Nitric oxide metabolism and its interaction with reactive oxygen species during the adaptation of plants to abiotic stress

一氧化氮(NO)是一种强大的生物活性分子，在植物的代谢和信号功能中发挥作用，提供灵活的新陈代谢，调节关键基因的表达和参与植物适应逆境的酶活性。植物已经进化到使用能量守恒和转换的机制，包括在胁迫条件下使用焦磷酸作为ATP的替代品，以及在含有NO的氧化还原反应中使用电子传递成分。我的长期研究目标是通过维持氧化还原和能量水平以及调节细胞程序性死亡、自噬、种子萌发和形态发生事件，确定NO代谢和植物珠蛋白在逆境植物细胞生物能量学中的生理作用。具体目标包括：1)探索植物珠蛋白-NO循环，包括a)闭合和开放模式之间的差异，b)利用氧和氮的稳定同位素，循环周转速率及其对氧可获得性的依赖，c)通过维持和形成ATP和焦磷酸，NO产生、清除和能量状态之间的联系，以及d)NO代谢和植物次生代谢/酚类合成调节之间的联系；2)研究线粒体电子传递在NO产生和清除中的作用以及与氧浓度的关系，包括交替氧化酶和细胞色素c氧化酶参与NO周转；3)研究低氧胁迫下植物体内植物球蛋白的诱导和维持NO周转的基因表达和表观遗传调控机制；4)探讨种子萌发过程中活性氧和氮物种之间的相互作用，重点是a)NO和超氧化物生成过氧亚硝酸盐的过程，b)氧浓度变化的依赖性，c)蛋白质的S亚硝化的参与。转基因大麦和拟南芥将被用来研究植物球蛋白在胁迫下维持低NO水平中的作用。将用蛋白质组学和代谢组学的方法研究植物珠蛋白、NO和硝酸盐/亚硝酸盐循环运行中闭合和开放模式之间的转换。NO，S-亚硝基谷胱甘肽和活性氧之间的串扰将被研究与藻红蛋白的表达和线粒体电子传递链的组成之间的关系。NO和活性氮、氧的代谢是提高农业植物对非生物/生物胁迫抗性的一个新的潜在靶点。制定减轻植物氧气供应有限的后果和调节种子萌发的战略，将提高农业植物的抗逆性并维持农业作物产量，特别是在面临越来越不可预测的天气事件和气候变化的情况下。

Nitric oxide (NO) is a potent bioactive molecule that plays a role in the metabolic and signaling functions of plants, providing flexible metabolism, regulation of key gene expression and enzyme activity involved in plant adaptations to stress. Plants have evolved to use mechanisms of energy conservation and transformation, including the use of pyrophosphate as a substitute for ATP in stress conditions and the use of electron transport components in redox reactions that contain NO. My long-term research goal is to establish the physiological role of NO turnover and phytoglobin function in the bioenergetics of stressed plant cells via the maintenance of redox and energy level and regulation of programmed cell death, autophagy, seed germination, and morphogenetic events. Specific objectives include: 1) exploring the phytoglobin-NO cycle, including a) differences between closed and opened modes, b) rates of cycle turnover and their dependence on oxygen availability using stable isotopes of oxygen and nitrogen, c) links between NO production, scavenging and energy status via the maintenance and formation of ATP and pyrophosphate, and d) links between NO metabolism and regulation of plant secondary metabolism/phenolics synthesis; 2) investigating the role of the mitochondrial electron transport in NO production and scavenging and associations with oxygen concentration, including the participation of alternative oxidase and cytochrome c oxidase in NO turnover; 3) studying the mechanisms of gene expression and epigenetic regulation leading to the induction of phytoglobins and the maintenance of NO turnover in plants under hypoxic stress; 4) exploring crosstalk between reactive oxygen and nitrogen species during seed germination, focusing on a) the formation of peroxynitrite from NO and superoxide, b) the dependence on changing oxygen concentrations, and c) the involvement of S-nitrosylation of proteins. Transgenic barley (Hordeum vulgare) and Arabidopsis (Arabidopsis thaliana) plants will be used to study the role of phytoglobins in maintaining low NO levels under stress. The switch between closed and open modes in operation of the cycle involving phytoglobin, NO and nitrate/nitrite will be studied using proteomic and metabolomic approaches. Crosstalk between NO, S-nitrosoglutathione and reactive oxygen species will be studied in relation to expression of phytoglobin and the components of the mitochondrial electron transport chain. The metabolism of NO and reactive nitrogen and oxygen species is a new potential target for improved resistance of agricultural plants to abiotic/biotic stress. The development of strategies for mitigating the consequences of limited oxygen availability in plants and in the regulation of seed germination will improve the resistance of agricultural plants to stress and maintain agricultural crop yields, particularly in the face of increasingly unpredictable weather events and climate change.