Poplar-Associated Bacterial Isolates Induce Additive Favorable Responses in a Constructed Plant-Microbiome System
These findings suggest microbiome phenotype can be predicted from phenotypes of individual community members.
A recent study showed that two species of plant growth-promoting bacteria enhanced beneficial plant traits such as root growth and photosynthetic potential in poplar trees, both by themselves and, in combination, in an additive manner.
The effects observed in this constructed microbial community study suggest that microbiome function may be predicted in these systems from the additive functions of selected individual microbial species.
The diverse microbial communities that inhabit the zones within and surrounding the roots of plants, the “root microbiome,” have a significant influence on the host plant’s health and vitality. The root microbiome of Populus, a genus of trees that are a potential bioenergy feedstock, contains a high abundance of microbes known as β- and γ-Proteobacteria. Both of these classes include multiple bacterial species known to promote plant growth. To understand the contribution of individual microbiome members in a community, researchers at Oak Ridge National Laboratory (ORNL), funded by the Department of Energy’s (DOE) Plant-Microbe Interfaces Science Focus Area and U.S. Department of Agriculture-DOE Plant Feedstocks Genomics for Bioenergy program, studied a simplified community consisting of Pseudomonas (γ-Proteobacteria) and Burkholderia (β-Proteobacteria) bacterial strains inoculated on sterile Populus cuttings under controlled laboratory conditions. Alone and in combination, the two species increased root growth and photosynthetic potential and activated unique pathways relative to uninoculated controls. Complementary data such as photosynthetic efficiency, gene expression, and metabolite expression data, in individual and in mixed inoculated treatments, indicate that the molecular effects of these bacterial strains are unique and additive. This work is the first constructed community study to show the additive host effects of bacteria, and the results suggest that microbiome function may be predicted from the synergistic effects of individual members of the microbial community.
Oak Ridge National Laboratory
This work was funded by DOE’s Office of Science, Office of Biological and Environmental Research, Biological Systems Science Division, Genomic Science and Plant Feedstock Genomics for Bioenergy programs (DE-SC0010423); and Plant-Microbe Interfaces Science Focus Area at Oak Ridge National Laboratory.
Timm, C. M., D. A. Pelletier, S. S. Jawdy, L. E. Gunter, J. A. Henning, N. Engle, J. Aufrecht, E. Gee, I. Nookaew, Z. Yang, T. Lu, T. J. Tschaplinksi, M. J. Doktycz, G. A. Tuskan, and D. J. Weston. 2016. “Two Poplar-Associated Bacterial Isolates Induce Additive Favorable Responses in a Constructed Plant-Microbiome System,” Frontiers in Plant Sciences 7:497. DOI: 10.3389/fpls.2016.00497.