Control of gibberellin metabolism and signaling during floral transition

Abstract

In angiosperms, the transition from vegetative to reproductive stage is a critical event for reproductive success and is tightly regulated by both environmental and endogenous signals. In the model plant Arabidopsis thaliana, flowering is strongly induced in response to long photoperiods (LDs), a characteristic seasonal cue for spring and summer. This photoperiodic floral induction is mediated by the function of FLOWERING LOCUS T (FT), a “florigen”, which is synthesized in the leaf vasculature and transported to the shoot apical meristem (SAM). On the other hand, the onset of flowering under short-day conditions (SDs) is severely delayed and occurs through a default pathway that absolutely requires the phytohormone gibberellin (GA). Although the exogenous application of GA accelerates flowering, it is still unclear how GA biosynthesis, catabolism and signaling contribute to flowering in many plant species. In this review, I summarize the recent progress in our understanding of GA signaling and discuss its possible link to the floral transition.