Linda E. Watson
, Professor
Ph.D.
(1989) University of Oklahoma
Areas of Expertise
Plant systematics and evolution, molecular systematics, phylogenetics, and biogeography
Research Interests
My research program is focused on using molecular phylogenetics as a framework to address systematic and evolutionary questions in plants, with a strong concentration on the Asteraceae - the Sunflower Family, and specifically in Tribes Anthemideae (Daisies and Chrysanthemums) and Senecioneae (the giant genus Senecio). I am particularly interested in using molecular markers to understand patterns of biogeography and species diversification. Our research on Tribe Anthemideae has revealed its South African origin with subsequent divergence and migration into western Eurasia and Far East Asia. Its success involves relatively recent radiations of large and widespread genera in the Northern Hemisphere correlated with polyploidy that includes Anthemis and Achillea, and a shift to wind pollination in Artemisia. In Tribe Senecioneae, we are utilizing molecular phylogenies to understand how climatic changes during the Tertiary drove species diversification in Mediterranean type climates on all five continents.
Molecular phylogenies are also effective for understanding evolutionary relationships or associations with other organisms. Graduate student research in my lab has focused on ant-plant mutualisms in a lineage of Central American Piper species to understand the evolution of obligate, facultative, vs. no ant associations to answer questions about what morphological traits facilitate these relationships and their pattern of occurrence (single vs. multiple origins, and facultative relationships as a transition to obligate ones). We also are examining the evolution of mycorrhizal relationships with non-photosynthetic orchids in the genus Hexalectris. It is unclear whether a one-to-one relationship between mycorrhizal fungal species and plant species exists, or whether host shifting by the plants among fungal species occurs, or whether or not these associations account for diversification in the orchid lineage.
My students have conducted research on a number of different plant groups including Artemisia (sagebrush), Trifolium (clover), Asclepias (milkweeds), Piper (pepper), Hexalectris (crested coralroot), Caribbean Rubiaceae (coffee family), Eriocaulaceae (pipeworts), and even nitrogen-fixing cyanobacteria. The thread that ties these studies together is the utilization of molecular phylogenetics as independenet frameworks with which to address systematic and evolutionary questions.
Selected Publications
Pelser, P.B., B. Nordenstam, J.W. Kadereit, and L.E. Watson. In review. An ITS phylogeny of Tribe Senecioneae (Asteraceae) and a new delimitation of Senecio. Taxon.
Oberprieler, Christoph, Robert Vogt, and Linda E. Watson. 2007. Tribe Anthemideae. In: J. Kadereit and Charles Jeffrey, [eds.], Families and Genera of Vascular Plants, Volume 8, Asterales, pp. 342-373. Springer, Inc.
Tepe, E.J., M.A. Vincent, and L.E. Watson. 2007. Comparative morphology of ant associated plant structures in Piper sect. Macrostachys (Piperaceae): Stem structure and excavation of cauline domatia. American Journal of Botany 94: 1-12.
Badr, A, H. El-Shazly, and L.E. Watson. 2007. Origin and ancestry of the Egyptian clover (Trifolium alexandrinum L.) revealed by AFLP markers. Genetic Resources and Crop Evolution.
Henson, Brian J., Linda E. Watson, and Susan R. Barnum. 2004. The evolutionary history of nitrogen fixation, as assessed by nifD. Journal of Molecular Evolution 58:390-399.