Fluoride, a naturally occurring element found in water, soil, food, and atmospheric precipitation, can lead to fluorosis and various health issues when consumed excessively. However, the mechanism of fluorosis is still under investigation. This study utilizes Caenorhabditis elegans as a model organism to investigate the effects of fluoride exposure on biological systems and to explore the mechanisms by which curcumin mitigates fluoride- induced toxicity. Three groups were established: a blank control, a sodium fluoride (NaF) exposure group (concentration 5 mmol/L), and a curcumin intervention group (concentration 25 mu mol/L). Physiological parameters, lipofuscin levels, intracellular reactive oxygen species (ROS) levels, mitochondrial membrane potential, and mitochondrial copy numbers were measured to assess the effects of fluoride toxicity and curcumin protection. RNA-seq and qRT-PCR were utilized to investigate the molecular mechanisms underlying fluoride- induced damage and curcumin's mitigating effects. Results indicated that fluoride-exposed nematodes displayed physiological abnormalities, increased ROS production, higher lipofuscin levels, altered mitochondrial membrane potential and mitochondrial copy number, and activated MAPK signaling pathway genes. Curcumin exhibited protective effects on these parameters, suggesting its potential in preventing fluoride-induced harm by modulating oxidative stress and preserving mitochondrial function. This research enhances our understanding of the mechanisms of fluoride toxicity and highlights the potential benefits of curcumin.

In recent years, the effects of fluoride (F) pollution in numerous ecosystems such as groundwater, soil, etc. Have become a major issue worldwide. This increase in F pollution is a direct consequence of the unbridled use of fertilizers in agricultural and several other human activities that require immediate and appropriate action. Therefore, this manuscript reveals important findings on the efficacy of bacteria isolated from agricultural fields in central Chhattisgarh in manifesting resistance to F and in reversing the F-induced oxidative damage in susceptible Oryza sativa L, (Var. MTU1010). Chronic exposure of Oryza sativa L. to sodium fluoride (NaF) (50 mg L- 1) severely impeded growth and various physiological parameters such as germination percentage, biomass and root and shoot length and stimulated the formation of reactive oxygen species (ROS), which enhanced electrolyte leakage and formation of cytotoxic products like malondialdehyde. To this end, potential bacterial strains, namely MT2A, MT3A, MT4A, and Du3A were isolated, screened for various plant growth promoting (PGP) traits and used to explore their efficiency to mitigate F toxicity in Oryza sativa L. in vivo. The seedlings inoculated with the bacterial strains showed significant development as evidenced by an increase in root and shoot length, biomass and chlorophyll content. Additionally, inoculation of these strains in combination with F stress significantly decreased oxidative stress by increasing the expression of protective genes encoding antioxidant enzymes and boosted agronomic traits remarkably. Overall, the manuscript demonstrates the pivotal role played by the isolated bacteria in abating ill effects of F in the Oryza sativa L. seedlings and proves their potential as protective bioagents against F stress.