Bacteria acts as nature's fertilizer
COLUMBIA, Mo 10/3/13 (Beat Byte) -- A beneficial bacteria may reduce an expensive environmental scourge: nitrogen fertilizer that leaches into rivers, streams, and groundwater, University of Missouri researchers claim.
So-called rhizobia bacteria produces nitrogen naturally when the bacteria interacts with certain crops -- soybeans and alfalfa, for instance.
But the bacteria produces little or no nitrogen with other crops such as corn and tomatoes. Plants use nitrogen as a crucial nutrient. If rhizobia produced nitrogen for all crops, farmers could reduce fertilizer costs that run $8 billion annually and water could run more cleanly.
"We're working to transfer rhizobia's [nitrogen-producing] trait to other plants like corn, wheat, tomatoes, or rice," said Gary Stacey, an investigator in the MU Bond Life Sciences Center and professor of plant sciences in the College of Agriculture, Food and Natural Resources.
Scientists have known about rhizobia's ability to produce nitrogen since 1888, but are just now starting to understand how it works. "Rhizobia developed a chemical to make legumes recognize it as a friend," said Yan Liang, a post-doctoral fellow at MU.
But many other important crops see rhizobia as a foe.
A chemical signal from the bacteria raises immunity defenses in some crops, but lowers those defenses in others. After legumes such as soybeans sense rhizobia, they create nodules where the bacteria gather and produce nitrogen the plants can then use.
Other crops -- corn, for instance -- fight the bacteria, preventing it from forming the nitrogen-producing nodules.
For a study published in the journal Science last month, Stacey and Liang characterized the different mechanisms plants use to fight -- or friend -- rhizobia. Their next step is to make plants such as corn and rice drop their guard the way soybeans do.
"We want to make the plants understand that this is a beneficial relationship, and get them to activate a different mechanism that will attract the bacteria instead of trying to fight them," Stacey said.