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

花代表了进化创新的一个经典例子，它使开花植物成为陆地植物中最成功和物种丰富的群体。因此，深入了解开花基因是植物进化生物学的一个重要课题。虽然没有花的植物具有与花发育基因明显同源的基因，但它们的功能大多未知。该研究小组将调查一种不开花植物中花发育基因的祖先作用，这种植物是新兴的模式蕨类植物Ceratopteris richardii。该项目将促进：1）与国家和地方方案合作，增加代表性不足的少数民族在科学领域的代表性（通过参与，例如，在国家实验室日和加州大学戴维斯分校生物学本科学者计划）; 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，为加州高中生提供夏季研究机会，并为没有计算经验的学生开发本科生生物信息学实验室课程; 3）用C.理查德进入教学实验室，并进入植物进化的实践研讨会，为每年伯克自然历史博物馆的女孩在科学计划（华盛顿大学，6 - 8年级）; 4）下一代科学家的培训。有越来越多的兴趣了解转录因子和发育程序是如何增选进化创新，以及基因复制在这一过程中发挥了什么作用。LEAFY（LFY）编码一种转录调节因子，在被子植物中诱导花的形成;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在花发育之外必须具有重要的祖先功能，这一假设得到了蕨类植物中最近发现的支持。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两个蕨类植物LEAFY基因之间的顶端细胞活性是如何分配的，并确定每个基因用于实现其细胞增殖功能的基因网络。具体的研究问题是：1）在水蕨中，LFY同源基因CrLFY 1和CrLFY 2的功能是什么？这将通过基因座特异性基因表达和原位杂交、功能丧失和获得以及每个基因的pCrLFY报告基因转基因来解决; 2）CrLFY 1和CrLFY 2的直接和下游靶点是什么？这将使用ChIP-Seq和诱导型LFY构建体来确定蕨类LFY基因的靶标。考虑到LFY在被子植物发展和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。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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.