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Updated: May 7, 2025

Workflow Based on the Combination of Isotopic Tracer Experiments to Investigate Microbial Metabolism of Multiple Nutrient Sources
Published on: January 22, 2018
Bacterial synergies amplify nitrogenase activity in diverse systems
Andrew W Sher1, Robert J Tournay1, Emma Gomez-Rivas2
1School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, WA 98195-2100, United States.
Diazotrophic endophytes, microbes that fix nitrogen, show amplified activity when paired with synergistic partners. These beneficial microbial interactions are common in nutrient-limited environments and have agricultural applications.
Area of Science:
- Microbial Ecology
- Plant-Microbe Interactions
- Biochemistry
Background:
- Endophytes are microbes residing within plant tissues.
- Some endophytes possess the ability to fix atmospheric nitrogen.
- These microbes are part of complex communities influencing plant symbiosis.
Purpose of the Study:
- To report the co-isolation of diazotrophic endophytes with synergistic partners.
- To investigate the impact of synergistic partners on nitrogen-fixing activity.
- To explore potential mechanisms behind these beneficial microbial interactions.
Main Methods:
- Co-isolation of diazotrophic endophytes and synergistic partners from nutrient-limited environments (Hawaiian lava field, Pacific Northwest gravel bar).
- Assaying nitrogenase activity in the presence of synergistic strains.
- Investigating the role of physical contact and secreted compounds in the synergy.
Main Results:
- Diazotrophic endophyte nitrogen-fixing activity was amplified in the presence of synergistic strains.
- Synergistic strains enhanced nitrogenase activity in various diazotrophic species.
- Evidence suggests both oxygen protection and secreted compounds mediate the synergy.
Conclusions:
- Beneficial endophytic microbial interactions are prevalent in nutrient-limited environments.
- Synergistic partners enhance nitrogen fixation through multiple mechanisms, including secreted compounds.
- These findings offer potential for optimizing microbial inocula in agriculture.
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