Mitochondrial regulation of nitrogen metabolism under hypoxic conditions

厌氧是一种广泛而有害的胁迫。植物在加拿大大面积的淹水和紧实的土壤上经历它。缺氧是由于其在水中的溶解度低和扩散速率低而引起的，并且主要损害根和种子。硝酸盐对淹水作物的改良作用已被人们认识多年，但其确切机理至今仍不清楚。该提案旨在通过增加参与氮代谢，特别是硝酸盐/亚硝酸盐/一氧化氮周转，为植物线粒体建立与其在缺氧条件下的功能相关的新功能。通过这项研究计划，我试图了解植物线粒体从使用氧气到减少亚硝酸盐，然后产生一氧化氮的分子机制。 我将探讨在低氧环境中线粒体对ATP合成的贡献，从而在缺氧期间维持细胞能量状态并减少乙醇和乳酸的产生的可能性。将研究通过涉及缺氧诱导的血红蛋白的反应去除毒性一氧化氮的途径。我的研究计划将对植物适应的基本过程产生直接和深远的影响。线粒体作为植物低氧防御系统的重要组成部分，是提高植物抗逆性的一个新的潜在靶点。证明厌氧线粒体ATP合成的操作作为经典发酵途径的替代方案，将使人们有可能制定策略，以科普植物系统中厌氧事件的负面后果，并选择耐洪水的作物。

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.