Collaborative Research: RUI SG: Evolutionary relationships and systematics of riverweeds (Podostemaceae)

Eastern Kentucky University, Richmond KY

Investigators

Abstract

The riverweed family (Podostemaceae) is the largest entirely aquatic family of flowering plants and provides important habitats and food sources for many aquatic animals. Many of the estimated 300 riverweed species are narrowly distributed and incompletely known, and genealogical relationships within the family are uncertain. This project will produce the first family-wide estimate of genealogical relationships among riverweeds using DNA sequence data, and a better understanding of relationships, morphological variation, and will clarify the number of different species that exist. This project will provide broad training opportunities for undergraduate students in both field and laboratory research, including molecular biology, plant structural analyses, database development and management, and taxonomomy at two Primarily Undergraduate Institutions located in Connecticut and Kentucky. DNA sequence data generated by the project will be disseminated via publicly accessible databases, and newly collected plant specimens will be deposited within natural history museums. This project will produce a molecular systematic and phylogenetic analysis of the flowering plant family Podostemaceae, and a taxonomic monograph of the genus Apiniagia (Podostemaceae). Podostemaceae species exhibit high phenotypic plasticity and have highly modified growth forms, both of which contribute to taxonomic confusion. This project will assemble a well-sampled and robust phylogeny of the family, with a focus on neotropical taxa, using morphological data and molecular data obtained via high throughput DNA sequencing. Molecular data will be collected from whole chloroplast genomes and select mitochondrial and nuclear loci. This phylogeny will be used to circumscribe all neotropical genera of Podostemaceae, understand convergent patterns of morphological evolution, and test the hypothesis that the distribution of the neotropical Podostemoideae clade is largely explained by major river capture events during the Cenozoic. Using the results of the phylogenetic analyses in combination with morphological investigations, a taxonomic monograph for the genus Apiniagia will be produced. This genus is the largest, most morphologically complex, and taxonomically difficult genus of neotropical Podostemaceae. The monograph will include nomenclatural updates, morphological descriptions, and taxonomic keys, in addition to newly developed online resources to broadly disseminate the results. This project will also produce a new, free tool for the systematics community, a Darwin Core Archive export option for the Symbiota platform specific to monographic data sets. 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.