From Roots to Atmosphere: Utilizing DOE Facilities to Track Drought’s Carbon Impact on Ecosystem Processes

Authors:

Malak M. Tfaily¹* ([email protected], PI), Laura Meredith¹, Linnea Honeker¹, Gina Hildebrand¹, Dusan Velickovic², David Hoyt², Rosalie Chu², Jason Toyoda², Christopher Anderton², Ben Yang¹, Mekayla Crawford¹

Institutions:

¹University of Arizona; ²Pacific Northwest National Laboratory

Abstract

Utilizing DOE user facilities, this team investigated plant-soil-microbe interactions that drive rhizosphere processes contributing to metabolite turnover and nutrient cycling. As climate warming increases water scarcity frequency and severity, understanding how plant-mediated processes like root exudation influence rhizosphere soil organic matter turnover is critical. Using 16S rRNA gene amplicon sequencing, rhizosphere metabolomics, and position-specific carbon-13 pyruvate labeling, researchers examined three tropical plant species (Piper auritum, Hibiscus rosa sinensis, and Clitoria fairchildiana) and their associated microbial communities’ effects on rhizosphere soil organic carbon turnover.

The findings indicate the rhizosphere metabolome is primarily shaped by the roots’ drought response rather than direct rhizosphere bacterial community composition shifts. Specifically, reduced root exudation notably affected the P. auritum rhizosphere metabolome, with less reliance on neighboring microbes. Contrary to P. auritum, H. rosa sinensis and C. fairchildiana experienced exudate composition changes during drought, altering bacterial communities and collectively impacting the rhizosphere metabolome. Furthermore, excluding phylogenetically distant microbes shifted the rhizosphere metabolome. Under drought, C. fairchildiana associated with only a subset of symbiotic bacteria.

These results indicate plant species-specific microbial interactions systematically change with the root metabolome. As roots respond to drought, associated microbial communities adapt, potentially reinforcing plant roots’ drought tolerance strategies. These findings have significant implications for maintaining plant health and performance during drought stress and improving plant performance under climate change.

Image

Red flower surrounded by slices of microbiome slices.

Hibiscus rosa sinensis. Scientists are studying this tropical beauty to learn more about the ways it and its neighbors respond to drought. [Courtesy Pacific Northwest National Laboratory]