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 SWEET 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 SiSWEET expression patterns and contrasting soluble sugar accumulation. Several SiSWEET 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.