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Adaptive responses of Trichlorobacter lovleyi to nitrite detoxification reveal overlooked contributions of Geobacterales to nitrate ammonification

  • 0Department of Microbiology, Genetics & Immunology, Michigan State University, East Lansing, MI 48824, United States.
The Isme Journal +

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March 18, 2025

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March 18, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

Certain soil microbes conserve nitrogen by converting nitrate to ammonium, a process vital for agriculture. This study reveals how *T. lovleyi* manages toxic byproducts, optimizing this crucial nitrogen cycle pathway.

Area Of Science

  • Microbiology
  • Environmental Science
  • Biogeochemistry

Background

  • Microorganisms play a key role in nitrogen cycling through dissimilatory nitrate reduction to ammonium (DNRA).
  • Understanding the adaptive mechanisms of bacteria like *Geobacterales* in DNRA is crucial for agricultural soil health.
  • Hotspots of nitrate ammonification suggest specific microbial adaptations warrant investigation.

Purpose Of The Study

  • To investigate the adaptive responses of *Trichlorobacter lovleyi* SZ to nitrate ammonification.
  • To identify pathways for efficient nitrate respiration and acetate utilization in *Geobacterales*.
  • To elucidate the role of carbon/nitrate ratios and nitrite toxicity in regulating DNRA.

Main Methods

  • Laboratory cultivation of *T. lovleyi* under varying carbon/nitrate ratios.
  • Analysis of microbial growth rates and adaptation to different environmental conditions.
  • Investigating the impact of electron donors (acetate, hydrogen) on DNRA and nitrite accumulation.

Main Results

  • *T. lovleyi* demonstrated rapid growth across a range of carbon/nitrate ratios when nitrite accumulation was limited.
  • Low nitrate concentrations were key for growth, contrary to the dogma of high C/N ratios stimulating DNRA.
  • Hydrogenotrophic growth alleviated nitrite toxicity, promoting DNRA even with limited acetate.

Conclusions

  • Nitrite toxicity is a critical factor regulating DNRA in *Geobacterales*.
  • Microbial adaptations in DNRA contribute significantly to soil nitrogen conservation.
  • Mechanistic insights can improve genomic-based environmental predictions and sustainable nitrogen management.

Keywords:

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