Transcriptome Reversal in Sulfate Transporter Involves Abiotic Stress in Sesuvium portulacastrum L.

Abstract

Simple Summary Sulfur is an important nutrient that supports plant growth, metabolism, and responses to environmental stress. Plants require efficient sulfur transport systems to maintain sulfur balance, especially when exposed to saline soils or heavy metal contamination. However, the regulation of sulfur transport in halophytes that naturally tolerate extreme environments remains largely unknown. In this study, we investigated sulfate transporter (SULTR) genes in Sesuvium portulacastrum, a coastal plant with strong salt tolerance. We identified 22 SpSULTRs and found that these genes have diversified during evolution and display distinct expression patterns in different tissues. When exposed to salt, cadmium, and copper stresses, several SpSULTRs showed stress-responsive expression changes. Of these, SpSULTR3;1 and SpSULTR3;2 exhibited strong responses to salt treatment, suggesting that they may contribute to sulfur regulation during stress adaptation. Protein interaction analysis further indicated that these transporters may be connected with sulfur metabolism and stress-related pathways. This study improves our understanding of how sulfate transport systems function in halophytes and provides a foundation for future research on sulfur-mediated stress tolerance in plants.