Investigating Gibberellin Phytohormone Metabolism

研究赤霉素植物激素代谢

• 批准号: 0919735
• 负责人: Reuben Peters
• 金额: $ 69.34万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0919735&HistoricalAwards=false
• 关键词: Investigating; Gibberellin; Phytohormone; Metabolism

Scientific MeritThe gibberellins are a large group of complex diterpenoid natural products, among which several have potent biological activity in plants, where they serve as hormones. Intriguingly, these phytohormones are made not only by the plants in which they serve to regulate growth and development, but by certain plant-associated fungal and bacterial microbes as well. While gibberellin phytohormone biosynthesis has been largely elucidated for higher plants and fungi, which seem to have independently evolved/assembled the corresponding metabolic pathway, the basis for such biosynthesis in bacteria remains enigmatic. Even in higher plants, the origins of gibberellin metabolism remains obscure. Further, there have been recent discoveries demonstrating the existence of novel gibberellin metabolism (particularly catabolism) in higher plants, which have unexplored implications in plant biology. Building on previous NSF-supported studies, this project will both further investigate gibberellin metabolism in higher plants and also define the analogous biosynthetic pathway in bacteria. The bacterial pathway appears to represent yet a third example of a convergent evolutionary solution to the puzzle presented by such complex natural products biosynthesis. These studies will also provide insight into the evolutionary origins of gibberellin metabolism in plants. Thus, the planned wide-ranging studies will provide a comprehensive overview of gibberellin phytohormone metabolism in a phylogenetically diverse group organisms. Gibberellins have played an important role in agriculture, as it was alterations in such phytohormone metabolism that led to high yielding semi-dwarf varieties of rice and wheat, which were a critical component of the "Green Revolution". The biosynthesis of gibberellin phytohormones by plant growth promoting bacteria that are commonly applied to legume crop plants offers additional agricultural significance. Further, the absolute requirement for gibberellin production in higher plants has provided a genetic reservoir of biosynthetic genes, duplication of which has led to a vast super-family (~7,000 known) of related diterpenoid natural products, exhibiting various biological activities and physiological roles (e.g., as defensive antibiotics). Hence, this project, while specifically directed at gibberellin metabolism, will offer insights into a much broader group of natural products.Broader ImpactOn-going broader outreach efforts also will be continued and expanded. Beyond the inclusion of undergraduate, graduate and postdoctoral students in research, work will be continued with high school students and those from under-represented groups. In addition, the project includes presentations to junior and senior high school science teachers to provide concrete examples of how basic research underlies and informs technological advancements that improve the human condition. An important example is the relationship of gibberellin to the "Green Revolution" as noted above.

科学价值赤霉素是一大类复杂的二萜类天然产物，其中几种在植物中具有强大的生物活性，它们在植物中充当激素。有趣的是，这些植物激素不仅由它们用于调节生长和发育的植物产生，而且还由某些与植物相关的真菌和细菌产生。虽然高等植物和真菌的赤霉素类植物激素的生物合成在很大程度上已经被阐明，它们似乎已经独立地进化/组装了相应的代谢途径，但细菌中这种生物合成的基础仍然是谜。即使在高等植物中，赤霉素代谢的起源也仍然不清楚。此外，最近的发现证明在高等植物中存在新的赤霉素代谢(特别是分解代谢)，这在植物生物学中还没有被探索的意义。在之前NSF支持的研究的基础上，该项目将进一步研究高等植物中赤霉素的代谢，并定义细菌中类似的生物合成途径。细菌途径似乎是这种复杂的天然产物生物合成所带来的谜题的收敛进化解决方案的第三个例子。这些研究还将提供对植物赤霉素代谢的进化起源的洞察。因此，计划中的广泛研究将全面概述赤霉素在不同系统发育的生物群中的植物激素代谢。赤霉素在农业中发挥了重要作用，因为正是这种植物激素代谢的变化导致了高产的半矮秆水稻和小麦品种，这些品种是“绿色革命”的关键组成部分。通常应用于豆科作物植物的植物生长促进菌生物合成赤霉素植物激素提供了额外的农业意义。此外，高等植物对赤霉素生产的绝对需求提供了生物合成基因的遗传库，这些基因的重复导致了一个庞大的超家族(已知约7000个)相关的二萜类天然产物，显示出各种生物活性和生理作用(例如，作为防御性抗生素)。因此，该项目虽然专门针对赤霉素代谢，但将提供对更广泛的天然产品组的洞察。Broader Impacton-更广泛的外展努力也将继续和扩大。除了将本科生、研究生和博士后纳入研究之外，将继续对高中生和来自代表性不足群体的学生进行研究。此外，该项目还包括对初中和高中科学教师的演示，以提供具体例子，说明基础研究如何支撑和宣传改善人类状况的技术进步。如上所述，赤霉素与“绿色革命”的关系是一个重要的例子。