Campus News

UGA scientists study how plants decipher complex, molecular messages for recognizing good bacteria

Bacteria can be a plant’s friend or foe and recognizing the difference is essential for survival. But while plants are able to decipher complex, molecular messages, University of Georgia scientists are working with international collaborators to understand how.

The team from UGA’s Complex Carbohydrate Research Center Analytical Services; the University of Otago, New Zealand; Aarhus University, Denmark; and the University of Copenhagen, Denmark published findings in 2015 in the journal Nature.

They studied how legumes, a family of plants that includes soybeans, alfalfa and peas, recognize rhizobia, friendly bacteria that live in the soil. The plant allows these bacteria to enter through its roots, forming a symbiotic relationship that helps convert atmospheric nitrogen into ammonia, which facilitates growth.

The team found a protein receptor for an exopolysaccharide that is secreted by the bacteria and allows the plant and bacteria to communicate by exchanging chemical signals. Now the researchers have identified the structure of that important exopolysaccharide, and they published their findings this past fall in the Journal of Biological Chemistry.

“Understanding the molecular details of how plants and microbes recognize each other will help us understand the very complex defense mechanism of plants, which will lead to methods to improve the health-and therefore the yield-of important crop plants,” said Russell Carlson, emeritus professor of biochemistry and molecular biology at the CCRC and one of the paper’s authors.

A photo of the ­exopolysaccharide (above), taken by the CCRC’s Stefan ­Eberhard, Artur Muszynski and co-author ­Christian T. Hjuler, is featured on the cover of the journal.

“Now having defined the structure, we can look closer at the unique building blocks and the roles they play in microbe-plant molecular cross-talk,” said Muszynski, an associate research scientist at the CCRC and lead author of the recent structural study.

This work was conducted through the Center for Plant and Microbial Complex Carbohydrates and the ­Analytical Service and Training Laboratory at the CCRC and The Centre for ­Carbohydrate Recognition and Signalling at Aarhus University in Denmark, with support from the U.S. Department of Energy and the Danish National Research Foundation.