nonexistent in higher plants. However, the recent discovery of Arab idopsis genes whose products are involved in trehalose synthesis has renewe d interest in the possibility of a function of trehalose in higher plants. We previously showed that trehalase, the enzyme that degrades trehalose, is present in nodules of soybean (Glycine max [L.] Merr.), and we characteriz ed the enzyme as an apoplastic glycoprotein. Here we describe the purificat ion of this trehalase to homogeneity and the cloning of a full-length cDNA encoding this enzyme, named GMTRE1 (G. max trehalase 1). The amino acid seq uence derived from the open reading frame of GMTRE1 shows strong homology t o known trehalases from bacteria, fungi, and animals. GMTRE1 is a single-co py gene and is expressed at a low but constant level in many tissues.