Antioxidant Responses in Cyanobacterial Salt Stress Adaptation

Cyanobacteria are photosynthetic microorganisms that frequently encounter saline environments, where high sodium chloride concentrations provoke osmotic imbalance and oxidative damage. Under salt stress, excess sodium ions disrupt cellular ionic homeostasis and impair photosynthetic electron transport, leading to overproduction of reactive oxygen species (ROS) such as superoxide anion and hydrogen peroxide. To mitigate oxidative injury, cyanobacteria deploy a coordinated antioxidant defence network. This comprises enzymatic quenchers—including superoxide dismutase, catalase and peroxidases—and non-enzymatic antioxidants such as carotenoids, flavonoids and phenolic compounds. Many strains also accumulate compatible solutes like glycine betaine and sucrose, which stabilise proteins and scavenge ROS directly. Exopolysaccharide production further contributes by binding sodium ions at the cell surface and reducing ion influx, thereby alleviating downstream oxidative stress. Recent studies have elucidated signalling cross-talk between ROS and small molecules such as nitric oxide, highlighting how redox sensing triggers gene expression programmes for antioxidant enzymes and transporters. Collectively, these responses enable cyanobacteria to maintain photosynthetic performance, membrane integrity and metabolic activity under fluctuating salinity. Understanding these mechanisms informs strategies for improving the resilience of biofertilisers and engineered strains for saline agriculture as well as guiding biotechnological applications in harsh environments.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Antioxidant Responses in Cyanobacterial Salt Stress Adaptation publication trend

The graph below shows the total number of articles in antioxidant responses in cyanobacterial salt stress adaptation across all publications each year (not limited to Nature Index journals).

Technical terms

Reactive oxygen species (ROS): Highly reactive oxygen derivatives formed under stress that can damage proteins, lipids and nucleic acids.

Superoxide dismutase (SOD): Enzyme that converts superoxide radicals into hydrogen peroxide and oxygen, initiating detoxification of ROS.

Catalase (CAT): Enzyme that decomposes hydrogen peroxide into water and oxygen, preventing oxidative damage.

Glutathione S-transferase (GST): Enzyme that conjugates glutathione to toxic substrates, aiding in detoxification of lipid peroxides.

Exopolysaccharide (EPS): High-molecular-weight polymers secreted by cyanobacteria that bind sodium ions and protect cells from osmotic and oxidative stress.

Flavonoid: Class of plant and microbial polyphenolic compounds with antioxidant properties that scavenge free radicals.

References

1. Effect of NaCl on Secondary Metabolites of Oscillatoria willei. International Journal of Scientific Research in Science and Technology (2023).
2. The Role of Cyanobacteria in Availability of Major Plant Nutrients and Soil Organic Matter to Rice Crop under Saline Soil Condition. Sarhad Journal of Agriculture (2017).