Transgenic Plant Analysis as a Tool for the Study of Maize Glutathione S-Transferases

Jepson, Ian; Holt, D. C.; Roussel, Véronique; Wright, Shamonia; Greenland, Andrew J.

doi:10.1007/978-94-015-8927-7_23

Cited by 31 publications

(17 citation statements)

References 12 publications

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“…Indeed, variation in substrate specificity of GSTs and P450s in different plant species can result in herbicide selectivity (Barrett et al 1997;Van Eerd et al 2003;Yuan et al 2007;Zhang et al 2007a). Furthermore, GSTs with herbicidedetoxifying activity were shown to result in herbicide tolerance in dicots when overexpressed in appropriate tissues (Jepson et al 1997;Skipsey et al 2005;Benekos et al 2010), and the development of herbicide resistance in weeds is often because of increased activities of specific P450s (Siminszky 2006). The failure of safeners to induce herbicide tolerance in Arabidopsis and other dicots may thus be caused by the properties of the enzymes that are induced after safener treatment rather than a general lack of safener responsiveness.…”

Section: Discussionmentioning

confidence: 99%

Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis

Behringer

Bartsch

Schaller

2011

Plant Cell & Environment

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Safeners enhance herbicide tolerance in crop plants but not in target weeds, thus improving herbicide selectivity. The safeners isoxadifen-ethyl and mefenpyr-diethyl protect cereal crops from sulfonyl urea herbicides in postemergence application. The two safeners were shown here to induce the cellular xenobiotic detoxification machinery in Arabidopsis thaliana when applied to leaves in a way mimicking field application. Gene expression profiling revealed the induction of 446 genes potentially involved in the detoxification process. Transgenic Arabidopsis plants expressing a reporter gene under control of a safenerresponsive maize promoter were used as a model system to study the safener signalling pathway. Reporter gene analysis in the tga2/3/5/6, sid2-2 and npr1 mutants as compared with the wild-type background showed that safener inducibility required TGA transcription factors and salicylic acid (SA) in a NON-EXPRESSOR of PR-1 (NPR1)-independent pathway converging on two as-1 promoter elements. For the majority of the safener-responsive Arabidopsis genes, a similar dependence on TGA transcription factors and/or SA was shown by gene expression profiling in wild-type plants as compared with the tga2/3/5/6 and sid2-2 mutants. Thirty-eight percent of the genes, however, were induced by safeners in a TGA/SA-independent manner. These genes are likely to be controlled by WRKY transcription factors and cognate W-boxes in their promoters.

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Section: Discussionmentioning

confidence: 99%

Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis

Behringer

Bartsch

Schaller

2011

Plant Cell & Environment

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“…plants have shown that expression of a maize GST in shoots is sufficient to confer tolerance to metolachlor, suggesting that expression of other components of the detoxification system may not limit herbicide metabolism in dicots (Jepson et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…Further evidence for the importance of GST expression in shoots comes from maize; a chloroacetamide-sensitive cultivar was deficient in ZmGST27 RNA in leaves, whereas herbicide tolerant lines expressed this GST in both roots and leaves (Rossini et al, 1998). When this maize GST was expressed in leaves of transgenic tobacco plants, it conferred a high level of tolerance to metolachlor compared to nontransgenic plants, demonstrating that GST expression in shoots can confer herbicide tolerance to dicots (Jepson et al, 1997). It is interesting that induction of AtGSTU19 by benoxacor occurs in tissues that include the shoot meristem (Fig.…”

Section: Discussionmentioning

confidence: 99%

Organ-Specific Expression of Glutathione S-Transferases and the Efficacy of Herbicide Safeners in Arabidopsis

DeRidder

Goldsbrough

2005

Plant Physiology

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The functions of plant glutathione S-transferases (GSTs) under normal growth conditions are poorly understood, but their activity as detoxification enzymes has been harnessed in agriculture for selective weed control. Herbicide safeners protect monocot crops from herbicide injury but have little effect on weedy monocot or dicot species. Protection by safeners is associated with expression of herbicide-metabolizing enzymes including GSTs, but the basis for selective action of safeners between monocots and dicots is not known. To address this question we have studied the response of Arabidopsis (Arabidopsis thaliana) to various safeners. Benoxacor, fenclorim, and fluxofenim did not protect Arabidopsis from herbicide injury but did induce RNA expression of the glutathione-conjugate transporters encoded by AtMRP1, AtMRP2, AtMRP3, and AtMRP4. These safeners also induced the organ-specific expression of AtGSTU19 and AtGSTF2, two previously characterized Arabidopsis GSTs from different classes of this enzyme family. RNA hybridization, immunoblot, and reporter gene analyses indicated expression of AtGSTU19 induced by safeners predominated in roots. To test the hypothesis that increased expression of AtGSTU19 would be sufficient to provide tolerance to chloroacetamide herbicides, a chimeric gene was produced containing the open reading frame for this GST driven by a constitutive promoter. Plants containing this transgene had a modest increase in AtGSTU19 protein, predominantly in roots, but this had no effect on tolerance to chloroacetamide herbicides. The localized induction of GSTs by safeners in roots of Arabidopsis may explain why these compounds are unable to provide herbicide tolerance to dicot plant species.

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“…There are few reports on the engineering of herbicide metabolism with plant genes (Jepson et al, 1996;Siminszky et al, 1999), but the rather scarce data available do not indicate how large increases in herbicide tolerance have been achieved. CYP76B1, a gene inducible by chemical stress isolated from Jerusalem artichoke, was previously shown to metabolize herbicides of the class of phenylurea with high turnover rates (Robineau et al, 1998).…”

Section: Factors Influencing Herbicide Tolerancementioning

confidence: 99%

Engineering Herbicide Metabolism in Tobacco and Arabidopsis with CYP76B1, a Cytochrome P450 Enzyme from Jerusalem Artichoke

et al. 2002

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The Jerusalem artichoke (Helianthus tuberosus) xenobiotic inducible cytochrome P450, CYP76B1, catalyzes rapid oxidative dealkylation of various phenylurea herbicides to yield nonphytotoxic metabolites. We have found that increased herbicide metabolism and tolerance can be achieved by ectopic constitutive expression of CYP76B1 in tobacco (Nicotiana tabacum) and Arabidopsis. Transformation with CYP76B1 conferred on tobacco and Arabidopsis a 20-fold increase in tolerance to linuron, a compound detoxified by a single dealkylation, and a 10-fold increase in tolerance to isoproturon or chlortoluron, which need successive catalytic steps for detoxification. Two constructs for expression of translational fusions of CYP76B1 with P450 reductase were prepared to test if they would yield even greater herbicide tolerance. Plants expressing these constructs had lower herbicide tolerance than CYP76B1 alone, which is apparently a consequence of reduced stability of the fusion proteins. In all cases, increased herbicide tolerance results from more extensive metabolism, as demonstrated with exogenously fed phenylurea. Beside increased herbicide tolerance, expression of CYP76B1 has no other visible phenotype in the transgenic plants. Our data indicate that CYP76B1 can function as a selectable marker for plant transformation, allowing efficient selection in vitro and in soil-grown plants. Plants expressing CYP76B1 may also be a potential tool for phytoremediation of contaminated sites.Engineering of herbicide tolerance in higher plants can be achieved in many ways: via introduction of an altered target protein that is insensitive to the herbicide, overexpression of a wild-type target, or modification of herbicide transport, compartmentation, or metabolism. Increasing metabolism may be the best strategy because the phytotoxic compound is chemically altered and there is no interference with primary metabolism and no residual herbicide remains in the plant. So far, most crops genetically modified for herbicide metabolism have been transformed with genes isolated from microorganisms (Duke, 1996); however, plants themselves offer a wide choice of herbicide-detoxifying enzymes. The introduction of different plant genes or appropriate alterations in expression levels in crop plants could be considered as an accelerated adjunct to classical breeding techniques to engender gene transfer between plants.The genes for herbicide-detoxifying enzymes in higher plants are just starting to be characterized. Efforts are focused on multigene families like those of glutathione S-transferases (McGonigle et al., 2000) or glycosyl transferases (Ross et al., 2001; Brazier et al., 2002), and cytochrome P450 monooxygenases . The latter, which is by far the largest family of enzymatic proteins in higher plants (272 P450 genes are found in the diminutive genome of Arabidopsis), offers the widest resource in terms of diversity and possible substrate specificity (http://drnelson.utmem.edu/cytochromep450.html; http://www.biobase.dk/P450/p450.shtml; Schuler, 19...

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Transgenic Plant Analysis as a Tool for the Study of Maize Glutathione S-Transferases

Cited by 31 publications

References 12 publications

Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis

Safeners recruit multiple signalling pathways for the orchestrated induction of the cellular xenobiotic detoxification machinery in Arabidopsis

Organ-Specific Expression of Glutathione S-Transferases and the Efficacy of Herbicide Safeners in Arabidopsis

Engineering Herbicide Metabolism in Tobacco and Arabidopsis with CYP76B1, a Cytochrome P450 Enzyme from Jerusalem Artichoke

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