Analysis and characterization of glutathione S-transferase subunits from wheat (Triticum aestivum L.)

Pascal, Sophie; Debrauwer, Laurent; Ferte, Marie-Pierre; Anglade, Patricia; Rouimi, Patrick; Scalla, René

doi:10.1016/s0168-9452(98)00067-3

Cited by 27 publications

(27 citation statements)

References 36 publications

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“…In an effort to identify homologous genes in Populus that were induced by safener, we constructed an SSH cDNA library and used it to construct a cDNA microarray to identify safenerinduced genes. Safeners are normally applied through seed imbibition (Edwards and Cole 1996), seed coating (Pascal et al 1998;Hirase and Molin 2001), in agar medium during seed germination (Wu et al 1999), or by spraying seedlings (Alla and Hassan 1998). Since Populus is a clonally propagated crop, application of safener through seeds is not feasible.…”

Section: Discussionmentioning

confidence: 99%

Identification and analysis of safener-inducible expressed sequence tags in Populus using a cDNA microarray

Rishi

Munir

Kapur

et al. 2004

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Safeners are the chemicals used to protect plants from detrimental effects of herbicides, but their mode of action at the molecular level is not well understood. As an initial step towards understanding the molecular mechanism of safener action in trees, homologous genes in hybrid poplar (Populus nigra x Populus maximowiczii) that were induced by a safener were identified. We here describe the identification of differentially expressed genes in Populus that are induced by Concep-III, a herbicide safener. Expressed sequence tags (ESTs) enriched for transcriptionally induced genes were isolated by suppressive subtractive hybridization (SSH). The SSH library cDNA inserts were used to construct a cDNA microarray for high-throughput validation of the up-regulated expression of safener-induced genes. Single-pass and partial sequences of 1,344 safener-induced ESTs were assembled into 418 singletons and 328 clusters, but the putative functions of almost 53% of the ESTs are not known. Genes encoding proteins involved in all three different phases of safener action, viz., oxidation, conjugation, and sequestration, were found in the SSH library. Almost 75% of genes that showed greater than 2-fold expression upon safener treatment were redundant in the SSH library. The expression pattern for selected genes was validated by reverse transcription-polymerase chain reaction. A few safener-induced genes that were not previously reported to be induced by safeners, but which may have a role in herbicide metabolism, were identified. The newly identified genes could have potential for application in genetic engineering of plants for herbicide detoxification and tolerance.

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Section: Discussionmentioning

confidence: 99%

Identification and analysis of safener-inducible expressed sequence tags in Populus using a cDNA microarray

Rishi

Munir

Kapur

et al. 2004

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“…To determine if specific GSTs were induced by benoxacor treatment, protein extracts from control and safener-treated Arabidopsis cultures were subjected to GSH-affinity chromatography, a method that is known to purify many plant GSTs (Pascal et al, 1998). The affinity-bound proteins were then resolved on two-dimensional gels into a large number of polypeptides (Fig.…”

Section: Table II Effect Of Safeners On Total Glutathione Content Inmentioning

confidence: 99%

Induction of Glutathione S-Transferases in Arabidopsis by Herbicide Safeners

et al. 2002

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Herbicide safeners increase herbicide tolerance in cereals but not in dicotyledenous crops. The reason(s) for this difference in safening is unknown. However, safener-induced protection in cereals is associated with increased expression of herbicide detoxifying enzymes, including glutathione S-transferases (GSTs). Treatment of Arabidopsis seedlings growing in liquid medium with various safeners similarly resulted in enhanced GST activities toward a range of xenobiotics with benoxacor, fenclorim, and fluxofenim being the most effective. Safeners also increased the tripeptide glutathione content of Arabidopsis seedlings. However, treatment of Arabidopsis plants with safeners had no effect on the tolerance of seedlings to chloroacetanilide herbicides. Each safener produced a distinct profile of enhanced GST activity toward different substrates suggesting a differential induction of distinct isoenzymes. This was confirmed by analysis of affinity-purified GST subunits by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. AtGSTU19, a tau class GST, was identified as a dominant polypeptide in all samples. When AtGSTU19 was expressed in Escherichia coli, the recombinant enzyme was highly active toward 1-chloro-2,4-dinitrobenzene, as well as chloroacetanilide herbicides. Immunoblot analysis confirmed that AtGSTU19 was induced in response to several safeners. Differential induction of tau GSTs, as well as members of the phi and theta classes by safeners, was demonstrated by RNA-blot analysis. These results indicate that, although Arabidopsis may not be protected from herbicide injury by safeners, at least one component of their detoxification systems is responsive to these compounds.Plants actively detoxify both endogenous toxins, such as secondary metabolites and degradation products arising from oxidative stress, and exogenous man-made chemicals, such as herbicides, using a three-phase detoxification system (Neuefeind et al., 1997). In the first phase, oxidation, reduction, or hydrolysis reactions catalyzed by enzymes such as cytochrome P450 monooxygenases result in the exposure, or introduction, of a functional group. Phase two enzymes then catalyze the conjugation of these metabolites with sugars or the tripeptide glutathione (GSH). In the case of GSH, glutathione S-transferases (GSTs) catalyze this conjugation reaction. In the third phase of metabolism, molecules "tagged" with GSH are recognized by ATP-binding cassette transporters in the tonoplast or plasma membrane, which then transfer these conjugates into the vacuole or apoplast (Rea, 1999).GSTs constitute a family of multifunctional enzymes present in both plants and animals. These dimeric enzymes catalyze the conjugation of GSH to a variety of electrophilic, hydrophobic, and often toxic substrates, thereby reducing their toxicity (Marrs, 1996;Dixon et al., 1998). In addition to GSH conjugation, GSTs may also exhibit glutathione peroxidase (GPOX) or isomerase activities, or function as binding proteins known as ligandins (Edwards et al., ...

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“…GSTs induced in response to safeners, herbicides, and pathogens have been identified and biochemically characterized in wheat (Mauch and Dudler 1993;Cummins et al 1997;Riechers et al 1997;Pascal et al 1998;Pascal and Scalla 1999;Theodoulou et al 2003). Our studies have utilized the diploid wheat Triticum tauschii (synonymous with Aegilops tauschii and Aegilops squarrosa), which is considered to be the D-genome donor to cultivated, hexaploid bread wheat Triticum aestivum.…”

Section: Introductionmentioning

confidence: 99%

Tissue-specific expression and localization of safener-induced glutathione S -transferase proteins in Triticum tauschii

Riechers

Zhang

et al. 2003

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Glutathione S-transferase (GST; EC 2.5.1.18) gene expression was examined in the coleoptile and new leaf tissue of etiolated shoots of the diploid wheat species Triticum tauschii (Coss.) Schmal., which is considered to be a progenitor and the D-genome donor to cultivated, hexaploid bread wheat Triticum aestivum L. GST expression (mRNA, protein, and enzyme activity with a herbicide substrate) in these shoot tissues was examined in response to herbicide safener treatment. Two different antibody probes, raised against the same safener-inducible GST protein (TtGSTU1) but differing in their specificity, were utilized to determine tissue distribution and subcellular localization of GST proteins in etiolated shoots. GST transcripts, immunoreactive GST proteins, and herbicide-metabolizing activity were all highest in the coleoptile of etiolated, safener-treated T. tauschii shoots. Anti-GST immunolabeling was strongest in the outer epidermal and adjoining sub-epidermal cells in both coleoptiles and new leaves following safener treatment. Our data indicate that safeners protect grass crops from herbicide injury by dramatically inducing the expression of GST proteins in the outer cell layers of the coleoptile, which prevents the herbicide from reaching the sensitive new leaves of etiolated shoots as they emerge from the soil.

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Analysis and characterization of glutathione S-transferase subunits from wheat (Triticum aestivum L.)

Cited by 27 publications

References 36 publications

Identification and analysis of safener-inducible expressed sequence tags in Populus using a cDNA microarray

Identification and analysis of safener-inducible expressed sequence tags in Populus using a cDNA microarray

Induction of Glutathione S-Transferases in Arabidopsis by Herbicide Safeners

Tissue-specific expression and localization of safener-induced glutathione S -transferase proteins in Triticum tauschii

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