Sam Houston State University
Department of Biological Sciences
Research Interests: My research interests lie primarily in the biology of parasitic plants with an emphasis on systematics and molecular evolution. Some parasitic plants rely on crop hosts, thereby posing a grave threat to global food security. Of the five most economically dangerous genera of parasitic plants, four belong to Orobanchaceae, a family of root parasites. Of these, three arose in a poorly understood tropical lineage. Other tropical genera of this lineage include few species that are rarely collected. However, as agriculture develops in former natural ranges of these plants, the potential for host switching may result in the evolution of new strains of crop pests, and ones that we are sorely unable to contain due simply to our ignorance of their biology. Orobanchaceae also allows a model system in which to study the evolution of holoparasitism, the condition in which plants become entirely dependent on host plants for water, minerals and photosynthates. The evolution of holoparasitism is often accompanied by the degradation or loss of genes associated with photosynthesis, and the loss of structures and functions associated with nutrient acquisition such as leaves, roots, or chlorophyll synthesis. The evolution of Orobanchaceae includes four transitions from partial parasitism to holoparasitism. An ongoing focus of my lab is to collect, document, and classify tropical parasites in this lineage using molecular phylogenetics to understand evolutionary patterns of host-preference and dependence. Goals of this research include A) the establishment of a classification system that incorporates tropical species, B) the creation of an on-line diagnostic key to tropical genera available to scientists and agricultural agents alike, C) investigation of the molecular changes that accompany the transition to holoparasitism.