Temperature-dependent control of flowering by the gibberellin pathway and interactions between DELLA proteins and APETALA1/VRN1 MADS-box factors.

温度是控制开花时间的重要环境信号。在拟南芥中，低温的经历延缓了生长和开花，在分子水平上，寒冷导致della蛋白的积累，这是赤霉素(GA)信号通路的主要植物生长和开花时间抑制因子。Della丰度对温度变化的反应相当迅速，Della积累的影响可以被GA(处理)抑制。我们先前已经证明，拟南芥MADS-box转录因子APETALA1(AP1)受到与Dellas的直接相互作用的抑制。此外，我们有证据表明，AP1表达的增加可能是导致两个拟南芥材料在低温下提前开花的原因。在这里，我们想要检验一种假设，即这些材料中AP1水平的提高超过了Dellas在寒冷条件下对生长的抑制效应。其次，我们想测试这个AP1-DELLA调控模块是否在谷类物种中保守。在大麦和小麦中，VERNALIZATION1(VRN1)蛋白是主要的开花时间调节蛋白，它与拟南芥AP1最接近。因此，我们想要研究大麦和小麦VRN1是否也可以与各自的Dellas相互作用，以及开花时间是否取决于这种相互作用对温度和GA的反应。

Temperature is an important environmental cue controlling flowering time. In Arabidopsis, the experience of cold temperatures delays growth and flowering and, at the molecular level, cold results in the accumulation of DELLA proteins, major plant growth and flowering time repressors of the gibberellin (GA) signalling pathway. DELLA abundance responds rather instantly to changes in the temperature and the effects of DELLA accumulation can be suppressed by GA (treatments). We have previously shown that the Arabidopsis MADS-box transcription factor APETALA1 (AP1) is repressed by direct interactions with DELLAs. Furthermore, we have evidence that increased AP1 expression may be causative for the early flowering of two Arabidopsis accessions in cold temperature. Here, we would like to test the hypothesis that increased AP1 levels in these accessions outcompete the growth repressive effects of DELLAs in the cold. Second, we would like to test whether this AP1-DELLA regulatory module is conserved in cereal species. In barley and wheat, VERNALIZATION1 (VRN1) proteins, the closest homologues to Arabidopsis AP1, are major flowering time regulators. We therefore would like to examine whether barley and wheat VRN1 can also interact with the respective DELLAs and whether flowering time control in response to temperature and GA is dependent on this interaction.