Collaborative Research: Comparative analysis of fern LEAFY genes and their regulatory network

花卉代表了进化创新的经典例子，它使开花植物成为最成功和物种最丰富的陆地植物群体。因此，深入了解植物开花的基因是植物进化生物学中的一个重要课题。虽然没有花的植物有明显与花发育基因同源的基因，但它们的功能大多尚不清楚。该研究小组将研究花发育基因在一种非开花植物--新兴模式蕨类植物--里卡迪亚蕨类植物中的祖先作用。该项目将促进：1)与国家和地方项目合作，增加未被充分代表的少数群体在科学领域的代表性(例如，通过参加国家实验室日和加州大学戴维斯分校生物学本科生计划)；2)整合研究和教学活动：例如，加州大学戴维斯分校青年学者计划，为加州大学高中生提供暑期研究机会，并为以前没有计算经验的学生开发本科生生物信息学实验班；3)将与C.richardii的实验纳入教学实验室，并为伯克大学自然历史女孩在科学年度计划(UW，6-8年级)的植物进化实践研讨会；4)培养下一代科学家。人们越来越有兴趣了解转录因子和发育程序是如何被用于进化创新的，以及基因复制在这一过程中扮演了什么角色。LEAFY(LFY)编码一种转录调节因子，诱导被子植物中的花形成；它也存在于苔藓中，在那里它控制受精卵的早期细胞分裂，在蕨类植物中，它促进配子体和孢子体世代的细胞分裂。LFY在陆地植物中的保守性表明，它一定在花发育之外具有重要的祖先功能(S)，这一假说得到了蕨类植物最近的发现的支持。蕨类植物C.richardii是维管植物谱系的代表，位于苔藓和开花植物之间的进化树的中间。该项目的目标是研究顶端细胞活性如何在两个蕨类植物叶基因之间分配，并确定每个基因网络用于实现其细胞增殖功能。具体的研究问题有：1)CrLFY1和CrLFY2的LFY同源基因在羊齿蕨类植物中的功能是什么？这将通过每个基因的位点特异性基因表达和原位杂交、功能丧失和功能获得以及pCrLFY报告基因的转基因来解决；2)CrLFY1和CrLFY2的直接和下游靶标是什么？这将使用ChIP-Seq和可诱导的LFY构建物来解决，以定义蕨类LFY基因的靶标。鉴于LFY在被子植物发育和整个陆地植物保护中的节点作用，这项研究应该成为其他主调节器进化研究的关键范例。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。

Flowers represent a classic example of evolutionary innovation, one that made the flowering plants the most successful and species rich group of land plants. Hence, a deep understanding of the genes underlying flowering is an important topic in plant evolutionary biology. While plants that do not have flowers have genes that are clearly homologous to flower development genes, their function is mostly unknown. The research team will investigate the ancestral role of a flower development gene in a non-flowering plant, the emerging model fern Ceratopteris richardii. This project will facilitate: 1) Working with national and local programs to increase the representation of under-represented minorities in the sciences (by participating e.g., in National Lab Day and UC Davis Biology Undergraduate Scholars Program); 2) Integrating research and teaching activities: e.g., UC Davis Young Scholars Program that provides summer research opportunities for California high school students, and development of undergraduate bioinformatics lab class for students without previous computational experience; 3) Incorporating experiments with C. richardii into teaching labs and into a hands-on workshop on plant evolution for the annual Burke Museum of Natural History Girls in Science program (UW, 6th-8th graders); 4) Training of the next generation of scientists.There is growing interest in understanding how transcription factors and developmental programs are co-opted for evolutionary innovation, and what role gene duplications play in this process. LEAFY (LFY) encodes a transcriptional regulator that induces flower formation in angiosperms; it is also present in mosses, where it governs early cell divisions of the zygote, and in ferns where it promotes cell division in both the gametophyte and the sporophyte generations. The conservation of LFY across land plants suggests that it must have important ancestral function(s) outside of flower development, a hypothesis supported by recent findings in fern. The fern C. richardii is a representative of a lineage of vascular plants that lies midway in the evolutionary tree between mosses and flowering plants. The goal of this project is to investigate how apical cell activity is partitioned among the two fern LEAFY genes and determine the gene network that each uses to achieve its cell proliferation functions. The specific research questions are: 1) What is the function of each LFY homolog CrLFY1 and CrLFY2 in the fern Ceratopteris richardii? This will be addressed via locus-specific gene expression and in situ hybridization, loss- and gain-of-function and pCrLFY-reporter transgenics for each gene; 2) What are the direct and downstream targets of CrLFY1 and CrLFY2? This will be addressed using ChIP-Seq and inducible LFY constructs to define targets of fern LFY genes. Given the nodal role of LFY in angiosperm development and its conservation throughout land plants, this research should serve as a key example for evolutionary studies of other master regulators.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.