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Evolving interactions between diazotrophic cyanobacterium and phage mediate nitrogen release and host competitive
Johannes Cairns1, Sebastián Coloma1, Kaarina Sivonen1
1Department of Food and Environmental Sciences/Microbiology and Biotechnology , University of Helsinki , PO Box 56, 00014 Helsinki , Finland.
Royal Society Open Science
|January 14, 2017
Summary
Interactions between nitrogen-fixing cyanobacteria and their viruses, cyanophages, significantly increase nitrogen release, boosting phytoplankton growth. Phage-resistant cyanobacteria evolved shorter filaments and reduced buoyancy.
Area of Science:
- Aquatic microbial ecology
- Virology
- Biogeochemistry
Background:
- Interactions between nitrogen-fixing cyanobacteria and cyanophages influence aquatic ecosystems.
- These interactions alter nutrient availability and cyanobacterial populations.
- Ecological and evolutionary feedbacks are not fully understood.
Purpose of the Study:
- To investigate the impact of cyanobacteria-phage interactions on nitrogen release and host properties.
- To assess the ecological effects of phage-mediated nitrogen release on phytoplankton communities.
Main Methods:
- Experimental evolution of nitrogen-fixing cyanobacteria (Nodularia sp.) and their phage.
- Measurement of cellular nitrogen release following viral lysis.
- Phytoplankton bioassays using cell-free filtrates and phage-resistant controls.
Main Results:
- Viral lysis significantly increased cyanobacterial nitrogen release.
- Phytoplankton growth was enhanced in filtrates from lysed cyanobacteria.
- Phage-evolved cyanobacteria developed phage resistance, shorter filaments, and reduced buoyancy.
Conclusions:
- Cyanobacteria-phage interactions can alter ecosystem biogeochemical cycles.
- Phage-induced nutrient release supports phytoplankton growth.
- Evolutionary changes in cyanobacteria affect their ecological fitness and competitive ability.
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