"Ignorance (about the movement of nitrogen) limits our understanding ... in what is arguably the world's most important symbiosis," says Yair Shachar-Hill, the lead MSU author on the study.
The success of the Green Revolution to increase agricultural yields around the world has relied on the use of synthetic nitrogen fertilizers. The price of fertilizers is increasing, however, as are concerns about nitrogen runoff from large agricultural operations. Nitrogen also is a component of acid rain, which remains common in rapidly industrializing parts of the world, such as China.
Eventually, an intricate knowledge of the nitrogen cycle might lead to more efficient use of fertilizers, more productive output on low-input and organic farming operations, and improved ability to stanch the effects of acid rain on natural ecosystems, Shachar-Hill says.
"These exciting results suggest that fungi are more important in plant nitrogen nutrition than we have hitherto suspected," says Alastair H. Fitter, a plant biologist at the University of York and an expert in root system functioning.
The fungus-plant partnership is one of the planet's oldest and dates back more than 400 million years, when plants began to move out of the oceans and onto land. Plants trade a bit of their sunlight-made sugars for building block nutrients that fungi wring from the soil. Scientists have understood broad outlines of this evolutionary bargain for years, but specific details remained fuzzy, especially those related to nitrogen.
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Contact: Yair Shachar-Hill
yairhill@msu.edu
517-355-4683
Michigan State University
8-Jun-2005