Graphene oxide remodels the rhizosphere microbiome and induces metabolic reprogramming of flavor-related compounds in tea leaves.

The flavor quality of Camellia sinensis is strongly influenced by their secondary metabolites and associated microbial communities. Graphene oxide (GO) is a carbon-based nanomaterial with unique physicochemical properties. While its potential to modulate plant physiology has been recognized, its specific effects on tea plant metabolism and associated rhizosphere microbiomes remain largely unexplored. To address this gap, a pot experiment was established to evaluate the impact of varying GO concentrations (0, 25, 50, 100 mg/L) on both the foliar metabolic profiles of tea plants and the structural composition of their rhizosphere microbial communities. Untargeted metabolomics and 16S rRNA sequencing were integrated to systematically analyze changes in metabolite accumulation and microbial composition under GO treatments. The results revealed that GO treatments significantly altered the metabolite composition in tea leaves, with key flavor-related compounds such as flavonoids, phenolic acids, amino acids, and their derivatives showing concentration-dependent accumulation. Furthermore, GO application notably increased the richness and diversity of the rhizosphere microbial community and shifted its structure. LEfSe analysis identified distinct microbial biomarkers across GO concentrations, including beneficial taxa (Micrococcaceae, Rhizobiales) in the low-dose group and stress-tolerant taxa (Rhodanobacter, γ-proteobacteria) in the high-dose group. GO treatments also enhanced microbial metabolic pathways associated with secondary metabolite biosynthesis, antibiotic production, and nutrient transport. Co-occurrence network analysis further revealed a reorganization of microbial interactions in the rhizosphere under GO treatment. This study uncovers novel mechanistic insights into the regulatory effects of graphene oxide on the metabolic pathways of tea plants and the compositional dynamics of their rhizosphere microbiomes.