Fructose 2,6-bisphosphate and plant carbohydrate metabolism.

The control of the fructose 2,6-bisphosphate (Fru2,6P(2)) concentration and its possible role in controlling carbohydrate synthesis and degradation are discussed. This regulator metabolite is involved in the fine tuning of photosynthetic metabolism, and in controlling photosynthetic partitioning, and may also be involved in the response to hormones, wounding, and changing water relations. Study of the mechanisms controlling Fru2,6P(2) concentrations could reveal insights into how these responses are mediated. However, the detailed action of Fru2,6P(2) requires more attention, especially in respiratory metabolism where the background information about the compartmentation of metabolism between the plastid and cytosol is still inadequate, and the potential role of pyrophosphate has to be clarified.