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1.
Molecules ; 27(12)2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35744974

RESUMO

We determined the allelopathic effects of crude organic (hexane, ethyl acetate, and methanol) extracts of the cyanobacterial Spirulina platensis on barnyardgrass (Echinochloa crus-galli (L.) Beauv.) and Chinese amaranth (Amaranthus tricolor L.). The crude ethyl acetate extract showed the highest inhibitory activity and was subsequently fractionated by column chromatography into 23 fractions based on thin-layer chromatography band pattern similarities. Four concentrations (2000, 1000, 500, and 250 ppm) of each fraction were tested for their allelopathic activity. Fractions E6 and E13 exhibited the most significant inhibitory effects against Chinese amaranth. The constituents of the highly active E6F3-E6F5 fractions determined by GC-MS, chromatography, and spectroscopy included the fatty acids, γ-linolenic acid 15, oleic acid 12, and predominantly palmitic acid 7; minor constituents included 2-ethyl-3-methylmaleimide 9 and C11 norisoprenoids (dihydroactinidiolide 10 and 4-oxo-ß-ionone 13). Isolation of E13 fraction by column chromatography revealed four C13 norisoprenoids: 3-hydroxy-ß-ionone 17, 3-hydroxy-5α,6α-epoxy-ß-ionone 18, 3-hydroxy-5ß,6ß-epoxy-ß-ionone 19, and loliolide 20. Their structures were elucidated by NMR spectroscopy. All six isolated norisoprenoids inhibited seed germination and seedling growth of Chinese amaranth at concentrations of 250-1000 ppm. Allelochemicals from S. platensis could be utilized in the development of novel bioactive herbicides.


Assuntos
Echinochloa , Spirulina , Alelopatia , Norisoprenoides/química , Extratos Vegetais/química
2.
Pestic Biochem Physiol ; 184: 105089, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35715035

RESUMO

Managing emerged weeds that have evolved resistance to acetyl CoA carboxylase (ACCase)-inhibiting herbicides is a challenging task. A dose-response experiment was conducted on barnyardgrass biotypes resistant (R) and susceptible (S) to three aryloxyphenoxypropionate herbicides cyhalofop-butyl (CyB), fenoxaprop-ethyl (FeE), and quizalofop-ethyl (QuE) along with investigations into the potential resistance mechanism of these biotypes. The tested R barnyardgrass biotypes had strong resistance to CyB and FeE (resistant/susceptible ratio: 7.9-14.4) but weak resistance to QuE (resistant/susceptible ratio: 2.4-3.1). Absorption, translocation, and total metabolism of CyB and QuE were not associated with differences among S and R barnyardgrass biotypes. However, differences between S and R barnyardgrass were observed in production of active acid forms of each herbicide (cyhalofop-acid and quizalofop-acid). Production of cyhalofop-acid was >1.6-fold less in R barnyardgrass (3-8%) for 24 h after herbicide application than in the S barnyardgrass (8-16%). Meanwhile, production of quizalofop-acid was less in R barnyardgrass (< 14%) throughout the study period than in the S barnyardgrass (< 22%). Sequencing results of ACCase gene showed no difference between S and R barnyardgrass. Overall results show that a non-target-site resistance mechanism altering metabolism of CyB and QuE likely contributes to resistance of the barnyardgrass biotypes to these herbicides.


Assuntos
Echinochloa , Herbicidas , Acetil-CoA Carboxilase/genética , Acetil-CoA Carboxilase/metabolismo , Echinochloa/metabolismo , Resistência a Herbicidas/genética , Herbicidas/metabolismo , Herbicidas/toxicidade , Plantas Daninhas/metabolismo
3.
Molecules ; 27(11)2022 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-35684420

RESUMO

Bio-based nanoemulsions are part of green pest management for sustainable agriculture. This study assessed the physicochemical properties and the herbicidal activities of the peppermint essential oil nanoemulsions (PNs) in concentrations 1.0-10% stabilized by Eco-Polysorbate 80 on germinating seeds and young plants of maize and barnyard grass. Based on the design of experiment (DOE) results, the final nanoemulsion formulations were obtained with 1, 1.5, 2, and 5% of essential oil concentration. Biological analyses were conducted to select the most promising sample for selective control of barnyard grass in maize. Seedlings growing in the presence of PNs displayed an overall inhibition of metabolism, as expressed by the calorimetric analyses, which could result from significant differences in both content and composition of carbohydrates. Concentration-response sub estimation showed that leaf-sprayed concentration of PN causing 10% of maize damage is equal to 2.2%, whereas doses causing 50% and 90% of barnyard grass damage are 1.1% and 1.7%, respectively. Plants sprayed with PN at 5% or 10% concentration caused significant drops in relative water content in leaves and Chlorophyll a fluorescence 72 h after spraying. In summary, peppermint nanoemulsion with Eco-Polysorbate 80 at 2% concentration is a perspective preparation for selective control of barnyard grass in maize. It should be analyzed further in controlled and field conditions.


Assuntos
Echinochloa , Herbicidas , Óleos Voláteis , Clorofila A , Herbicidas/farmacologia , Mentha piperita , Óleos Voláteis/farmacologia , Óleos Vegetais , Plantas , Polissorbatos , Zea mays
4.
Molecules ; 27(11)2022 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-35684491

RESUMO

Plant antimicrobial peptides from the α-hairpinins family (hairpin-like peptides) are known to possess a wide range of biological activities. However, less is known about the structural determinants of their antimicrobial activity. Here, we suggest that spatial structure as well as surface charge and hydrophobicity level contribute to the antimicrobial properties of α-hairpinin EcAMP1 from barnyard grass (Echinochloa cruss-galli) seeds. To examine the role of the peptide spatial structure, two truncated forms of EcAMP1 restricted by inner and outer cysteine pairs were synthesized. It was shown that both truncated forms of EcAMP1 lost their antibacterial activity. In addition, their antifungal activity became weaker. To review the contribution of surface charge and hydrophobicity, another two peptides were designed. One of them carried single amino acid substitution from tryptophan to alanine residue at the 20th position. The second one represented a truncated form of the native EcAMP1 lacking six C-terminal residues. But the α-helix was kept intact. It was shown that the antifungal activity of both modified peptides weakened. Thereby we can conclude that the secondary structural integrity, hydrophobic properties, and surface charge all play roles in the antimicrobial properties of α-hairpinins. In addition, the antibacterial activity of cereal α-hairpinins against Gram-positive bacteria was described for the first time. This study expands on the knowledge of structure-function interactions in antimicrobial α-hairpinins.


Assuntos
Anti-Infecciosos , Echinochloa , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Peptídeos/farmacologia
5.
J Hazard Mater ; 436: 129191, 2022 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-35739721

RESUMO

Glyphosate is a dominant organophosphate herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) of the shikimate pathway. Glyphosate is extensively applied since manufactured, which has led to the emergence of various glyphosate-resistant crops and weeds. However, the molecular mechanism of many glyphosate-resistance machineries remains unclear. Recently, the upregulated expression of two homologous aldo-keto reductases (AKRs), designated as AKR4C16 and AKR4C17, were found to contribute to the glyphosate resistance in Echinochloa colona. This represents the first naturally evolved glyphosate-degrading machinery reported in plants. Here, we report the three-dimensional structure of these two AKR enzymes in complex with cofactor by performing X-ray crystallography. Furthermore, the binding-mode of glyphosate were elucidated in a ternary complex of AKR4C17. Based on the structural information and the previous study, we proposed a possible mechanism of action of AKR-mediated glyphosate degradation. In addition, a variant F291D of AKR4C17 that was constructed based on structure-based engineering showed a 70% increase in glyphosate degradation. In conclusion, these results demonstrate the structural features and glyphosate-binding mode of AKR4C17, which increases our understanding of the enzymatic mechanism of glyphosate bio-degradation and provides an important basis for the designation of AKR-based glyphosate-resistance for further applications.


Assuntos
Echinochloa , Herbicidas , Aldo-Ceto Redutases/genética , Aldo-Ceto Redutases/metabolismo , Echinochloa/genética , Echinochloa/metabolismo , Glicina/análogos & derivados , Glicina/química , Resistência a Herbicidas/genética , Herbicidas/farmacologia
6.
Water Sci Technol ; 85(9): 2613-2624, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35576256

RESUMO

The use of biochar in constructed wetlands for domestic wastewater treatment is gradually being acclaimed by environmentalists due to its high specific surface area and porosity. In this study, the effectiveness of corn cob biochar (CCB) and rice husk biochar (RHB) in vertical flow constructed wetlands vegetated with Echinochloa pyramidalis was studied with sand as common reference material. The filters were fed with primarily treated domestic wastewater at a hydraulic loading rate of about 350 L/m2/day for 6 months. Water samples were collected monthly for physicochemical and bacteriological analysis and plant growth assessed every two weeks throughout the study. Biochar filters were highly performant in wastewater improvement with no significant differences between the biochar types. Both biochars were more efficient than sand in the removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD), true colour, total suspended solids (TSS) and total dissolved solids (TDS). However, sand filters performed better in the reduction of nutrients. All wetlands showed positive plant growth though the plants did not significantly affect the performance of the different filters for most parameters. However, a better plant growth was observed in the CCB filters. The study shows that CCB and RHB can effectively replace sand as substrates in constructed wetlands for wastewater treatment.


Assuntos
Echinochloa , Purificação da Água , Análise da Demanda Biológica de Oxigênio , Carvão Vegetal , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Áreas Alagadas
7.
Pest Manag Sci ; 78(8): 3287-3293, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35484723

RESUMO

BACKGROUND: The efficacy of a herbicide as soil treatment agent may be largely affected by soil characteristics. Understanding the relationship between herbicide efficacy and soil characteristics can provide decision basis for herbicide application according to local conditions. This study was aimed towards exploring the effect of soil characteristics on herbicidal activity of atrazine as a model herbicide to barnyard grass and thus to find an indicator for the herbicidal activity assessment of a herbicide against weeds. RESULTS: The herbicidal activity of atrazine to barnyard grass varied greatly among the tested soils with the medium inhibition concentration (IC50 ), based on the amended concentration, ranging from 1.07 to 10.91 mg kg-1 . Uptake of atrazine by barnyard grass was negatively correlated with its adsorption onto soils, whereas it was positively related to the concentration of the herbicide in in situ pore water (CIPW ). Comparable IC50 values ranging from 1.14 to 1.38 were obtained from CIPW in the tested soils with much smaller variation coefficient compared to those based on the traditional concentration (Csoil ) of this herbicide in soils determined by extraction with organic solvents. CONCLUSION: The concentration of atrazine in in situ pore water could be reliable to evaluate its bioavailability and herbicidal activity to barnyard grass. CIPW of a herbicide in soil could be an indicator for guiding the practical application rate. © 2022 Society of Chemical Industry.


Assuntos
Atrazina , Echinochloa , Herbicidas , Poluentes do Solo , Atrazina/farmacologia , Herbicidas/análise , Herbicidas/farmacologia , Solo , Poluentes do Solo/análise , Água
8.
Pestic Biochem Physiol ; 183: 105086, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35430076

RESUMO

To improve the selectivity of the fenoxaprop herbicide to rice and barnyard grass, a series of fenoxaprop-P-ethyl-amino acid ester conjugates were designed and synthesized, and tested for biological activity as well as their phloem mobility. The bioassay results indicated that the target compounds possessed better activity against barnyard grass (Echinochloa crusgalli) than rape (Brassica campestris L.) at the concentration of 0.5 mmol/L. Compounds 3h and 3i, showed more than 70% control efficiency against barnyard grass, while less than 30% for rape. The compounds showed less impact on rice after spray treatment than in the germination test. Compounds 3i, 3j, and 3k showed excellently herbicidal activities against barnyard grass and low phytotoxicity to rice. Compound 3k showed 6.1% phytotoxicity to rice at a spray concentration of 0.25 mmol/L, better than fenoxaprop-P-ethyl (61.6%) at the same concentration. The selectivity results of the target compounds revealed that most of compounds obviously reduced phytotoxicity to rice while retaining herbicidal activity of barnyard grass. The herbicidal activity of compound 3d compared to FPE was increased by 50%, while its safety on rice was also increased by 50%. The concentration of the compounds in barnyard grass roots was higher than in rice roots, showing greater phloem mobility. In particular, the concentration of compound 3d on barnyard grass exhibited 142.72 mg/kg which was 3 times as much as Fenoxaprop, while its concentration on rice exhibited 3.65 mg/kg, the results revealed that the difference of phloem mobility might be the important reason for causing the selectivity.


Assuntos
Echinochloa , Herbicidas , Oryza , Aminoácidos/metabolismo , Echinochloa/metabolismo , Ésteres/metabolismo , Herbicidas/química , Herbicidas/toxicidade , Oryza/metabolismo , Floema/fisiologia
9.
Pestic Biochem Physiol ; 182: 105038, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35249656

RESUMO

Echinochloa crus-galli L., a notorious weed in rice paddy fields, is usually kept under control by mefenacet application at the pre-emergence or early post-emergence stage. Due to continuous and repeated usage, E. crus-galli is developing resistance to mefenacet in China. Two putative resistant and one susceptible E. crus-galli populations were collected from paddy fields in Jiangsu Province to characterize their herbicide resistance. Compared with the susceptible population, the two mefenacet-resistant populations had 2.8- and 4.1-times greater pre-emergence resistance, and 10- and 6.8-times greater early post-emergence resistance to mefenacet. These mefenacet-resistant E. crus-galli populations also exhibited cross- or multiple-resistance to acetochlor, pyraclonil, imazamox, and quinclorac. However, when the glutathione S-transferase (GST) inhibitor 4-chloro-7-nitrobenzoxadiazole (NBD-Cl) was applied prior to post-emergence treatment, mefenacet resistance levels were reduced in both populations. Additionally, GST activity in vivo in one resistant population was much higher than the susceptible population after mefenacet application. The very long chain fatty acid elongases (VLCFAEs) from both mefenacet-resistant populations required much higher mefenacet concentration to inhibit their activity. The reduced sensitivity of VLCFAEs to mefenacet indicates the presence of a target-site resistance mechanism and induction of high GST activity may provide additional contribution to E. crus-galli mefenacet resistance through a non-target-site mechanism.


Assuntos
Echinochloa , Herbicidas , Acetanilidas , Benzotiazóis , Resistência a Herbicidas , Herbicidas/farmacologia
10.
Chem Biodivers ; 19(4): e202100746, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35233905

RESUMO

Three series of secondary ammonium chloride from turpentine were synthesized and evaluated as botanical herbicides. The preemergence herbicidal activities against ryegrass (Loliun multiflorum) and barnyard grass (Echinochloa crus-galli) were investigated using water as the only solvent. Their toxicity was evaluated by cytotoxicity assays. Preliminary results demonstrated that the herbicidal performance of the prepared salts was similar or much higher than that of corresponding secondary amines and even commercial herbicide glyphosate. Promisingly, compound 14e containing a cyclohexyl-substituted p-menthene skeleton with an IC50 value of 0.0014 mM against root growth of ryegrass showed 39-fold higher herbicidal activity than glyphosate. Besides, this compound was found to be nontoxic to human and animal cells, indicating the potential application as a water-soluble herbicide for ryegrass control.


Assuntos
Compostos de Amônio , Echinochloa , Herbicidas , Herbicidas/toxicidade , Sais , Terebintina , Água , Controle de Plantas Daninhas
11.
Genes (Basel) ; 13(3)2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35328069

RESUMO

Echinochloa colona and other species in this genus are a threat to global rice production and food security. Quinclorac, an auxin mimic, is a common herbicide for grass weed control in rice, and Echinochloa spp. have evolved resistance to it. The complete mode of quinclorac action and subsequent evolution of resistance is not fully understood. We analyzed the de novo transcriptome of multiple-herbicide-resistant (ECO-R) and herbicide-susceptible genotypes in response to quinclorac. Several biological processes were constitutively upregulated in ECO-R, including carbon metabolism, photosynthesis, and ureide metabolism, indicating improved metabolic efficiency. The transcriptional change in ECO-R following quinclorac treatment indicates an efficient response, with upregulation of trehalose biosynthesis, which is also known for abiotic stress mitigation. Detoxification-related genes were induced in ECO-R, mainly the UDP-glycosyltransferase (UGT) family, most likely enhancing quinclorac metabolism. The transcriptome data also revealed that many antioxidant defense elements were uniquely elevated in ECO-R to protect against the auxin-mediated oxidative stress. We propose that upon quinclorac treatment, ECO-R detoxifies quinclorac utilizing UGT genes, which modify quinclorac using the sufficient supply of UDP-glucose from the elevated trehalose pathway. Thus, we present the first report of upregulation of trehalose synthesis and its association with the herbicide detoxification pathway as an adaptive mechanism to herbicide stress in Echinochloa, resulting in high resistance.


Assuntos
Echinochloa , Herbicidas , Oryza , Echinochloa/genética , Echinochloa/metabolismo , Resistência a Herbicidas/genética , Herbicidas/metabolismo , Herbicidas/farmacologia , Ácidos Indolacéticos/metabolismo , Oryza/genética , Quinolinas , Transcriptoma , Trealose/metabolismo , Difosfato de Uridina/metabolismo , Xenobióticos/metabolismo
12.
Pest Manag Sci ; 78(6): 2560-2570, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35334143

RESUMO

BACKGROUND: Barnyardgrass (Echinochloa crus-galli (L.) P. Beauv) has evolved resistance to the acetolactate synthase (ALS) inhibitor penoxsulam which is used to control weeds in rice fields in China. The present study is conducted to identify the target-site resistance (TSR) mechanisms conferring resistance in a penoxsulam-resistant population. RESULTS: The ALS sensitivity in vitro of the resistant population was sixfold lower to penoxsulam than that of the sensitive population. ALS sequencing revealed that no known mutation conferring ALS herbicide resistance was detected. However, a novel mutation Phe-206-Leu was identified in the ALS gene. Additionally, ALS gene expression level of the resistant population was lower than that of the sensitive population. Therefore, the penoxsulam resistance was not due to the overexpression of ALS gene. Molecular docking revealed that this mutation may change the interaction of the penoxsulam-ALS binding and weaken its mutual affinity by approximately 10%. Arabidopsis thaliana transformed with mutant ALS had fourfold greater resistance to penoxsulam and varied cross-resistance to other ALS herbicides than those transformed with sensitive ALS. Mutant and sensitive ALS proteins expressed by the baculovirus system exhibited different in vitro penoxsulam sensitivity levels. Mutant ALS had eightfold lower sensitivity to penoxsulam than sensitive ALS. CONCLUSION: This report provides clear evidence that the ALS mutation at position 206 (Phe-206-Leu) confers penoxsulam resistance in barnyardgrass. Phe-206 was confirmed to be the ninth amino acid residue related to ALS herbicide resistance in weeds. © 2022 Society of Chemical Industry.


Assuntos
Acetolactato Sintase , Echinochloa , Herbicidas , Echinochloa/genética , Inibidores Enzimáticos/farmacologia , Resistência a Herbicidas/genética , Herbicidas/metabolismo , Herbicidas/farmacologia , Simulação de Acoplamento Molecular , Mutação , Proteínas de Plantas/metabolismo , Plantas Daninhas/genética , Plantas Daninhas/metabolismo , Sulfonamidas , Uridina/análogos & derivados
13.
J Agric Food Chem ; 70(6): 1766-1775, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35107011

RESUMO

The expansion of weed infestation has increased the demand on new herbicides. A series of novel galactosyl moiety-conjugated furylchalcones was facilely synthesized in which the furyl group (A ring) was combined with the substituted benzene group (B ring), and a galactosyl moiety was introduced. All these galactosyl furylchalcones were predicted to be phloem-mobile. Most of the galactosyl furylchalcones significantly promoted early seedling growth of sorghum and barnyardgrass under dark conditions, but all of them revealed considerable anti-growth ability on illuminated pot plants; especially, 1-(3'-(4″-O-ß-d-galactopyranosyl)furyl)-3-(4″-nitrophenyl)-2-en-1-one (B11) had a better herbicidal activity against rapeseed and Chinese amaranth than haloxyfop-R-methyl. The median efficient concentrations (EC50) of compound B11 against cucumber and wheat were 9.55 and 26.97 mg/L, respectively, also showing a stronger suppressing capacity than 2,4-D. Molecular docking with phosphoenolpyruvate carboxylase protein showed a stable binding conformation in which the galactosyl group interacted with LYS363 and GLU369, the furan ring and carbonyl bound with ARG184, and the crosslink of the nitro group with GLU240 formed a salt bridge. The results demonstrate that galactosyl furylchalcones possess the great potential as new herbicides for weed management, and further evaluations on more weeds are required for practical application.


Assuntos
Echinochloa , Herbicidas , Herbicidas/farmacologia , Simulação de Acoplamento Molecular , Desenvolvimento Vegetal , Plantas Daninhas
14.
Nat Commun ; 13(1): 689, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115514

RESUMO

As one of the great survivors of the plant kingdom, barnyard grasses (Echinochloa spp.) are the most noxious and common weeds in paddy ecosystems. Meanwhile, at least two Echinochloa species have been domesticated and cultivated as millets. In order to better understand the genomic forces driving the evolution of Echinochloa species toward weed and crop characteristics, we assemble genomes of three Echinochloa species (allohexaploid E. crus-galli and E. colona, and allotetraploid E. oryzicola) and re-sequence 737 accessions of barnyard grasses and millets from 16 rice-producing countries. Phylogenomic and comparative genomic analyses reveal the complex and reticulate evolution in the speciation of Echinochloa polyploids and provide evidence of constrained disease-related gene copy numbers in Echinochloa. A population-level investigation uncovers deep population differentiation for local adaptation, multiple target-site herbicide resistance mutations of barnyard grasses, and limited domestication of barnyard millets. Our results provide genomic insights into the dual roles of Echinochloa species as weeds and crops as well as essential resources for studying plant polyploidization, adaptation, precision weed control and millet improvements.


Assuntos
Produtos Agrícolas/genética , Echinochloa/genética , Evolução Molecular , Genoma de Planta/genética , Genômica/métodos , Plantas Daninhas/genética , Adaptação Fisiológica/genética , Produtos Agrícolas/classificação , Domesticação , Echinochloa/classificação , Fluxo Gênico , Genes de Plantas/genética , Especiação Genética , Geografia , Resistência a Herbicidas/genética , Filogenia , Plantas Daninhas/classificação , Polimorfismo de Nucleotídeo Único , Especificidade da Espécie
15.
Pest Manag Sci ; 78(6): 2287-2298, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35220677

RESUMO

BACKGROUND: Some herbicides are commercially formulated with safeners to increase crop selectivity. Fenoxaprop-p-ethyl is formulated with the safener isoxadifen-ethyl for Echinochloa crus-galli control in rice. Safeners act on crops by increasing herbicide metabolism, but this effect may also occur in weeds. The objective of this study was to investigate the effect of the safener isoxadifen-ethyl on the resistance to fenoxaprop-p-ethyl in a biotype of E. crus-galli. RESULTS: A screening of 52 biotypes identified lack of control in the biotype SANTPAT-R treated with the recommended dose of 69 g ha-1 of the commercial formulation of fenoxaprop-p-ethyl with the safener isoxadifen-ethyl. While this biotype survived doses greater than 2208 g ha-1 of the formulation fenoxaprop-p-ethyl + isoxadifen-ethyl, it was killed with 69 g ha-1 of fenoxaprop-p-ethyl without the safener. A glutathione-s-transferase (GST) enzymes inhibitor reduced the resistance factor in two dose-response curves. A minor effect of a CytP450 inhibitor was observed. The previous spraying of the safener isoxadifen-ethyl followed by fenoxaprop-p-ethyl induced survival in the resistant but not in the susceptible biotype. The GST1 and GSTF1 genes were up-regulated in the resistant biotype. ACCase gene mutations were not found, and no cross-resistance to other ACCase inhibitors was identified. CONCLUSION: The safener isoxadifen-ethyl present in the commercial herbicide formulation of fenoxaprop-p-ethyl is associated with resistance in the E. crus-galli SANTPAT-R biotype. This resistance is related with herbicide metabolization mediated by GST pathways. This is the first field-selected weed biotype with herbicide resistance due to safener presence in the sprayed formulation. © 2022 Society of Chemical Industry.


Assuntos
Echinochloa , Herbicidas , Oryza , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Plantas Daninhas/genética
16.
J Hazard Mater ; 428: 128225, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35032953

RESUMO

Long-term and excessive herbicide use has led to some environmental concerns and especially, herbicide resistance evolution in weeds. Here, we confirmed acetolactate synthase (ALS) inhibiting herbicide penoxsulam resistance and cross resistance to acetyl-coenzyme carboxylase (ACCase) inhibiting herbicides (cyhalofop-butyl and metamifop) in a global weed Echinochloa crus-galli population resistant to these herbicides (R). Penoxsulam metabolism study indicated that degradation rate was significantly higher in R than susceptible E. crus-galli population (S). RNA-sequencing revealed that a cytochrome P450 (P450) gene, CYP81A68, expressed higher in R versus S. Rice seedlings overexpressing this CYP81A68 gene are resistant to penoxsulam, cyhalofop-butyl and metamifop, and penoxsulam resistance is due to enhanced metabolism via O-demethylation. Deletion analysis of the CYP81A68 gene promoter identified an efficient region, in which differential methylation of CpG islands occurred between R and S. Collectively, these results demonstrate that upregulation of E. crus-galli CYP81A68 gene endows generalist metabolic resistance to commonly used ALS- and ACCase-inhibiting herbicides in rice fields and epigenetic regulation may play a role in the resistance evolution. This research could contribute to strategies reducing herbicide environmental impacts by judicious selection of alternative herbicide and non-chemical control tactics.


Assuntos
Acetolactato Sintase , Echinochloa , Herbicidas , Acetolactato Sintase/genética , Acetolactato Sintase/metabolismo , Echinochloa/genética , Echinochloa/metabolismo , Epigênese Genética , Resistência a Herbicidas/genética , Herbicidas/toxicidade , Proteínas de Plantas/genética
17.
Pestic Biochem Physiol ; 181: 105007, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35082030

RESUMO

Quintrione is a new post-emergence herbicide developed for use in rice; however, the mechanism of action remains unclear. We determined the phytotoxicity of quintrione, and the contributions of hormone levels and lipid peroxidation to phytotoxicity, by comparing them to those induced by quinclorac. We also investigated 4-hydroxyphenylpyruvate dioxygenase (HPPD) activity and carotenoid content following treatment with quintrione by comparing them to those induced by quinclorac and mesotrione. We found that quintrione and quinclorac both inhibited the growth of Echinochloa crusgalli var. zelayensis, but that quinclorac was a little more effective. At 24 h, quintrione and quinclorac significantly increased ethylene production and the contents of abscisic acid (ABA) and indole acetic acid (IAA) compared with the control. No significant differences were observed between quintrione and quinclorac on the three plant hormones. Quintrione and quinclorac also induced the formation of malondialdehyde (MDA), which is associated with lipid peroxidation, with no significant difference between them. Carotenoid content was reduced in E. crusgalli var. zelayensis following treatments with quintrione, quinclorac, and mesotrione. At 120 h, carotenoid contents were significantly higher following the quintrione and quinclorac treatments, in comparison with mesotrione treatment. There were no significant differences between quintrione and quinclorac in the inhibition of HPPD activity, and the effects of both were significantly less than the effect of mesotrione. In summary, E. crusgalli var. zelayensis was susceptible to both quintrione and quinclorac. The mechanism of action of quintrione, like that of quinclorac, was related to levels of plant hormones and lipid peroxidation; however, quintrione was a poor inhibitor of HPPD activity compared to mesotrione.


Assuntos
Echinochloa , Herbicidas , Oryza , Quinolinas , Herbicidas/toxicidade
18.
Nat Prod Res ; 36(6): 1659-1662, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33691539

RESUMO

Eugenol is a phenylpropanoid with a wide range of documented biological activities. Due to its versatility, it is incorporated as an active ingredient in numerous products including those intended for agriculture. We assessed the phytotoxic potential of the vapor phase of eugenol tested at 2 and 20 µl against the seeds of five weeds, both monocots and dicots. The lowest dose was able to prevent the germination of Echinochloa oryzoides, while the highest amount fully inhibited the germination of Lolium multiflorum and Sinapis alba. Trifolium incarnatum and Vicia sativa were significantly controlled only by the effect of 20 µl of eugenol. Their germination was reduced by 58.6% and 62.1%, respectively, with values of the seedling vigour index lower by more than 80% than those of the controls. It is reasonable to think of eugenol as a lead molecule in the development of new bioformulates useful in integrated weed management programs.


Assuntos
Echinochloa , Eugenol , Eugenol/farmacologia , Germinação , Plantas Daninhas , Plântula , Sementes
19.
Pest Manag Sci ; 78(1): 287-295, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34482604

RESUMO

BACKGROUND: Florpyrauxifen-benzyl (FPB) is an arylpicolinate herbicide (Group IV) for barnyardgrass control in rice. One susceptible (Sus) and three putative FPB-resistant (R1, R2, and R3) barnyardgrass biotypes were selected based on resistant/susceptible (R/S) ratios obtained from dose-response tests and used to investigate the potential resistance mechanisms. RESULTS: Based on visual control results, the R/S ratios of barnyardgrass biotypes R1, R2, and R3 were 60-, 33-, and 16-fold greater than the Sus standard, respectively. Sequencing results of TIR1 and AFB genes in the tested barnyardgrass revealed no difference between Sus and R barnyardgrass biotypes. Absorption of [14 C]-FPB in Sus barnyardgrass increased over time and reached 90%, which was >10 percentage points greater than that in R biotypes. The [14 C]-FPB absorption in all R barnyardgrass equilibrated after 48 h. For both Sus and R barnyardgrass, most [14 C]-FPB absorbed was present in the treated leaf (79.8-88.8%), followed by untreated aboveground (9.5-18.6%) and belowground tissues (1.3-2.2%). No differences in translocation were observed. Differences between Sus and R barnyardgrass biotypes were found for FPB metabolism. Production of the active metabolite, florpyrauxifen-acid, was greater in Sus barnyardgrass (21.5-52.1%) than in R barnyardgrass (5.5-34.9%). CONCLUSION: In conclusion, reductions in FPB absorption and florpyrauxifen-acid production may contribute to the inability to control barnyardgrass with FPB. © 2021 Society of Chemical Industry.


Assuntos
Echinochloa , Herbicidas , Oryza , Echinochloa/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Folhas de Planta
20.
Pestic Biochem Physiol ; 180: 104999, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34955183

RESUMO

Dose-response experiments were conducted to assess the sensitivity of one susceptible and three putative resistant (R1, R2, and R3) barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] biotypes to florpyrauxifen-benzyl and cyhalofop-butyl alone and as a formulated premix. Subsequently, potential resistance mechanisms of the barnyardgrass were evaluated. Based on biomass reduction results, resistant/susceptible ratios were calculated for R1 (7.0-50), R2 (7.0-150), and R3 (18-214) biotypes. Absorption and translocation of [14C]-florpyrauxifen-benzyl decreased in R1 and R3 biotypes, but not for [14C]-cyhalofop-butyl. The metabolism of [14C]-florpyrauxifen-benzyl to [14C]-florpyrauxifen-acid was >2-fold less in resistant biotypes (9-11%) than in the susceptible biotype (23%). Moreover, the production of [14C]-florpyrauxifen-acid in susceptible barnyardgrass (not in the R biotypes) increased 3-fold when florpyrauxifen-benzyl and cyhalofop-butyl were applied in mixture compared to florpyrauxifen-benzyl applied alone. The tested barnyardgrass biotypes had no mutation in the Transport Inhibitor Response1, auxin-signaling F-box, and acetyl coenzyme A carboxylase genes. Although further studies on cyhalofop-butyl resistance with respect to analysis of specific metabolites are needed, our findings in this study demonstrates that the evolution of florpyrauxifen-benzyl resistance in multiple resistant barnyardgrass can be related to non-target-site resistance mechanisms reducing absorption and translocation of the herbicide and causing reduced conversion or rapid degradation of florpyrauxifen-acid.


Assuntos
Echinochloa , Herbicidas , Butanos , Echinochloa/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Nitrilas/farmacologia
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