Trehalose in plant stress responses: Mechanisms and agricultural applications

Trehalose is a non-reducing disaccharide widely distributed in microorganisms, fungi, invertebrates, and certain plant species.Although higher plants accumulate only trace amounts of trehalose, its biosynthetic intermediate, trehalose-6-phosphate (T6P), functions as a central signaling molecule that integrates carbon status, energy homeostasis, plant growth, and stress adaptation.Recent studies have revealed that trehalose metabolism serves as a key regulatory network linking carbohydrate metabolism with plant responses to diverse environmental stresses.Trehalose enhances tolerance to drought, salinity, heat, and cold stresses, and the T6P-SnRK1 signaling pathway coordinates carbon allocation and energy utilization, enabling plants to optimize growth and survival under adverse conditions.Both exogenous trehalose application and genetic manipulation of trehalose biosynthetic pathways have been shown to improve abiotic stress tolerance in a wide range of crops.Beyond its role in abiotic stress adaptation, trehalose also contributes to plant immunity by acting as an elicitor-like signal that induces reactive oxygen species production, activates defense-related gene expression, enhances salicylic acid-mediated signaling, and promotes stomatal closure, thereby strengthening resistance against diverse pathogens.Conversely, trehalose metabolic pathways are important for virulence, stress adaptation, and survival in several plant pathogenic fungi and bacteria.Owing to its unique physiological functions and protective properties, trehalose has attracted increasing attention as a promising agricultural biomolecule with numerous potential applications.This review summarizes current advances in trehalose biosynthesis, metabolism, and signaling, discusses its roles in abiotic and biotic stress responses, and highlights emerging opportunities for the application of trehalose in sustainable crop production and climate-resilient agriculture.