Collaborative Research: RESEARCH-PGR: Comparative genomics of the capitulum: deciphering the molecular basis of a key floral innovation

向日葵、雏菊及其近缘植物属于一个植物科，约占开花植物生物多样性的10%，包括许多具有园艺、药用和工业价值的物种。这组开花植物还包括重要的经济作物，如洋蓟、生菜、红花和向日葵。由于其庞大的体型和全球分布，它被认为是最成功的植物家族之一。该家族成功的关键是它的花序(头状花序或花头)，它看起来像一朵大花，但实际上是许多小花的聚合体。这种独特的花结构在吸引传粉者方面发挥着重要作用，也是该科许多作物品种产量的主要决定因素。尽管头状花序很重要，但人们对它的发育所涉及的基因知之甚少。了解花序是如何发育的，有可能通过优化作物产量的花结构，并通过加快新作物开发的进展来改善粮食安全。该项目将增加家庭可用的基因组资源，并导致开发用于家庭基因编辑的新工具。这项工作将揭示一个重要的经济家族头状花序发育所涉及的基因，并为优化相关作物的花序结构提供有价值的信息。该项目将通过有针对性地努力从传统上代表性不足的群体中招募个人，为不同级别的学生和研究人员提供教育机会。该项目结合了比较基因组学、花序发育转录学、分子进化分析和功能方法，以破译向日葵家族(菊科)和相关的开花植物谱系中一个关键的花特征--头状花序--的基因组基础。该项目将能够测试与基因复制和基因组进化在推动进化新颖性方面的作用、头状茎起源所涉及的进化力以及进化过程在植物谱系中的重复性有关的假说。这种综合的方法将能够测试关于菊科和相关开花植物谱系的花序发育的预测假说。主要的科学目标是：(1)利用比较转录学方法破译菊科头状结构的分子基础；(2)确定头状结构的独立起源是否通过共同的进化过程和基因组机制产生；以及(3)分析关键头状结构基因的功能作用，针对已建立的干细胞调节基因和通过比较/进化基因组分析确定的候选基因。该项目将为多个物种生成高质量的基因组和精选的花序转录本，并辅之以比较基因组和进化分析。这些资源和由此产生的数据将通过同行评议的出版物和公开演示文稿传播，并将通过存放在公共储存库和数据库中免费提供，这些数据库包括国家生物技术信息序列读取档案(NCBI-SRA；https://www.ncbi.nlm.nih.gov/sra)，Phytozome(https://phytozome-next.jgi.doe.gov/)，)；Http://ncbi.nlm.nih.gov/geo)，FigShare(https://figshare.com/)，)和Dryad(https://dryad.org/).This)奖项反映了国家科学基金会的法定使命，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。

Sunflowers, daisies, and their relatives belong to a family of plants that make up ca. 10% of flowering plant biodiversity and include numerous species of horticultural, medicinal, and industrial value. This group of flowering plants also contains economically important food crops including artichoke, lettuce, safflower, and sunflower. It is considered one of the most successful plant families due to its large size and global distribution. Key to the success of the family is its inflorescence (a capitulum or flower head) which resembles a single, large flower but is actually an aggregate of many small flowers. This unique floral structure plays an important role in pollinator attraction and is a major determinant of yield in many of the family’s crop species. Despite the importance of the capitulum, little is known about the genes involved in its development. Understanding how inflorescences develop has the potential to improve food security through optimization of floral structures for yield in crops, and by accelerating progress toward new crop development. This project will increase available genomic resources for the family and result in the development of novel tools for gene editing in the family. This work will shed light on the genes involved in the development of the capitulum inflorescence in an economically important family and provide valuable information that will facilitate efforts for optimizing inflorescence architecture in related crops. This project will provide educational opportunities for diverse students and researchers at multiple training levels, through directed efforts to recruit individuals from traditionally underrepresented groups. This project integrates comparative genomics, inflorescence developmental transcriptomics, molecular evolutionary analyses, and functional approaches to decipher the genomic basis of a key floral trait – the capitulum – in the sunflower family (Asteraceae) and related flowering plant lineages. This project will enable the testing of hypotheses related to the role of gene duplication and genome evolution in driving evolutionary novelty, the evolutionary forces involved in the origin of the capitulum, and the repeatability of the evolutionary process across plant lineages. The integrated approach will enable the testing of predictive hypotheses about inflorescence development in Asteraceae and related flowering plant lineages. The primary scientific goals are to: (1) decipher the molecular basis of the Asteraceae capitulum using comparative transcriptomic approaches; (2) determine whether the independent origins of capitula arose via common evolutionary processes and genomic mechanisms; and (3) analyze the functional role of key capitulum genes, targeting established stem cell regulatory genes and candidates identified through comparative/evolutionary genomic analyses. This project will generate high-quality genomes and curated inflorescence transcriptomes for multiple species complemented by comparative genomic and evolutionary analyses. These resources and the resulting data will be disseminated via peer-reviewed publications and public presentations and will be made freely available via deposition in public repositories and databases including the National Center for Biotechnology Information Sequence Read Archive (NCBI-SRA; https://www.ncbi.nlm.nih.gov/sra), Phytozome (https://phytozome-next.jgi.doe.gov/), the Gene Expression Omnibus (GEO; http://ncbi.nlm.nih.gov/geo), FigShare (https://figshare.com/), and Dryad (https://dryad.org/).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.