A Phylogenetic Study of Apiaceae Tribe Oenantheae

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

0089452 Downie Dr. Stephen Downie of the University of Illinois will lead an international collaborative effort to study the evolution and classification of the Apiaceae (carrot family) tribe Oenantheae, a group of plants not recognized in any traditional classification of the family but clearly showing close relationship among themselves from DNA sequence comparisons. Many of these plants have tuberous roots, spongy thickened fruits, and often highly simplified leaves in association with their semi-aquatic growth. Some are economically and ecologically important, including the genus Cicuta, water hemlock, reputedly the source of the poison used by Socrates. The overall goal of the project is to produce a comprehensive phylogenetic tree for all 120 or so species in the group, using new DNA sequence data and traditional fruit anatomical and morphological characters. Molecular data will be obtained from the nuclear ribosomal DNA internal transcribed spacer region and from five chloroplast introns, the latter not yet fully exploited for their ability to help resolve genealogical relationships. In collaboration with specialists Krzysztof Spalik in Poland and Mark Watson in Scotland, and with colleague James Affolter at University of Georgia, detailed anatomical and morphological investigations will be made of fruit and leaf structures, to assess features reliable for classification and to chart likely trends of evolutionary change in association with the plants' adaptation to aquatic habitats. Tribe Oenantheae contains many edible, medicinal, or highly toxic members, exhibits a complex and diverse natural-products chemistry, includes three species that are federally listed as endangered, and can serve as a model system for the study of plant-insect interactions. A phylogenetic framework for the group will serve further studies of phenotypic character evolution, ecological associations, conservation biology, and historical biogeography. The results will also provide an independent evaluation of the utility of traditional taxonomic characters of fruit and seed in the family, long considered of importance in classification.