Partial root‐zone drying irrigation enhances synthesis of glutathione in barley roots to improve low temperature tolerance

SUMMARY Partial root‐zone drying irrigation (PRD) has been widely employed to regulate crop root development and responses to environmental fluctuations. However, its role in reprogramming rhizospheric microorganisms and inducing plant stress tolerance remains largely unexplored. This study aimed to investigate the effects of PRD on the response of barley ( Hordeum vulgare ) plants to low temperatures under various irrigation regimes. Under low temperature, barley plants subjected to PRD exhibited a significantly enhanced net photosynthetic rate, stomatal conductance, and maximum quantum efficiency of photosystem II compared to fully irrigated plants. Additionally, these plants showed a reduction in relative conductance. These results suggest that PRD could be a viable strategy for enhancing crop stress tolerance through irrigation management. Metabolomic analysis revealed that PRD influenced the accumulation of glutathione and 9‐octadecenamide in roots under low temperature, which was corroborated by transcriptome profiling data. Furthermore, the study highlighted the close association between this regulatory process and rhizosphere core microorganisms, such as Sphingobium and Mortierella , enriched in barley roots under PRD. This study revealed the mechanism underlying plant stress tolerance induction by PRD and the roles of rhizosphere microorganisms in this process. Also, the current study suggests that PRD is a promising strategy for enhancing crop stress tolerance through effective irrigation management.