Mitochondrial regulation of nitrogen metabolism under hypoxic conditions

缺氧条件下线粒体对氮代谢的调节

• 批准号: 355753-2008
• 负责人: Igamberdiev, Abir
• 金额: $ 2.64万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=459546
• 关键词: Mitochondrial; regulation; nitrogen; metabolism; under

Anaerobiosis is one of the widespread and damaging stresses. Plants experience it on flooded and compact soils which occupy large areas in Canada. Oxygen deficiency arises due to its low solubility and low diffusion rate in water and damages mostly roots and seeds. It has been known for many years that nitrate has ameliorating effect on flooded crops but the exact mechanism of this phenomenon is not understood to date. The proposal aims to establish novel functions for plant mitochondria connected with their functionality under hypoxic conditions via increased involvement in nitrogen metabolism and in particular in nitrate/nitrite/nitric oxide turnover. Through this research program, I seek to understand the molecular mechanism by which plant mitochondria switch from the use of oxygen to the reduction of nitrite followed by nitric oxide production. I will explore the possibility of mitochondrial contribution to ATP synthesis in low oxygen environments, leading to the maintenance of cell energy status during hypoxia and to the decreased production of ethanol and lactic acid. The pathway of removal of toxic nitric oxide via reactions involving the hypoxically induced hemoglobin will be studied. My research program will have immediate and far-reaching impacts on fundamental processes of plant adaptation. Mitochondria as major components of the defense system under hypoxia represent a new potential target for improving resistance to stress in plants. Proving the operation of anaerobic mitochondrial ATP synthesis as an alternative to classic fermentation pathways will make it possible to develop strategies to cope with negative consequences of anaerobic events in plant systems and select flood-tolerant crops.

厌氧菌是一种广泛存在的破坏性压力。在加拿大，植物在洪水泛滥的紧实土壤上经历了这种情况。缺氧是由于其在水中的低溶解度和低扩散速率而引起的，主要伤害根和种子。多年来，人们已经知道硝酸盐对淹水作物有改善作用，但到目前为止，人们还不清楚这种现象的确切机制。该提案旨在通过更多地参与氮代谢，特别是硝酸盐/亚硝酸盐/一氧化氮的转化，为植物线粒体建立与其在低氧条件下的功能相关的新功能。通过这个研究项目，我试图了解植物线粒体从利用氧气转变为还原亚硝酸盐进而产生一氧化氮的分子机制。我将探索线粒体在低氧环境下参与ATP合成的可能性，导致细胞在缺氧时保持能量状态，并减少乙醇和乳酸的产生。通过涉及低氧诱导的血红蛋白的反应来清除有毒的一氧化氮的途径将被研究。我的研究计划将对植物适应的基本过程产生直接而深远的影响。线粒体作为低氧下防御系统的主要组成部分，为提高植物的抗逆性提供了一个新的潜在靶点。证明厌氧线粒体ATP合成作为经典发酵途径的替代方案，将使我们有可能制定策略来应对植物系统中厌氧事件的负面后果，并选择耐涝作物。