赤霉素调控植物生长发育和开花。虽对赤霉素信号传导途径的认识逐步深入，但对其关键元件DELLA 蛋白的功能以及赤霉素与生长素互作的分子机制的认识还非常有限。本项目通过筛选sgd 突变体（suppressor of gai gar2-1 dwarfism），并通过图位克隆技术克隆了SGD88 基因，证实了乙烯信号途径和DELLA蛋白间互作来调控植物生长。同时，我们发现DELLA蛋白能与生长素信号途径的重要元件：AUX/IAA蛋白直接互作，影响其受auxin介导的蛋白降解，进而抑制生长素运输的PIN蛋白的表达，导致生长素分布和信号传递的改变，进而影响生长素生理效应。反之， AUX/IAA蛋白与DELLA结合后也影响GA介导的DELLA蛋白降解，导致DELLA蛋白积累，进而影响赤霉素的生物学效应。

Gibberellins are one of the most important plant hormones, regulate the multiple developmental progress. Although the key components of GA signaling, such as DELLA proteins and GA receptor were identified, but the signal transduction pathway still remians unclear, in particular the mechanism how auxin and GA control the stability of DELLA protein. In this proposal, we isolated several sgd mutants（suppressor of gai gar2-1 dwarfism）by screening gai gar2-1 mutant, we iedntified the SGD88 genes by map-based cloning and analyze its function in GA signaling. we also show that DELLA proteins control auxin distribution and root meristem size in Arabidopsis. Furthermore, we showed that DELLA proteins directly interact with AUX/IAA proteins and delay auxin-mediated destabilization of AUX/IAA protein that negatively regulates the PIN auxin efflux facilitators. In turn, GA opposes this action through degradation of DELLA proteins and thus releases their negative effect on AUX/IAA proteins, consequently sustaining PIN activities and leading to diverse downstream effects. Our data reveal a molecular interaction network of auxin and gibberellin signaling that coordinately regulates plant organ growth.

赤霉素调控植物生长发育和开花。虽对赤霉素信号传导途径的认识逐步深入，但对其关键元件DELLA 蛋白的功能以及赤霉素与生长素互作的分子机制的认识还非常有限。本项目通过筛选sgd 突变体（suppressor of gai gar2-1 dwarfism），并通过图位克隆技术克隆了SGD88 基因，证实了乙烯信号途径和DELLA蛋白间互作来调控植物生长。同时，我们发现DELLA蛋白能与生长素信号途径的重要元件：AUX/IAA蛋白直接互作，影响其受auxin介导的蛋白降解，进而抑制生长素运输的PIN蛋白的表达，导致生长素分布和信号传递的改变，进而影响生长素生理效应。反之， AUX/IAA蛋白与DELLA结合后也影响GA介导的DELLA蛋白降解，导致DELLA蛋白积累，进而影响赤霉素的生物学效应。