Unraveling Plant-Microbe Communication

The Science

The soil environment contains a complex of microbial communities living in close association with plants, both outside the root (rhizosphere) and within (endosphere). These interactions between plants and microbes can significantly influence plant growth and development and, in the case of beneficial microorganisms, increase plant health and yield. These complex interactions involve cell-to-cell communication, but very little is known about how these signals are triggered and regulated. To better understand the dynamics of these systems, scientists at Oak Ridge National Laboratory have undertaken an extensive survey of the “microbiome” of the woody perennial Populus, a tree that has intimate associations with many types of beneficial fungi and bacteria and is a potential biofuel feedstock for cellulosic ethanol production. Focusing on a specific type of sensing molecule known as acyl-homoserine lactone (AHL), the researchers screened 129 bacterial isolates from P. deltoides (Eastern cottonwood) and found that 40% were AHL positive. Furthermore, they found a subgroup of AHL-controlled regulators that respond to unknown plant-derived signals rather than bacterial AHLs. The results indicate that the microbiota that comprises the Populus root zone has substantial capacity for cell-to-cell communication, furthering our understanding of the role these microbial signaling molecules play in the plant’s biology.

BER Program Manager

Kari Perez

U.S. Department of Energy, Biological and Environmental Research (SC-33)
Biological Systems Science Division
[email protected]


Schaefer, A. L., C. R. Lappala, R. P. Morlen, D. A. Pelletier, T.-Y. S. Lu, P. K. Lankford, C. S. Harwood, and E. P. Greenberg. 2013. “LuxR- and LuxI-type Quorum Sensing Circuits Are Prevalent in Members of the Populus deltoides Microbiome,” Applied and Environmental Microbiology 79 , 5745–52. DOI: 10.1128/AEM.01417-13.