Regulation of Flowering by Trehalose-6-Phosphate Signaling in Arabidopsis thaliana

Sweet Enough to Flower In making the developmental switch from vegetative growth to flowering, plants integrate diverse information, including photoperiod, hormone signals, and carbohydrate status. Wahl et al. (p. 704 ; see the Perspective by Danielson and Frommer ) analyzed the physiology of the signaling sugar trehalose-6-phosphate (T6P) in Arabidopsis . Quantities of T6P cycle in daily rhythms that peak toward the end of the day. T6P levels in the shoot apical meristem mirrored sucrose levels. Disruption of T6P production also disrupted expression of the FLOWERING LOCUS T gene, which responds in leaves to day length and generates signals that direct the meristem to initiate flowering programs. T6P production also affected the signaling pathway that links the age of the plant to flowering. By incorporating requirements for T6P signaling in the flowering induction pathways, the plant ensures that adequate carbohydrate reserves have been accumulated. Thus, T6P regulates the shift to flowering by linking carbohydrate status to day length in the leaves and to developmental age in the shoot apical meristem.