Perspectives Online

College Profile, An early fascina-tion with genes and DNA leads to Dr. Ralph Dean's search for biology-based solutions to agri-cultural problems. By Dee Shore

Dr. Ralph Dean created the Fungal Genomics Laboratory on Centennial Campus and is director of the College's Center for Integrated Fungal Research. Last fall he was awarded the Huxley Memorial Medal (shown above) for his research accomplishments in the natural sciences.
Photo by Daniel Kim

When Dr. Ralph Dean talks about his work as a plant pathologist at N.C. State University, he invokes the imagery of war - of big guns and tanks, of soldiers and generals, of fortress walls that can stand only so much pounding.

The imagery would seem histrionic if it were not for two simple facts: His enemy, rice blast disease, destroys enough food for 60 million people annually. And while the disease inflicts damage on U.S. rice, it exacts its greatest toll in the poor countries of Asia and Latin America where farmers and consumers can ill afford it.

So Dean the crusader continues fighting. With his colleagues in the College of Agriculture and Life Sciences and around the world, he has been at the forefront of the effort to gain a deeper and broader understanding of the disease, the fungus that causes it and the plant it infects.

As director of the College of Agriculture and Life Sciences' Center for Integrated Fungal Research, Dean has been part of an international research team responsible for determining the genome sequence of the japonica subspecies of rice. And he led the effort to sequence Magnaporthe grisea, the fungus that causes rice blast disease.

In his latest research, he's looking at unusual classes of genes and novel proteins as a way to understand the interactions between the fungus and its host.

Through such research, Dean hopes to build up "an arsenal of information on what genes are involved in plant-pathogen interactions."

That information arsenal, he believes, will be key to finding ways to disarm the fungus, to protect rice and thus to sustain or increase the supply of rice, a dietary staple for more than half of the world's people.

Dr. Ralph Dean.
(Photo by Daniel Kim)
Perhaps as important, what Dean learns about rice and rice blast has implications for understanding how a range of plants deal with disease. Fungal diseases reduce crop yields by 20 to 35 percent annually. And strategies that reduce those losses could play a significant role in increasing world food production at a time when population growth is fueling increased demand.

Dean's interest in finding biology-based solutions to agricultural problems was sparked during his childhood in England. He grew up in what he calls a book-rich, back-to-nature family, and most of his early years were spent near Cambridge, England.

Cambridge, he says, was then a "hot spot for biology and science," the place where James Watson and Francis Crick raced in the 1950s to figure out the structure of DNA, confirming suspicions that it carries life's hereditary information.

It was a stimulating, awe-inspiring environment, he says, a place where he could watch Nobel laureates stroll past the windows of his high school.

In the nearby countryside, Dean spent his summers doing contract work for farmers. He recalls a time when as a 12- or 13-year-old, he accidentally splattered passengers of a passing train with what he euphemistically calls "muck." And he recalls a day when he couldn't get a combine harvester he was driving to stop.

Despite (or perhaps because of) the adventure and danger, Dean developed an affinity for agriculture. "During the summers, I was very, very busy, working six or seven days a week. But I made money that I needed for college, and I liked the work," he says.

His exposure to agriculture converged with curiosity about biology right as he entered Imperial College at the University of London.

"It was the 1970s, and the gas shortages in the United States had everyone concerned that we were about to run out of oil, that natural resources were disappearing and that agriculture was very energy-consuming," Dean says. "I knew it was true, and I wanted to focus on this."

Dean earned his undergraduate degree in botany in 1980, then loaded two suitcases and headed to the United States to study plant pathology at the University of Kentucky in Lexington under Dr. Joseph A. Kuc. Dean was drawn to Kuc because of the professor's unconventional approach to solving agricultural problems. Kuc was a pioneer in plant disease resistance, one of the first to recognize that plants had immune systems.

"Remember, this was at the time when people would talk to plants," Dean says. "And so you had to wonder if there were ways to boost plants' immunity, eliminate the need for pesticides and at the same time boost agricultural productivity."

The goal was lofty, but the work slow and frustrating. "This was the era of grind-and-find. We made progress, but it seemed like there had to be another way," Dean says. "Genes and DNA fascinated me, and I wanted to get back to that."

After earning his Ph.D. in 1986, he focused on learning molecular biology tools for agricultural research, briefly at the University of California-Davis, then at the University of Georgia. From there, he became associate director of Clemson University's Genomics Institute, dedicated to applying genomics research to improve crop plants.

"When I was recruited at Clemson, I was told you can go in any department you want and do what you want," he says. "So although they don't grow much rice in South Carolina, I decided to focus on rice and rice diseases. Rice is the food staple for the world, and it is the poorest people who depend on it most. And diseases are a serious challenge."

In 1998, Dean helped launch the International Rice Blast Genome Initiative, an effort by a widespread group of scientists studying M. grisea. The next year, the College of Agriculture and Life Sciences lured Dean to Raleigh. His wife, Nancy, had earned a master's degree under the late horticultural science professor J.C. Raulston, and she was determined to move back to North Carolina. She now works for the College arboretum that bears his name.

Once at N.C. State, Dean created the Fungal Genomics Laboratory on Centennial Campus. Later, he founded the state-of-the-art Center for Integrated Fungal Research.

The center incorporates the Fungal Genomics Laboratory and four other labs sharing the common mission of understanding major plant pathogens and industrially important fungi. The center also trains graduate students and scientists in fungal biology and genomics and provides educational programs for public school students and their teachers.

Dean's research and that of the center have garnered increasing attention and recognition from the scientific community. In 2004, his alma mater, Imperial College, awarded Dean the Huxley Memorial Medal, an annual prize that goes to a student or former student for research accomplishments in the natural sciences.

That same year, his work with the U.S. Rice Genome Consortium earned him one of the U.S. Department of Agriculture's top awards, the Secretary's Honor Award.

In April, an article for which he was lead author appeared in the prestigious international science journal Nature. In the article, Dean and his co-authors reveal insights into the adaptations that the fungus makes to cause disease. They identify novel receptors that allow the rice blast fungus to recognize its environment and secrete proteins that are likely to damage rice plants, and they pinpoint duplicate mechanisms that protect the fungus from efforts to fight it.

"We've identified the big guns, but there are lots of other soldiers out on the battlefield." he says. "So we'll have to keep pounding."