Genomic Science Program
U.S. Department of Energy | Office of Science | Biological and Environmental Research Program

Plant-Microbe Interfaces: Microbially Mediated Host Stress Response—Bridging Field and Laboratory Experiments to Gain Insights into the Populus-Microbiome Symbiosis Under Abiotic Stress

Authors:

Alyssa A. Carrell1* (carrellaa@ornl.gov), William A. Argiroff1, Kelsey Carter2, Jun Lee1, Sara S. Jawdy1, Dawn M. Klingeman1, Leah Burdick1, Dale A. Pelletier1, Christopher W. Schadt1, Larry York1, Mircea Podar1, Melissa A. Cregger1, David J. Weston1, Mitchel J. Doktycz1

Institutions:

1Biosciences Division, Oak Ridge National Laboratory; 2Environmental Sciences Division, Oak Ridge National Laboratory

URLs:

Goals

The overriding goal of the Oak Ridge National Laboratory (ORNL) Plant-Microbe Interfaces (PMI) Science Focus Area (SFA) is to predictively understand the productive relationship between a plant host and its microbiome based on molecular and environmentally defined information. Populus and its associated microbial community serve as the experimental system for understanding this dynamic, complex multiorganism system. To achieve this goal, the project focuses on: (1) defining the bidirectional progression of molecular and cellular events involved in selecting and maintaining specific, mutualistic Populus-microbe interfaces; (2) defining the chemical environment and molecular signals that influence community structure and function; and (3) understanding the dynamic relationship and extrinsic stressors that shape microbiome composition and affect host performance.

Abstract

Plants are colonized by beneficial microbes that may enhance their resistance to both abiotic and biotic stress, yet the mechanisms underlying these benefits remain largely unexplored. Coupling field observations to laboratory experiments is essential for understanding these microbe-mediated benefits, yet these cross-scale linkages remain a critical knowledge gap. In this study, researchers sampled Populus trichocarpa microbiomes across gradients in temperature and precipitation in Oregon and Washington. These sites revealed distinct microbial communities correlated with varying levels of temperature and moisture. To assess the potential benefits conferred by these microbial communities to host plants under thermal stress, whole soil microbiomes from the sites experiencing the coldest and hottest temperatures were transferred to axenic Populus tissue culture plants in a greenhouse environment. Notably, poplars receiving the microbiome from the highest temperature site demonstrated enhanced growth when placed in a high-temperature chamber, suggesting the microbiomes from warmer sites confer greater thermal tolerance to the host plant. Next, the team employed direct plating and flow sorting microbiome isolation approaches to obtain individual isolates from field sites at the thermal extremes. The project will next compare the isolates with taxa enriched in the microbiome of plants demonstrating thermal tolerance to identify potentially beneficial strains. Building on these findings, the research’s subsequent phase will utilize individual isolates assembled into Populus synthetic communities (SynCom) to dissect the molecular mechanisms underpinning the observed benefits, bridging the gap between field-based microbial ecology and controlled laboratory experiments. This research contributes to an understanding of the complex interactions between plants and their associated microbial communities, and findings have important implications for leveraging these relationships to enhance plant resilience in the face of changing environmental conditions.

Funding Information

ORNL is managed by UT-Battelle, LLC for the U.S. DOE under contract no. DE-AC05-00OR22725. The PMI SFA is supported by the U.S. DOE, Office of Science, through GSP, BER program under FWP ERKP730.