Herbicide resistance and supersensitivity in photosystem II

Oettmeier, Walter

doi:10.1007/s000180050370

Cited by 167 publications

(157 citation statements)

References 74 publications

(111 reference statements)

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“…Phenylurea herbicides inhibit photosynthesis by blocking electron transport in the photosystem II complex (Oettmeier, 1999). Susceptible plant treatment leads to leaf chlorosis followed by complete necrosis, resulting in a dramatic dose-dependent reduction of growth.…”

Section: Herbicide Tolerance Of Transformed Tobaccomentioning

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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Section: Herbicide Tolerance Of Transformed Tobaccomentioning

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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“…This conclusion agrees with DCMU being significantly less inhibitory for the mapA mutant than for wild-type cells. DCMU binds synergistically and non-covalently to the Q B binding pocket and displaces the natural quinones due to its higher affinity for the binding site (Oettmeier, 1999). As a consequence, electron transport in PSII breaks down, which inhibits cell growth and finally leads to cell death (Rutherford & Kriger-Liszkay, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…Resistance to DCMU can already be caused by subtle modification of the D1 protein such as single amino acid substitutions (Dalla Chiesa et al, 1997;Oettmeier, 1999 (Ikeuchi et al, 1991). The low-molecular-mass subunit PsbX is essential for binding and turnover of quinone molecules at the Q B site.…”

Section: Discussionmentioning

confidence: 99%

An alternative methionine aminopeptidase, MAP-A, is required for nitrogen starvation and high-light acclimation in the cyanobacterium Synechocystis sp. PCC 6803

2009

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Methionine aminopeptidases (MetAPs or MAPs, encoded by map genes) are ubiquitous and pivotal enzymes for protein maturation in all living organisms. Whereas most bacteria harbour only one map gene, many cyanobacterial genomes contain two map paralogues, the genome of Synechocystis sp. PCC 6803 even three. The physiological function of multiple map paralogues remains elusive so far. This communication reports for the first time differential MetAP function in a cyanobacterium. In Synechocystis sp. PCC 6803, the universally conserved mapC gene (sll0555) is predominantly expressed in exponentially growing cells and appears to be a housekeeping gene. By contrast, expression of mapA (slr0918) and mapB (slr0786) genes increases during stress conditions. The mapB paralogue is only transiently expressed, whereas the widely distributed mapA gene appears to be the major MetAP during stress conditions. A mapA-deficient Synechocystis mutant shows a subtle impairment of photosystem II properties even under non-stressed conditions. In particular, the binding site for the quinone QB is affected, indicating specific N-terminal methionine processing requirements of photosystem II components. MAP-A-specific processing becomes essential under certain stress conditions, since the mapA-deficient mutant is severely impaired in surviving conditions of prolonged nitrogen starvation and high light exposure.

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“…However, it is known from experimental evidence that the ethylamino side chain of atrazine orients towards S264 and can form a hydrogen bond with the hydroxymethyl group of serine. 32 Further, the aromatic ring nitrogen is hydrogen-bonded to the backbone amide nitrogen of F265. 32 S264 and F265 not only participate in atrazine binding but also in the binding of the native plastoquinone at the QB-site.…”

Section: Docking Studiesmentioning

confidence: 99%

Structure‐based design of novel Chlamydomonas reinhardtii D1‐D2 photosynthetic proteins for herbicide monitoring

et al. 2009

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The D1-D2 heterodimer in the reaction center core of phototrophs binds the redox plastoquinone cofactors, Q A and Q B , the terminal acceptors of the photosynthetic electron transfer chain in the photosystem II (PSII). This complex is the target of the herbicide atrazine, an environmental pollutant competitive inhibitor of Q B binding, and consequently it represents an excellent biomediator to develop biosensors for pollutant monitoring in ecosystems. In this context, we have undertaken a study of the Chlamydomonas reinhardtii D1-D2 proteins aimed at designing site directed mutants with increased affinity for atrazine. The three-dimensional structure of the D1 and D2 proteins from C. reinhardtii has been homology modeled using the crystal structure of the highly homologous Thermosynechococcus elongatus proteins as templates. Mutants of D1 and D2 were then generated in silico and the atrazine binding affinity of the mutant proteins has been calculated to predict mutations able to increase PSII affinity for atrazine. The computational approach has been validated through comparison with available experimental data and production and characterization of one of the predicted mutants. The latter analyses indicated an increase of one order of magnitude of the mutant sensitivity and affinity for atrazine as compared to the control strain. Finally, D1-D2 heterodimer mutants were designed and selected which, according to our model, increase atrazine binding affinity by up to 20 kcal/mol, representing useful starting points for the development of high affinity biosensors for atrazine.

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Herbicide resistance and supersensitivity in photosystem II

Cited by 167 publications

References 74 publications

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

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

An alternative methionine aminopeptidase, MAP-A, is required for nitrogen starvation and high-light acclimation in the cyanobacterium Synechocystis sp. PCC 6803

Structure‐based design of novel Chlamydomonas reinhardtii D1‐D2 photosynthetic proteins for herbicide monitoring

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