Sugar signaling networks in plant life cycle: Insights for horticultural crop research

Sugars are not only essential energy sources but also central signaling molecules that orchestrate the entire plant life cycle. This review comprehensively outlines the signal transduction pathways mediated by core sugar sensors, including Hexokinase 1 (HXK1), Target of Rapamycin (TOR), and Sucrose Non-Fermenting 1-Related Protein Kinase 1 α (SnRK1α), highlighting the diverse perception mechanisms of glucose, sucrose, and trehalose-6-phosphate. We synthesize how sugar signals interact with phytohormones and environmental factors to form extensive regulatory networks controlling key developmental processes from seed germination to leaf senescence. By systematically integrating these mechanisms across the plant life cycle, this review provides a holistic conceptual framework and mechanistic insights specifically for horticultural crop research. We further identify key knowledge gaps, such as the characterization of sugar sensor interactors and signal integration mechanisms, offering novel targets for future research aimed at improving horticultural crop quality, yield, and stress resistance.