The plastidial MEP-pathway signature in mitochondrial structure and function

线粒体在动植物细胞中都被称为“能量屋”。在植物细胞中，线粒体是呼吸作用的场所，叶绿体中来自光合作用的燃料在这里被转化为能量货币。线粒体可以在细胞内移动，当彼此相遇时进行融合，导致两个线粒体合并成一个更大的线粒体。相反，单个线粒体可以通过分裂分裂成两个不同的线粒体。融合和分裂的平衡频率决定了线粒体群体的整体形态，对于维持线粒体的功能，如呼吸能力和对应激信号的反应至关重要。该项目将使用对胁迫反应的生化途径(“MEP途径”)的遗传操作，以揭示叶绿体新陈代谢的变化如何影响决定线粒体形状和活性的基因和蛋白质。这项研究的结果将确定叶绿体通过MEP途径的潜在信号功能，并确定叶绿体是否直接影响线粒体，或者信号是否必须首先通过细胞核才能重塑线粒体的形状和功能。这些结果可以用来帮助植物变得对寄生虫更具抵抗力，并对干旱或其他压力地区的生长耐受。该项目还将为本科生和研究生以及博士后研究员提供实验室培训；并将使高中生了解植物生物化学及其对植物生长的重要性和在食品生产中的作用。虽然甲戊酸途径和MEP途径都合成植物异戊二烯类化合物，但MEP途径对植物生长是不可或缺的，这表明它还有其他功能。MEP途径中的突变导致线粒体分裂和融合率改变的细胞，导致形态改变。这个项目将通过两个目标来研究叶绿体和线粒体之间的通讯：A)改变MEP途径的特定步骤，并通过生化、遗传学、荧光和电子显微镜断层扫描检查线粒体的形态；B)使用生理学、遗传学和转录组学技术来研究线粒体形态发生的哪些步骤受到干扰。这项工作将提供对植物中两种相互依赖的细胞器功能协调所需的分子和生化联系的基本见解，从而更好地理解所有真核细胞中的细胞器间通信以及植物对恶劣条件的抗性的生物化学。此外，PI将把附近五所资金不足的高中的当地学生带到实验室进行为期一年的培训。PI以及实验室中的学生和博士后研究员也将参与组织和评判当地的科学博览会。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Mitochondria are known as the ‘power-house’ in both animal and plant cells. In plant cells, mitochondria are the site of respiration where fuel derived from photosynthesis in the chloroplasts is converted to energy currency. Mitochondria can move within the cell, and upon encountering each other undergo fusion, resulting in the merger of two mitochondria into a single larger mitochondrion. Conversely, a single mitochondrion can divide into two distinct mitochondria via fission. The balanced frequencies of fusion and fission determine the overall morphology of the mitochondrial population, and are crucial for maintaining mitochondrial functions such as respiratory capacity and response to stress signals. This project will use genetic manipulations of a biochemical route (the “MEP pathway”) used to respond to stress, in order to uncover how alteration of a chloroplast’s metabolism affects the genes and proteins that determine the shape and activity of mitochondria. The outcome of this research will determine the potential signaling functions of chloroplasts through the MEP-pathway and determine if chloroplasts affect mitochondria directly, or if the signal must first travel through the cell nucleus in order to remodel mitochondrial shape and function. These results could be used to help plants become more resistant to parasites, and tolerant of growth in dry or other stressful areas. This project will also provide laboratory training for undergraduate and graduate students as well as postdoctoral fellows; and will expose high school students to the study of plant biochemistry and its importance to the growth of plants and role in food production.Although both the mevalonic acid pathway and MEP pathway synthesize plant isoprenoids, the MEP pathway is indispensable to plant growth, which suggests that it has other functions. Mutants in the MEP pathway give rise to cells with altered mitochondrial fission and fusion rates leading to altered morphologies. This project will investigate communication between chloroplast and mitochondria via the MEP-pathway through two Aims: A) Alter specific steps of the MEP pathway and examine mitochondrial morphology via biochemistry, genetics, and fluorescent and electron microscope tomography; B) Use physiological, genetic, and transcriptomics techniques to investigate which steps of mitochondrial morphogenesis are perturbed. This work will provide fundamental insights into the molecular and biochemical links required for functional coordination of two interdependent types of organelles in plants, providing greater understanding of interorganellar communication in all eukaryotic cells as well as understanding of biochemistry of plant resistance to harsh conditions. In addition, the PI will bring local students from five nearby underfunded high schools into the laboratory for yearlong training. The PI as well as students and postdoctoral fellows in the laboratory will also participate in organizing and judging local science fairs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.