title: Nitric Oxide Ameliorates Zinc Oxide Nanoparticles Phytotoxicity in Wheat Seedlings: Implication of the Ascorbate-Glutathione Cycle.
abstract: The present study investigates ameliorative effects of nitric oxide (NO) against zinc oxide nanoparticles (ZnONPs) phytotoxicity in wheat seedlings. ZnONPs exposure hampered growth of wheat seedlings, which coincided with reduced photosynthetic efficiency (Fv/Fmand qP), due to increased accumulation of zinc (Zn) in xylem and phloem saps. However, SNP supplementation partially mitigated the ZnONPs-mediated toxicity through the modulation of photosynthetic activity and Zn accumulation in xylem and phloem saps. Further, the results reveal that ZnONPs treatments enhanced levels of hydrogen peroxide and lipid peroxidation (as malondialdehyde; MDA) due to severely inhibited activities of the following ascorbate-glutatione cycle (AsA-GSH) enzymes: ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase, and its associated metabolites ascorbate and glutathione. In contrast to this, the addition of SNP together with ZnONPs maintained the cellular functioning of the AsA-GSH cycle properly, hence lesser damage was noticed in comparison to ZnONPs treatments alone. The protective effect of SNP against ZnONPs toxicity on fresh weight (growth) can be reversed by 2-(4carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, and thus suggesting that NO released from SNP ameliorates ZnONPs toxicity. Overall, the results of the present study have shown the role of NO in the reducing of ZnONPs toxicity through the regulation of accumulation of Zn as well as the functioning of the AsA-GSH cycle.
authors.affiliation: Centre of Advanced in Botany, Banaras Hindu University VaranasiVaranasi, India; Centre for Medical Diagnostic and Research, Motilal Nehru National Institute of TechnologyAllahabad, India.
authors.forename: Durgesh K
authors.initials: DK
authors.lastname: Tripathi
authors.affiliation: Centre for Medical Diagnostic and Research, Motilal Nehru National Institute of Technology Allahabad, India.
authors.forename: Rohit K
authors.initials: RK
authors.lastname: Mishra
authors.affiliation: D D Pant Interdisciplinary Research Lab, Department of Botany, University of Allahabad Allahabad, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Singh
authors.affiliation: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad Allahabad, India.
authors.forename: Samiksha
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, India.
authors.forename: Kanchan
authors.initials: K
authors.lastname: Vishwakarma
authors.affiliation: Centre for Medical Diagnostic and Research, Motilal Nehru National Institute of TechnologyAllahabad, India; Department of Biotechnology, Motilal Nehru National Institute of TechnologyAllahabad, India.
authors.forename: Shivesh
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Government Ramanuj Pratap Singhdev Post Graduate College Koriya, India.
authors.forename: Vijay P
authors.initials: VP
authors.lastname: Singh
authors.affiliation: Nanotechnology Application Centre, University of Allahabad Allahabad, India.
authors.forename: Prashant K
authors.initials: PK
authors.lastname: Singh
authors.affiliation: Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad Allahabad, India.
authors.forename: Sheo M
authors.initials: SM
authors.lastname: Prasad
authors.affiliation: Centre of Advanced in Botany, Banaras Hindu University Varanasi Varanasi, India.
authors.forename: Nawal K
authors.initials: NK
authors.lastname: Dubey
authors.affiliation: Nanotechnology Application Centre, University of Allahabad Allahabad, India.
authors.forename: Avinash C
authors.initials: AC
authors.lastname: Pandey
authors.affiliation: Department of Biology, Western Kentucky University, Bowling Green KY, USA.
authors.forename: Shivendra
authors.initials: S
authors.lastname: Sahi
authors.affiliation: D D Pant Interdisciplinary Research Lab, Department of Botany, University of Allahabad Allahabad, India.
authors.forename: Devendra K
authors.initials: DK
authors.lastname: Chauhan
keywords: DNA damage; ZnONPs; amelioration; ascorbate–glutathione cycle; nanotoxicity; nitric oxide