Regulation of seedling de-etiolation by light

光对幼苗脱黄的调控

• 批准号: 0418653
• 负责人: Enamul Huq
• 金额: --
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0418653&HistoricalAwards=false
• 关键词: Regulation; seedling; de; etiolation; light

PROJECT SUMMARYIntellectual Merits: The phytochrome (phy) family of sensory photoreceptors in Arabidopsis consists of five members (phyA to phyE) that control many developmental responses to the ambient light environment. Significant progress has been made on characterization of photosensory and biochemical functions and in the identification and functional characterization of signaling intermediates. However, the biochemical mechanism of phy signaling is still not clear. To examine early phy signaling events, phy interacting factors such as PIF1 have been isolated and characterized. PIF1 is a basic helix-loop-helix (bHLH) transcription factor that interacts strongly with the biologically active form of phyA and phyB, as well as another bHLH factor, PIF3. PIF1 binds to a G-box (CACGTG) DNA sequence motif commonly found in many light regulated promoters. PIF1 has also been shown to activate transcription in a transient assay, and the transcriptional activation activity was downregulated by far-red and red light in a phyA- and phyB-dependent manner, respectively. PIF1 overexpressors and pif1 T-DNA insertional mutants showed defective seedling de-etiolation, including aberrant hypocotyl elongation and developmentally regulated loss of greening. These results suggest that PIF1 is a key regulator of the phy-mediated control of the seedling de-etiolation process. The proposed study will investigate the molecular mechanism by which PIF1 controls seedling de-etiolation using molecular genetic, biochemical and functional genomic approaches. Specifically, the PIF1 target genes will be identified and functionally characterized, and the molecular function of PIF1 will be investigated to examine whether it acts as a transcriptional activator or repressor from a native target gene promoter. In addition, the biological significance of physical interactions between PIF1-phy and PIF1-PIF3 will be investigated in vivo. Since PIF1 is a primary phy-signaling partner whose activity is regulated by phy, the results from this study will provide fundamental information on the mechanism of phy signaling.Expected Broader Impacts: Light is arguably one of the most important environmental factors controlling plant growth and development, including many agronomically important traits such as seed germination, seedling establishment and survival, plant height, leaf area, flowering time and plantation density. Understanding the mechanism of light-regulated plant growth and development will provide excellent tools to apply in agricultural biotechnology for increased crop production using reduced amount of fertilizers. This proposal is also ideally suited for training of the next generation of scientists, including undergraduate, graduate and postdoctoral students. Their training in light signaling will give them a unique opportunity to make significant contributions to the field of photobiology and biotechnology.

项目总结知识价值：拟南芥光敏色素（phytochrome，phy）家族由5个成员（phyA至phyE）组成，控制着植物对外界光环境的多种发育反应。 在光敏和生物化学功能的表征以及信号中间体的鉴定和功能表征方面取得了重大进展。 然而，phy信号转导的生化机制仍不清楚。为了检查早期phy信号传导事件，phy相互作用因子如PIF 1已被分离和表征。 PIF 1是一种碱性螺旋-环-螺旋（bHLH）转录因子，与phyA和phyB的生物活性形式以及另一种bHLH因子PIF 3强烈相互作用。 PIF 1结合到在许多光调节启动子中常见的G盒（CACGTG）DNA序列基序。PIF 1也已被证明激活转录在一个短暂的测定，和转录激活活性下调的远红光和红光的phyA和phyB依赖的方式，分别。PIF 1过表达和pif 1 T-DNA插入突变体表现出有缺陷的幼苗脱黄化，包括异常的下胚轴伸长和发育调节的绿化损失。 这些结果表明，PIF 1是一个关键的调节剂的phy介导的控制幼苗去黄化过程。 本研究拟采用分子遗传学、生物化学和功能基因组学方法，探讨PIF 1调控水稻幼苗黄化的分子机制。 具体而言，将鉴定PIF 1靶基因并对其进行功能表征，并研究PIF 1的分子功能，以检查其是否作为天然靶基因启动子的转录激活因子或阻遏物。 此外，将在体内研究PIF 1-phy和PIF 1-PIF 3之间物理相互作用的生物学意义。由于PIF 1是一种主要的phy信号伴侣，其活性受phy调节，因此本研究的结果将提供有关phy信号机制的基本信息。预期更广泛的影响：光可以说是控制植物生长和发育的最重要的环境因素之一，包括许多农艺学上重要的性状，如种子萌发、幼苗建立和存活、植物高度、叶面积、开花时间和种植园密度。 了解光调控植物生长发育的机制，将为农业生物技术的应用提供很好的工具，以减少化肥用量，提高作物产量。 这一建议也非常适合培养下一代科学家，包括本科生，研究生和博士后学生。 他们在光信号方面的培训将为他们提供一个独特的机会，为光生物学和生物技术领域做出重大贡献。