Nitrifier genomics and evolution of the nitrogen cycle.
1Evolutionary and Genomic Microbiology Laboratory, Department of Biology, University of Louisville, Louisville, KY 40292, USA. martin.klotz@louisville.edu
FEMS Microbiology Letters
|November 23, 2007
Summary
New genomic data redraws the nitrogen cycle's history. Anaerobic ammonia oxidation (ANAMMOX) emerged from incomplete denitrification, forming the basis for the modern nitrogen cycle before nitrification evolved.
Area of Science:
- Microbiology
- Geochemistry
- Evolutionary Biology
Background:
- High-throughput sequencing of prokaryotic genomes has advanced understanding of the nitrogen cycle.
- Integrating genomic, post-genomic, and experimental data allows reevaluation of geochemical and oceanographic information.
Purpose of the Study:
- To reevaluate the evolution of the nitrogen cycle using new genomic and experimental data.
- To characterize the natural history of the nitrogen cycle from its primordial origins to the oxic era.
Main Methods:
- Analysis of high-throughput prokaryotic genome sequencing data.
- Application of molecular genetic and evolutionary analyses.
- Integration with post-genomic, biochemical, and physiological experimentation.
- Reevaluation of existing geochemical and oceanographic data.
Main Results:
- The natural history of the nitrogen cycle has been redrawn based on new data.
- Incomplete denitrification and ammonification played early roles in driving the nitrogen cycle.
- Anaerobic ammonia oxidation (ANAMMOX) emerged as a foundational process for a complete nitrogen cycle.
Conclusions:
- Anaerobic ammonia oxidation (ANAMMOX) predates nitrification in the nitrogen cycle's evolution.
- The emergence of nitrification occurred later, coinciding with the oxic era.
- This revised history emphasizes the early microbial roles in shaping Earth's biogeochemical cycles.
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