Plant Transverse Microtubule Array Organization

植物利用太阳的能量将二氧化碳气体转化为生命所需的有机物质。这种初级生产力的关键是植物茎向大气的轴向延伸，在那里叶子可以捕捉阳光并交换气体。同样的轴向生长过程驱使根系进入土壤，为有机体寻找水、养分和稳定的立足点。本项目的重点是阐明种子植物在细胞水平上执行轴向生长计划的分子机制。种子植物采用了真核细胞中存在的主要聚合物系统之一微管，并将其重新用作图案剂。植物细胞在细胞膜下产生特定的微管模式，这些微管作为构建细胞外部纤维壁的模板。正是细胞壁最终赋予了植物结构和硬度。植物细胞壁的精细纳米结构是所有种子植物轴向向上延伸到阳光下或向下延伸到土壤中的能力的基础。本研究在拟南芥模型系统中采用现代分子遗传学技术和先进的细胞生物学方法，目的是发现轴向细胞生长中组织微管阵列特别需要哪些基因。更广泛的影响正在进行的基础科学影响着实际和商业利益的几个领域。作物种植密度直接取决于轴向生长习性（如玉米或大豆田）。这项工作将进一步阐明在种子萌发这一作物植物发育的关键时期参与下胚轴机械延伸的基因。这项工作为植物微管动力学（一种常见的除草剂靶标）和细胞壁中纤维素聚合物（主要的生物燃料原料）的模式提供了有价值的信息。该项目为一名博士后和两名（连续）研究生提供高级培训。培训将包括接触前沿成像技术和综合数学建模。至少2名本科生将在这个项目上工作，作为他们本科荣誉论文要求的一部分。为获取和分析活细胞图像数据而开发的专门技术正在以技术报告和研讨会的形式提出，以推动这一领域的发展。

Intellectual MeritPlants use the sun's energy to convert carbon dioxide gas into the organic materials required for life. Key to this primary productivity is the axial extension of plant stems into the atmosphere where leaves can capture sunlight and exchange gases. The same axial growth process drives roots into the soil to find water, nutrients and a stable footing for the organism. This project is focused on elucidating the molecular mechanisms by which seed plants execute this axial growth plan at a cellular level. Seed plants have taken one of the major polymer systems found in all eukaryotic cells, the microtubules, and repurposed them as patterning agents. The plant cell creates specific patterns of microtubules just underneath the cell's membrane that act as templates for the construction of the fibrous walls created on the outside of the cell. It is the cell wall that ultimately gives the plant its structure and rigidity. The finely detailed nanofabrication of the plant cell wall underlies the ability of all seed plants to extend axially up into the sunlight or down into the soil. This work employs modern molecular genetic techniques and advanced cell biological methods in the Arabidopsis model system with the aim of discovering what genes are specifically required for organizing the microtubule arrays for axial cell growth.Broader impactsThe basic science being performed impacts several areas of practical and commercial interest. Crop plant plot density is directly dependent upon the axial growth habit (e.g. corn or soybean fields). This work will further elucidate the genes involved in mechanical extension of the hypocotyl during seed germination, a critical period in crop plant development. This work provides valuable information about plant microtubule dynamics, a common herbicide target, and the patterning of cellulose polymers in the cell wall, the major biofuels feedstock. This project provides advanced training for a post-doctoral fellow and two (sequential) graduate students. The training will include exposure to leading-edge imaging technologies and integrated mathematical modeling. At least 2 undergraduate students will be working on this project as part of their undergraduate honors thesis requirements. Specialized techniques developed for acquisition and analysis of live-cell image data are being presented as technical reports and in seminars to advance the field.