SWEET Genes in Fruit Crops: Evolution, Mechanisms, and Agricultural Significance

The SWEET (Sugars Will Eventually be Exported Transporters) gene family plays a critical role in the transport of sugars across plant cells, influencing key physiological processes such as phloem loading, fruit development, ripening, and stress responses. Discovered through genome-wide analyses, SWEET genes are integral to sugar distribution in plants, enabling efficient transport of sucrose, glucose, and other monosaccharides. Structurally, SWEET transporters are characterized by a conserved sugar transporter domain and a characteristic 7-transmembrane helix configuration. These genes are classified into several subfamilies, each with specific roles in different tissues. In fruit crops, SWEETs regulate sugar accumulation, which directly impacts fruit quality, yield, and stress tolerance. This review highlights recent advances in the plant SWEET gene family, covering their discovery, protein structure characteristics, classification, and physiological functions. It emphasizes the pivotal role of SWEETs in regulating sugar transport and distribution, which directly influences fruit development and quality.