April 9, 2007

Alum follows interest in chemical ecology to the top of his field

By Tim Stephens

As director of the Max Planck Institute for Chemical Ecology in Jena, Germany, Jonathan Gershenzon is still pursuing some of the same ideas that first fascinated him as an undergraduate at UCSC in the 1970s.

Jean Langenheim and Jonathan Gershenzon Photo: Tim Stephens

Here he was taught and inspired by a formidable group of plant scientists on the biology faculty, including Jean Langenheim, now a professor emerita of ecology and evolutionary biology, Lincoln Taiz, professor of molecular, cell, and developmental biology, and the late Harry Beevers and Kenneth Thimann.

Langenheim, a pioneer in the field of chemical ecology, advised Gershenzon on his senior thesis and was especially influential.

"She introduced me to the basic concepts of plant defense, to the idea that the world is green because plants are generally protected from herbivore attack by chemical and morphological defenses," Gershenzon said.

In January, Gershenzon returned to UCSC to give a seminar and meet with faculty and students. It was an opportunity, he said, "to thank the university and the faculty here for introducing me to this fascinating area of research that has led to a very rewarding career."

Chemical ecology focuses on the chemical substances involved in interactions between organisms, from chemical signals used for communication to toxins used for defense. In plants, the largest group of chemical defenses are the terpenes, and Gershenzon is one of the world's leading experts on terpenes.

"The terpenes include such diverse substances as the resins of conifers, flavor substances of mints, fragrance components of many flowers and fruits, as well as the toxic principles of milkweed, foxglove, and other plants," he said.

For his senior thesis, Gershenzon studied the terpenes produced by yerba buena, a common herb found in and around California's redwood forests.

"At that time, Jean Langenheim was establishing a pioneering research program at UCSC to study the chemical ecology of terpenes, and she got me hooked on this crazy group of chemicals," he said. "I became fascinated with the diversity of terpenes and the complex mixtures present in individual plants and their ecological functions."

Graduating in 1977 with highest honors and a B.A. in biology, Gershenzon went on to graduate school at the University of Texas at Austin, earning a Ph.D. in botany. After 10 years as a researcher at Washington State University, he was invited to take on the task of establishing the first Max Planck Institute devoted to ecological research.

"It's a plum job, and it's very unusual for someone that young to be named director of a Max Planck Institute," Langenheim said.

The institutes are internationally renowned research facilities, each devoted to basic research in a promising field and supported by the Max Planck Society. For Gershenzon, however, the decision to go to Germany was not easy. For one thing, he didn't speak the language. He also had offers for faculty positions at two major U.S. universities.

"My wife made a big chart of the pros and cons of each position and hung it on the wall in our kitchen," he said.

In the end, it was just too good an opportunity to pass up. They moved to Germany in 1997.

"It was a once-in-a-lifetime opportunity to design my own laboratory from the ground up," Gershenzon said. "Planning for the institute had just begun, and as director I was involved in everything--negotiating the budget, picking a site for the lab, designing the floor plan, choosing the architects, ordering equipment--and to do it all in a foreign culture and language was an enormous challenge."

The building, which the institute moved into in 2001 after four years in temporary facilities, has won awards for its design. Gershenzon now oversees a staff of 265, including 128 scientists and 86 junior scientists and researchers, as well as visiting researchers from around the world. The institute has five scientific departments, and Gershenzon leads the Department of Biochemistry.

English being the lingua franca of scientific communication, most of the scientists he works with speak English. But Gershenzon said he makes a point of speaking German as much as he can, especially with the nonscientific staff members.

"The language is just part of the adventure, but I have to admit that I sometimes use my lack of fluency as an administrative tool," he said.

Planning the institute, nurturing it, and watching it grow has been very satisfying, he said, and the job has enabled Gershenzon to do scientific research on a scale not usually possible in a U.S. university. His research in Germany has been directed at understanding the chemical ecology of plant-insect interactions. Gershenzon's group has made important contributions to scientific understanding of these interactions.

Insects use chemistry to select plants for feeding and egg-laying, flowers use chemicals to attract insects for pollination, and plants use chemicals to defend themselves from munching insects. When bark beetles attack spruce, for example, the trees increase their resin content, and Gershenzon's lab has demonstrated that these once-attacked trees with more resin are more resistant to future attack. Certain kinds of insect feeding trigger plants to emit volatile terpenes, and he showed that these volatiles serve as signals to attract enemies of the plant-eating insects, such as parasitic wasps.

"It seems that plants have the ability to cry for help, and the expectation is that something will answer," Gershenzon said.

An important task of the institute is training young researchers in modern techniques of chemical ecology. Gershenzon holds an honorary professorship at Friedrich Schiller University in Jena, and his institute works with the university to run an international doctoral program for highly qualified young researchers. According to Gershenzon, his approach to teaching is strongly influenced by his undergraduate experience at UCSC.

"The Santa Cruz system really served me well. I developed a strong sense of responsibility because I was given so much freedom to pursue my own interests," he said. "Looking back, it is striking to realize how many of my major scientific preoccupations can be traced back to my time as an undergraduate at UCSC. My interests in plants, plant ecology, and plant chemistry all seem to have begun under the redwoods. Clearly, I must have been inspired."