Signaling and Gene Regulation In The Arabidopsis Oxidative Stress Response

植物对来自环境的化学和生物挑战的反应是生化过程和基因表达的快速变化。 这些反应导致植物通过改变其化学成分，细胞结构和生长方式来适应。这组直接的生化和遗传变化被称为应激反应或防御反应，这取决于激发因子是生物体还是环境应激，如过度光照或空气污染物。臭氧是一种常见的空气污染物，会影响城市环境中的植物、农作物的生产力以及高海拔地区森林的健康。本项目主要研究模式植物拟南芥对臭氧的响应。 叶组织对臭氧气体的反应非常迅速（即使在大都市地区夏季达到的水平），通过产生高活性形式的氧气（称为活性氧）的爆发。 这种反应被称为“氧化爆发”，既有信号功能，也是细胞死亡的触发器。信号在细胞内通过3组分（异源三聚体）G蛋白以及通过其他信号传导途径（包括促分裂原活化蛋白激酶级联）进行传递。本研究旨在了解G蛋白在臭氧氧化应激反应中的作用。 第一个目标是要问的异源三聚体G蛋白的组分如何相互作用，以及与其他蛋白质，在臭氧诱导的应激反应，以及是否一个亚基的G蛋白是直接的目标激活响应臭氧。 这些实验将使用荧光共振能量转移、免疫化学方法、串联亲和纯化和质谱法进行。 第二个目的是确定基因的转录丰度通过G蛋白和通过其他信号的cDNA微阵列表达谱通过传输的信号进行调节。 更广泛的影响：这项工作的重要性在于这样一个事实，即代谢变化，包括胁迫反应抑制植物生产力，从而降低作物产量。了解植物在分子水平上如何应对压力是未来农业和可持续发展的最重要领域之一。扩大有关由压力激活的分子和遗传网络的知识，将为提高植物在次优条件下的生产力开辟新的知识途径，这是实现全球粮食安全的一项中心任务。此外，该项目还将为几名本科生和研究生提供培训。

Plants react to chemical and biological challenges from the environment with rapid changes in biochemical processes and gene expression. These responses cause plants to adapt by altering their chemical composition, their cell structure and how they grow. The set of immediate biochemical and genetic changes is termed the stress- or defense response, depending on whether the inciting agent is an organism or an environmental stress, such as excess light or an air pollutant. Ozone is a common air pollutant that affects plants in urban environments, the productivity of crop plants, and the health of forests at high altitudes. The present project focuses on the response of the model plant Arabidopsis to ozone. Leaf tissues respond very rapidly to ozone gas (even at levels reached in summer in large metropolitan areas) by producing bursts of highly reactive forms of oxygen, called reactive oxygen species. This response is called the "oxidative burst" and serves both a signaling function and as a cell-death trigger. Signals are transmitted within cells by a 3-component (heterotrimeric) G protein, as well as through other signaling pathways, including mitogen activated protein kinase cascades. The present research seeks to understand the role of the G protein in the oxidative stress response to ozone. The first objective is to ask how the components of the heterotrimeric G protein interact with each other, as well as with other proteins, during the ozone-induced stress response, and whether a subunit of the G protein is the direct target of activation in response to ozone. These experiments will be carried out using fluorescence resonance energy transfer, immunochemical methods, tandem affinity purification, and mass spectrometry. The second objective is to identify genes whose transcript abundance is regulated through signals transmitted through the G protein and those regulated through other signals using cDNA microarray expression profiling. Broader Impact: The importance of this work lies in the fact that the metabolic changes that comprise the stress response depress plant productivity; thereby decreasing crop yields. Understanding how plants respond to stress at the molecular level is one of the most important areas for the future of agriculture and sustainable development. Expanding knowledge about molecular and genetic networks activated by stress will open new knowledge-based avenues for enhancing the productivity of plants under suboptimal conditions, a central task in achieving global food security. In addition, this project will also provide training for several undergraduate and graduate students.