FIG 3.
Trehalose biosynthesis pathways in fungi. (A) The Tps1/Tps2 (TPS/TPP) pathway consists of two main enzymes: trehalose-6-phosphate synthase (Tps1) and trehalose-6-phosphate phosphatase (Tps2). (B) The alternative trehalose phosphorylase pathway (TreP) consists of a trehalose phosphorylase enzyme that reversibly converts glucose and glucose-1-phosphate (G1P) into trehalose and inorganic phosphate (Pi). (C) The TreY/TreZ pathway consists of a maltooligosyl trehalose synthase enzyme (TreY) and a maltooligosyl trehalose trehalohydrolase (TreZ). TreY converts maltooligosaccharides, glycogen, and starch (maltodextrins) into maltooligosyl trehalose, and TreZ releases trehalose from maltooligosyl trehalose. (D) Trehalose synthase (TreS) changes maltose directly into trehalose. (E) ADP-glucose and glucose are reversibly converted into trehalose by trehalose glycosyl-transferring synthase (TreT).