Oxaziclomefone, a New Herbicide, Inhibits Wall Expansion in Maize Cell-cultures without Affecting Polysaccharide Biosynthesis, Xyloglucan Transglycosylation, Peroxidase Action or Apoplastic Ascorbate Oxidation

O'Looney, Nichola; Fry, Stephen C.

doi:10.1093/aob/mci261

Cited by 13 publications

(4 citation statements)

References 54 publications

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“…To exert its toxicity in plant cells, DM first needs to pass through the cell wall. Several studies have shown that both biotic stresses (e.g., bacteria, fungi, and virus) and abiotic stresses (metals, pesticide, UV–B, and temperature) may alter the composition of cell wall by inducing a thickening of cuticles or trichomes. , The present study confirms that the herbicide DM may strongly affect the cell wall of O. sativa . Our results show that a 48-h exposure to trace DM concentrations may increase the proportion of uronic acid and polysaccharides in cell wall fractions (SI Figure SI.2A, B) and induce the transcription of various genes involved in the biosynthesis of cell wall ( pectin methylesterase , pectinesterase , cellulose synthase , phenylalanine ammonia-lyase genes) (SI Figure SI.2C; Table SI.1 and SI.2).…”

Section: Discussionsupporting

confidence: 85%

Unraveling the Toxicity Mechanisms of the Herbicide Diclofop-Methyl in Rice: Modulation of the Activity of Key Enzymes Involved in Citrate Metabolism and Induction of Cell Membrane Anion Channels

Ding

Lavoie

et al. 2014

J. Agric. Food Chem.

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Residual soil concentrations of the herbicide diclofop-methyl (DM) can be toxic to other nontarget plant species, but the toxicity mechanisms at play are not fully understood. In the present study, we analyzed the toxic effect of DM on root growth and metabolism in the rice species Oryza sativa. The results show that a 48-h exposure to a trace level (5 μg/L) of DM inhibits rice root growth by almost 70%. A 48-h exposure to 5 μg/L DM also leads to an ≈2.5-fold increase in citrate synthase (CS) activity (and CS gene transcription) and an ≈2-fold decrease in the citrate lyase gene transcripts, which lead to an increase in the intracellular concentration of citrate and in citrate exudation rate. Addition of a specific inhibitor of cell membrane anion channel, anthracene-9-carboxylic acid, decreased citrate release in the culture, suggesting that DM-induced citrate loss from the cells is mediated by a specific membrane-bound channel protein. This study brings new insights into the key biochemical mechanisms leading to DM toxicity in rice.

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Section: Discussionsupporting

confidence: 85%

Unraveling the Toxicity Mechanisms of the Herbicide Diclofop-Methyl in Rice: Modulation of the Activity of Key Enzymes Involved in Citrate Metabolism and Induction of Cell Membrane Anion Channels

Ding

Lavoie

et al. 2014

J. Agric. Food Chem.

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“…So far, the MoA of oxaziclomefone has remained elusive 35,36 and it is therefore classified in the HRAC class 0. Here, we present data on oxaziclomefone that show strong FAT thermal stabilization, strong FAT binding in the active center, strong inhibition of FFA production in the FAT activity assay and the clear FAT-like fingerprint in the P-Profile.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of acyl‐ACP thioesterase as site of action of the commercial herbicides cumyluron, oxaziclomefone, bromobutide, methyldymron and tebutam

Johnen¹,

Zimmermann²,

Betz

et al. 2022

Pest Management Science

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BACKGROUND: Understanding the mode and site of action of a herbicide is key for its efficient development, the evaluation of its toxicological risk, efficient weed control and resistance management. Recently, the mode of action (MoA) of the herbicide cinmethylin was identified in lipid biosynthesis with acyl-ACP thioesterase (FAT) as the site of action (SoA). Cinmethylin was registered for selective use in cereal crops for the control of grass weeds in 2020.RESULTS: Here, we present a high-resolution co-crystal structure of FAT in complex with cumyluron identified by a high throughput crystallization screen. We show binding to and inhibition of FAT by cumyluron. Furthermore, in an array of experiments consisting of FAT binding assays, FAT inhibition assays, physiological and metabolic profiling, we tested compounds that are structurally related to cumyluron and identified the commercial herbicides oxaziclomefone, methyldymron, tebutam and bromobutide, with so far unknown sites of action, as FAT inhibitors. Additionally, we show that the previously described FAT inhibitors cinmethylin and methiozolin bind to FAT in a nanomolar range, inhibit FAT enzymatic activity and lead to similar metabolic changes.CONCLUSION: Based on presented data, we corroborate cinmethylin and methiozolin as potent FAT inhibitors and identify FAT as the SoA of the herbicides cumyluron, oxaziclomefone, bromobutide, methyldymron and tebutam.

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“…Even neutral sugars can be analysed by PE if a borate buffer is used, with which the sugar reversibly forms an anionic borate ester (e.g. O ' Looney & Fry 2005 ). Electrophoretic mobility depends on both the charge ( Q ) of the compound (which at pH 6.5 will be about − 1 in the case of GalA and GlcA → Man, and nearly − 2 in the case of GalA → GalA) and its molecular weight ( M r ).…”

Section: Paper E Lectrophoresis ( Pe )mentioning

confidence: 99%

Cell Wall Polysaccharide Composition and Covalent Crosslinking

Fry¹

2010

Annual Plant Reviews

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Genetics now potentially lets us modify the production, crosslinking and degradation of cell wall polysaccharides. There remains, however, the need to test experimentally whether intended modifi cations of polysaccharide metabolism have successfully been effected in vivo . Simple methods for this are described, including in -vivo radiolabelling, enzymic dissection (e.g. with Driselase) and chromatographic/electrophoretic fractionation of dissection products.After an overview of polysaccharide chemistry, I discuss the structures and taxonomic distribution of wall polysaccharides in charophytes and land plants. Primary and secondary walls are compared.The major wall polysaccharides are cellulose [microfi brillar β -(1 → 4) -d -glucan], pectins ( α -d -galacturonate -rich) and hemicelluloses (lacking galacturonate; hydrogen -bonding to cellulose; extractable by 6 M NaOH at 37 ° C). Land -plant pectins are anionic polymers built of about four glycosidically interconnected domains (homogalacturonan, rhamnogalacturonans I and II, xylogalacturonan). Hemicelluloses occurring in most/all land plants are α -xylo -β -glucans, β -xylans (including α -arabino -β -xylans, α -glucurono -β -xylans, etc.) and β -mannans (including α -galacto -β -mannans, β -gluco -β -mannans, etc.). Another hemicellulose [mixed -linkage β -(1 → 3)(1 → 4) -d -glucan) is confi ned to Equisetum and some Poales.Other taxonomically restricted features of angiosperm primary walls occur in Poales (xylose -poor xyloglucans; feruloylated arabinoxylans); Solanales and Lamiales (characteristic xyloglucans); Caryophyllales (feruloylated pectins); and Alismatales (apiogalacturonan). I also summarize characteristic wall features of charophytes, bryophytes, lycopodiophytes, fern -allies and gymnosperms.

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Oxaziclomefone, a New Herbicide, Inhibits Wall Expansion in Maize Cell-cultures without Affecting Polysaccharide Biosynthesis, Xyloglucan Transglycosylation, Peroxidase Action or Apoplastic Ascorbate Oxidation

Abstract: OAC decreased wall extensibility without influencing the synthesis or post-synthetic modification of major architectural wall components, or the redox environment of the apoplast. The possible value of OAC as a probe to explore aspects of primary cell wall physiology is discussed.

Cited by 13 publications

References 54 publications

Unraveling the Toxicity Mechanisms of the Herbicide Diclofop-Methyl in Rice: Modulation of the Activity of Key Enzymes Involved in Citrate Metabolism and Induction of Cell Membrane Anion Channels

Unraveling the Toxicity Mechanisms of the Herbicide Diclofop-Methyl in Rice: Modulation of the Activity of Key Enzymes Involved in Citrate Metabolism and Induction of Cell Membrane Anion Channels

Inhibition of acyl‐ACP thioesterase as site of action of the commercial herbicides cumyluron, oxaziclomefone, bromobutide, methyldymron and tebutam

Cell Wall Polysaccharide Composition and Covalent Crosslinking

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