T6P

Trehalose-6-phosphate (T6P) is a phosphorylated glucose derivative that serves as an intermediate in the biosynthesis of trehalose and, in many organisms, as a regulatory signaling molecule. It is produced by trehalose-6-phosphate synthase (TPS) from UDP-glucose and glucose-6-phosphate and is subsequently dephosphorylated by trehalose-6-phosphate phosphatase (TPP) to trehalose. In many bacteria, fungi, and plants, the same core enzymes drive the trehalose biosynthetic pathway, although some organisms use additional or bifunctional enzymes.

In plants, T6P is recognized as a key signal of carbon status rather than merely an intermediate metabolite. Its levels correlate with sucrose availability and influence carbon allocation, growth, and development. A central aspect of T6P biology is its interaction with the SnRK1 kinase pathway, a major energy-sensing system: high T6P levels inhibit SnRK1 activity, promoting biosynthetic processes and growth when carbon supply is ample. Through this signaling relationship, T6P affects processes such as starch production in leaves, sucrose transport to sink tissues, seed filling, flowering time, and responses to environmental stress.

Beyond plants, the role of T6P varies by organism but is generally linked to trehalose metabolism and stress adaptation. In microbial systems, trehalose metabolism contributes to osmotolerance and energy balance, with T6P participating in the regulation of carbon flux in some contexts.

Overall, T6P is studied as a crucial metabolite that links carbohydrate status to growth, development, and stress responses, with ongoing research aimed at leveraging its signaling properties for crop improvement and metabolic engineering.