Metabolic and signaling interactions between plant mitochondria and chloroplasts

作物的生长和生产力取决于植物新陈代谢在田间经历的各种环境条件下有效发挥作用的能力。世界范围内提高作物产量的努力的一个核心主题是需要更好地了解新陈代谢如何发挥作用，特别是在预计未来将变得更加普遍的不利(压力)条件下。因此，我的研究项目调查了关键的非生物和生物压力以及全球变化因素(如大气中二氧化碳浓度升高)对新陈代谢的影响。其目的是揭示碳和能量代谢对胁迫的标志性反应，阐明这些反应如何支持对胁迫的适应，并生成在胁迫下改善代谢功能和植物表现所需的知识基础。重点是植物细胞的两个主要能量传递细胞器(线粒体和叶绿体)以及发生在主要代谢中心之间的相互作用，包括呼吸作用、光合作用和营养同化。此外，还对相关的活性氧代谢网络和活性氮代谢网络的影响进行了研究。这些活性物质可以破坏新陈代谢，但也是支持生长、发育和压力适应的关键信号分子。为了实现我们的目标，采取了一种综合的方法，即使用生理、生化和分子生物学方法在整个植物、细胞和细胞器水平上研究过程。拟议的研究将为7名研究生(4名博士，3名硕士)提供指导和培训。和无数的本科生。这将包括促进独立性和多学科方法，同时在支持性和包容性的环境中工作。交替氧化酶(AOX)是一种降低植物呼吸能量产量的代谢成分。尽管在理解AOX的遗传和生化控制方面取得了重要进展，但它在新陈代谢中的作用及其对植物表现的整体影响仍然知之甚少。这代表了我们对初级新陈代谢的理解上的一个重大差距。AOX基因的表达对环境提示高度敏感，有证据表明，它在可变和应激条件下可能具有特别重要的作用。从理论上讲，AOX应该会对增长产生负面影响，因为它会降低能源产量。然而，它可能在新陈代谢和线粒体功能方面发挥关键作用，超过了这一能量成本。我们推测，虽然AOX是一种呼吸成分，但它与叶绿体光合作用有广泛的相互作用。这些相互作用反过来又提高了光合作用的表现。为了验证这一假设，AOX含量增加或减少的植物可以与野生型植物进行比较。植物的生长和新陈代谢可以在一系列环境和胁迫条件下，以及在受控环境和田间环境中得到表征。

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.