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The Microbes That Lie Nearby

When pathogens attack the leaf of a plant, the leaf sends out an S.O.S. to the plant's roots, which respond by secreting an acid that brings beneficial bacteria to the attack site. Research at the University of Delaware shows how this process affects crops.

Harnessing the collaboration between plants and soil microbes could improve agricultural crop performance and extend yields beyond conventional plant genetics and breeding.

Scientists have long known about the symbiotic relationship between legume plants, such as beans, and the bacteria known as rhizobia that colonize their roots and enable them to convert nitrogen from the air into fertilizer.

In earlier work, Harsh Bais of the University of Delaware and his colleagues showed that the plant Arabidopsis thaliana secreted an acid to recruit beneficial bacteria in the soil (Bacillus subtilis) when its leaves were infected by a pathogen.

Shifting to food crops, Bais and his colleagues are setting up a controlled experimental system to dissect the impact of microbial associations on rice, one of the world's most important food crops. Profiling techniques will reveal the genes actively being expressed by the plants in response to a variety of conditions. The identity of soil microbes found especially helpful to the rice plants will be discerned.

Uncovering the diversity and potential impacts of microbes that literally lie at the roots of rice plants may provide new avenues to increase rice crop yields.


  • bacteria clings to root
Bacteria (green) clings to plant root.
Thimmaraju Rudrappa

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