Silicon nanoparticles (SiNPs) mediate GABA, SOD and ASA-GSH cycle to improve cd stress tolerance in Solanum lycopersicum

Contamination of agricultural products with Cadmium (Cd) is a global problem that should be considered for minimizing the risks to human health. Considering the potential effects of SiNPs in decreasing abiotic stress, a study was conducted to investigate the effect of SiNPs in the reduction of Cd stress on Solanum lycopersicum. SiNPs was used at 0, 25, 50 and 100 mg/l and CdCl2 at 0, 100 and 200 mu M concentrations. The results showed that Cd stress caused a significant decrease in dry weight, content of GSH, ASA, significently increasing the activity of GR, APX, GST, SOD, as well as content of H2O2, MDA, proline, and GABA in shoots and roots compared to the control. SiNPs significantly increased shoot and root dry weight compared to the control. As a coenzyme, SiNPs induced the activity of antioxidant enzymes and significantly increased GST and GR gene expression compared to the control. SiNPs also caused a substantial increase in the content of ASA, GSH, proline and GABA compared to the control. By inducing the activity of antioxidant enzymes and metabolites of the ascorbate-glutathione (ASA-GSH) cycle, SiNPs removed a large content of H2O2 and significantly reduced the MDA content, and as a result led to the stability of cell membrane under Cd stress. Induction of ASA-GSH, GABA and SOD cycle by SiNPs clearly showed that SiNPs could be a potential tool to alleviate Cd stress in plants cultivated in areas contaminated with this heavy metal.