Metabolism of clomazone herbicide in soybean

El-Naggar, Sha'aban F.; Creekmore, R. W.; Schocken, Mark J.; Rosén, Robert; Robinson, Raoul A.

doi:10.1021/jf00017a036

Cited by 31 publications

(37 citation statements)

References 4 publications

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“…Low temperatures cause less activation of the herbicide, less volatilization and thus lower the activity of the monooxygenases of the Cytochrome P450 enzymes, which would normally cause low phytotoxicity. However, while there is a decrease of the fluidity of membranes, providing a decrease in the metabolic rate of the plant and impairing its enzyme activity (Murata & Los, 1997), there is a decrease in the herbicide detoxification process, which is mainly based on N-dealkylation reactions followed by glycosidic combination (Elnaggar, 1992).…”

Section: Resultsmentioning

confidence: 99%

Volatility of Different Formulations of Clomazone Herbicide

et al. 2015

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-Volatilization represents an important process in the displacement of pesticides for the environment. The physicochemical properties of the clomazone molecule indicate its relative volatility. Therefore, this study was carried out to assess the volatilization of different clomazone herbicide formulations using bioindicator species. To that end, airtight glass boxes were used with the presence of different clomazone formulations and plant species. The formulations used were Gamit 360 CS ®

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Section: Resultsmentioning

confidence: 99%

Volatility of Different Formulations of Clomazone Herbicide

et al. 2015

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“…1). Each of these labeled precursors was fed to Arabidopsis seedlings in the presence of KC, which blocks the endogenous MEP pathway (20,35), to allow efficient labeling (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

Agrobacterium tumefaciens increases cytokinin production in plastids by modifying the biosynthetic pathway in the host plant

Sakakibara

Kasahara

Ueda

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

108

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Agrobacterium tumefaciens infects plants and induces the formation of tumors called ''crown galls'' by integrating the transferred-DNA (T-DNA) region of the Ti-plasmid into the plant nuclear genome. Tumors are formed because the T-DNA encodes enzymes that modify the synthesis of two plant growth hormones, auxin and cytokinin (CK). Here, we show that a CK biosynthesis enzyme, Tmr, which is encoded by the Agrobacterium T-DNA region, is targeted to and functions in plastids of infected plant cells, despite having no typical plastid-targeting sequence. Evidence is provided that Tmr is an adenosine phosphate-isopentenyltransferase (IPT) that creates a new CK biosynthesis bypass by using 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate (HMBDP) as a substrate. Unlike in the conventional CK biosynthesis pathway in plants, transzeatin-type CKs are produced directly without the requirement for P450 monooxygenase-mediated hydroxylation. Consistent with the plastid localization of Tmr, HMBDP is an intermediate in the methylerythritol phosphate pathway, a plastid-localized biosynthesis route for universal isoprenoid precursors. These results demonstrate that A. tumefaciens modifies CK biosynthesis by sending a key enzyme into plastids of the host plant to promote tumorigenesis.crown gall ͉ isopentenyltransferase ͉ methylerythritol phosphate pathway C ytokinins (CKs) are a group of plant hormones essential for cell division and differentiation in plants (1). Most natural CKs, including isopentenyladenine (iP) and trans-zeatin (tZ) (Fig. 1), are derivatives of N 6 -prenylated adenine (1). The prenyl side chain of CKs can be derived from the methylerythritol phosphate (MEP) pathway or the mevalonate (MVA) pathway, both of which supply common C 5 units for isoprenoid biosynthesis (2, 3). The MEP pathway widely occurs in the bacterial kingdom and the plastids of plants, whereas the MVA pathway is commonly found in the cytosol of eukaryotes (2, 3). Thus, plants have the two different isoprenoid pathways in separate subcellular compartments. Recent work has shown that the majority of the prenyl side chain of iP and tZ is derived from the MEP pathway in Arabidopsis seedlings (4).To initiate CK biosynthesis, an isoprenoid precursor is transferred to AMP, ADP or ATP by adenosine phosphateisopentenyltransferase (IPT, EC 2.5.1.27) ( Fig. 1) (5-7). At least two routes have been proposed for the formation of tZ, an active CK, in plants. In the conventional iP riboside 5Ј-monophosphate (iPRMP)-dependent pathway, dimethylallyl diphosphate (DMAPP) is used as the side chain precursor for iPRMP, which is then converted to tZ riboside 5Ј-monophosphate (tZRMP) by P450 monooxygenases (8) (CYP735A1 and CYP735A2 in Arabidopsis; Fig. 1). The other proposed pathway is an iPRMPindependent bypass, in which an unidentified hydroxylated derivative of DMAPP is directly transferred to the adenine moiety (9). A candidate for this putative substrate is 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate (HMBDP) (10), which has recently been shown to occur as an int...

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“…20 It has been reported that clomazone and ketoclomazone cause significantly lower chlorophyll and carotenoid levels in barley leaves. 21 By contrast, other studies have suggested that ketoclomazone, but not clomazone, inhibits DXP synthase activity in vitro.…”

Section: Introductionmentioning

confidence: 99%

The herbicide ketoclomazone inhibits 1-deoxy-D-xylulose 5-phosphate synthase in the 2-C-methyl-D-erythritol 4-phosphate pathway and shows antibacterial activity against Haemophilus influenzae

et al. 2010

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Two distinct metabolic pathways have been elucidated for the formation of isopentenyl diphosphate and dimethylallyl diphosphate, essential metabolic precursors for isoprenoid biosynthesis: the mevalonate pathway, found ubiquitously in mammals, and the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, found in most bacteria. As the MEP pathway is absent from mammals, all MEP pathway enzymes represent effective targets for the development of antibacterial drugs. In this study, we found that a herbicide, ketoclomazone, exhibited antibacterial activity against a pathogenic bacterium, Haemophilus influenzae, with an MIC value of 12.5 lg ml À1 and that antibacterial activity was suppressed by adding 1-deoxyxylulose, a free alcohol of 1-deoxy-D-xylulose 5-phosphate (DXP). DXP is an MEP pathway intermediate synthesized from pyruvate and D-glyceraldehyde 3-phosphate (D-GAP) by the action of DXP synthase. Thus, we investigated the enzyme kinetics of DXP synthase of H. influenzae (HiDXS) to elucidate an inhibitory mechanism of ketoclomazone on HiDXS. The dxs gene was cloned from H. influenzae and overexpressed in Escherichia coli, and the enzyme was purified to homogeneity. The purified HiDXS was a soluble dimeric 70-kDa protein. Steady-state kinetic constants for HiDXS were calculated, and Lineweaver-Burk plots were consistent with a ping-pong bi bi mechanism. The kinetics of inhibition by ketoclomazone suggested that ketoclomazone binds to an unidentified inhibitor-binding site that differs from both the pyruvate-binding site and the D-GAP-binding site on DXP synthase. These data reveal the inhibitory mechanism of ketoclomazone on DXP synthase.

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Metabolism of clomazone herbicide in soybean

Cited by 31 publications

References 4 publications

Volatility of Different Formulations of Clomazone Herbicide

Volatility of Different Formulations of Clomazone Herbicide

Agrobacterium tumefaciens increases cytokinin production in plastids by modifying the biosynthetic pathway in the host plant

The herbicide ketoclomazone inhibits 1-deoxy-D-xylulose 5-phosphate synthase in the 2-C-methyl-D-erythritol 4-phosphate pathway and shows antibacterial activity against Haemophilus influenzae

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