Collaborative Research: Phylogenetics, biogeography, and morphological evolution of the flowering plant genus Salvia (sages and relatives)

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Sages and relatives (the flowering plant genus Salvia) within the mint family (Lamiaceae) comprises approximately 1000 species, including the economically important herbs sage and rosemary, in addition to many garden ornamentals. Sages play important ecological roles in a diversity of habitats, including providing food for butterfly and moth larvae, and nectar sources for bees and other pollinators. This study will reconstruct genealogical relationships among different sage species, and address important questions concerning the evolution of flower shape and pollination mechanisms within the group. Undergraduates, graduate students, and post-doctoral researchers at the University of Wisconsin, Madison and University of Nebraska at Kearney will be trained in a broad range of morphological and molecular systematic skills, and University of Wisconsin, Madison undergraduate students will gain tropical field biology experience through a planned capstone field course. Information about Salvia will be disseminated through a project website geared towards professional botanists and sage enthusiasts, while other project data will be presented more broadly through publically-accessible databases. The ability to reconstruct phylogenetic relationships using genome-wide DNA sequence data and powerful computational resources has revolutionized the field of systematics. These new phylogenies now provide a framework to investigate the different processes that facilitate the diversification of species within a lineage. Salvia (Lamiaceae) has a worldwide distribution and diversified extensively, both in terms of the number of species, and the variety of floral and vegetative morphologies present within the group. This research will investigate the evolution of the unique staminal feature present in members of the genus, and test whether the origin of this character is correlated with an increase in rates of speciation. Researchers will sample about 650 of the 1000 described Salvia species and use Next Generation Sequencing approaches to estimate phylogenetic relationships among Salvia and close relatives using over 450 nuclear genes and the chloroplast genome. This phylogenetic framework will then be used to determine the timing and biogeographic location of increased rates of speciation within the group. Morphometric analyses of key floral features will then be evaluated within the context of the Salvia phylogeny to test the hypothesis that the evolution of floral features have served as key innovations within the group.