Collaborative Research: Transitions and Transcriptomics: a Novel Approach to Understanding Shifts in Floral Developmental Pathways Preceding the Origin of the Pentapetalae

合作研究：转变和转录组学：理解五瓣花起源之前花发育途径转变的新方法

• 批准号: 1457440
• 负责人: Dianella Howarth
• 金额: $ 36.73万
• 依托单位: Saint John's University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457440&HistoricalAwards=false
• 关键词: Collaborative; Research; Transitions; Transcriptomics; Novel

Flowering plants are the most abundant and diverse form of plant life on Earth. This dominance is largely due to the evolutionary success of one group, the Pentapetalae, characterized by whorled flower parts in multiples of five, which account for over 70% of described species. In contrast, flower parts are arranged in multiples of three (monocots, for example), two, or a variable number in less abundant groups of flowering plants. The shift to whorled pentamery of the Pentapetalae occurred about 100 million years ago, and appears to have been one of the most successful evolutionary innovations of not only flowering plants, but of green plants in general. This research will investigate the evolution of the underlying genetic changes that contributed to this ancient evolutionary event. It promises to discover the new and/or modified genetic pathways that produced the typical Pentapetalae flower, one of the major mysteries of plant evolution. Several undergraduates will be trained in phylogenetic and molecular biology methods and analyses, and high school teachers will participate in the research through a summer workshop. Data generated will be shared freely online and will provide tools for other researchers and the public to investigate other questions about flowering plant evolution. The researchers will sequence genes expressed during flower development in a phylogenetically representative sample of flowering plants and employ state-of-the-art transcriptome analysis techniques to achieve three major goals. Firstly, phylogenetic relationships among lineages subtending the Pentapetalae clade will be reconstructed. Robustly resolved phylogenetic relationships of the lineages preceding the shift to the pentamerous whorled flower are currently lacking but pivotal to interpreting the evolutionary sequence of genetic changes that underlie this key morphological innovation. Secondly, several comparative methods will be used to identify, date, and determine the evolutionary impact of whole-genome and/or gene duplication event(s) that predate the origin of the Pentapetalae. The occurrence of whole-genome duplication events prior to Pentapetalae is widely acknowledged but their precise positions are uncertain. Lastly, RNA-seq and in situ hybridization approaches will be used to infer spatial patterns of gene expression in non-Pentapetalae versus Pentapetalae flowers to identify gene expression changes that correlate with a shift to whorled pentamery in the latter. Together, this integration of approaches will provide exciting new insights into our understanding of flowering plant evolution

开花植物是地球上数量最多、种类最多的植物。这种优势在很大程度上是由于一个群体的进化成功，五瓣花，其特征是轮生的花部分为五倍，占所描述物种的70%以上。相比之下，花的部分以三个（例如单子叶），两个或在较少的开花植物群中以可变数量排列。五瓣植物向轮生五元体的转变发生在大约1亿年前，这似乎不仅是开花植物，而且是一般绿色植物最成功的进化创新之一。这项研究将调查促成这一古老进化事件的潜在遗传变化的演变。它有望发现产生典型五瓣花的新的和/或修改的遗传途径，这是植物进化的主要奥秘之一。几名本科生将接受系统发育和分子生物学方法和分析方面的培训，高中教师将通过暑期研讨会参与研究。生成的数据将在网上免费共享，并将为其他研究人员和公众调查开花植物进化的其他问题提供工具。研究人员将在开花植物的系统发育代表性样本中对花发育过程中表达的基因进行测序，并采用最先进的转录组分析技术来实现三个主要目标。首先，重建五瓣门分支谱系之间的系统发育关系。在向五分生轮生花转变之前，谱系的系统发育关系目前尚缺乏明确的解决方案，但对于解释这一关键形态创新背后的遗传变化的进化序列至关重要。其次，将使用几种比较方法来识别，确定日期，并确定全基因组和/或基因复制事件的进化影响，这些事件发生在五瓣花序起源之前。全基因组复制事件的发生早于五瓣花被广泛承认，但他们的精确位置是不确定的。最后，RNA-seq和原位杂交方法将用于推断非五无瓣花与五无瓣花基因表达的空间模式，以确定基因表达变化与后者向轮生五聚体转变相关。总之，这些方法的整合将为我们对开花植物进化的理解提供令人兴奋的新见解