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Nitrogen Substrate Impacts Microcystis aeruginosa Exometabolome Composition
Caroline M Peck1, Lauren N Hart2,3, Roland Kersten4
1Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan, USA.
Environmental Microbiology Reports
|September 3, 2025
Summary
Nitrogen source impacts Microcystis aeruginosa exometabolome. Different nitrogen substrates alter released molecules, influencing cyanobacterial harmful algal blooms (cyanoHABs) and community dynamics.
Area of Science:
- Environmental microbiology
- Metabolomics
- Cyanobacterial research
Background:
- Microcystis aeruginosa is a key species in freshwater cyanobacterial harmful algal blooms (cyanoHABs).
- The composition of released molecules (exometabolome) can influence bloom dynamics and ecological interactions.
- Understanding how environmental factors shape M. aeruginosa exometabolomes is crucial for predicting bloom events.
Purpose of the Study:
- To investigate the effect of different nitrogen (N) substrates on the exometabolome of toxic and non-toxic Microcystis aeruginosa strains.
- To identify specific metabolites and metabolic pathways affected by N availability.
- To understand how N assimilation influences M. aeruginosa ecological interactions.
Main Methods:
- Untargeted metabolomics using liquid chromatography-mass spectrometry (LC-MS).
- Feature-based molecular networking for metabolite analysis.
- In silico metabolite annotation for identification.
- Culturing M. aeruginosa on different N substrates (ammonium, urea, nitrate).
Main Results:
- Exometabolome profiles differed significantly based on the N substrate provided.
- Cultures grown on ammonium and urea showed similar exometabolomes, distinct from those on nitrate.
- Amino acids, peptides, lipids, cyanotoxins, and photoprotectants were significantly altered by N treatments.
- Differences suggest varying N assimilation energetic requirements drive exometabolome composition.
Conclusions:
- Nitrogen availability is a critical factor shaping the M. aeruginosa exometabolome.
- Changes in N substrate influence the release of diverse compounds, including toxins and signaling molecules.
- Environmental factors like N availability and oxidative stress may synergistically impact M. aeruginosa fitness and bloom succession.
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