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Agrobacterium tumefaciens Is a Diazotrophic Bacterium
1Department of Genetics, University of Leeds, Leeds LS2 9JT, United Kingdom.
Applied and Environmental Microbiology
|July 1, 1990
Summary
Agrobacterium tumefaciens can fix nitrogen independently, a novel finding for this plant pathogen. Nitrogen fixation is repressed by ammonium and requires molybdenum, offering new insights into bacterial evolution.
Area of Science:
- Microbiology
- Molecular Biology
- Plant Pathology
Background:
- Agrobacterium tumefaciens is a well-known plant pathogen.
- Nitrogen fixation is a critical process in many bacteria.
- The nitrogen-fixing capabilities of A. tumefaciens were previously unknown.
Purpose of the Study:
- To investigate the nitrogen-fixing potential of Agrobacterium tumefaciens.
- To understand the conditions affecting nitrogen fixation in A. tumefaciens.
- To explore the implications of nitrogen fixation for the bacterium's evolution.
Main Methods:
- Culturing A. tumefaciens on nitrogen-free medium.
- Measuring acetylene reduction to ethylene.
- Assessing nitrogen incorporation from N(2).
Main Results:
- A. tumefaciens demonstrated nitrogen fixation in free-living conditions.
- Nitrogen fixation was repressed by ammonium and aerobic conditions.
- Molybdenum was essential for the nitrogen fixation system.
- No nodulation was observed in associated legumes.
Conclusions:
- Agrobacterium tumefaciens possesses nitrogen-fixing capabilities.
- This finding challenges the traditional view of A. tumefaciens as solely a pathogen.
- Understanding this ability may illuminate the evolution of pathogenic versus symbiotic relationships.