Regulates plant architecture, shape of epidermal pavement cells and branching of trichomes. D-glucose 6-phosphate + UDP-alpha-D-glucose = alpha,alpha-trehalose 6-phosphate + H(+) + UDP Binds to the phosphopeptide-binding site of GRF/14-3-3. Expressed in seedlings, leaves, stems, flowers, siliques and roots. Phosphorylated. In the N-terminal section; belongs to the glycosyltransferase 20 family. In the C-terminal section; belongs to the trehalose phosphatase family.