Isolation of trehalose-6-phosphate phosphatase gene from tobacco and its functional analysis in yeast cells.

Trehalose is a nonreducing disaccharide composed of two glucose units joined by an alpha, alpha-1, 1 linkage, and has been found in bacteria, yeast, fungi, invertebrates and plants. Accumulation of trehalose in organisms plays a role in enhancing the stress tolerance. A trehalose-6-phosphate phosphatase gene, NtTPPL, was isolated from tobacco in this report. The predicted NtTPPL protein has a putative trehalose_PPase domain. The transcription of the NtTPPL gene was significantly induced by heat stress, and was only slightly induced by NaCl, PEG and low-temperature treatments. When expressing in yeast tps2 mutant, NtTPPL rescued the mutant phenotype under high temperature. This result indicated that NtTPPL functioned as a trehalose-6-phosphate phosphatase in yeast and may play similar roles in plants.