Gibberellins modulate multiple aspects of plant behavior. The molecular mechanism by which these hormones are perceived and how this information is translated into transcriptional changes has been elucidated in vascular plants: gibberellins are perceived by the nuclear receptor GID1, which then interacts with the DELLA nuclear proteins and promote their degradation, resulting in the modification of the activity of transcription factors with which DELLAs interact physically. However, several important questions are still pending: how does a single molecule perform such a vast array of functions along plant development? What property do gibberellins add to plant behavior? A closer look at gibberellin action from an evolutionary perspective can help answer these questions. DELLA proteins are conserved in all land plants, and predate the emergence of a full gibberellin metabolic pathway and the GID1 receptor in the ancestor of vascular plants. The origin of gibberellin signaling is linked to the exaptation by GID1 of the N-terminal domain in DELLA, which already acted as a transcriptional coactivator domain in the ancestral DELLA proteins. At least the ability to control plant growth seems to be encoded already in the ancestral DELLA protein too, suggesting that gibberellins’ functional diversity is the direct consequence of DELLA protein activity. Finally, comparative network analysis suggests that gibberellin signaling increases the coordination of transcriptional responses, providing a theoretical framework for the role of gibberellins in plant adaptation at the evolutionary scale, which further needs experimental testing.

赤霉素调节植物行为的多个方面。在维管植物中已经阐明了感知这些激素的分子机制以及这些信息如何转化为转录变化：赤霉素被核受体 GID1 感知，然后与 DELLA 核蛋白相互作用并促进它们的降解，导致DELLA 与其物理相互作用的转录因子活性的改变。然而，几个重要的问题仍然悬而未决：单个分子如何在植物发育过程中发挥如此广泛的功能？赤霉素对植物行为有何影响？从进化的角度仔细观察赤霉素的作用可以帮助回答这些问题。DELLA 蛋白在所有陆地植物中都是保守的，并且早于维管植物祖先中完整的赤霉素代谢途径和 GID1 受体的出现。赤霉素信号传导的起源与 DELLA 中 N 端结构域的 GID1 的扩展有关，DELLA 已经作为祖先 DELLA 蛋白中的转录共激活因子域。至少控制植物生长的能力似乎也已经在祖先的 DELLA 蛋白中编码，这表明赤霉素的功能多样性是 DELLA 蛋白活性的直接结果。最后，比较网络分析表明，赤霉素信号传导增加了转录反应的协调，为赤霉素在进化尺度上的植物适应中的作用提供了理论框架，这还需要进一步的实验测试。