Root Microbial Populations May Enhance Tree Productivity


Bacterial and fungal communities inhabiting the soil around a plant’s roots (the rhizosphere) as well as within the roots (the endosphere) can signifi­cantly benefit the plant’s overall health and productivity, especially in long-lived perennials such as trees. However, the molecular mechanisms that regulate these very complex interactions between plants and microbes are difficult to study and poorly understood. To gain insight into these interactions, researchers at Oak Ridge National Laboratory conducted a detailed study of the rhizosphere and endosphere “microbiomes” of the Eastern Cottonwood tree (Populus deltoides), a promising bioenergy feedstock candidate, from two natural settings in North Carolina and Tennessee and over two seasons. While much of the observed variation is still to be explained, the group did find significant differences in microbial communities between the two locations and between the fall and spring seasons. Additionally, they found that microbes within roots were very different from those just outside the roots, indicating that selection for specific, rather than random, microbes to colonize plant roots may occur. The results suggest that these beneficial microbes might be manipulated to enhance plant growth and productivity as well as increase resistance and adaptability to environmental stresses.


Shakya, M., N. Gottel, H. Castro, Z. K. Yang, L. Gunter, J. Labbé, W. Muchero, G. Bonito, R. Vilgalys, G. Tuskan, M. Podar, and C. W. Schadt. 2013 “A Multifactor Analysis of Fungal and Bacterial Community Structure in the Root Microbiome of Mature Populus deltoides Trees,” PLoS ONE 8(10), e76382. DOI:10.1371/journal.pone.0076382.