Physiological and metabolomic analyses reveal that Fe3O4 nanoparticles ameliorate cadmium and arsenic toxicity in Panax notoginseng.

Heavy metal(loid)-contaminated available arable land seriously affects crop development and growth. Engineered nanomaterials have great potential in mitigating toxic metal(loid) stress in plants. However, there are few details of nanoparticles (NPs) involved in Panax notoginseng response to cadmium (Cd) and arsenic (As). Herein, integrating physiological and metabolomic analyses, we investigated the effects of Fe 3 O 4 NPs on plant growth and Cd/As responses in P. notoginseng. Cd/As treatment caused severe growth inhibition. However, foliar application of Fe 3 O 4 NPs increased beneficial elements in the roots and/or leaves, decreased Cd/As content by 10.38% and 20.41% in the roots, reduced membrane damage and regulated antioxidant enzyme activity, thereby alleviating Cd/As-induced growth inhibition, as indicated by increased shoot fresh weight (FW), the rootlet length and root FW by 40.14%, 15.74%, and 46.70% under Cd stress and promoted the shoot FW by 27.00% under As toxicity. Metabolomic analysis showed that 227 and 295 differentially accumulated metabolites (DAMs) were identified, and their accumulation patterns were classified into 8 and 6 clusters in the roots and leaves, respectively. Fe 3 O 4 NPs altered metabolites significantly involved in key pathways, including amino sugar and nucleotide sugar metabolism, flavonoid biosynthesis and phenylalanine metabolism, thus mediating the trade-off between plant growth and defense under stress. Interestingly, Fe 3 O 4 NPs recovered more Cd/As-induced DAMs to normal levels, further supporting that Fe 3 O 4 NPs positively affected seedling growth under metal(loid)s stress. In addition, Fe 3 O 4 NPs altered terpenoids when the seedlings were subjected to Cd/As stress, thus affecting their potential medicinal value. This study provides insights into using nanoparticles to improve potential active ingredients of medicinal plants in metal(loid)-contaminated areas. [Display omitted] • Cd/As stress disturbed mineral element balance and repressed seedling growth. • Fe 3 O 4 NPs ameliorated mineral elements and antioxidant content under Cd/As stress. • Fe 3 O 4 NPs restored Cd/As-induced metabolites to normal levels under Cd/As stress. • Fe 3 O 4 NPs altered terpenoids and flavonoids, thus affecting medicinal value. • Fe 3 O 4 NPs could be used for medicinal plant sustainability under toxic metal (loid). [ABSTRACT FROM AUTHOR]