scholarly journals Resistance ofEchinochloa crus-galliPopulations to Acetolactate Synthase-Inhibiting Herbicides

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Dilpreet S. Riar ◽  
Jason K. Norsworthy ◽  
Jason A. Bond ◽  
Mohammad T. Bararpour ◽  
Michael J. Wilson ◽  
...  

ThreeEchinochloa crus-galli(barnyardgrass) populations from rice fields in Arkansas (AR1 and AR2) and Mississippi (MS1), USA, were recently confirmed to be resistant to imazethapyr. Experiments were conducted to characterize cross-resistance to acetolactate synthase- (ALS-) inhibiting herbicides and determine if malathion, a known cytochrome P450 monooxygenase (CYP) inhibitor, would overcome resistance. The AR1 and MS1 populations were cross-resistant to bispyribac-sodium; however, AR2 was sensitive to bispyribac-sodium. The AR1, AR2, and MS1 populations were >94, >94, and 3.3 times, respectively, more resistant to imazamox; >94, 30, and 9.4 times, respectively, more resistant to penoxsulam; and 15, 0.9, and 7.2 times, respectively, more resistant to bispyribac-sodium compared to a susceptible population. Addition of malathion to penoxsulam reduced dry weight of all populations and increased mortality of AR2 and MS1 populations compared to penoxsulam alone. Addition of malathion to imazethapyr and bispyribac-sodium increased the mortality of MS1 population in mixture with imazethapyr and AR1 population in mixture with bispyribac-sodium compared to treatments with imazethapyr and bispyribac-sodium applied alone. Synergism of ALS-inhibiting herbicides with malathion indicates increased herbicide degradation by CYP as partial mechanism of resistance to penoxsulam in all resistant populations and probably to imazethapyr in MS1 and bispyribac-sodium in AR1 populations.

2018 ◽  
Author(s):  
Sabine Frabel ◽  
Bastian Wagner ◽  
Markus Krischke ◽  
Volker Schmidts ◽  
Christina M Thiele ◽  
...  

Plants are versatile chemists producing a tremendous variety of specialized compounds. Here, we describe the engineering of entirely novel metabolic pathways in planta enabling generation of halogenated indigo precursors as non-natural plant products. Indican (indolyl-beta-D-glucopyranoside) is a secondary metabolite characteristic of a number of dyers plants. Its deglucosylation and subsequent oxidative dimerization leads to the blue dye, indigo. Halogenated indican derivatives are commonly used as detection reagents in histochemical and molecular biology applications; their production, however, relies largely on chemical synthesis. To attain the de novo biosynthesis in a plant-based system devoid of indican, we employed a sequence of enzymes from diverse sources, including three microbial tryptophan halogenases substituting the amino acid at either C5, C6, or C7 of the indole moiety. Subsequent processing of the halotryptophan by bacterial tryptophanase TnaA in concert with a mutant of the human cytochrome P450 monooxygenase 2A6 and glycosylation of the resulting indoxyl derivatives by an endogenous tobacco glucosyltransferase yielded corresponding haloindican variants in transiently transformed Nicotiana benthamiana plants. Accumulation levels were highest when the 5-halogenase PyrH was utilized, reaching 0.93 +/-0.089 mg/g dry weight of 5-chloroindican. The identity of the latter was unambiguously confirmed by NMR analysis. Moreover, our combinatorial approach, facilitated by the modular assembly capabilities of the GoldenBraid cloning system and inspired by the unique compartmentation of plant cells, afforded testing a number of alternative subcellular localizations for pathway design. In consequence, chloroplasts were validated as functional biosynthetic venues for haloindican, with the requisite reducing augmentation of the halogenases as well as the cytochrome P450 monooxygenase fulfilled by catalytic systems native to the organelle. Thus, our study puts forward a viable alternative production platform for halogenated fine chemicals, eschewing reliance on fossil fuel resources and toxic chemicals. We further contend that in planta generation of halogenated indigoid precursors previously unknown to nature offers an extended view on and, indeed, pushes forward the established frontiers of biosynthetic capacity of plants.


2021 ◽  
Author(s):  
Ansgar Bokel ◽  
Michael C. Hutter ◽  
Vlada B. Urlacher

Engineered cytochrome P450 monooxygenase CYP154E1 enables the effective synthesis of the potential antidepressant (2R,6R)-hydroxynorketamine via N-demethylation and regio- and stereoselective hydroxylation of (R)-ketamine.


mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Erin M. Ostrem Loss ◽  
Mi-Kyung Lee ◽  
Ming-Yueh Wu ◽  
Julia Martien ◽  
Wanping Chen ◽  
...  

ABSTRACT Soil-dwelling fungal species possess the versatile metabolic capability to degrade complex organic compounds that are toxic to humans, yet the mechanisms they employ remain largely unknown. Benzo[a]pyrene (BaP) is a pervasive carcinogenic contaminant, posing a significant concern for human health. Here, we report that several Aspergillus species are capable of degrading BaP. Exposing Aspergillus nidulans cells to BaP results in transcriptomic and metabolic changes associated with cellular growth and energy generation, implying that the fungus utilizes BaP as a growth substrate. Importantly, we identify and characterize the conserved bapA gene encoding a cytochrome P450 monooxygenase that is necessary for the metabolic utilization of BaP in Aspergillus. We further demonstrate that the fungal NF-κB-type velvet regulators VeA and VelB are required for proper expression of bapA in response to nutrient limitation and BaP degradation in A. nidulans. Our study illuminates fundamental knowledge of fungal BaP metabolism and provides novel insights into enhancing bioremediation potential. IMPORTANCE We are increasingly exposed to environmental pollutants, including the carcinogen benzo[a]pyrene (BaP), which has prompted extensive research into human metabolism of toxicants. However, little is known about metabolic mechanisms employed by fungi that are able to use some toxic pollutants as the substrates for growth, leaving innocuous by-products. This study systemically demonstrates that a common soil-dwelling fungus is able to use benzo[a]pyrene as food, which results in expression and metabolic changes associated with growth and energy generation. Importantly, this study reveals key components of the metabolic utilization of BaP, notably a cytochrome P450 monooxygenase and the fungal NF-κB-type transcriptional regulators. Our study advances fundamental knowledge of fungal BaP metabolism and provides novel insight into designing and implementing enhanced bioremediation strategies.


2015 ◽  
Vol 113 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Rohan Karande ◽  
Linde Debor ◽  
Diego Salamanca ◽  
Fabian Bogdahn ◽  
Karl-Heinrich Engesser ◽  
...  

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 389-398
Author(s):  
Parsa Tehranchian ◽  
Jason K. Norsworthy ◽  
Matheus Palhano ◽  
Nicholas E. Korres ◽  
Scott McElroy ◽  
...  

A yellow nutsedge biotype (Res) from an Arkansas rice field has evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. TheResbiotype previously exhibited cross-resistance to ALS inhibitors from four chemical families (imidazolinone, pyrimidinyl benzoate, sulfonylurea, and triazolopyrimidine). Experiments were conducted to evaluate alternative herbicides (i.e., glyphosate, bentazon, propanil, quinclorac, and 2,4-D) currently labeled in Arkansas rice–soybean production systems. Based on the percentage of aboveground dry weight reduction, control of the yellow nutsedge biotypes with the labeled rate of bentazon, propanil, quinclorac, and 2,4-D was < 44%. Glyphosate (867 g ae ha−1) resulted in 68 and > 94% control of theResand susceptible yellow nutsedge biotypes, respectively, at 28 d after treatment. Dose-response studies were conducted to estimate the efficacy of glyphosate on theResbiotype, three susceptible yellow nutsedge biotypes, and purple nutsedge. Based on the dry weights, theResbiotype was ≥ 5- and ≥ 1.3-fold less responsive to glyphosate compared to the susceptible biotypes and purple nutsedge, respectively. Differences in absorption and translocation of radiolabeled glyphosate were observed among the yellow nutsedge biotypes and purple nutsedge. The susceptible biotype had less14C-glyphosate radioactivity in the tissues above the treated leaf and greater radioactivity in tissues below the treated leaf compared to theResbiotype and purple nutsedge. Reduced translocation of glyphosate in tissues below the treated leaf of theResbiotype could be a reason for the lower glyphosate efficacy in theResbiotype. No amino acid substitution that would correspond to glyphosate resistance was found in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene of theResbiotype. However, an amino acid (serine) addition was detected in the EPSPS gene of theResbiotype; albeit, it is not believed that this addition contributes to lower efficacy of glyphosate in this biotype.


2010 ◽  
Vol 10 (6) ◽  
pp. 791-791 ◽  
Author(s):  
Inge N.A. Van Bogaert ◽  
Marjan De Mey ◽  
Dirk Develter ◽  
Wim Soetaert ◽  
Erick J. Vandamme

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