CAREER: Molecular Mechanisms of Plant Cell Tip Growth

职业：植物细胞尖端生长的分子机制

• 批准号: 0747231
• 负责人: Magdalena Bezanilla
• 金额: $ 82.56万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0747231&HistoricalAwards=false
• 关键词: CAREER; Molecular; Mechanisms; Plant; Cell

Research Activity: Tip growth is a form of plant cell growth that although restricted to a few cell types, is essential for the development of plant species ranging from algae to flowering plants. In seed plants in particular, the tip-growing pollen tube is required for fertilization and thus propagation of the species. The root hair is important for absorption of water and minerals required for growth and development of the entire plant. This project will focus on deciphering the molecular signals that control tip growth, thus impacting an evolutionarily wide range of plant cell development. The research will be carried out in an emerging plant model system, the moss Physcomitrella patens. The ease of molecular genetic manipulation and the abundance of tip growing cells make moss ideal for these studies. The moss system is unique among plants for its gene-targeting capabilities. Additionally Dr. Bezanilla recently developed a rapid RNA interference assay, which rapidly reveals plant gene function and is unparalleled in any plant system. Using this assay, Dr. Bezanilla found that certain proteins participating in the actin cytoskeletal network are critical for tip growth. These studies have lead to a working model whereby growth polarization is controlled by a molecular signaling cascade stemming from activation of the plant-specific small GTPase ROP, which in turn signals to the actin monomer binding protein profilin via formins, cellular nucleators of actin filaments, thus coordinating actin dynamics to occur at the site of growth. The project will test this model using a combination of reverse genetics, dynamic live-cell imaging, and molecular interaction screens. Three major questions will be addressed: (1) How is ROP regulated? (2) Do formins function in the ROP-profilin pathway? and (3) What is the molecular composition of the ROP-profilin pathway? Many organisms, including fungi and animals, control cellular morphogenesis via a similar signaling cascade. Thus this research will provide novel comparative insights into this evolutionarily conserved process.Broader Impacts: This project has potential agricultural benefits for society. By elucidating the fundamental mechanisms controlling plant cell tip growth, this research will impact the understanding of important plant cell types, which are involved in determining overall plant fitness and thus crop yields. The project will also integrate research with teaching and training and will broaden the participation of underrepresented groups in science. Dr. Bezanilla, herself a member of an underrepresented minority in science, has recruited and mentored an excellent minority postdoctoral researcher. Dr. Bezanilla will also develop a course on moss methods that will be taught both at the University of Massachusetts as well as at partner minority serving institutions through an NSF-funded Northeast Alliance for Graduate Education and the Professoriate to further enhance recruitment of underrepresented groups in science.

研究活动：尖端生长是植物细胞生长的一种形式，尽管仅限于几种细胞类型，但对于从藻类到开花植物的植物物种的发展至关重要。 尤其是在种子植物中，施肥需要尖端生长的花粉管，从而繁殖该物种。根毛对于吸收整个植物的生长和发育所需的水和矿物质很重要。该项目将着重于破译控制尖端生长的分子信号，从而影响植物细胞的发展范围广泛。这项研究将在新兴的植物模型系统苔藓物理学系统中进行。分子遗传操作的易于性和尖端生长细胞的丰度使得苔藓是这些研究的理想选择。苔藓系统在植物中的基因靶向能力是独一无二的。此外，Bezanilla博士最近开发了一种快速的RNA干扰测定法，该测定法迅速揭示了植物基因功能，并且在任何植物系统中都是无与伦比的。使用此测定，Bezanilla博士发现，参与肌动蛋白细胞骨架网络的某些蛋白质对于尖端生长至关重要。这些研究导致了一个工作模型，在该模型中，生长极化是由分子信号传导级联反应控制的，该级联因植物特异性的小GTPase ROP的激活而导致，进而向肌动蛋白单体结合蛋白通过甲蛋白（通过formins，肌动蛋白丝的细胞成核）进行信号，从而在肌动蛋白丝中的细胞成核，从而在生长的位置均衡。该项目将使用反向遗传学，动态活细胞成像和分子相互作用屏幕的组合来测试该模型。将解决三个主要问题：（1）ROP如何受到监管？ （2）formins在ROP-profilin途径中是否功能？ （3）ROP-易期途径的分子组成是什么？许多生物，包括真菌和动物，通过类似的信号级联反应控制细胞形态发生。因此，这项研究将为这一进化保守的过程提供新颖的比较见解。BROADER的影响：该项目对社会具有潜在的农业利益。通过阐明控制植物细胞尖端生长的基本机制，这项研究将影响对重要的植物细胞类型的理解，这些植物细胞类型涉及确定植物整体适应性，从而涉及农作物的产量。该项目还将将研究与教学和培训相结合，并将扩大代表性不足的科学的参与。 Bezanilla博士本人是科学代表性不足的少数群体的成员，曾招募并指导了一位优秀的少数派博士后研究员。 Bezanilla博士还将通过NSF资助的东北研究生教育联盟和教授进一步增强科学科学中代表性不足的团体的招聘，还将在马萨诸塞大学和少数民族服务机构中开发有关MOSS方法的课程。