Action of Hormones in Plant Development: Hormonal Regulationof Gene Expression in Barley Aleurone Layers

赤霉素（Gibberellic acid， GA）是一种植物激素，调控种子萌发、萌发后生长、茎伸长和花诱导等重要的生理和发育过程。GA与另一种激素脱落酸（ABA）一起调节几种酶的合成和分泌，这些酶负责利用种子中储存的营养物质。这些酶是许多谷物萌发后生长所必需的。这些酶中含量最多的是α -淀粉酶，它能降解淀粉。作为阐明GA和ABA作用模式的长期努力的一部分，本研究将集中在萌发大麦种子糊粉层的基因表达上。以往的研究表明，激素介导的大麦-糊粉系统中酶表达的调控主要在基因转录水平。本研究将探讨大麦糊粉系统中特定蛋白因子与激素调控基因调控区域（启动子）之间的特定相互作用。本研究的目标包括：(1)确定α -淀粉酶启动子中与蛋白质因子相互作用的特定DNA序列；(2)研究激素处理对蛋白质因子活性的影响；(3)确定糊粉细胞内启动子序列的重要性；(4)研究这些因子在对GA和ABA敏感性改变的基因突变体中的活性。本研究结果将进一步加深我们对GA和ABA的主要作用的认识，从而对植物中激素调控基因表达的信号转导途径有新的认识。

Gibberellic acid (GA), a plant hormone, regulates several important physiological and developmental processes such as seed germination, post-germination growth, stem elongation and flower induction. Together with another hormone, abscisic acid (ABA), GA is known to regulate the synthesis and secretion of several enzymes which are responsible for the utilization of nutrients stored in the seed. The enzymes are essential for post-germination growth of many cereal grains. The most abundant of these enzymes is alpha-amylase, which degrades starch. As part of a long term effort to elucidate the mode of action of GA and ABA this research will focus on gene expression in the aleurone layers of germinating barley seeds. Previous research has revealed that hormone-mediated regulation of enzyme expression in the barley-aleurone system is mainly at the level of gene transcription. The proposed research will investigate specific interactions between specific protein factors with regulatory regions (promoters) of hormone-regulated genes in the barley-aleurone system. Goal for this research include: (1) determination of specific DNA sequences in the alpha-amylase promoters that interact with protein factors, (2) investigation of the effect of hormonal treatments on the activity of the protein factors, (3) determination of the importance of promoter sequences inside the aleurone cells and (4) investigation of the activity of these factors in genetic mutants with altered sensitivities to GA and ABA. Results from this research should improve our understanding of the primary action of GA and ABA, thus revealing new insights into the signal transduction pathway governing hormonal regulation of gene expression in plants.