Sulfur Metabolism and Stress Responses in Plant Systems

Sulfur is a vital macronutrient in plants, fundamental to the synthesis of amino acids, vitamins and cofactors, and central to redox balance and defence against environmental stresses. In the soil, sulfur primarily exists as organic forms or as soluble sulfate (SO₄²⁻), the latter being the chief source for root uptake via specialised sulfate transporters (SULTRs). Once inside the plant, sulfate is activated by ATP-sulfurylase to form adenosine-5′-phosphosulfate (APS) and is subsequently reduced and incorporated into cysteine, which serves as a precursor for glutathione, methionine and other key thiols. These sulfur-containing metabolites mediate detoxification of reactive oxygen species, regulation of stomatal aperture and signal transduction under drought, salinity and pathogen attack. Dynamic control of transporter expression, enzyme activities and inter-organ allocation allows plants to maintain sulfur homeostasis and to mount rapid adaptive responses. Emerging evidence highlights interactions between sulfur pathways and other nutrient networks, as well as the role of soil microbiota in enhancing sulfur availability and stress resilience.

Research from Nature Portfolio

Field trials investigating sulphur-enriched organic amendments have demonstrated that applications of leonardite or humic acid fortified with sulfur substantially bolster maize tolerance to combined drought and phosphorus deficiency. Under water-limited and low-P conditions, treated plants maintained higher chlorophyll content, enhanced antioxidative enzyme activities and improved membrane integrity. These crops exhibited greater biomass and grain yield compared with untreated controls, indicating that sulphur-enriched soil amendments can mitigate the synergistic impacts of multiple abiotic stresses in calcareous soils and contribute to sustainable yield stability.

Sulfur Metabolism and Stress Responses in Plant Systems publication trend

The graph below shows the total number of articles in sulfur metabolism and stress responses in plant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Sulfate (SO₄²⁻): The primary inorganic form of sulfur absorbed by plant roots.

SULTR (Sulfate Transporter): A family of membrane proteins responsible for uptake and distribution of sulfate within the plant.

ATP-sulfurylase: An enzyme catalysing the activation of sulfate to adenosine-5′-phosphosulfate (APS), initiating sulfur assimilation.

Cysteine (Cys): The first organic sulfur compound produced from reduced sulfate, precursor to key thiols.

Glutathione (GSH): A tripeptide thiol critical for redox homeostasis, detoxification and signalling under stress.

References

1. Sulfur nutrition and its role in plant growth and development. Plant Signaling & Behavior (2022).
2. Sulfur Homeostasis in Plants. International Journal of Molecular Sciences (2020).
3. ATP-sulfurylase, sulfur-compounds, and plant stress tolerance. Frontiers in Plant Science (2015).
4. Sulfur-enriched leonardite and humic acid soil amendments enhance tolerance to drought and phosphorus deficiency stress in maize (Zea mays L.). Scientific Reports (2020).