GIGANTEA Enables Drought Escape Response via Abscisic Acid-Dependent Activation of the Florigens and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1
GIGANTEA Enables Drought Escape Response via Abscisic Acid-Dependent Activation of the Florigens and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1
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DOI：
10.1104/pp.113.217729
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发表时间：
2013-07-01
期刊：
影响因子：
7.4
通讯作者：
Conti, Lucio
中科院分区：
文献类型：
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作者：
Riboni, Matteo;Galbiati, Massimo;Conti, Lucio
开花转变的调节在植物对干旱的适应中起着重要的作用。干旱逃逸（DE）反应允许植物适应性地缩短生命周期，以便在严重胁迫导致死亡之前产生种子。然而，DE反应的分子基础是未知的。在DE-触发条件下筛选不同的拟南芥（Arabidopsis thaliana）开花时间突变体揭示了促花基因GIGANTEA（GI）和成花基因FLOWANGLOCUS T（FT）和FT的双姐妹（TSF）在DE响应中的中心作用。进一步的筛选表明，植物激素脱落酸是DE反应所必需的，在长日照条件下积极调节开花。干旱胁迫以脱落酸和光周期依赖的方式促进成花因子的转录上调，因此仅在长日照下才发生早期开花。沿着成花素，成花整合素CONSTANS 1过表达的辅助因子也以类似的方式上调，并促进TSF的激活。DE反应恢复短天在没有花抑制短营养期或GI-过表达植物。我们的数据揭示了GI在连接光周期线索和环境压力中的关键作用，独立于中央FT/TSF激活剂CONSTANS。这一机制解释了环境因素如何以光周期控制的方式作用于成花素基因，从而使塑料开花反应成为可能。
Modulation of the transition to flowering plays an important role in the adaptation to drought. The drought-escape (DE) response allows plants to adaptively shorten their life cycle to make seeds before severe stress leads to death. However, the molecular basis of the DE response is unknown. A screen of different Arabidopsis (Arabidopsis thaliana) flowering time mutants under DE-triggering conditions revealed the central role of the flower-promoting gene GIGANTEA (GI) and the florigen genes FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) in the DE response. Further screens showed that the phytohormone abscisic acid is required for the DE response, positively regulating flowering under long-day conditions. Drought stress promotes the transcriptional up-regulation of the florigens in an abscisic acid- and photoperiod-dependent manner, so that early flowering only occurs under long days. Along with the florigens, the floral integrator SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 is also up-regulated in a similar fashion and contributes to the activation of TSF. The DE response was recovered under short days in the absence of the floral repressor SHORT VEGETATIVE PHASE or in GI-overexpressing plants. Our data reveal a key role for GI in connecting photoperiodic cues and environmental stress independently from the central FT/TSF activator CONSTANS. This mechanism explains how environmental cues may act upon the florigen genes in a photoperiodically controlled manner, thus enabling plastic flowering responses.