LEAFY expression and flower initiation in Arabidopsis.
LEAFY expression and flower initiation in Arabidopsis.
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发表时间：
1997-10
期刊：
影响因子：
4.6
通讯作者：
Miguel A. Blázquez;Lara N. Soowal;Ilha Lee;Detlef Weigel
中科院分区：
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作者：
Miguel A. Blázquez;Lara N. Soowal;Ilha Lee;Detlef Weigel
在最初的营养阶段，拟南芥枝条分生组织在其侧面产生带有相关侧枝的叶子，而后期的生殖阶段的特征是形成花。 LEAFY 基因是从营养阶段过渡到生殖阶段的重要元素，因为 LEAFY 对于单朵花的形成来说既是必要的又是充分的。我们详细分析了LEAFY在植物生命周期中的表达情况，发现LEAFY在营养期广泛表达。在长日照条件下，拟南芥植物在发芽后很快就会开花，同时 LEAFY 的快速上调也与之平行。在短日照下，拟南芥植物比在长日照下开花晚几周，但 LEAFY 表达在开花开始前逐渐增加。使用可在短日照下加速开花的植物激素赤霉素，增强了短日照下观察到的 LEAFY 表达的逐渐变化。向开花转变之前 LEAFY 表达的变化表明，这种转变的时间点至少部分受到生命周期给定时间普遍存在的 LEAFY 活性水平的控制。这一假设得到了以下发现的证实：增加内源性 LEAFY 的拷贝数会减少第一朵花形成之前产生的叶子数量。因此，LEAFY 结合了开花时间和花分生组织识别基因的特性，表明 LEAFY 是花诱导的全局过程和与单花起始相关的区域事件之间的直接联系。
During the initial vegetative phase, the Arabidopsis shoot meristem produces leaves with associated lateral shoots at its flanks, while the later reproductive phase is characterized by the formation of flowers. The LEAFY gene is an important element of the transition from the vegetative to the reproductive phase, as LEAFY is both necessary and sufficient for the initiation of individual flowers. We have analyzed in detail the expression of LEAFY during the plant life cycle, and found that LEAFY is extensively expressed during the vegetative phase. In long days, Arabidopsis plants flower soon after germination, and this is paralleled by rapid upregulation of LEAFY. In short days, Arabidopsis plants flower several weeks later than in long days, but LEAFY expression increases gradually before flowering commences. Application of the plant hormone gibberellin, which hastens flowering in short days, enhances the gradual change in LEAFY expression observed in short days. Changes in LEAFY expression before the transition to flowering suggest that the time point of this transition is at least partly controlled by the levels of LEAFY activity that are prevalent at a given time of the life cycle. This assumption is borne out by the finding that increasing the copy number of endogenous LEAFY reduces the number of leaves produced before the first flower is formed. Thus, LEAFY combines properties of flowering-time and flower-meristem-identity genes, indicating that LEAFY is a direct link between the global process of floral induction and the regional events associated with the initiation of individual flowers.