Trehalose 6-phosphate: a signal of sucrose status.

T6P (trehalose 6-phosphate), the precursor of trehalose, has come out of obscurity over 10 years to be appreciated as an important regulator of plant metabolism and development, quite possibly linking the two. This information has been gained from analysis of mutant and transgenic plants, which show strong, diverse and strategically important phenotypes. Plant genes that encode the trehalose pathway are numerous and highly regulated transcriptionally and post-translationally, responding sensitively to the environment in a developmentally programmed and tissue-specific manner further suggestive of a vital function. Yet the precise role of T6P has not been clear. In an article published in the Biochemical Journal in 2006, John Lunn and colleagues addressed a major obstacle to understanding the function of T6P through development of a method capable of resolving femtomolar quantities of T6P from very small amounts of tissue. Using this technology, the authors showed large changes in T6P content that reflect tissue sucrose status. Overall, this elegant work makes an important contribution towards our understanding of the function of T6P in plants.