Gibberellin metabolism and its regulation in plants

赤霉素（giberellin， GA）是植物产生的一种活性化合物，在极低浓度下就能影响植物的生长和发育过程，通常被称为“植物激素”。GA控制着广泛的植物发育事件，包括种子萌发、茎伸长、叶片膨胀以及花、果实和种子的发育。植物中GA的缺乏或过量都会影响植物的正常生长发育。GA含量低的植株矮化，肥力低，种子发育不全。相比之下，植物中过量的GA会引发过度生长、不育和种子过早发芽。因此，植物通过平衡GA的形成和降解来控制其生长活性形式的水平是很重要的。植物采用不同的策略来确保这种平衡并限制GA的数量。已经确定了在生长活性GA的形成或降解中起作用的几种策略和调控元件。然而，鉴于其多重作用和复杂的代谢途径，很可能存在未知的策略。我的研究计划的长期目标是详细了解植物在发育过程中如何微调其组织中生长活性GA的数量并对环境做出反应。本研究的具体目的是调查和确定参与植物GA水平调节的新策略。这项研究的结果将提高我们对植物如何维持最佳GA量以确保其正常生长和发育的认识。由于GA在植物中具有多种功能；这项工作的发现将为提高作物性能和产量提供有力的工具。此外，由于这项研究涉及研究生和本科生的培训，它将有助于加拿大对高素质植物生物学家的需求。

Gibberellin (GA) is one of the plant produced compounds that are active and influence growth and developmental processes at very low concentrations, usually coined as "plant hormones". GA controls a wide range of plant developmental events including seed germination, stem elongation, leaf expansion, and flower, fruit and seed development. Deficiency or excess amounts of GA in plants affects their normal growth and development. Plants with low amounts of GA are dwarf, and exhibit low fertility and failure in seed development. By contrast, excess amounts of GA in plants triggers excessive growth, sterility and premature seed germination. Therefore, it is important for plants to control the levels of the growth-active form of GA by balancing its formation and degradation. Plants employ different strategies to ensure this balance and limit the amounts of GA. Several strategies and regulatory elements acting in the formation or degradation of the growth-active GA have been identified. However, given its multiple roles and complex metabolic pathways, it is more than likely that unknown strategies exist. The long term goal of my research program is to understand in detail how a plant fine-tunes the amounts of growth-active GA in its tissues during development and in response to the environment. The specific objective of this research is to investigate and identify new strategies that are involved in the regulation of plant GA levels. The outcomes of this study will advance our knowledge of how a plant maintains optimal amounts of GA for ensuring its normal growth and development. Since GA has diverse functions in plants; the findings of this work will provide powerful tools for improving crop performance and yield. Further, as this research involves training of graduate and undergraduate students, it will contribute to Canada's need for highly qualified plant biologists.