We are interested in learning how plants use chemical signals to coordinated their interactions with other plants. The most commonly studied chemical exchanges between plants are allelopathic processes in which a plant releases phytotoxins that inhibit the growth of neighboring plants. While allelopathic interactions have been recognized since the Roman Empire, it remains difficult to harness allelopathic mechanisms to control weeds in agricultural settings. We are identifying the genetic mechanisms controlling how parasitic angiosperms recognize and invade their plant hosts because these plants provide the most robust phenotypes of plant-plant signaling.
We study plant parasitism in the Orobanchaceae, a family of root parasites that includes some of the world’s worst agricultural pests, notably Striga and Orobanche. Because of the invasive potential of weedy Orobanchaceae, we use the closely related parasite Triphysaria as an experimental organism. The Orobanchaceae use chemical and tactile stimuli provided by host roots to initiate the development of haustoria, parasitic plant specific organs used to attach to and invade host roots. The competence to develop haustoria is the key character of parasitic plants and enables them to adapt a heterotrophic lifestyle.
We are taking genomic approaches to define the genetic processes regulating haustorium growth and function. Once candidate parasite genes are identified, their functions are evaluated in transgenic parasite roots. Genes identified as critical for parasite survival are being incorporated into an RNAi based strategy for developing parasitic weed resistant crops.