Phylogeny, historical biogeography, and floral ecological-evolutionary-developmental studies in Mariposa lilies and relatives (Calochortus, Liliaceae)

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Mariposa lilies and relatives (Calochortus, family Liliaceae) are a genus of roughly 80 species of bulbous herbs. Most Calochortus species are found in California but the group can also be found in other parts of western North America and Central America. Calochortus species occur in diverse habitats and have repeatedly evolved four striking floral syndromes (mariposas, cat's ears, star tulips, fairy lanterns) marked by differences in flower shape, color, hairiness, and whether flowers are nodding or erect. Most species are individually restricted to narrow geographic areas, and 25% are associated with serpentine soils. This project will examine the forces that have shaped both differences in flower appearance of this charismatic group and driven their geographic spread across the western US. The researchers will test theories for how different habitats may favor the different four floral syndromes, and evaluate whether the same or different genes or genetic pathways underlie the development of similar floral syndromes. The study will provide unique insights into the evolution of biological diversity by integrating ecology, evolution, genomics, development, and biogeography. Two post-doctoral researchers, two graduate students, and three undergraduates will be trained in diverse molecular biology, developmental and evolutionary techniques. Results from the study will be disseminated to the public via popular articles, outreach to K-12 teachers and students, and by developing teaching materials for a college-level laboratory study on floral evolution and California biogeography. Public displays on Calochortus diversity will be exhibited at the Rancho Santa Ana Botanical Garden and Cornell Botanic Gardens. A field course will provide college students with hands-on experience involving natural history collections, bioinformatics, and comparative biology. A multimedia presentation will be developed and shown on public TV, with excerpts posted on YouTube. All data will be made available publicly, including a database and dedicated website for the extensive genomic resources that will be developed. This project will develop Calochortus as a model for macro- and microevolutionary studies by: (1) sequencing 350 low-copy nuclear loci and whole plastid genomes to derive fully resolved, strongly supported phylogenies; (2) reconstructing trait evolution, climatic niche shifts, and historical biogeography, including investigating the implications of an apparent ring species complex in the Bay Area clade; (3) testing geographic-speciation theory by determining whether sister taxa show a significant tendency to have abutting/nearby ranges; and (4) conducting floral ecological-evolutionary-developmental studies that examine the genetic, developmental, and ecological bases for the cat's-ear and fairy-lantern floral syndromes. Researchers will use analyses of selection on candidate genes, gene expression and evolution of genetic networks, functional gene analysis through CRISPR genome editing and comparative studies of developmental allometry, climatic niches, and genomic data to better understand the mechanisms driving the recurrent evolution of floral traits in specific environmental contexts.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.