Collaborative Research: RESEARCH-PGR: Comparative Genomics of the Capitulum: Deciphering the Molecular Basis of a Key Floral Innovation

About This Grant

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.