Parasitic plants · Plant communication · Weed evolution

Jim Westwood in lab examining cuscuta damage.

My research focuses on parasitic plants, which are interesting because of their remarkable adaptations to a parasitic lifestyle as well as their economic impact in 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 gone so far as to completely lose their capacity for photosynthesis, and thus depend entirely on their hosts for survival.

Considering the importance to the parasite of finding and attaching to a host plant, it is no surprise that parasitic plants are highly adept at plant communication. All plants sense their environment by detecting shades of light, chemical signals, and physical contact, but parasitic plants show some of the clearest examples of this. For example, seeds of some parasites only germinate when they detect the root of an appropriate host nearby. 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

STUDENTS

Hailey Larose defended her Ph.D. in February: “Exploring the genetic basis of germination specificity in the parasitic plants Orobanche cernua and O. cumana”. Graduation in May!

LATEST PUBLICATIONS

Weed Science: Weed control in 2050: Imagining the future of weed science. Go to: DOI: org/10.1017/wsc.2017.78

Genes: Identification of differentially methylated sites with weak methylation effect. Go to: DOI: 10.3390/genes9020075

Nature: MicroRNAs from the parasitic plant Cuscuta campestris target host messenger RNAs.  Go to: DOI: 10.1038/nature25027