Objective Sorbitol, a important hexitol, plays a significant regulatory role in plant growth, development, and stress responses. This study aimed to elucidate the effect and underlying physiological and molecular mechanisms of sorbitol-induced resistance in Lycium barbarum against Fusarium solani, thereby providing a theoretical foundation for the green prevention and control of Lycium barbarum root rot.

Method First, sorbitol content in Lycium barbarum roots was quantified at various time points post-infection to determine its dynamic changes and correlation with pathogen infection. The effects and underlying mechanisms of exogenous sorbitol were then systematically evaluated using a multifaceted approach, including: antifungal activity assays at different concentrations; disease assessment via both in vitro leaf and in vivo pot inoculation; detection of reactive oxygen species (ROS) burst; measurement of peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD) activities; and expression analysis of key jasmonic acid (JA) signaling pathway genes (LOX3.1, AOS1).

Result (1) Infection by Fusarium solani induced a significant accumulation of endogenous sorbitol in the roots of Lycium barbarum at 24−72 h post-infection, suggesting that sorbitol may serve as an early response molecule involved in Lycium barbarum resistance to this pathogen. (2) In vitro antifungal assays showed that sorbitol at concentrations of 0−20 μmol/L exhibited no direct inhibitory effect on the mycelial growth of Fusarium solani, indicating that its disease resistance function relies on the activation of endogenous defense responses in host plants. (3) In this study, 5 μmol/L sorbitol was determined as the optimal induction concentration, which significantly suppressed leaf lesion expansion and root rot development, promoted moderate ROS accumulation, enhanced the activities of antioxidant enzymes (POD, PPO, and SOD), and upregulated the expression of LOX3.1 and AOS1 genes, thereby systemically boosting disease resistance in Lycium barbarum.

Conclusion Fusarium solani infection induces sorbitol accumulation in Lycium barbarum roots. Exogenous application of sorbitol at appropriate concentrations significantly enhances the resistance of Lycium barbarum to Fusarium solani by activating plant ROS signaling, increasing antioxidant enzyme activities, and synergistically regulating the JA pathway. This study preliminarily reveals the core physiological and molecular regulatory mechanisms of sorbitol-induced resistance to root rot in Lycium barbarum, and will provide an important theoretical basis and practical reference for the development of novel biogenic immune elicitors and the construction of a green prevention and control technology system for Lycium barbarum diseases.