Sulfonylurea herbicides as inhibitors of amino acid biosynthesis in plants

Ray, Thomas B.

doi:10.1016/0968-0004(86)90137-4

Cited by 49 publications

(37 citation statements)

References 12 publications

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“…Within the biosynthetic pathway of the branched chain amino acids Val, Leu, and Ile, the enzyme ALS (EC 4.1.3.18) has attracted a great deal of attention as the target for several structurally distinct classes of commercially successful herbicides, namely sulfonylureas, imidazolinones, and triazolopyrimidines (Mazur and Falco, 1989). Plants treated with these herbicides respond with growth retardation caused by inhibition of DNA synthesis and cell division, followed by chlorosis and necrosis of meristematic tissues (Ray, 1984;Scheel and Casida, 1985a;Ray, 1986). Mature tissues die slowly and death of the whole plant can take several weeks.…”

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confidence: 99%

Repression of Acetolactate Synthase Activity through Antisense Inhibition (Molecular and Biochemical Analysis of Transgenic Potato (Solanum tuberosum L. cv Desiree) Plants)

Höfgen¹,

Laber²,

Schüttke³

et al. 1995

Plant Physiol.

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Acetolactate synthase (ALS), the first enzyme in the biosynthetic pathway of leucine, valine, and isoleucine, is the biochemical target of different herbicides. To investigate the effects of repression of ALS activity through antisense gene expression we cloned an ALS gene from potato (Solanum fuberosum L. cv Désirée), constructed a chimeric antisense gene under control of the cauliflower mosaic virus 35s promoter, and created transgenic potato plants through Agrobacterium fumefaciens-mediated gene transfer. Two regenerants revealed severe growth retardation and strong phenotypical effects resembling those caused by ALS-inhibiting herbicides. Antisense gene expression decreased the steady-state leve1 of ALS mRNA in these plants and induced a corresponding decrease in ALS activity of up to 85%. This reduction was sufficient to generate plants almost inviable without amino acid supplementation. In both ALS antisense and herbicide-treated plants, we could exclude accumulation of 2-oxobutyrate and/or 2-aminobutyrate as the reason for the observed deleterious effects, but we detected elevated levels of free amino acids and imbalances in their relative proportions. Thus, antisense inhibition of ALS generated an in vivo model of herbicide action. Furthermore, expression of antisense RNA to the enzyme of interest provides a general method for validation of potential herbicide targets.

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confidence: 99%

Repression of Acetolactate Synthase Activity through Antisense Inhibition (Molecular and Biochemical Analysis of Transgenic Potato (Solanum tuberosum L. cv Desiree) Plants)

Höfgen¹,

Laber²,

Schüttke³

et al. 1995

Plant Physiol.

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“…Recovery time was also found to be comparatively long at up to 4 d after a single 3-h exposure [20]. Mechanistically, sulfonylureas appear to inhibit cell division before depletion of the branched-chain amino acid pools, suggesting a block in the cell cycle at G1 and G2, preventing cells from entering mitosis [38][39][40]. Although the effects of sulfonylurea herbicides are reversible, there is a lagtime associated with the resumption of amino acid synthesis and consequently the cascading resumption of cell division [40].…”

Section: Discussionmentioning

confidence: 97%

Effects of repeated pulsed herbicide exposures on the growth of aquatic macrophytes

Boxall

Fogg

Ashauer

et al. 2012

Enviro Toxic and Chemistry

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Abstract-Many contaminants are released into aquatic systems intermittently in a series of pulses. Pulse timing and magnitude can vary according to usage, compound-specific physicochemical properties, and use area characteristics. Standard laboratory ecotoxicity tests typically employ continuous exposure concentrations over defined durations and thus may not accurately and realistically reflect the effects of certain compounds on aquatic organisms, resulting in potential over-or underestimation. Consequently, the relative effects of pulsed (2 and 4 d) and continuous exposures of the duckweed Lemna minor to isoproturon, metsulfuron-methyl, and pentachlorophenol over a period of 42 d were explored in the present study. At the highest test concentrations, exposure of L. minor to pulses of metsulfuronmethyl resulted in effects on growth similar to those of an equivalent continuous exposure. For isoproturon, pulsed exposures had a lower impact than a corresponding continuous exposure, whereas the effect of pentachlorophenol delivered in pulses was greater. These differences may be explained by compound-specific uptake and degradation or dissipation rates in plants and the recovery potential that occurs following pulses for different pesticides. Given these results, use of a simple time-weighted average approach to estimate effects of intermittent exposures from short-term standard toxicity studies may not provide an accurate prediction that reflects realistic exposure scenarios. Development of mechanistic modeling approaches may facilitate better estimates of effects from intermittent exposures.

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“…Sulfonylurea herbicides inhibit the enzyme acetolactate synthase (ALS), which catalyzes the biosynthesis of three amino acids, valine, leucine, and isoleucine (Ray 1986). Because both herbicide families inhibit protein synthesis, it is possible that treatment at the appropriate growth stage may eliminate viable seed production but this is unknown for downy brome or Japanese brome.…”

Section: Matrixmentioning

confidence: 99%

Seed Bank Depletion: The Key to Long-Term Downy Brome ( Bromus tectorum L.) Management

Sebastian

Nissen

Sebastian³

et al. 2017

Rangeland Ecology & Management

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Sulfonylurea herbicides as inhibitors of amino acid biosynthesis in plants

Cited by 49 publications

References 12 publications

Repression of Acetolactate Synthase Activity through Antisense Inhibition (Molecular and Biochemical Analysis of Transgenic Potato (Solanum tuberosum L. cv Desiree) Plants)

Repression of Acetolactate Synthase Activity through Antisense Inhibition (Molecular and Biochemical Analysis of Transgenic Potato (Solanum tuberosum L. cv Desiree) Plants)

Effects of repeated pulsed herbicide exposures on the growth of aquatic macrophytes

Seed Bank Depletion: The Key to Long-Term Downy Brome ( Bromus tectorum L.) Management

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