Integrated transcriptomic and metabolomic analysis reveals the mechanism of cross-adaptation in Krascheninnikovia arborescens to combined drought and cold stress

Cold and drought stress are important environmental factors limiting agricultural production, especially in the northwestern region of China. However, few studies have examined the responses of plants to combined drought and cold stress. Here, we analyzed the cross-adaptation of Krascheninnikovia arborescens to these two stresses based on physiological, comparative transcriptomics, and metabolomics analyses. Drought pretreatment significantly enhanced cold tolerance of the plants. Physiological analyses showed that combined drought and cold stress caused less cellular damage than cold stress alone, as evidenced by lower relative electrical conductivity and reduced ROS accumulation. Plants subjected to combined stress also showed improved photosynthetic parameters during the recovery stage. Transcriptomics analyses identified a large number of differentially expressed genes (DEGs) under different stress conditions. A portion of the DEGs under conditions of combined stress were common to both drought and cold stress, and these genes were involved in processes such as defense and photosynthesis. Metabolomics analysis identified metabolites, and more metabolites from the metabolic pathways of flavonoids, lignin, and carbohydrates were accumulated under combined stress conditions. Integrated transcriptomics and metabolomics analyses revealed significant enrichment of the flavonoid and phenylpropanoid biosynthesis pathways. These findings suggest that drought pretreatment enables K. arborescens to withstand cold stress more effectively by enhancing its antioxidant capacity, accumulating osmoprotectants, and activating specific metabolic pathways. These findings reveal novel molecular and metabolic mechanisms underlying cross-adaptation, providing potential targets for breeding multi-stress–resilient crops suited to harsh environments.