The DELLA-CONSTANS Transcription Factor Cascade Integrates Gibberellic Acid and Photoperiod Signaling to Regulate Flowering
The DELLA-CONSTANS Transcription Factor Cascade Integrates Gibberellic Acid and Photoperiod Signaling to Regulate Flowering
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DELLA-CONSTANS 转录因子级联整合赤霉酸和光周期信号来调节开花
DOI：
10.1104/pp.16.00891
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发表时间：
2016-09-01
期刊：
影响因子：
7.4
通讯作者：
Yu, Diqiu
中科院分区：
文献类型：
--
作者：
Wang, Houping;Pan, Jinjing;Yu, Diqiu
赤霉素（GA）和光周期途径最近被证明是协同调节开花下长日照（LD）。然而，这种合作背后的分子机制在很大程度上仍不清楚。在这项研究中，我们发现，GA诱导的表达FLOWERLOCUS T（FT）下LD依赖于CONSTANS（CO），一个关键的转录因子积极参与光周期信号。机制研究表明，DELLA蛋白是GA信号传导中的一组重要阻遏蛋白，它与CO发生物理相互作用，DELLA与CO的相互作用抑制了CO蛋白的转录功能。遗传分析表明，CO作用于DELLA蛋白的下游以调节开花。CO的破坏拯救了gai-t6 rga-t2 rgl 1 -1 rgl 2 -1突变体（dellap）的早期开花表型，而GA不敏感（GAI，DELLA基因的一员）的功能获得性突变抑制了CO过表达植物的早期开花表型。此外，DELLA蛋白和mRNA的积累是有节奏的，并且在长日照的下午，CO蛋白丰富的时间，GA 1 -3蛋白的恢复显著减少。总的来说，这些结果表明，DELLA-CO级联抑制CO/FT介导的开花下LD，从而提供证据，直接整合GA和光周期信号，协同调节开花下LD。
Gibberellin (GA) and photoperiod pathways have recently been demonstrated to collaboratively modulate flowering under long days (LDs). However, the molecular mechanisms underlying this collaboration remain largely unclear. In this study, we found that GA-induced expression of FLOWERING LOCUS T (FT) under LDs was dependent on CONSTANS (CO), a critical transcription factor positively involved in photoperiod signaling. Mechanistic investigation revealed that DELLA proteins, a group of crucial repressors in GA signaling, physically interacted with CO. The DELLA-CO interactions repressed the transcriptional function of CO protein. Genetic analysis demonstrated that CO acts downstream of DELLA proteins to regulate flowering. Disruption of CO rescued the earlier flowering phenotype of the gai-t6 rga-t2 rgl1-1 rgl2-1 mutant (dellap), while a gain-of-function mutation in GA INSENSITIVE (GAI, a member of the DELLA gene) repressed the earlier flowering phenotype of CO-overexpressing plants. In addition, the accumulation of DELLA proteins and mRNAs was rhythmic, and REPRESSOR OF GA1-3 protein was noticeably decreased in the long-day afternoon, a time when CO protein is abundant. Collectively, these results demonstrate that the DELLA-CO cascade inhibits CO/FT-mediated flowering under LDs, which thus provide evidence to directly integrate GA and photoperiod signaling to synergistically modulate flowering under LDs.