Sulfate Transporters in Plants: Functions, Regulation, and Interactions

Sulfur is an essential macronutrient in plants, involved in the synthesis of proteins, amino acids, cofactors, and secondary metabolites, as well as in stress responses. In plants, sulfate transporters (SULTRs) are membrane proteins that mediate the uptake, distribution, and remobilization of sulfate. This review examines the diversity of functions, physiological roles, and interactions of plant SULTRs. We also review the complex regulatory mechanisms that control SULTR gene expression and transporter activity, enabling plants to dynamically adapt to environmental fluctuations and changing nutrient requirements. Additionally, we review the role of SULTRs in mediating plant responses to abiotic and biotic stresses, including drought, salinity, heavy metal toxicity, and pathogen infections. Recent evidence highlights extensive crosstalk between SULTRs and other nutrient pathways, particularly nitrogen and phosphate, as well as their integration with phytohormone signaling networks. Advances in genomics, transcriptomics, and proteomics over the past decade have significantly enhanced our understanding of the complex interactions between SULTRs and other nutrient pathways, phytohormones, and signaling molecules. These findings highlight the pivotal role of SULTRs in maintaining sulfur homeostasis and enhancing nutrient use efficiency. By synthesizing recent discoveries, this review identifies SULTRs as promising molecular targets for crop improvement, stress resilience, and sustainable nutrient management, particularly under sulfur-deficient conditions.