Structure and mechanism of inhibition of plant acetohydroxyacid synthase

Duggleby, Ronald G.; McCourt, Jennifer A.; Guddat, L.W.

doi:10.1016/j.plaphy.2007.12.004

Cited by 314 publications

(337 citation statements)

References 60 publications

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“…To determine the prevalence of AHAS isozymes across a sample of clinically relevant bacteria, we performed a phylogenetic analysis on the AHAS catalytic subunit, which contains the SH binding site (2,16). As seen previously (13,22,23), type I AHAS was exclusively present in Enterobacteriaceae (Fig.…”

Section: Resultsmentioning

confidence: 85%

“…imately 10 Ϫ8 . Similar to plants (2,29), a single mutation in the catalytic subunit of AHAS was sufficient to confer resistance to chlorimuron ethyl and other SHs. To counter the rapid emergence of single-step, high-level SH-resistant mutants, AHAS inhibitors could be used in combination with other antibiotics (30) or inhibitors of BCAA biosynthesis (31)(32)(33).…”

Section: Resultsmentioning

confidence: 92%

“…Bacterial isozymes of AHAS are composed of a catalytic and a regulatory subunit that are encoded by adjacent genes. Catalytic subunits of AHAS were identified by searching the genomes of select organisms using the Enzyme Commission number 2.2.1.6 (2,16). In most genomes, multiple genes have been annotated as AHAS catalytic subunits.…”

Section: Methodsmentioning

confidence: 99%

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Growth Inhibition of Pathogenic Bacteria by Sulfonylurea Herbicides

Kreisberg

Ong

Krishna

et al. 2013

Antimicrob Agents Chemother

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Emerging resistance to current antibiotics raises the need for new microbial drug targets. We show that targeting branchedchain amino acid (BCAA) biosynthesis using sulfonylurea herbicides, which inhibit the BCAA biosynthetic enzyme acetohydroxyacid synthase (AHAS), can exert bacteriostatic effects on several pathogenic bacteria, including Burkholderia pseudomallei, Pseudomonas aeruginosa, and Acinetobacter baumannii. Our results suggest that targeting biosynthetic enzymes like AHAS, which are lacking in humans, could represent a promising antimicrobial drug strategy.

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Section: Resultsmentioning

confidence: 85%

Section: Resultsmentioning

confidence: 92%

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Growth Inhibition of Pathogenic Bacteria by Sulfonylurea Herbicides

Kreisberg

Ong

Krishna

et al. 2013

Antimicrob Agents Chemother

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“…The survival of biotypes can occur due to factors that may be related to the herbicide target site or non-target-site (Yuan, Tranel, & Stewart, 2007). The occurrence of DNA mutations in the gene sequence and the overexpression of the ALS enzyme are possible factors resulting in reduced sensitivity to the herbicide due to insufficient or excessive levels of biosynthetic product (Duggleby, McCourt, & Guddat, 2008;Han et al, 2012). Mutations in the ALS gene can affect enzyme structure and function, thereby reducing the enzyme activity and herbicide affinity with the target site .…”

Section: Introductionmentioning

confidence: 99%

<b>Mutation of Trp-574-Leu ALS gene confers resistance of radish biotypes to iodosulfuron and imazethapyr herbicides

et al. 2017

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ABSTRACT. Acetolactate synthase inhibitors are the main group of herbicides used in winter crops in Southern Brazil where their intensive use has selected for herbicide-resistant biotypes of radish. The resistance affects the efficacy of herbicides, and identifying the resistance mechanism involved is important for defining management strategies. The aim of this study was to elucidate the resistance mechanism of radish biotypes by quantifying the enzyme activity, ALS gene sequencing and evaluating the response of biotypes to iodosulfuron and imazethapyr herbicide application after treatment with a cytochrome P 450 monooxygenase inhibitor. The susceptible (B 1 ) and resistant (B 4 and B 13 ) biotypes were from wheat fields in the Northwest of Rio Grande do Sul State. The results demonstrated that the enzyme affinity for the substrate (K M ) was not affected in biotypes B 4 and B 13 but that the V max of the resistant biotypes was higher than that of biotype B 1 . The resistant biotypes showed no differential metabolic response to iodosulfuron and imazethapyr herbicides when inhibited by malathion and piperonyl butoxide. However, gene sequencing of ALS showed a mutation at position 574, with an amino acid substitution of tryptophan for leucine (Trp-574-Leu) in resistant biotypes.Keywords: Raphanus sativus, mechanism of resistence, ALS enzyme activity, gene mutation, metabolism.Mutação da Trp-574-Leu do gene ALS confere resistência de biótipos de nabo ao herbicida iodosulfurom e imazetapir RESUMO. Os inibidores da acetolactato sintase são o principal grupo de herbicidas usados em culturas de inverno do Sul do Brasil onde seu uso intenso selecionou biótipos resistentes de nabo. A resistência afeta a eficácia dos herbicidas, e a identificação do mecanismo de resistência envolvido é importante na definição de estratégias de manejo. O objetivo deste estudo foi elucidar o mecanismo de resistência em biótipos de nabo através da quantificação da atividade da enzima, sequenciamento do gene ALS e avaliar a resposta dos biótipos à aplicação do herbicida iodosulfurom e imazetapir após tratamento com inibidores do metabolismo da citocromo P 450 monooxigenase. Os biótipos suscetível (B 1 ) e resistentes (B 4 e B 13 ) eram de lavouras de trigo da região Noroeste do Estado do Rio Grande do Sul. Os resultados demonstraram que a afinidade da enzima pelo substrato (K M ) não foi afetada nos biótipos B 4 e B 13 , porém o V max dos biótipos resistentes foi superior quando comparado ao biótipo B 1 . Os biótipos resistentes não apresentaram resposta metabólica diferencial ao herbicida iodosulfurom e imazetapir quando inibidos pelo malathion e butóxido de piperolina. Entranto, o sequenciamento do gene ALS evidenciou mutação na posição 574 com uma substituição do aminoácido triptofano por leucina (Trp-574-Leu) nos biótipos resistentes. Palavras-chave:Raphanus sativus, mecanismo de resistência, atividade da enzima ALS, mutação gênica, metabolismo.

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“…These herbicides act in the first enzyme of the synthesis rout of the valine, leucine and isoleucine side chain amino acids, where there is a blockage of cell division and DNA synthesis (Duggleby et al, 2008). Although it is efficient, the dependence on a single action mechanism enabled the emergence of resistance cases (Walsh et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Resistence of Radish Biotypes to Iodosulfuron and Alternative Control

et al. 2016

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-The repetitive use of iodosulfuron for the control of weeds in winter cereals in the south of Brazil has favored the emergence of resistant Raphanus sativus biotypes. The objective of this study was to evaluate: the response of Raphanus sativus biotypes susceptible and resistant to different dosages of iodosulfuron; the control of biotypes with alternative registered herbicides for the control of the species in crops of wheat, corn and soybean; and the existence of cross-resistance of the biotypes. Thus, four experiments were done in a greenhouse, with a completely randomized design and four replicates. The experimental units were composed of vases with a volumetric capacity of 0.75 L filled with substrate, containing a plant each. For the dose-response curve, three biotypes (factor A) and nine doses of the iodosulfuron herbicide (factor B) were used. For the alternative control, the recommendation was herbicides in pre or postemergence of the crops, and the crossedresistance was evaluated by using herbicides that inhibit the ALS enzyme of different chemical groups. The analyzed variables were control and shoot dry matter. GR 50 of the susceptible biotype (B 1 ) was 0.11 g a.i. ha -1 , whereas GR 50 of resistant biotypes (B 4 and B 13 ) was 102.9 and 86.8 g a.i. ha -1 of the iodosulfuron herbicide, respectively. The resistant biotypes presented crossed resistance to herbicides that inhibit the ALS enzyme, where the control can be efficient with the use of herbicides with different action mechanisms. Keywords:Raphanus sativus, dose-response, acetolactate synthase, weed. RESUMO -O uso repetido do herbicida iodosulfurom para controle de plantas daninhas em cereais de inverno no Sul do Brasil favoreceu o surgimento de biótipos de Palavras-chave:Raphanus sativus, dose-resposta, acetolactato sintase, planta daninha.

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Structure and mechanism of inhibition of plant acetohydroxyacid synthase

Cited by 314 publications

References 60 publications

Growth Inhibition of Pathogenic Bacteria by Sulfonylurea Herbicides

Growth Inhibition of Pathogenic Bacteria by Sulfonylurea Herbicides

<b>Mutation of Trp-574-Leu ALS gene confers resistance of radish biotypes to iodosulfuron and imazethapyr herbicides

Resistence of Radish Biotypes to Iodosulfuron and Alternative Control

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