Proteomic, biochemical, and anatomical influences of nanographene oxide on soybean (Glycine max)

Nano-graphene oxide (NGO) is an engineered nanostructure that is used in various fields including biology, chemistry, medicine, and environmental protection. This kind of highly used nanomaterial (NM) is being released and accumulated gradually in nature and can have some adverse influences on living organisms including plants. Soybean as a cultivated plant with a high importance in food industry, but sensitive to stresses, was chosen in the present study to be examined in terms of proteomic, biochemical, and anatomical properties under the NGO stress. Accordingly, a 2-dimensional gel electrophoresis (2-DE) approach was adopted for proteomic analysis of the NGO treated soybean roots, where significant changes were observed in the abundance of 48 proteins. MALDI TOF/TOF analysis revealed the upregulation of the proteins involved in the redox regulation in plants. Furthermore, anatomical examination of soybean roots under light microscopy showed that the NGO could enter into the root epidermis through the apoplastic pathway and accumulated in some parts of the root. With increasing NGO concentration, the diameter of the vascular apertures increased and then decreased at higher concentrations. To evaluate the toxicity of NGO, some of the growth parameters including fresh and dry weight, and height of the shoots, as well as some stress-related biochemical properties such as H₂O₂ production, antioxidant enzymes activity, and phenolics and flavonoids contents were measured. The results indicated that NGO could cause an oxidative stress, which can be considered a toxic effect evoking antioxidative and detoxification mechanisms in soybean.