Phytotoxicity and phytoremediation of 2,6-dinitrotoluene using a model plant, Arabidopsis thaliana

• Published in: Chemosphere (Oxford) 2007-06, Vol.68 (6), p.1050-1057
• Main Authors: Yoon, Jong Moon, Oliver, David J., Shanks, Jacqueline V.
• Format: Article
• Language: English
• Subjects: 2,6-dinitrotoluene; Applied sciences; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis thaliana; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; Carbon Radioisotopes - metabolism; Decontamination. Miscellaneous; Dinitrobenzenes - pharmacokinetics; DNA, Bacterial; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Regulation, Plant; Germ-Free Life; Glutathione S-transferase; glutathione transferase; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Groundwaters; Inactivation, Metabolic; Industrial applications and implications. Economical aspects; metabolic detoxification; Miscellaneous; Mutagenesis, Insertional; Natural water pollution; organic nitrogen compounds; Phytoremediation; phytotoxicity; pollutants; Pollution; Pollution, environment geology; Real time PCR; root growth; seedlings; Soil and sediments pollution; Toxicity; Uptake; Water treatment and pollution
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2007.02.003

Biochemical and genetic studies of xenobiotic metabolism in the model plant Arabidopsis have significant potential in providing information for phytoremediation. This paper presents the toxicity of 2,6-dinitrotoluene (2,6-DNT) to Arabidopsis under axenic conditions, the fate and transformation of 2,6-DNT after uptake by the plant, and the effect of a putative glutathione S-transferase (GST), which is highly induced by 2,4,6-trinitrotoluene (TNT) in the previous study, on the detoxification of 2,6-DNT. 2,6-DNT had toxic effects on the growth of Arabidopsis based on whole seedling as well as root growth assays. Using [U- 14C]2,6-DNT, the recovery was over 87% and less than 2% accounted for the mineralization of 2,6-DNT in axenic liquid cultures during the 14 d of exposure. About half (48.3%) of the intracellular radioactivity was located in the root tissues in non-sterile hydroponic cultures. 2-Amino-6-nitrotoluene (2A6NT) and two unknown metabolites were produced as transformation products of 2,6-DNT in the liquid media. The metabolites were further characterized by proton NMR spectra and the UV-chromatograms when the plant was fed with either 2,6-DNT or 2A6NT. In addition, polar unknown metabolites were detected at short retention times from radiochromatograms of plant tissue extracts. The GST gene of the wild-type of Arabidopsis in response to 2,6-DNT was induced by 4.7-fold. However, the uptake rates and the tolerance at different concentrations of 2,6-DNT and TNT were not significantly different between the wild-type and the gst mutant indicating that induction of the GST gene is not related to the detoxification of 2,6-DNT.