NSF Postdoctoral Fellowship in Biology FY 2019: Transcriptional Regulation and Evolution of the Maize Tapetum

这项行动为2019财年的NSF国家植物基因组计划生物学博士后研究奖学金提供资金。该研究金支持研究员在东道实验室的研究和培训计划，研究员还提出了扩大生物学参与的计划。丹尼尔布莱恩·马钱特博士的研究和培训计划的标题是“玉米绒毡层的转录调节和进化”。该奖学金的主办机构是斯坦福大学，赞助科学家是Virginia Walbot博士。从应用和基础科学的角度来看，了解花药发育是植物生物学的基础。作为花粉和雄配子的来源，花药是作物控制育种和杂交种子生产的关键变量。到目前为止，对植物体细胞从非生殖体细胞到生殖体细胞的转变的线索和途径还知之甚少。该研究的总体目标是利用玉米花药和最先进的技术和遗传资源来解决问题，并通过进化为花药发育和开花植物繁殖的细胞和遗传调控提供新的见解。玉米是这项研究的理想的主要系统，因为每个玉米植株都有单独的雄性和雌性器官系统，每株植株有数百个发育同步的花药，并且存在大量的雄性不育和雌性可育突变体。 更广泛的影响包括通过培训和指导学生以及建立一个“植物模型系统活体收藏”来扩大植物科学家的有机体和进化知识库，其中最广泛使用的植物基因组学模型系统的标本将在斯坦福大学保存。将通过提供学习资源，如网上手册，提供关于每个物种的繁殖、自然历史和进化、解剖学以及植物研究中常用的方法，如组织培养和DNA/RNA提取的信息，加强公众的利用。 培训目标包括获得新的转录组学和基因组学方法以及生物信息学工具的专业知识。体细胞重新分化和发育为生殖生殖细胞对于植物生殖是最重要的，因为植物不像有性动物那样具有已建立的生殖细胞系。因此，了解调控花药中孢子发生的细胞层的遗传线索对植物生物学至关重要，而且对农业也至关重要，因为控制花粉生产是大多数作物杂交种子生产的基础。下一代测序和微尺度RNA分离已经完全改变了我们对花药细胞层如何分化以准备减数分裂以及这些过程受到调节的线索的认识。本研究将扩展这些研究，深入研究整个花药孢子发生的细胞层的遗传调控和层次结构，重点是绒毡层，围绕萌发细胞的细胞层。将采用最先进的技术和资源，首先在玉米中分析这种特定的细胞层，然后在维管植物的分类群中分析。具体目标包括：1）鉴定野生型和绒毡层相关雄性不育基因型中绒毡层特异性和跨发育差异表达的基因和转录因子; 2）开发和实施两种新的方案，用于在单细胞规模上研究绒毡层，以解决有关花药内细胞同步性，绒毡层的精确发育阶段，和亚细胞定位的转录本的比较技术框架;和，3）提供了新的见解绒毡层遗传层次和绒毡层特异性基因的进化保护跨维管植物。这项研究的结果将在年度国际植物和动物基因组（PAG）和玉米遗传学会议上传播，并通过在高知名度的科学期刊上发表。序列数据将通过NCBI Sequence Read Archive（SRA）以及Gramene和MaizeGDB公开提供。此外，为“植物模型系统活体收藏”制作的学习资源将通过斯坦福大学生物系网站在线提供。关键词：花药，玉米，绒毡层，发育，减数分裂，花粉，孢子发生，进化该奖项反映了NSF的法定使命，并已被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This action funds an NSF National Plant Genome Initiative Postdoctoral Research Fellowship in Biology for FY 2019. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Dr. Daniel Blaine Marchant is "Transcriptional Regulation and Evolution of the Maize Tapetum". The host institution for the fellowship is Stanford University and the sponsoring scientist is Dr. Virginia Walbot.Understanding anther development is fundamental to plant biology from both applied and basic science perspectives. As the source of pollen and male gametes, anthers are a key variable in controlled crop breeding and hybrid seed production. As of yet, the cues and pathways that permit the alternation from a non-reproductive somatic cell to a reproductive germinal cell in plants are poorly understood. The overarching goal of the research is to use maize anthers and state-of-the-art technologies and genetic resources to address questions and provide new insights into the cellular and genetic regulation of anther development and flowering plant reproduction through evolution. Maize is the ideal primary system for this study because each maize plant has separate male and female organ systems, hundreds of developmentally synchronous anthers per plant, and there exists a large collection of male-sterile and female-fertile mutants. Broader impacts include expanding the organismal and evolutionary knowledge base of plant scientists by training and mentoring of students and by building a "Plant Model Systems Living Collection" in which specimens of the most widely used plant genomics model systems will be housed and maintained at Stanford University. Public access will be enhanced by the availability of learning resources such as web-based manuals providing information on the propagation, natural history and evolution, and anatomy of each species as well as on methods routinely used in plant research such as tissue culture and DNA/RNA extraction. Training objectives include acquiring expertise with new transcriptomic and genomics methods, and bioinformatics tools. The de novo differentiation and development of somatic cells into reproductive germ cells is of the upmost importance for plant reproduction as plants do not have established germlines unlike sexual animals. Understanding the genetic cues of the cell layers that regulate sporogenesis in anthers is therefore fundamental to plant biology, but also to agriculture because controlled pollen production underlies hybrid seed production of most crops. Next-generation sequencing and micro-scale RNA isolation have completely altered our knowledge of how anther cell layers differentiate in preparation for meiosis and the cues by which these processes are regulated. This study will expand upon those studies, delving further into the genetic regulation and hierarchies of the cell layers throughout anther sporogenesis with a focus on the tapetum, the cell layer surrounding the germinal cells. State of the art techniques and resources will be implemented to analyze this specific cell layer first in maize, then in taxa across vascular plants. Specific aims include: 1) identifying tapetum-specific and differentially expressed genes and transcription factors across development in wildtype and tapetum-related male-sterile genotypes; 2) developing and implementing two new protocols for investigating the tapetum at the single cell scale to address questions regarding cellular synchroneity within an anther, the precise developmental stages of the tapetum, and sub-cellular localization of transcripts in a comparative techniques framework; and, 3) providing new insights into the evolutionary conservation of the tapetum genetic hierarchy and tapetum-specific genes across vascular plants. The results of this research will be disseminated at the annual International Plant and Animal Genome (PAG) and Maize Genetics Conferences, and through publications in high profile scientific journals. Sequence data will be made publicly available through the NCBI Sequence Read Archive (SRA) and through Gramene and MaizeGDB. In addition, the learning resources produced for the "Plant Model Systems Living Collection" will be available online through the Stanford Biology Department website.Keywords: anthers, maize, tapetum, development, meiosis, pollen, sporogenesis, evolutionThis 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.