Beneath the surface of the earth, an influential community of microbes mingles with plant roots. In the first large-scale analysis of those communities, scientists have now catalogued and compared the hundreds of types of bacteria that associate with the roots of the model plant Arabidopsis under various conditions. The work establishes an experimental framework for examining how plants interact with a microbial community that can influence their growth and development, productivity, and impact on the environment.
The analysis, led by Jeff Dangl, a Howard Hughes Medical Institute-Gordon and Betty Moore Foundation investigator at the University of North Carolina at Chapel Hill, identifies a core group of bacterial types that are consistently found inside Arabidopsis roots. Other bacterial associations, the researchers find, are dependent on the type of soil in which a plant grows. The work is published in the August 2, 2012, issue of the journal Nature.
"It's been known for decades that plants have growth-promoting interactions with microbes," says Dangl, who is a biology professor at UNC's College of Arts and Sciences. Researchers had examined some of those interactions on a case-by-case basis, testing individual microbial strains for their effects on plant growth. But outside the controlled environment of a laboratory greenhouse, a single microbe never acts alone. "Every shovelful of soil is different, and the microbial community is very diverse and extremely complicated," Dangl says. "And everybody in that community is talking to each other using complex molecular signals."
Stuck in the same plot of soil for its entire life cycle, a plant must sense and adapt to its nutritional environment, Dangl explains. Scientists speculate that a plant may recruit certain microbial aides to help it thrive under certain conditions, but these types of interactions remain largely unstudied. Almost nothing is known abou
|Contact: Jennifer Michalowski|
Howard Hughes Medical Institute