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Parasitic plants · Plant communication · Weed evolution

My research focuses on parasitic plants, which are interesting because of their remarkable adaptations to a parasitic lifestyle as well as their economic impact on agriculture.

Parasitic plants differ from typical autotrophic plants in that they obtain their water and nutrients from a "host" plant. To accomplish this, they have evolved a unique structure called a haustorium, which invades the host and connects to the host vascular system to enable the parasite to siphen off host resources. Some species of parasitic plants have evolved so far as to completely lose their capacity for photosynthesis, and thus depend entirely on their hosts for survival.

Parasitic plants are masters of plant communication. The ability to locate and attach to a host plant is essential for survival of parasites, so it is no surprise that they have highly developed strategies for interacting with other plants. In fact, all plants have capacity to respond to their environment and communicate with other organisms, although this is widely overlooked by people outside of plant science. Plants are good at detecting shades of light, chemical signals, and physical contact, but parasitic plants provide some of the clearest illustrations of this. For example, seeds of some parasite species only germinate after they detect the presence of a root of an appropriate host. Additional communication takes place between cells of the two species after the parasite contacts the host, and parasite cells must interact with those of the host to coordinate nutrient transfer and avoid host defenses. We are especially interested in the roles played by the exchange of RNAs and other large molecules between parasites and their hosts.

Parasitic plants that attack crop plants are some of the world's most troublesome weeds. They can be especially destructive because they directly take resouces from the host crop, and are difficult to control due to their close connections to the host. All weeds evolve in response to selective pressures, adapting to survive control measures and expand their ranges. Parasitic weeds demonstrate exceptional ability to adapt, modifying their host preferences and moving to new parts of the world. Understanding how they do this is an important step in devising effective plans to manage parasitic weed problems.

Current News

Catch the podcast where Jim discusses the future of weed control! 

Croptastic, the Inner Plant podcast, Episode 20.


  • PeerJ: Multiple immune pathways control susceptibility of Arabidopsis thaliana to the parasitic weed Phelipanche aegyptiaca.  Go to: DOI: 10.7717/peerj.9268
  • Weed Science: A new race of sunflower broomrape (Orobanche cumana) with a wider host range due to changes in seed response to strigolactones. Go to: DOI: 10.1017/wsc.2019.73