SAGE Analysis of Transcriptome Responses in Arabidopsis Roots Exposed to 2,4,6-Trinitrotoluene

Ekman, Drew R.; Lorenz, W. Walter; Przybyla, Alan; Wolfe, N. Lee; Dean, Jeffrey F. D.

doi:10.1104/pp.103.028019

Cited by 110 publications

(107 citation statements)

References 47 publications

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“…Both GST-U24 and GST-U25 have similar rates of activity toward TNT, and, in combination with other endogenous GSTs, there is likely to be considerable overlapping activity toward TNT in vivo. Although not up-regulated in our microarray study (Gandia Herrero et al, 2008), GST-U19, which is closely related to GST-U24 and GST-U25, can also be up-regulated in response to TNT (Ekman et al, 2003), and it is likely that GST-U19 also has activity toward TNT. Root length studies of knockout GST-U24 mutant plants were reported to have a similar response to TNT to wild-type plants .…”

Section: Glutathione-tnt Productsmentioning

confidence: 94%

“…While we saw a decrease in glutathione pools in plants grown in TNT-contaminated soil, studies using monochlorobimane, which binds glutathione to form a fluorescent compound, indicated that glutathione pools increase in the presence of TNT (Mezzari et al, 2005). Additionally, gene expression studies in Arabidopsis show that glutathione reductases, which are involved in sustaining glutathione pools, can be upregulated in response to TNT treatment (Ekman et al, 2003).…”

Section: Glutathione-tnt Productsmentioning

confidence: 99%

“…Traditional breeding or genetic modification techniques might be a way to enhance the ability of plants to withstand and detoxify TNT. Brentner et al (2008) have extrapolated the results of a TNT-treated Arabidopsis microarray study (Ekman et al, 2003) to identify GST homologs in poplar. The corresponding poplar homolog (GST173) to GST-U24 was up-regulated in response to TNT.…”

Section: Glutathione-tnt Productsmentioning

confidence: 99%

“…Since GSTs have evolved the ability to catalyze glutathionelinked reactions with thousands of different chemical structures, it has been hypothesized that GSTs should play a central role, alongside glucosyltransferases, in the detoxification of TNT (Mezzari et al, 2005;Brentner et al, 2008). Gene expression studies in poplar (Tanaka et al, 2007;Brentner et al, 2008) and Arabidopsis (Ekman et al, 2003;Mezzari et al, 2005;Gandia-Herrero et al, 2008) have identified GSTs up-regulated in response to TNT; however, to date, the biochemical response of GSTs toward TNT has not been investigated. The overexpression of plant GSTs has been shown to increase resistance to a range of stresses, with some t class GSTs shown to detoxify herbicides via a conjugation activity (Dixon and Edwards, 2010;Cummins et al, 2011).…”

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confidence: 99%

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Arabidopsis Glutathione Transferases U24 and U25 Exhibit a Range of Detoxification Activities with the Environmental Pollutant and Explosive, 2,4,6-Trinitrotoluene

et al. 2014

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The explosive 2,4,6-trinitrotoluene (TNT) is a major worldwide military pollutant. The presence of this toxic and highly persistent pollutant, particularly at military sites and former manufacturing facilities, presents various health and environmental concerns. Due to the chemically resistant structure of TNT, it has proven to be highly recalcitrant to biodegradation in the environment. Here, we demonstrate the importance of two glutathione transferases (GSTs), GST-U24 and GST-U25, from Arabidopsis (Arabidopsis thaliana) that are specifically up-regulated in response to TNT exposure. To assess the role of GST-U24 and GST-U25, we purified and characterized recombinant forms of both enzymes and demonstrated the formation of three TNT glutathionyl products. Importantly, GST-U25 catalyzed the denitration of TNT to form 2-glutathionyl-4,6-dinitrotoluene, a product that is likely to be more amenable to subsequent biodegradation in the environment. Despite the presence of this biochemical detoxification pathway in plants, physiological concentrations of GST-U24 and GST-U25 result in only a limited innate ability to cope with the levels of TNT found at contaminated sites. We demonstrate that Arabidopsis plants overexpressing GST-U24 and GST-U25 exhibit significantly enhanced ability to withstand and detoxify TNT, properties that could be applied for in planta detoxification of TNT in the field. The overexpressing lines removed significantly more TNT from soil and exhibited a corresponding reduction in glutathione levels when compared with wild-type plants. However, in the absence of TNT, overexpression of these GSTs reduces root and shoot biomass, and although glutathione levels are not affected, this effect has implications for xenobiotic detoxification.The containment and cleanup of environmental pollutants is increasingly both a legal requirement and a responsible action in many developed countries. The most commonly used explosives in military weapons are 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and their continual use, along with production and decommissioning, are progressively contaminating millions of hectares of military land . Bioremediation of TNT is particularly challenging, as the electron-withdrawing properties of the three nitro groups render the aromatic ring particularly resistant to oxidative attack and ring cleavage by microbial oxygenases, which in the environment are normally central to the biodegradation of aromatic compounds (Qasim et al., 2007). In the United States, the Environmental Protection Agency and the military are addressing methods by which toxic TNT and RDX can be contained and detoxified on active military training ranges. One way this problem might be tackled is through the use of plants that are adapted to detoxify these compounds. This could be achieved either by traditional breeding programs or by genetic modification, as has been demonstrated previously for both RDX and TNT (Hannink et al., 2001;Rylott et al., 2006;Jackson et al., 2007).In t...

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Section: Glutathione-tnt Productsmentioning

confidence: 94%

Section: Glutathione-tnt Productsmentioning

confidence: 99%

Section: Glutathione-tnt Productsmentioning

confidence: 99%

mentioning

confidence: 99%

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Arabidopsis Glutathione Transferases U24 and U25 Exhibit a Range of Detoxification Activities with the Environmental Pollutant and Explosive, 2,4,6-Trinitrotoluene

et al. 2014

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“…4 Previously, GSTs had been shown to be upregulated in response to TNT Keywords: Arabidopsis thaliana, environmental pollutant, Glutathione transferases, TNT, xenobiotic detoxification, 2, 4, 6-trinitrotoluene treatment, and their involvement in TNT detoxification hypothesized. [8][9][10][11][12] Our study 13 investigated GST-U24 and GST-U25, the 2 Arabidopsis GSTs most highly upregulated in response to TNT under our treatment conditions. We demonstrated that Arabidopsis plants overexpressing GST-U24 or GST-U25 removed more TNT from soil and were more resistant to TNT toxicity than wild type plants, due to the direct glutathionylation of TNT.…”

mentioning

confidence: 99%