Phytotransformation of 2,4-Dinitrotoluene in Arabidopsis thaliana: Toxicity, Fate, and Gene Expression Studies in Vitro

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• 作者：Jong M. Yoon ; David J. Oliver ; Jacqueline V. Shanks
• 刊名：Biotechnology Progress
• 出版年：2006
• 出版时间：December 2006
• 年：2006
• 卷：22
• 期：6
• 页码：1524 - 1531
• 全文大小：161K
• 年卷期：v.22,no.6(December 2006)
• ISSN：1520-6033

文摘

Basic knowledge of the plant transformation pathways and toxicity of 2,4-dinitrotoluene (2,4-DNT) will assist in the design and assessment of a phytoremediation strategy. This study presentsthe toxicity and fate of 2,4-DNT and gene expression in response to 2,4-DNT exposure usingthe model plant Arabidopsis thaliana, an increasingly popular system for genetic and biochemicalstudies of phytotransformation of explosives. From the results of biomass and root growth assaysfor toxicity, 2,4-DNT was toxic to the plants at concentrations as low as 1 mg/L. In the uptakestudy, 95% of the initial 2,4-DNT was removed by 15-day-old seedlings from liquid mediaregardless of the initial 2,4-DNT concentrations while 30% accounted for the adsorption to theautoclaved plant materials. The mass balance was over 86% using [U-¹⁴C]2,4-DNT, and themineralization by the plants was less than 1% under sterile conditions during 14 days of exposure.The percentage of the bound radioactivity increased from 49% to 72% of the radioactivity inthe plants, suggesting transformed products of 2,4-DNT may be incorporated into plant tissuessuch as lignin and cellulose. Monoaminonitrotoluene isomers and unknown metabolites withshort retention times were detected as transformed products of 2,4-DNT by the plants. Most(68%) of the radioactivity taken up by the plants was in the root tissues in nonsterile hydroponiccultures. Glutathione and expression of related genes (GSH1 and GSH2) in plants exposed to2,4-DNT were 1.7-fold increased compared to untreated plants. Genes of a glutathioneS-transferase and a cytochrome P450, which were induced by 2,4,6-trinitrotoluene exposure inprevious studies, were upregulated by 10- and 8-fold, respectively. The application ofphytoremediation and the development of transgenic plants for 2,4-DNT may be based on TNTphytotransformation pathway characteristics because of the similar fate and gene expression inplants.