Image: Plants produce an outstanding diversity of chemicals to ward off insects and other herbivores intent on consuming them. For centuries, people have used these plant chemicals to season food, create fragrances, or as healing medicine. The chemicals and compounds that these plants produce are extraordinarily useful for medicinal purposes. In fact, nearly 75 percent of pharmaceuticals developed over the past 30 years are derived from natural products, such as plants. Plants are responsible for such drugs as the cardiac stimulant digitoxin derived from foxglove, the decongestant ephedrine found in joint fir, and the anti-malarial drug quinine in yellow cinchoma. Nick Batora, a doctoral candidate in the Department of Genetics, studies the Purple Passionflower (Passiflora incarnata) and the chemical repellant it produces to ward off specialized caterpillars intent on devouring it. His research is specifically aimed at “understanding the dynamics between plants and herbivores resulting in the evolution of such a wide variety of useful chemicals.” The USDA categorizes the Purple Passionflower as an L48 N, meaning that is it native to the lower 48 states. By comparing the chemicals produced by northern and southern purple passionflowers, Batora can infer whether the variation is indicative of the amount of damage the southern plants sustain from the caterpillars. To determine this, Batora collects passionflowers from both regions and measures their chemical compounds using the newest metabolomics technologies. Perhaps not surprisingly, the compounds produced by southern Passionflowers are more chemically diverse than those found further north such as in Virginia. “I’ve also found that the amount of certain chemicals, such as cyanogenic glycoside, is associated with how much the caterpillars eat the plant.” In this instance, increased cyanogenic glycoside coincided with an increased caterpillar presence, although more research needs to be done before a relationship can be attributed to the increased cyanogenic glycoside. Currently, in the last year of his dissertation research, Batora is now working to identify additional chemicals produced by the Purple Passionflower. He is also interested in further research on how the production of these chemicals is under natural selection from herbivores such as caterpillars. After graduation, Batora plans to pursue a career in medicinal plant research. “That has been a lifelong passion of mine and I know if I continue to pursue something like that, then I will continue to be a very happy person.” “If we understand better the specific purposes of these chemicals in an ecological sense, then we can search in a more strategic way for new plant-derived medicines.”
