Metabolic and signaling interactions between plant mitochondria and chloroplasts

作物的生长和生产力取决于植物代谢在田间各种环境条件下有效发挥作用的能力。全世界努力提高作物产量的一个核心主题是需要更好地了解新陈代谢的功能，特别是在不利（压力）条件下，预计在未来将变得更加普遍。因此，我的研究计划调查了关键的非生物和生物压力，以及大气中二氧化碳浓度升高等全球变化因素对新陈代谢的影响。目的是揭示碳和能量代谢对胁迫的特征响应，阐明这些响应如何支持胁迫适应，并为改善胁迫下的代谢功能和植物性能提供必要的知识基础。重点是植物细胞的两个主要的能量传导细胞器（线粒体和叶绿体），以及主要代谢中心之间发生的相互作用，包括呼吸，光合作用和营养同化。此外，还研究了相关活性氧和活性氮代谢网络的影响。这些活性物质可以破坏新陈代谢，但也是支持生长、发育和应激适应的关键信号分子。为了实现我们的目标，我们采用了一种综合的方法，即在整个植物、细胞和细胞器水平上使用生理、生化和分子生物学方法的组合来研究过程。拟议的研究将为7名研究生（4名博士，3名硕士）和众多本科生提供指导和培训。这将包括培养独立性和多学科方法，同时在一个支持性和包容性的环境中工作。

Crop growth and productivity depends on the capacity of plant metabolism to function effectively over the wide range of environmental conditions experienced in the field. A core theme of worldwide efforts to improve crop yield is the need to better understand how metabolism functions, particularly under the less favorable (stress) conditions that are expected to become more prevalent in the future. Hence, my research program investigates the impact of key abiotic and biotic stresses, as well as global change factors such as elevated atmospheric concentrations of CO2, on metabolism. The goal is to uncover the signature responses of carbon and energy metabolism to stress, to elucidate how these responses support acclimation to stress, and to generate the knowledge foundation required to improve metabolic function and plant performance under stress. Emphasis is on the two major energy-transducing organelles of the plant cell (the mitochondrion and the chloroplast) and on the interactions that occur between major metabolic hubs including respiration, photosynthesis and nutrient assimilation. In addition, the impact of the related reactive oxygen and reactive nitrogen metabolic networks is investigated. These reactive species can damage metabolism but are also key signaling molecules supporting growth, development and stress acclimation. To achieve our goals, an integrative approach is taken, whereby processes are studied at the whole plant, cell and organelle levels using a combination of physiological, biochemical and molecular biological approaches. The proposed research will provide mentorship and training to seven graduate students (4 Ph.D, 3 M.Sc.) and numerous undergraduate students. This will include a fostering of independence and multidisciplinary approaches, while working in a supportive and inclusive environment. Alternative oxidase (AOX) is a metabolic component that reduces energy yield in plant respiration. Despite key advances in understanding the genetic and biochemical control of AOX, its role in metabolism and its overall impact on plant performance remains poorly understood. This represents a major gap in our understanding of primary metabolism. AOX gene expression is highly responsive to environmental cues and evidence indicates that it may be of particular importance under variable and stress conditions. Theoretically, AOX should negatively affect growth since it reduces energy yield. However, it may have key roles in metabolism and mitochondrial function that outweigh this energy cost. We hypothesize that, while AOX is a respiratory component, it interacts extensively with chloroplast photosynthesis. These interactions, in turn, improve photosynthetic performance. To test this hypothesis, plants with increased or decreased AOX amount can be compared to wild-type plants. Plant growth and metabolism can be characterized under a range of environmental and stress conditions, and in both controlled-environment and field settings.