The regulation of soluble sugar transport and metabolism in fleshy fruits

Abstract

Sugars are fundamental to plant growth and fruit quality, functioning both as metabolic substrates and signaling molecules. During fleshy fruit development and ripening, the coordinated regulation of sugar transport and metabolism determines sugar accumulation, thereby shaping fruit sweetness and overall quality. This review provides a comprehensive synthesis of recent advances in soluble sugar transport and metabolism in fleshy fruits. We summarize major sugar types and their biosynthetic pathways, including sucrose, glucose, fructose and sugar alcohols such as sorbitol. We then discuss the roles of key transporter families, sucrose transporters (SUTs), monosaccharide transporters (MSTs), sugars will eventually be exported transporters (SWEETs), and tonoplast sugar transporters (TSTs), in source–sink allocation and intracellular partitioning. Furthermore, we integrate current knowledge on transcriptional, epigenetic, post-transcriptional, post-translational, hormonal and environmental regulation of sugar transport and metabolism. Finally, we highlight emerging biotechnological and management strategies for improving fruit quality through targeted manipulation of sugar-related pathways. This review provides an integrated framework for understanding sugar regulation in fruits and offers valuable insights for crop improvement and sustainable fruit production.