Regulation of Gibberellin Biosynthesis in Arabidopsis

拟南芥中赤霉素生物合成的调控

• 批准号: 0080934
• 负责人: Valerie Sponsel
• 金额: $ 30万
• 依托单位: University of Texas at San Antonio
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0080934&HistoricalAwards=false
• 关键词: Regulation; Gibberellin; Biosynthesis; Arabidopsis

The gibberellin (GA) group of plant hormones controls many processes and developmental events in plants, such as seed germination, stem growth, flowering and fruit development. These processes are often not controlled by GAs alone, but by an interplay of GAs with other hormones. The proposed research will investigate whether auxin can exert a regulatory effect on GA biosynthesis, and thus provide one mechanism for cross-talk between these two types of growth promoting hormones. Previous work in the principal investigator's laboratory led to the isolation of a mutant of Arabidopsis thaliana (previously known as 10.3 or ga6) which had reduced stem growth, delayed flowering and reduced fruit size. These symptoms could be overcome by treatment of mutant plants with certain GAs, leading to the hypothesis that biosynthesis of active GA hormone was blocked in this mutant. It has now known that this mutation is allelic to the transport inhibitor3 (tir3) mutation, which leads to an alteration in polar transport of auxin. The proposed research will examine whether auxins exert control at two stages in the GA biosynthetic pathway, namely 20-oxidation and 3b-hydroxylation. Since the genes encoding these biosynthetic enzymes have been cloned, the possible effect of auxins on GA biosynthesis will be examined at the level of gene expression. It is proposed to compare the expression of these genes in wildtype and tir3 plants by RNA blotting, and by using reporter gene fusions. The altered auxin response 1 (axr1) mutant will also be examined to see if this mutation, which dramatically reduces the sensitivity of plants to auxin, also affects the expression of genes encoding these GA biosynthetic enzymes. Finally, the auxin status of wildtype plants will be perturbed pharmacologically, and possible effects on GA response and expression of genes for GA biosynthetic enzymes will be examined.The work will be carried out at the University of Texas at San Antonio. This University is one in which the majority of students are undergraduates from ethnic minorities. The research program presents an opportunity to provide training in practical aspects of plant physiology and biochemistry to undergraduates from groups who are historically under-represented in science and technology.

赤霉素 (GA) 植物激素组控制着植物的许多过程和发育事件，例如种子发芽、茎生长、开花和果实发育。这些过程通常不仅仅由 GA 控制，而是由 GA 与其他激素的相互作用控制。该研究将探讨生长素是否能够对 GA 生物合成发挥调节作用，从而为这两类生长促进激素之间的相互作用提供一种机制。首席研究员实验室之前的工作导致分离出拟南芥突变体（以前称为 10.3 或 ga6），该突变体会减少茎生长、延迟开花并减小果实大小。 这些症状可以通过用某些 GA 处理突变植物来克服，从而得出这样的假设：活性 GA 激素的生物合成在该突变体中被阻断。现在已知该突变与转运抑制剂 3 (tir3) 突变等位，导致生长素极性转运发生改变。拟议的研究将检验生长素是否在 GA 生物合成途径的两个阶段（即 20-氧化和 3b-羟基化）发挥控制作用。 由于编码这些生物合成酶的基因已被克隆，因此将在基因表达水平上研究生长素对GA生物合成的可能影响。 建议通过 RNA 印迹和使用报告基因融合来比较这些基因在野生型和 tir3 植物中的表达。 还将检查改变的生长素反应 1 (axr1) 突变体，看看这种显着降低植物对生长素敏感性的突变是否也会影响编码这些 GA 生物合成酶的基因的表达。 最后，野生型植物的生长素状态将在药理学上受到干扰，并检查对 GA 反应和 GA 生物合成酶基因表达的可能影响。这项工作将在德克萨斯大学圣安东尼奥分校进行。这所大学是一所大多数学生是少数民族本科生的大学。 该研究项目提供了一个机会，为历史上在科学和技术领域代表性不足的群体的本科生提供植物生理学和生物化学实践方面的培训。