Gunjune Kim

Graduate student works to defend tomato plants against sneaky, ninja-like invaders

In the same way that a coach tirelessly reviews an offensive play made against his or her team, scientists who study parasitic plants also analyze attacks, hoping to understand what mechanisms these sneaky invaders use to conquer defenseless host plants.

Gunjune Kim of Chicago, Ill., a fourth year doctoral student in the department of plant pathology, physiology and weed science in the College of Agriculture and Life Sciences, is working with Jim Westwood, a professor in that department, to analyze the attack methods of Cuscuta pentagona, a thin weedy, vine-like plant native to North America.

The parasitic plant has earned many old folk names, including devil’s guts, strangleweed, and witch’s hair, and is commonly known as dodder. It attacks common crop plants like tomatoes, potatoes, and alfalfa by coiling itself around the stem and then penetrating between host cells. Once the parasitic plant has penetrated the host plant, the plants begin swapping ribonucleic acid (RNA), according to data from Westwood and Kim’s study.

“We’re fascinated by what our data shows,” Kim said. “Our hypothesis is that both plants are sending gene transcripts to each other. This is truly a strange phenomenon.” Kim’s research approach uses a new twist on next-generation sequencing.  He generates millions of RNA sequences from the parasite tissue and then uses powerful computers to sort out the host and parasite RNAs.

For Kim’s dissertation, he will continue to test the RNA exchange hypothesis, and examine what becomes of the RNAs once they are transferred to the other plant.  Overall, Kim and Westwood want to understand this mechanism better so that they can determine what role it plays in the parasite’s interaction with the host plant.  It is possible that tampering with this mechanism could stop the parasitism affecting food and forage crops throughout the world.

 “Dodder is one of the most difficult weeds to control.  Once it is established on a crop, about all you can do is plow under the plants in hopes of keeping it from spreading and reproducing,” Westwood said.

Kim is also a member of the Graduate Program in Molecular Plant Sciences at Virginia Tech, an interdisciplinary program that brings together faculty and students from seven departments and three colleges to understand how plants grow and interact with their environments.  He said that the program further convinced him that Virginia Tech was the right place to complete his Ph.D. He holds a master’s degree in plant sciences from Southern Illinois University and a bachelor’s degree in chemistry from the University of Illinois-Chicago. After completing his doctoral degree, Kim plans to stay on with Westwood as a postdoctoral researcher.