Abstract:
Objectives Sulfur (S) is an essential elemental nutrient for plant growth and development. It is involved in the production of primary (e.g., cysteine and protein) and secondary metabolites (e.g., glucosinolate, plant defensins, phytochelatins, vitamins, and coenzyme A).
Main advances Plants take up sulfate from soils via roots and convert it into sulfide in plant cells through adenosine triphosphate sulfurylase, adenosine 5′-phosphosulfate reductase, and sulfite reductase. Sulfide reacts with O-acetylserine to form cysteine, catalyzed by OAS (thiol)-lyase. Studies have shown that plants’ uptake, transport, assimilation, and redistribution of sulfate is modified. Accordingly, plants cope with S starvation at the transcription, post-transcription, translation, post-translation, and epigenetic levels. Sulphur stress up-regulates or down-regulates transcription of some genes, or protein translation and degradation, which are involved in S uptake, transport, and assimilation. This alters S uptake and utilization in plants, maintains plant growth and development, and increases S uptake and use efficiency.
Outlook At the transcription level, there is a need to study other transcription factors regulating plants’ responses to low S. Further, the post-transcription level research needed to include studying how novel miRNAs regulate the transcript level of S-responsive genes. More research is needed to understand how transporters are localized, modified, and degraded at the translation and epigenetic levels. How do DNA methylation, histone and RNA modification modulate the activities of S uptake- and assimilation-related genes and proteins? The molecular mechanisms underlying interactions between S and other nutrients are unclear, suggesting the need to study the aforementioned research questions.