Systematics of Cyperaceae: diversification, biogeography and evolution

点击翻译按钮获取中文摘要

My research focuses on the systematics of the sedge family (Cyperaceae), a remarkable group of plants characterized by their exceptional diversity (~5500 species), varied habitats (deserts to rain forests), unusual cytology (n = 6 - 56) and diverse biogeographical patterns. In the Flora of North America region (FNA), sedges represent nearly 4% of our native flora (10% in Canada); they are common to every floral region, and they dominate vast areas of the continent in terms of diversity and biomass. Nevertheless, sedges remain a poorly studied group whose classification and relationships are still unresolved. My long-term research goal is to discover and conserve sedge biodiversity and to arrange it in predictive, phylogenetic classifications that provide a comparative framework for testing evolutionary, biogeographic, and ecological hypotheses.Towards this long-term goal, we will focus on three short-term objectives. Objective 1 will develop a strongly supported phylogenetic hypothesis for Cyperaceae using next generation sequencing (NGS) to circumscribe sedge tribes and genera. The emphasis of sampling will be on the Cariceae-Dulichieae-Scirpeae (CDS) Clade to complete a reclassification of CDS (three new tribes and a subtribe; PhD continued) and on tribe Fuireneae (PhD 1) where data suggests Fuireneae could consist of as many as four separate tribes (collaboration with Drs. I. Larridon, Kew, and A. Monfils, Central Michigan Univ.). Objective 2 will build on two significant discoveries, the fact there are eight, not five major clades in the giant genus Carex (~2150 species), and that the small genus Sumatroscirpus (4 species) is sister to Carex, a result with far reaching implications for studying Carex evolution. PhD 2 will study all aspects of Sumatroscirpus biology for polarising Carex comparative analyses, and they will finally resolve Carex major clade relationships using NGS. Moreover, we will continue to collaborate with the Global Carex Group to produce a complete molecular phylogeny for Carex (~46% sequenced for ITS, ETS, matK; BSc students contributing), and to build on a four marker (ITS, ETS, matK, rps16) dataset for all FNA species to explore whole phenotype evolution and Carex diversification (PhD 3, collaboration with Drs. H. Cui, Univ. of Arizona and J. Macklin, Ag Canada). Objective 3 will revise and study the biology of the early diverging Carex sections Euprepes and Mapaniifoliae (MSc 1 s goal of polarising comparative analyses in Carex, and the training provided will address a problematic reduction in taxonomic capacity in Canada. The wider scientific impact of this research ranges from the discovery of new tribes, genera and species, to targeted drug discovery, an improved understanding of world biogeography and the role of chromosome evolution on plant diversification.