Integration of transcriptome and metabolome provides new insights into the response mechanism of Camellia oleifera to aluminum stress

Aluminum (Al) toxicity restricts plant growth and development. Camellia oleifera is a typical aluminum-accumulating plant and currently serves as an emerging species for the remediation of aluminum pollution in mining areas. This study combined phenotyping, physiological, transcriptomics, and metabolomics to analyze the responses of C. oleifera seedlings to Al stress. The morphological data indicated that roots adapted through lateral root elongation and tip proliferation, whereas leaves mitigated stress damage by decreasing their surface area and biomass. Malondialdehyde (MDA) accumulation correlated directly with Al content. Catalase (CAT) and superoxide dismutase (SOD) synergistically neutralized H 2 O 2 under short-term low Al stress, while peroxidase (POD) dominated under prolonged high concentrations. KEGG mapping indicated that differentially expressed genes (DEGs) were primarily enriched in amino acid metabolism and phenylpropanoid biosynthesis, while differentially accumulated metabolites DAMs were mainly linked to amino acid biosynthesis and fatty acid metabolism. Integrating transcriptomic and metabolomic datasets underscored that α-linolenic acid and tryptophan metabolic pathways are crucial for leaf adaptation under aluminum (Al) toxicity. Through weighted gene co-expression network analysis (WGCNA), three modules (Gene_MEbrown, Gene_MEmagenta, and Metabo_MEblue) were discovered to have strong associations with physiological parameters, particularly MDA levels. Consequently, central Al-responsive genes and target metabolites were identified, which were majorly enriched in the α-linolenic acid metabolism pathway. This research delivers deeper mechanistic insights into how C. oleifera orchestrates metabolic pathways to mitigate Al toxicity.