Insecticide and Insecticide Metabolite Interactions with Cytochrome P450 Mediated Activities in Maize

Baerg, Roger J.; Barrett, Michael; Polge, Nicholas D.

doi:10.1006/pest.1996.0030

Cited by 55 publications

(38 citation statements)

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“…Diclofop metabolites formed were a mixture of ring-hydroxylated isomers at position 4 and 5 (6, 7). Chlortoluron was monoand di-demethylatedand ring-hydroxylated (11).RP-HPLC analysis of bentazon metabolites showed a similar pattern of polar metabolites as previously described by Baerg et al (12) and they were not further characterized. The herbicide simazine was not metabolized by wheat microsomes under our experimental conditions.…”

Section: P450-dependent Reactions In Wheat Microsomesmentioning

confidence: 55%

Induction and inactivation of a cytochrome P450 confering herbicide resistance in wheat seedlings

Forthoffer

Helvig

Dillon

et al. 2001

Eur. J. Drug Metab. Pharmacokinet.

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Cytochrome P450-dependent enzymes from wheat catalyze the oxidation of endogenous compounds (lauric and oleic acids) and of several herbicides (diclofop, chlortoluron, bentazon). Treatment of wheat seedlings with the safener, naphthalic anhydride and with phenobarbital increases dramatically several P450-dependent enzyme activities including diclofop and lauric acid hydroxylation. The parallel induction of lauric acid (omega-1)-hydroxylase and diclofop hydroxylase activities suggests that both compounds proceeds from the same or very similar forms of P450. To test whether either one or multiple P450 forms are involved in these oxidations, we have designed selective irreversible inhibitors of lauric acid (omega-1)-hydroxylase. Results of in vivo and in vitro experiments with acetylenic analogs of lauric acid (10- and 11-dodecynoic acids) strongly suggest that a single P450 catalyzes both laurate and diclofop hydroxylation. Treatment of wheat seedlings with these acetylenes results in a strong inhibition of the in vivo metabolism of diclofop although oxidation of chlortoluron and bentazon are not affected. Our results suggest that at least three distinct P450 forms are involved in the detoxification process of the three herbicides. Interestingly, we also demonstrate that herbicides themselves are potent inducers of the amount of total P450 and laurate/diclofop hydroxylase activies. This increased capacity of wheat to detoxify the herbicide through the induction of P450 enzymes seems to be for a large extend the mechanism which confers a tolerance on various herbicides.

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Section: P450-dependent Reactions In Wheat Microsomesmentioning

confidence: 55%

Induction and inactivation of a cytochrome P450 confering herbicide resistance in wheat seedlings

Forthoffer

Helvig

Dillon

et al. 2001

Eur. J. Drug Metab. Pharmacokinet.

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“…To investigate a non-target site based resistance mechanism we utilized malathion, a known inhibitor of cytochrome P450 monooxygenases, that has been shown to be eVective in synergizing ALS-inhibiting herbicides by inhibiting P450-mediated herbicide metabolism in maize (Kreuz and Fonne-PWster 1992) and L. rigidum (Christopher et al 1994;Preston et al 1996). In addition, malathion has also been demonstrated to increase phytotoxicity of the ALS-inhibiting imadazolinone herbicide imazethapyr in Digitaria sanguinalis (Hidayat and Preston 2001), and to inhibit imazethapyr hydroxylation in maize microsomes (Baerg et al 1996). Here, we have established that inhibition of P450 by malathion in seedlings of WALR70 reverses chlorsulfuron resistance to full susceptibility (Fig.…”

Section: Discussionmentioning

confidence: 99%

Distinct non-target site mechanisms endow resistance to glyphosate, ACCase and ALS-inhibiting herbicides in multiple herbicide-resistant Lolium rigidum

Abdallah

Han

et al. 2009

Planta

145

130

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This study investigates mechanisms of multiple resistance to glyphosate, acetyl-coenzyme A carboxylase (ACCase) and acetolactate synthase (ALS)-inhibiting herbicides in two Lolium rigidum populations from Australia. When treated with glyphosate, susceptible (S) plants accumulated 4- to 6-fold more shikimic acid than resistant (R) plants. The resistant plants did not have the known glyphosate resistance endowing mutation of 5-enolpyruvylshikimate-3 phosphate synthase (EPSPS) at Pro-106, nor was there over-expression of EPSPS in either of the R populations. However, [(14)C]-glyphosate translocation experiments showed that the R plants in both populations have altered glyphosate translocation patterns compared to the S plants. The R plants showed much less glyphosate translocation to untreated young leaves, but more to the treated leaf tip, than did the S plants. Sequencing of the carboxyl transferase domain of the plastidic ACCase gene revealed no resistance endowing amino acid substitutions in the two R populations, and the ALS in vitro inhibition assay demonstrated herbicide-sensitive ALS in the ALS R population (WALR70). By using the cytochrome P450 inhibitor malathion and amitrole with ALS and ACCase herbicides, respectively, we showed that malathion reverses chlorsulfuron resistance and amitrole reverses diclofop resistance in the R population examined. Therefore, we conclude that multiple glyphosate, ACCase and ALS herbicide resistance in the two R populations is due to the presence of distinct non-target site based resistance mechanisms for each herbicide. Glyphosate resistance is due to reduced rates of glyphosate translocation, and resistance to ACCase and ALS herbicides is likely due to enhanced herbicide metabolism involving different cytochrome P450 enzymes.

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“…Varsano et al (1992) showed that if P450 monooxygenase deliberately was inhibited in maize plants, their susceptibility to triazine herbicides increased (Varsano et al 1992). Additionally, tests on maize concluded that malathion, a commonly used organophosphorous insecticide, could inhibit the hydroxylation of bentazone (Baerg et al 1996). Hence, there is evidence suggesting that P450 monooxygenases play a role in the detoxification of xenobiotics in higher plants.…”

Section: Introductionmentioning

confidence: 95%

“…The insecticides malathion, endosulfan and chlorpyrifos were chosen due to their occurrence in surface waters (Van Wijngaarden et al 2005;Tauler et al 2001;Pedersen et al 2006;Barlas et al 2006), while the herbicides metsulfuron-methyl, terbuthylazine and bentazone were chosen as representatives for herbicide classes whose metabolism had been shown to be affected by P450 monooxygenases (Varsano et al 1992;Baerg et al 1996;Inui and Ohkawa, 2005;Moreland et al 1993). The experiments were carried out on the two aquatic species Pseudokirchneriella subcapitata and Lemna minor.…”

Section: Introductionmentioning

confidence: 99%

Organophosphorous insecticides as herbicide synergists on the green algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor

2007

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Models proposed for risk assessment of chemical mixtures assume no interactions between the chemicals. There are, however, studies indicating that some organophosporous insecticides can inhibit the detoxification of other chemicals in plants thereby enhancing their effect. The present study investigates whether interactions between selected organophosporous insecticides and herbicides can take place in the aquatic algae Pseudokirchneriella subcapitata and the aquatic macrophyte Lemna minor. For both species binary mixtures of the organophosphate insecticides: malathion, endosulfan and chlorpyrifos were tested together with the herbicides metsulfuron-methyl, terbutylazine and bentazone. For mixtures with malathion on algae, dose-response surfaces were made and the results tested against the model of concentration addition (CA) and independent action (IA). The Lemna minor tests showed no indication of synergy for any of the combinations, on the contrary, significant antagonism was found for several of the mixtures. The response surface analysis showed antagonism in relation to both concentration addition and independent action for mixtures between malathion and metsulfuron-methyl and terbuthylazine, while the mixtures with bentazone could be explained with CA. The study shows no indications of synergistic interactions between the tested pesticides, confirming the applicability of CA as a reference model predicting mixture effects of pesticides for aquatic plants and algae.

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Insecticide and Insecticide Metabolite Interactions with Cytochrome P450 Mediated Activities in Maize

Cited by 55 publications

References 0 publications

Induction and inactivation of a cytochrome P450 confering herbicide resistance in wheat seedlings

Induction and inactivation of a cytochrome P450 confering herbicide resistance in wheat seedlings

Distinct non-target site mechanisms endow resistance to glyphosate, ACCase and ALS-inhibiting herbicides in multiple herbicide-resistant Lolium rigidum

Organophosphorous insecticides as herbicide synergists on the green algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor

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