REGULATION OF PLANT GENES INVOLVED IN MODULATION OF NH3 ASSIMILATION

参与调节 NH3 同化的植物基因的调控

• 批准号: 6107198
• 负责人: CHAMPA SENGUPTA-GOPALAN
• 金额: $ 4.41万
• 依托单位: NEW MEXICO STATE UNIVERSITY LAS CRUCES
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6107198
• 关键词: Rhizobiaceae; alfalfa; ammonia; ammonia lyase; enzyme activity; flavonoids; gene expression; genetic regulatory element; isomerase; molecular cloning; nitrogen fixation; plant genetics; soybeans; symbiosis; transcription factor

Most of the nutritionally significant biological nitrogen fixation is carried out by Rhizobia/Bradyrhizobia, bacteria that fix nitrogen only within the nodules they form on the roots of legumes. Our long-term goal is to improve the efficiency of fixation and to broaden the host range to nonlegumes. The research proposed here is to understand the initial interaction between the host an the symbiont and how the plant utilizes the reduced nitrogen. The proposal focuses on two major aspects: (i) to determine the role of flavonoids in nodule initiation; (ii) to determine if ammonia assimilation can be improved and if that would have an impact on the overall N-status of the plant. For the first part of our project, the focus is on genes encoding for key enzymes in the phenylpropanoid pathway leading to flavonoid synthesis - phenylalanine ammonia lyase (PAL), chalcone synthase (CHS) and chalcone isomerase (CHI). The study involves studying the regulation of the different members of the family and the effect of over/under expressing key members, on nodule initiation. Glutamine synthetase (GS), the key enzyme in ammonia assimilation, is central to our understanding of ammonia assimilation and is the theme of the second part. Our research combines a molecular and biochemical approach to understand the functional role and regulatory mechanism underlying expression of different GS gene members. Furthermore, the effect of down and up regulation of different GS gene members on the efficiency of ammonia assimilation and N2-fixation, is being studied. A second project aimed towards improving the nutritional quality of legume seeds and forage, that is being pursued in the lab, is to introduce into these plants highly expressing genes encoding for high sulfur amino acid proteins. Altogether, the projects in the lab utilize state-of-the-art techniques in molecular biology, biochemistry and cell biology to address important issues in plant biology that have a direct impact on human nutrition.

大多数具有营养意义的生物固氮作用是 由根瘤菌/缓生根瘤菌（仅固氮细菌）进行 它们在豆科植物根部形成的根瘤内。 我们的长期目标 是为了提高固定效率并拓宽宿主范围 非豆类。 这里提出的研究是为了了解最初的 宿主与共生体之间的相互作用以及植物如何利用 减少的氮。 该提案主要关注两个方面：(i) 确定类黄酮在结节形成中的作用； (二) 确定 氨同化是否可以改善以及是否会产生影响 植物的整体 N 状态。 对于我们项目的第一部分， 重点是编码苯丙素中关键酶的基因 类黄酮合成途径——苯丙氨酸解氨酶 (PAL)、查尔酮合酶 (CHS) 和查尔酮异构酶 (CHI)。 研究 涉及研究家庭不同成员的调节 以及关键成员过度/不足表达对结节形成的影响。 谷氨酰胺合成酶 (GS) 是氨同化的关键酶， 是我们理解氨同化的核心，也是 第二部分。 我们的研究结合了分子和生物化学 了解功能作用和调节机制的方法 不同GS基因成员的潜在表达。 此外， 不同GS基因成员的下调和上调对 氨同化和固氮的效率正在研究中。 第二个项目旨在提高豆类的营养质量 实验室正在研究的种子和饲料将引入 这些植物高度表达编码高硫氨基酸的基因 蛋白质。 总而言之，实验室的项目利用了最先进的技术 分子生物学、生物化学和细胞生物学解决重要问题 植物生物学问题对人类营养有直接影响。