Ion flux integrated with transcriptomic and metabolomics analysis uncover molybdenum mitigation on cadmium toxicity...

Both preventing cadmium (Cd) from entering the food system and maximizing the utility of Cd-contaminated soils are of paramount importance. This study investigated the mitigation of Cd²⁺ toxicity in clove basil seedlings, an aromatic plant producing essential oil, by molybdenum (Mo) supplementation. The results revealed a distinct, Mo-mediated defense mechanism. First, phenotypic assessments showed that exogenous Mo application (0.08 μM) restored Cd-inhibited seedling growth, increasing whole-plant fresh weight by 37.62%. Concurrently, Mo application reduced Cd²⁺ levels by at least 8.31% and suppressed net Cd²⁺ translocation from roots to shoots. Second, transcriptomic analysis integrating WGCNA and GSEA revealed that Cd + Mo combination treatment induced lipid biosynthesis pathways while retarding detrimental lipid metabolism. These results were corroborated by metabolomics analysis, which showed that the most altered metabolites by Cd + Mo were lipids. Third, physiological measurements demonstrated that Cd + Mo enhanced the antioxidant activity. Specifically, glutathione reductase activity and glutathione content increased by 112.07% and 17.79%, respectively, while glutathione peroxidase activity was reduced by 92.18%. Mechanistically, multi-omics and physiological analyses highlighted that Mo mitigated Cd²⁺ toxicity primarily by reducing Cd²⁺ uptake, enhancing antioxidant activity, and modulating lipid metabolism. Therefore, this study provides critical mechanistic insights into Mo-mediated Cd tolerance, offering a significant contribution to the field by establishing a highly practical paradigm for both phytoremediation and safe land utilization. Cultivating non-food economic crops, such as clove basil, potentially represents an effective strategy for safely utilizing heavy metal-contaminated land.