Genome-Wide Identification of SWEET Gene Family and Integrative Transcriptomic–Metabolomic Analysis Reveal Sugar Transport-Mediated Chilling Responses in Sesame (Sesamum indicum L.)

Sesame is a thermophilic oilseed crop that is vulnerable to low-temperature stress. SWEET sugar transporters are important for sugar allocation, but their roles in sesame cold responses remain poorly understood. In this study, 24 <i>SWEET</i> genes were identified in the sesame genome and classified into six conserved groups with high structural conservation and limited duplication. Comparative transcriptomic and metabolomic analyses of cold-tolerant and cold-sensitive sesame accessions under chilling stress revealed distinct <i>SiSWEET</i> expression patterns and contrasting soluble sugar accumulation. Several <i>SiSWEET</i> genes showed significant correlations with glucose, fructose, and sucrose contents. These results suggest that SWEET-mediated sugar transport is involved in sesame chilling responses and provide candidate genes for improving cold tolerance.