Doctoral Candidate Uses Biotechnology Tools
for Vanguard Research

Catalano gets to the root of legumes

Twenty-seven-year-old Christina Catalano has been interested in plants since she was a little girl. Born Christina Williams into a Woodstown, N.J. family of farmers and farm suppliers, she spent her days helping in the fields and listening as her parents discussed farming problems and possible solutions with their customers. After graduating as valedictorian from Woodstown High School in 1996, Catalano brought her passion for plants to the University of Delaware, where she received her bachelor's degree in plant biology in 2000.

"I have strong ties to the rural farming community in Southern New Jersey. Supporting farming, and in particular farmers, is very important to me. I chose to study plant molecular biology because I believe we need to apply the best possible science to today's farming," she says.

Christina Catalano

Today Catalano is working toward a doctorate through UD's department of plant and soil sciences at the Delaware Biotechnology Institute. Her research involves legumes-plants that produce pods with tidy rows of seeds inside. These include soybeans, peas, peanuts and lentils.

"Legumes are important food and feed crops grown on approximately 395 million acres worldwide," says Catalano, "and they account for at least 33 percent of dietary protein nitrogen required for human nutrition."

Unlike other types of crops, legumes are also valued for their ability to associate with soil bacteria that supply atmospheric nitrogen to the plant, an association that non-legume crop plants cannot develop. "Legumes offer human health benefits from reduced environmental pollution and for subsistence farmers who cannot afford commercial fertilizers," Catalano says. "This natural ability of legumes is of interest to modern agricultures an environmentally friendly, low-cost alternative to applied fertilizers."

Research like Catalano's is considered at the vanguard of plant and soil sciences. Legume root nodules, the site of nitrogen assimilation into the plant, result from a symbiotic interaction that occurs between a type of soil bacteria called rhizobia and the legume roots. The plant becomes infected with the bacteria and eventually nodules-small, pink, bump-like organs-form on the root.

"Each nodule harbors thousands of beneficial bacteria that convert nitrogen from the air into a form of nitrogen that the plant can utilize," Catalano explains. "It's remarkable. Annually, about 90 million pounds of atmospheric nitrogen is assimilated to agriculture legumes through this process."

In peas and other legumes, each bacterium within the nodule is enclosed with a membrane known as the symbiosome membrane. The symbiosome membrane is important because it serves as a structural interface between the plant and bacteria and controls metabolite exchange, such as nitrogen, between the partners.

This membrane is the focus of Catalano's research. While much has been documented in the scientific world about how nodules begin to form and how they function, Catalano says that little is known about the proteins found in the symbiosome membrane. Her goal is to study the biochemical composition of the symbiosome membrane and how individual proteins contribute to its formation and function.

"We are trying to meet three goals through this research," Catalano says. "One goal is to understand how the rhizobia-legume symbiosis works, especially by understanding better how the symbiosome membrane forms and functions. The second, long-term goal of research such as this is to improve and/or preserve the rhizobia-legume symbiosis in crops that may have lost this ability during evolution. The third, also a long-term goal, is one day to apply our knowledge of the rhizobia-legume symbiosis to non-legume plants, thereby providing them with a natural nitrogen source."

To achieve these objectives, Catalano is studying the model legume, Medicago truncatula , more commonly referred to in the lab of her adviser, Dr. Janine Sherrier, as barrel medic.

For the last four and a half years, Catalano has studied under Sherrier, which has developed into a strong bond and deep respect for the six-year University of Delaware associate professor.

"My experience at UD has been phenomenal," Catalano says. "Whether it's the faculty always being there for the students or the outstanding facilities (on a scale from one to 10, I would give it a 12), I've had a great experience at the university. Dr. Sherrier, in particular, has encouraged me and allowed me to explore my research, opening my eyes to opportunities around me and, overall, just being a great support line."

Sherrier says she has seen tremendous growth in Catalano over the years and describes her as an intelligent, passionate scientist, committed to her research.

"Christina has made the transition from student in the field of plant biology to expert in plant biology, and is unique because of her background in farming," Sherrier says. "She understands the day-to-day issues of farmers and is carrying out research that can have a positive impact on the farming community."

Catalano was recently recognized by the International Society for Molecular Plant-Microbe Interactions for her research, was awarded the 2004 Women in Science and Engineering award for Plant and Soil Sciences in October, and is currently serving as secretary of the Woodstown Pilesgrove Agricultural Education Advisory Committee. She is also a member of the Salem County Board of Agriculture.

She and her husband, James Catalano II, operate and farm 500 acres in Mannington, N.J., a diverse farming operation that has been passed down through the Catalano family. Catalano, her husband and his parents were awarded the New Jersey Farm Service Agency's Farm Family of the Year award for 2003.

Of late, Catalano has gained a new interest in public relations. "I hope to find a career," she says, "that allows me to combine my research experience with my interest in educating the public about plant biotechnology."

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