A four-year, $3.9 million grant from the National Science Foundation will allow University of Georgia scientists to develop new tools to study the genes and enzymes that make plant cell wall materials and to investigate cell wall structure.

“We are delighted with news of this significant NSF grant, which comes during a time when external funding is especially critical,” said UGA President Michael F. Adams. “Plant genomics has been one of UGA’s most successful research areas over the past several years, and this latest grant continues that success. Dr. Hahn and his colleagues are poised to make significant contributions in this field.”

Michael G. Hahn, a plant biochemist in UGA’s Complex Carbohydrate Research Center and department of plant biology, is the project’s principal investigator. Co-principal investigators are Christopher S. King, College of Veterinary Medicine; Geert-Jan Boons, CCRC and department of chemistry; Malcolm O’Neill, CCRC; and William S. York, CCRC and department of biochemistry and molecular biology.

Plant cell walls are composed primarily of polysaccharides – complex molecules made of sugars. These molecules have important roles in plant growth and development, mechanical strength and defense against diseases. Cell wall polysaccharides also have commercial value in food processing, human nutrition and paper production.

“As many as 2,000 genes are involved in plant cell wall synthesis, modification and degradation,” said Hahn. “But we have very few ways of proving that these genes are actually doing what we think they are.”

One difficulty is that the order of sugars within a polysaccharide is not directly related to the genetic code. Rather, the genes code for the enzymes that make sugars (the building blocks of polysaccharides) and for the enzymes that link sugars together to form polysaccharides. This apparent lack of a template for polysaccharide structure and the inherent structural complexity of polysaccharides have complicated studies of how plant cell walls are made.

“The current approaches for identifying these genes have encountered unanticipated roadblocks,” said Hahn, who is the lead researcher on the new grant. “We propose to provide some different molecular tools that we expect will assist scientists studying wall synthesis.”

The UGA researchers plan to produce more than 100 distinct monoclonal antibodies that bind to well-defined polysaccharide structures. The antibodies can be used in tests to detect a specific structure in plant cell walls.

“We can then mutate a gene and use antibodies to detect when a structure disappears from the wall,” said Hahn. “If a structure disappears, then we’ll know the gene or gene product is involved in building or modifying the wall.”

The antibodies also will be useful tools in studies of plant cell wall structure and function.

The project will make antibodies available to researchers around the world. Hahn said an antibody repository has already been established at UGA, with a back-up collection at the University of Leeds, United Kingdom. Information about the polysaccharide structures that the antibodies recognize will be made available through the NSF-funded Plant Cell Wall Biosynthesis Research Network Web site (http://xyloglucan.prl.msu.edu).

The project also will provide research training for undergraduates, particularly minority students.

“Our infrastructure and the expertise of our faculty and staff make us very competitive for these proposals,” said Alan Darvill, Regents Professor of Molecular Biology and Biochemistry and director of the Complex Carbohydrate Research Center.

The grant is funded by the National Science Foundation’s Plant Genome Research Program.

Since the program began in 1998, it has provided UGA scientists with more than $36 million to study genomes of plants such as rice, cotton, sorghum and loblolly pine. In July, this NSF program also awarded a $5.6 million grant titled “Functional Genomics of the Maize Centromere” to a UGA team led by plant biologist Kelly Dawe.