Shedding light on integrative GA signaling

Gibberellic acid (GA) regulates a diversity of processes associated with plant growth and development. The DELLA proteins act as repressors of GA signaling, and are destabilized by GA. Although it is known that GA signaling integrates various endogenous and environmental signals, the molecular basis of their modulation of plant growth and development is only now beginning to be understood. The current suggestion is that the DELLA proteins act as one possible quantitative modulator of plant growth, achieved by integrating multiple environmental and hormonal signals via protein–protein interactions. This review discusses recent elaborations of the de-repression model proposed to describe the GA response, and focuses on integrative networks thought to regulate plant growth, development and the adaptation to a fluctuating environment.