Engineered nickel oxide nanoparticles affect genome stability in Allium cepa (L.)

Area of Science:

• Environmental Science
• Toxicology
• Plant Science

Background:

• Engineered nanoparticles, such as nickel oxide nanoparticles (NiO-NPs), are increasingly used in industries, leading to their release into the environment.
• While NiO-NP toxicity in animals is documented, their impact on plants (phytotoxicity) remains poorly understood.
• NiO-NPs can disrupt cellular functions by inducing excessive reactive oxygen species (ROS), affecting antioxidant systems in both animals and plants.

Purpose of the Study:

• To investigate the phytotoxic potential of NiO-NPs on the model plant Allium cepa.
• To assess the effects of NiO-NP exposure on reactive oxygen species (ROS) production and genotoxicity in A. cepa.
• To elucidate the environmental hazard posed by NiO-NPs to plant ecosystems.

Main Methods:

• Allium cepa bulbs were treated with varying concentrations of NiO-NPs (10–500 mg L⁻¹).
• Intracellular ROS accumulation was quantified using the DCFH-DA assay.
• Genotoxicity was evaluated by analyzing Random Amplified Polymorphic DNA (RAPD) profiles to assess genomic DNA integrity and stability.

Main Results:

• A dose-dependent increase in intracellular ROS was observed with increasing NiO-NP concentrations.
• The DCFH-DA assay showed a significant increase in ROS production, with a 70% fluorescence rise over control at 125 mg L⁻¹ NiO-NP.
• RAPD analysis revealed significant alterations in DNA profiles, including changes in band intensity, loss/appearance of bands, and reduced genomic template stability, even at the lowest concentration (10 mg L⁻¹).

Conclusions:

• Nickel oxide nanoparticles induce significant oxidative stress and genotoxicity in Allium cepa.
• NiO-NPs demonstrate considerable phytotoxic potential, acting as a potent environmental hazard.
• This study provides the first evidence of NiO-NP-induced genotoxicity in A. cepa, highlighting the need for careful environmental risk assessment.