Light and Ethylene Coordinately Regulate the Phosphate Starvation Response through Transcriptional Regulation of PHOSPHATE STARVATION RESPONSE1
Light and Ethylene Coordinately Regulate the Phosphate Starvation Response through Transcriptional Regulation of PHOSPHATE STARVATION RESPONSE1
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光和乙烯通过磷酸盐饥饿反应的转录调节协调调节磷酸盐饥饿反应1
DOI：
10.1105/tpc.17.00268
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发表时间：
2017-09-01
期刊：
影响因子：
11.6
通讯作者：
Wang, Haiyang
中科院分区：
文献类型：
--
作者：
Liu, Yang;Xie, Yurong;Wang, Haiyang
植物针对低磷有效性已经进化出一系列适应性反应，这一过程受各种外部刺激和内源性生长调节信号的调控。然而，对于这些信号传导过程如何相互作用以产生综合反应，我们知之甚少。拟南芥中的磷酸盐饥饿响应1（PHR1）编码一种保守的MYB型转录因子，该因子对于调控磷饥饿诱导的基因表达以及下游的磷饥饿响应（PSR）至关重要。在此，我们发现，编码光敏色素信号传导的两个正调控因子的FHY3和FAR1，以及编码乙烯响应主调控因子的EIN3发生功能丧失突变时，会导致PHR1表达减弱；而编码光信号传导另一个正调控因子的HY5发生突变，则会使PHR1表达增加。FHY3、FAR1、HY5和EIN3通过不同的顺式作用元件直接结合到PHR1启动子上。FHY3、FAR1和EIN3激活PHR1表达，而HY5则抑制其表达。FHY3与EIN3直接相互作用，HY5抑制FHY3和EIN3对PHR1的转录激活活性。最后，光和乙烯均促进FHY3蛋白积累，且乙烯会阻断光促进的HY5蛋白稳定。我们的研究结果表明，光和乙烯通过在PHR1启动子处的信号汇聚，协同调控PHR1表达和磷饥饿响应。
Several transcription factors interact with each other and bind directly to the PHOSPHATE STARVATION RESPONSE1 promoter to coordinately regulate its expression in response to light and ethylene. Plants have evolved an array of adaptive responses to low Pi availability, a process modulated by various external stimuli and endogenous growth regulatory signals. Little is known about how these signaling processes interact to produce an integrated response. Arabidopsis thaliana PHOSPHATE STARVATION RESPONSE1 (PHR1) encodes a conserved MYB-type transcription factor that is essential for programming Pi starvation-induced gene expression and downstream Pi starvation responses (PSRs). Here, we show that loss-of-function mutations in FHY3 and FAR1, encoding two positive regulators of phytochrome signaling, and in EIN3, encoding a master regulator of ethylene responses, cause attenuated PHR1 expression, whereas mutation in HY5, encoding another positive regulator of light signaling, causes increased PHR1 expression. FHY3, FAR1, HY5, and EIN3 directly bind to the PHR1 promoter through distinct cis-elements. FHY3, FAR1, and EIN3 activate, while HY5 represses, PHR1 expression. FHY3 directly interacts with EIN3, and HY5 suppresses the transcriptional activation activity of FHY3 and EIN3 on PHR1. Finally, both light and ethylene promote FHY3 protein accumulation, and ethylene blocks the light-promoted stabilization of HY5. Our results suggest that light and ethylene coordinately regulate PHR1 expression and PSRs through signaling convergence at the PHR1 promoter.