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1.
J Agric Food Chem ; 67(39): 10844-10852, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31525997

RESUMO

The discovery of 4-hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) inhibitors has been an active area of research due to their great potential as herbicides for weed control. Starting from the binding mode of known inhibitors of HPPD, a series of HPPD inhibitors with new molecular scaffolds were designed and synthesized by hybridizing 2-benzoylethen-1-ol and isoindoline-1,3-dione fragments. The results of the in vitro tests indicated that the newly synthesized compounds showed good HPPD inhibitory activity with IC50 values against the recombinant Arabidopsis thaliana HPPD (AtHPPD) ranging from 0.0039 µM to over 1 µM. Most promisingly, compound 4ae, 2-benzyl-5-(5-hydroxy-1,3-dimethyl-1H-pyrazole-4- carbonyl)isoindoline-1,3-dione, showed the highest AtHPPD inhibitory activity with a Ki value of 3.92 nM, making it approximately 10 times more potent than pyrasulfotole (Ki = 44 nM) and slightly more potent than mesotrione (Ki = 4.56 nM). In addition, the cocrystal structure of the AtHPPD-4ae complex was successfully resolved at a resolution of 1.8 Å. The X-ray diffraction analysis indicated that the two carbonyl groups of 2-benzoylethen-1-ol formed a bidentate chelating interaction with the metal ion, while the isoindoline-1,3-dione moiety formed pronounced π-π stacking interactions with Phe381 and Phe424. Moreover, water-mediated hydrogen bonding interactions were observed between Asn282 and the nitrogen atoms of the pyrazole ring of 4ae. The above results showed that the pyrazole-isoindoline-1,3-dione hybrid is a promising scaffold for developing HPPD inhibitors.


Assuntos
4-Hidroxifenilpiruvato Dioxigenase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Herbicidas/farmacologia , Isoindóis/farmacologia , Proteínas de Plantas/antagonistas & inibidores , Pirazóis/farmacologia , 4-Hidroxifenilpiruvato Dioxigenase/química , 4-Hidroxifenilpiruvato Dioxigenase/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/crescimento & desenvolvimento , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Herbicidas/síntese química , Herbicidas/química , Isoindóis/química , Cinética , Estrutura Molecular , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/crescimento & desenvolvimento , Pirazóis/química , Relação Estrutura-Atividade
2.
Pestic Biochem Physiol ; 158: 143-148, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378350

RESUMO

Chinese sprangletop (Leptochloa chinensis (L.) Nees) is one of the most troublesome grass weeds in rice in China. Seven suspected cyhalofop-butyl-resistant L. chinensis populations were collected from different rice fields with a history of cyhalofop-butyl use. The level of resistance and resistance mechanisms in seven populations were studied. Dose-response tests indicated that five populations (JS3, JS4, JS6, JS7 and JS8) had evolved high-level resistance (26.9 to 123.0-fold) to cyhalofop-butyl compared with the susceptible (S) population, and other two populations (JS2 and JS5) were still sensitive to the herbicide. Two acetyl-coenzyme A carboxylase (ACCase) genes were cloned from each population, and three different ACCase mutations (Ile-1781-Leu, Trp-1999-Cys, and Trp-2027-Cys) in ACCase2 gene were determined in different resistant (R) populations. In addition, no resistance-conferring mutations was detected in the R population (JS7), and ACCase gene expression was similar between the S and R populations. Thus, non-target-site resistance mechanisms may be involved in the JS7 population. Moreover, the patterns of cross-resistance of JS6 (Ile-1781-Leu), JS4 (Trp-1999-Cys), JS8 (Trp-2027-Cys), and JS7 (unknown resistance mechanisms) populations to other ACCase-inhibiting herbicides were determined. The JS6 and JS8 populations showed resistance to fenoxaprop-P-ethyl, metamifop, clethodim and pinoxaden, the JS4 population was resistant to fenoxaprop-P-ethyl, metamifop and pinoxaden, and the JS7 population had resistance only to fenoxaprop-P-ethyl and metamifop. These results indicated the diversity of the target-site mutations in ACCase gene of L. chinensis, and provide a better understanding of cross-resistance in L. chinensis, which would be helpful for the management of cyhalofop-butyl-resistant L. chinensis.


Assuntos
Acetil-CoA Carboxilase/metabolismo , Butanos/farmacologia , Herbicidas/farmacologia , Nitrilos/farmacologia , Poaceae/metabolismo , Acetil-CoA Carboxilase/genética , China , Resistência a Herbicidas/genética , Poaceae/efeitos dos fármacos
3.
Pestic Biochem Physiol ; 159: 17-21, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31400779

RESUMO

Capsella bursa-pastoris is a serious broadleaf weed in winter wheat fields in China. It has evolved high levels of resistance to acetolactate synthase (ALS) inhibiting herbicides and has caused substantial losses of wheat yield in recent years. We monitored the herbicide resistance of Capsella bursa-pastoris collected from 18 regions of Shandong Province in 2009, 2013 and 2017, respectively. Compared with the 2009 populations, the number of populations resistant to florasulam had increased in 2013 and 2017. Resistance to tribenuron-methyl increased in 2013, but decreased in 2017. The 2009 and 2013 populations developed resistance only to tribenuron-methyl, but some 2017 populations developed cross-resistance to imazethapyr and florasulam as well. Mutations in ALS (Pro-197-Thr/Ser/His/Arg/Leu/Gln) were identified in the 2009 and 2013 populations; however, two ALS mutations (Pro197 and/or Trp574) were identified in 2017 plants. Meanwhile, plants containing both point mutations (Pro197 + Trp574) were identified in the 2017 populations. This study demonstrated that target site gene mutations were the main reason for Capsella bursa-pastoris resistance to ALS-inhibiting herbicides. Although target-site mutation is the reason for resistance to ALS-inhibiting herbicides in Capsella bursa-pastoris, the resistance patterns and mutations identified have changed over time.


Assuntos
Acetolactato Sintase/genética , Capsella/efeitos dos fármacos , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Proteínas de Plantas/genética , Sulfonatos de Arila/farmacologia , Capsella/enzimologia , Capsella/genética , Mutação/genética , Ácidos Nicotínicos/farmacologia , Mutação Puntual/genética , Pirimidinas/farmacologia , Sulfonamidas/farmacologia
4.
Pestic Biochem Physiol ; 159: 80-84, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31400787

RESUMO

The plastid acetyl coenzyme carboxylase (ACCase) Trp1999Leu mutation was identified in a Beckmannia syzigachne population resistant to fenoxaprop-p-ethyl. The pattern of cross-resistance for the Trp1999Leu mutation is still ambiguous. In this paper, mutant homozygote (1999Leu/Leu, RR) and wild type (1999Trp/Trp, SS) B. syzigachne plants with the same genetic background were purified from the JS-26 population using the dCAPS method. The activity of ACCase in RR and SS was determined. Then, the cross-resistance pattern to ACCase inhibiting herbicides of the Trp1999Leu mutation was determined using the whole-plant method. ACCase activity showed that the Trp1999Leu mutation decreased ACCase sensitivity to fenoxaprop-p-ethyl by 2.73-fold. A dose-response experiment indicated that the Trp1999Leu mutation conferred high resistance to quizalofop-p-ethyl (20.29-fold), metamifop (12.22-fold) and pinoxaden (18.60-fold), moderate resistance to fenoxaprop-p-ethyl (8.20-fold) and sethoxydim (6.38-fold), low resistance to cyhalofop-butyl (2.73-fold) and no resistance to clodinafop-propargyl (1.42 fold) and clethodim (1.59-fold). This is the first report of the role of Trp1999Leu in fenoxaprop-p-ethyl resistance and of the patterns of cross-resistance to ACCase-inhibiting herbicides in B. syzigachne.


Assuntos
Acetil-CoA Carboxilase/genética , Herbicidas/farmacologia , Poaceae/efeitos dos fármacos , Poaceae/genética , Anilidas/farmacologia , Benzoxazóis/farmacologia , Cicloexanonas/farmacologia , Resistência a Herbicidas/genética , Compostos Heterocíclicos com 2 Anéis/farmacologia , Mutação/genética , Propionatos/farmacologia , Piridinas/farmacologia , Quinoxalinas/farmacologia
5.
J Agric Food Chem ; 67(37): 10489-10497, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31452371

RESUMO

In order to develop a novel herbicide containing the ß-triketone motif, a series of 4-hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one derivatives were designed and synthesized. The bioassay results showed that compound II15 had good pre-emergent herbicidal activity even at a dosage of 187.5 g ha-1. Moreover, compound II15 showed a broader spectrum of weed control when compared with a commercial herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), and displayed good crop safety to Triticum aestivum L. and Zea mays Linn. when applied at 375 g ha-1 under pre-emergence conditions, which indicated its great potential as a herbicide. More importantly, studying the molecular mode of action of compound II15 revealed that the novel triketone structure is a proherbicide of its corresponding phenoxyacetic acid auxin herbicide, which has a herbicidal mechanism similar to that of 2,4-D. The present work indicates that the 4-hydroxyl-3-(2-phenoxyacetyl)-pyran-2-one motif may be a potential lead structure for further development of novel auxin-type herbicides.


Assuntos
Herbicidas/síntese química , Herbicidas/farmacologia , Plantas Daninhas/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Desenho de Drogas , Herbicidas/química , Estrutura Molecular , Plantas Daninhas/crescimento & desenvolvimento , Relação Estrutura-Atividade , Controle de Plantas Daninhas , Zea mays/efeitos dos fármacos
7.
J Agric Food Chem ; 67(36): 10010-10017, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31414816

RESUMO

Dominican farmers have started to apply synthetic auxin herbicides (SAHs) as the main alternative to mitigate the impacts of the occurrence of glyphosate-resistant (GR) Parthenium hysterophorus populations in citrus orchards. A GR P. hysterophorus population survived field labeled rates of glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), dicamba, and picloram, which showed poor control (<50%). In in vivo assays, resistance levels were high for glyphosate and moderate for picloram, dicamba, and 2,4-D. Sequencing the 5-enolpyruvylshikimate-3-phosphate synthase gene revealed the double Thr-102-Ile and Pro-106-Ser amino acid substitution, conferring resistance to glyphosate. Additionally, reduced absorption and impaired translocation contributed to this resistance. Regarding SAH, impaired 2,4-D transport and enhanced metabolism were confirmed in resistant plants. The application of malathion improved the efficacy of SAHs (control >50%), showing that metabolism of these herbicides was mediated by cytochrome P450 enzymes. This study reports, for the first time, multiple resistance to SAHs and glyphosate in P. hysterophorus.


Assuntos
Asteraceae/efeitos dos fármacos , Citrus/crescimento & desenvolvimento , Glicina/análogos & derivados , Resistência a Herbicidas , Herbicidas/farmacologia , Ácidos Indolacéticos/farmacologia , Ácido 2,4-Diclorofenoxiacético/metabolismo , Ácido 2,4-Diclorofenoxiacético/farmacologia , Asteraceae/metabolismo , Dicamba/metabolismo , Dicamba/farmacologia , Glicina/metabolismo , Glicina/farmacologia , Herbicidas/metabolismo , Ácidos Indolacéticos/metabolismo
8.
J Agric Food Chem ; 67(33): 9254-9264, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31356740

RESUMO

In continuation of our search for potent protoporphyrinogen IX oxidase (PPO, EC 1.3.3.4) inhibitors, we designed and synthesized a series of novel herbicidal cycloalka[d]quinazoline-2,4-dione-benzoxazinones. The bioassay results of these synthesized compounds indicated that most of the compounds exhibited very strong Nicotiana tabacum PPO (NtPPO) inhibition activity. More than half of the 37 synthesized compounds displayed over 80% control of all three tested broadleaf weeds at 37.5-150 g ai/ha by postemergent application, and a majority of them showed no phytotoxicity toward at least one kind of crop at 150 g ai/ha. Promisingly, 17i (Ki = 6.7 nM) was 6 and 4 times more potent than flumioxazin (Ki = 46 nM) and trifludimoxazin (Ki = 31 nM), respectively. Moreover, 17i displayed excellent, broad-spectrum herbicidal activity, even at levels as low as 37.5 g ai/ha, and it was determined to be safe for wheat at 150 g ai/ha in postemergent application, indicating the great potential for 17i development as a herbicide for weed control in wheat fields.


Assuntos
Benzoxazinas/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Herbicidas/química , Herbicidas/farmacologia , Proteínas de Plantas/antagonistas & inibidores , Protoporfirinogênio Oxidase/antagonistas & inibidores , Quinazolinas/química , Benzoxazinas/farmacologia , Desenho de Drogas , Cinética , Proteínas de Plantas/química , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/enzimologia , Protoporfirinogênio Oxidase/química , Relação Quantitativa Estrutura-Atividade , Quinazolinas/farmacologia , Tabaco/efeitos dos fármacos , Tabaco/enzimologia , Controle de Plantas Daninhas
9.
J Agric Food Chem ; 67(28): 7783-7792, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31267752

RESUMO

The increasing use of pesticides in agriculture and gardening has caused severe deterioration to both the ecosystem and the health of users (human beings), so there is an urgent need for eco- and user-friendly pesticides. Among a variety of herbicides, paraquat (PQ), frequently used as an effective herbicidal agent worldwide, is well-known for its serious toxicity that has killed, and harmed, thousands of people and countless wildlife such as fish. Herein, we present a facile supramolecular formulation of PQ@cucurbit[7]uril (PQ@CB[7]), prepared by simply mixing PQ with equivalent (molar) CB[7] in water. With addition of CB[7], PQ's cellular uptake was dramatically inhibited. The reactive oxygen species (ROS) generation and the associated apoptosis otherwise induced by PQ in cellular models were both reduced, resulting in increased cellular viability. In a wildtype zebrafish model that is a typical fragile wildlife species in the ecosystem, the supramolecular formulation exhibited significantly reduced hepatotoxicity and increased survival rate, in comparison with those of the fish exposed to free PQ. In a mouse model that is clinically relevant to human being, the administration of PQ@CB[7] significantly alleviated major organ injuries and unusual hematological parameters that were otherwise induced by free PQ, resulting in a significantly increased survival rate. Meanwhile, this formulation maintained effective herbicidal activity that was equivalent to that of free PQ. Taken together, this facile supramolecular PQ formulation is providing not only an extremely rare example of an eco- and user-friendly herbicide that has been desired for decades but also a practical solution for green agriculture.


Assuntos
Herbicidas/farmacologia , Paraquat/farmacologia , Animais , Apoptose/efeitos dos fármacos , Química Verde , Herbicidas/síntese química , Herbicidas/química , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Estresse Oxidativo/efeitos dos fármacos , Paraquat/síntese química , Paraquat/química , Poaceae/efeitos dos fármacos , Poaceae/crescimento & desenvolvimento , Peixe-Zebra/metabolismo
10.
J Agric Food Chem ; 67(29): 8085-8095, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31265279

RESUMO

Herbicide resistance identification is essential for effective chemical weed control. In this study, we quantified the differences in growth response between penoxsulam resistant (R) and sensitive (S) Echinochloa crus-galli populations, explored the changes in ALS, and performed genetic analyses to identify metabolic genes that are up-regulated by the application of penoxsulam and other common herbicides. The R population showed a 26.0-fold higher resistance to penoxsulam and varied resistance to most tested herbicides with indices ranging from 4.9 to 145.9. A Trp-574-Arg amino acid mutation in ALS and low penoxsulam ALS sensitivity were the main mechanisms underlying herbicide resistance. The penoxsulam resistance can be significantly reversed by two P450s inhibitors and one GST inhibitor. By RNA-Seq, thirty-six highly expressed contigs were selected, and 30 of them were up-regulated in the R population treated by penoxsulam. Many of these genes were significantly expressed when treated with pyroxsulam, metamifop, and quinclorac. These upregulated genes appear to be complementary for plant resistance to penoxsulam and other common herbicides.


Assuntos
Echinochloa/efeitos dos fármacos , Resistência a Herbicidas , Herbicidas/farmacologia , Sulfonamidas/farmacologia , Uridina/análogos & derivados , Acetolactato Sintase/genética , Acetolactato Sintase/metabolismo , Echinochloa/genética , Echinochloa/crescimento & desenvolvimento , Echinochloa/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Uridina/farmacologia
11.
Chemosphere ; 233: 905-912, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340418

RESUMO

We investigated the interconnected roles of reactive oxygen species (ROS) generated upon seed exposure to glyphosate and/or gibberellic acid (GA3), and the possible interaction between the herbicide and the plant hormone during germination of sorghum seeds. GA3 decreased antioxidant enzyme activity in embryos, and the over accumulation of hydrogen peroxide (H2O2) in 1000 mM GA3-treated seeds resulted in the lowest germinability among treatments. The deleterious effects of glyphosate on germination rate, in contrast, were not related to H2O2 accumulation, but to its interference with the mitochondrial electron transport chain. However, interactions among glyphosate, GA3 and H2O2 during seed germination were observed. Similar to paclobutrazol, glyphosate appears to interfere with the de novo synthesis of gibberellin, which modulates seed germination through oxidative metabolism. Seeds experiencing increased oxidative status due to GA3 (100 mM) or H2O2 (50 mM) applications had the effects of glyphosate on germination rate reversed. Since decreased ATP synthesis is a secondary effect of glyphosate, increased H2O2 concentrations in embryos must facilitate germination by decreasing the energy required by ATP-demanding metabolism. Our results showed that glyphosate affect seed germination of sorghum, and that the herbicide interacts with oxidative and gibberellin metabolisms.


Assuntos
Germinação/efeitos dos fármacos , Giberelinas/metabolismo , Glicina/análogos & derivados , Herbicidas/farmacologia , Peróxido de Hidrogênio/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Sorghum/metabolismo , Antioxidantes/metabolismo , Grão Comestível/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Glicina/farmacologia , Sementes/efeitos dos fármacos
12.
Environ Sci Pollut Res Int ; 26(25): 26216-26228, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31286378

RESUMO

The use of allelopathic compounds is an alternative for weeds control, since they present low toxicity when compared with the synthetic herbicides, that may cause several damages, as the contamination of the environment. Our objective was to determine the chemical composition and allelopathic properties of the essential oils of Psidium cattleianum, P. myrtoides, P. friedrichsthalianum, and P. gaudichaudianum on the germination and root growth of Lactuca sativa and Sorghum bicolor, and to evaluate their action on the cell cycle of root meristematic cells of L. sativa. The main compound found in all the studied species was (E)-caryophyllene (P. cattleianum-23.4 %; P. myrtoides-19.3%; P. friedrichsthalianum-24.6% and P. gaudichaudianum-17.0%). The different essential oils were tested at different concentrations on L. sativa and S. bicolor, reducing germination, germination speed index, and root and shoot growth of lettuce and sorghum seedlings. The cytotoxicity and aneugenic potential of these oils were evidenced by the reduction of the mitotic index and increase of the frequency of chromosomal alterations in L. sativa. The essential oils of the species of Psidium studied have potential to be used in weeds control.


Assuntos
Germinação/efeitos dos fármacos , Herbicidas/farmacologia , Alface/efeitos dos fármacos , Meristema/química , Óleos Voláteis/química , Óleos Vegetais/farmacologia , Psidium/química , Plântula/efeitos dos fármacos , Sorghum/química , Alelopatia , Herbicidas/química , Alface/química , Compostos Fitoquímicos , Psidium/efeitos dos fármacos , Sesquiterpenos
13.
Anal Bioanal Chem ; 411(21): 5531-5543, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31201458

RESUMO

Single cell-inductively coupled plasma-mass spectrometry (SC-ICP-MS) is an emerging technology. In this work, we have developed a novel SC-ICP-MS method to quantify metal ions in individual cells of a toxic cyanobacterial species, Microcystis aeruginosa (M. aeruginosa), without complicated post-dosing sample preparation, and applied this method to study the treatment effectiveness of copper-based algaecides (cupric sulfate and EarthTec®) on the toxic algae M. aeruginosa. The developed SC-ICP-MS method uses new intrinsic metal element magnesium to determine real transport efficiency and cell concentration. The cell viability and microcystin-LR release by algaecide treatment were studied by flow cytometry and ultra-fast liquid chromatography-tandem mass spectrometry, respectively. The results showed that this novel method was very rapid, highly sensitive (detection limits of intracellular copper and magnesium were 65 ag/cell and 98 ag/cell, respectively), and reproducible (relative standard deviation within 12%). The algaecide effectiveness study further demonstrated that copper in the forms of cupric sulfate and copper-based algaecide EarthTec® successfully diminished M. aeruginosa populations. The higher the copper concentration used to treat the cells, the faster the speeds of copper uptake and cell lysis in the copper concentrations ranged from 0 to 200 µg/L of copper-based algaecide. The cells exhibit obvious heterogeneity in copper uptake. The result suggests that M. aeruginosa cells uptake and cumulate copper followed by cellular lysis and microcystin-LR release. These novel results indicated that though the copper-based algaecides could control this type of harmful algal bloom, further treatment to remove the released algal toxin from the treated water would be needed. Graphical abstract.


Assuntos
Cobre/química , Herbicidas/farmacologia , Microcystis/efeitos dos fármacos , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida/métodos , Cobre/análise , Cobre/metabolismo , Citometria de Fluxo , Herbicidas/análise , Herbicidas/química , Limite de Detecção , Reprodutibilidade dos Testes
14.
Fitoterapia ; 136: 104183, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31150767

RESUMO

Diterpenoids are the main secondary metabolites of plants and with a range of biological activities. In the present study, 7 compounds were isolated from the hulls of rice (Oryza sativa L.). Among them, 3 diterpenoids are new namely, 3,20-epoxy-3α-hydroxy- 8,11,13-abietatrie-7-one (1), 4,6-epoxy-3ß-hydroxy-9ß-pimara-7,15-diene (2) and 2-((E)-3- (4-hydroxy-3-methoxyphenyl) allylidene) momilactone A (3). While, 4 terpenoids are known, namely momilactone A (4), momilactone B (5), ent-7-oxo-kaur-15-en-18-oic acid (6) and orizaterpenoid (7). The structures of these diterpenoids were elucidated using 1D and 2D NMR in combination with ESI-MS and HR-EI-MS. Furthermore, all isolated compounds displayed antifungal activities against four crop pathogenic fungi Magnaporthe grisea, Rhizoctonia solani, Blumeria graminearum and Fusarium oxysporum, and phytotoxicity against paddy weed Echinochloa crusgalli. The results suggested that rice could produce plenty of secondary metabolites to defense against weeds and pathogens.


Assuntos
Diterpenos/farmacologia , Fungicidas Industriais/farmacologia , Herbicidas/farmacologia , Oryza/química , Sementes/química , Diterpenos/isolamento & purificação , Echinochloa/efeitos dos fármacos , Fungicidas Industriais/isolamento & purificação , Herbicidas/isolamento & purificação , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia
15.
Mycorrhiza ; 29(4): 341-349, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31190279

RESUMO

The extraradical mycelium (ERM) produced by arbuscular mycorrhizal fungi is fundamental for the maintenance of biological fertility in agricultural soils, representing an important inoculum source, together with spores and mycorrhizal root fragments. Its viability and structural traits, such as density, extent and interconnectedness, which are positively correlated with the growth and nutrition of host plants, may be affected by different agronomic practices, including the use of pesticides and by different mycorrhizospheric communities. This work, carried out using a whole-plant experimental model system, showed that structural traits of ERM, such as length and density, were strongly decreased by the herbicides dicamba and glufosinolate and the fungicides benomyl and fenhexamid, while anastomosis frequency and hyphal branching were differentially modulated by singly inoculated mycorrhizospheric bacteria, depending on their identity.


Assuntos
Fenômenos Fisiológicos Bacterianos , Chicória/microbiologia , Fungicidas Industriais/farmacologia , Glomeromycota/efeitos dos fármacos , Glomeromycota/crescimento & desenvolvimento , Herbicidas/farmacologia , Micélio/crescimento & desenvolvimento , Micorrizas/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Benomilo/farmacologia , Chicória/crescimento & desenvolvimento , Dicamba/farmacologia , Hifas/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Micélio/efeitos dos fármacos , Micorrizas/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação , Esporos Bacterianos/fisiologia
16.
Pestic Biochem Physiol ; 157: 53-59, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153477

RESUMO

Indian hedge mustard (Sisymbrium orientale) (IHM) is an important broadleaf weed across southern Australia. Resistance to sulfonylurea (SU) herbicides that inhibit acetohydroxyacid synthase (AHAS) is extensive in Australia, but resistance to imidazolinone (IMI) herbicides has only been reported recently. The AHAS-mutation profile of 65 IHM populations collected randomly from cropped fields was investigated to better understand the extent and types of resistance present. Resistance to SU herbicides was present in 40% of the populations and resistance to IMI herbicides in 11%. Mutations were identified in SoAHAS by sequence analysis, and included previously reported amino-acid substitutions at Pro197 and Trp574, but also new substitutions at Pro197 and Asp376 for this species. One population with possible non-target-site resistance was identified. Germination studies with fresh seed found no significant effect by mutations in SoAHAS on germination; however, population factors had a large effect on germination in S. orientale. Resistance to AHAS-inhibiting herbicides in populations of S. orientale is endowed by mutations in SoAHAS in all but one population examined. Mutations at Pro197 conferring resistance to SU herbicides were most common, while mutations at Trp574 that provide resistance to IMI herbicides are also present.


Assuntos
Acetolactato Sintase/genética , Herbicidas/farmacologia , Mostardeira/genética , Mutação/genética , Austrália , Germinação/efeitos dos fármacos , Germinação/genética , Mostardeira/efeitos dos fármacos
17.
Pestic Biochem Physiol ; 157: 60-68, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153478

RESUMO

A series of novel substituted oxazole isoxazole carboxamides derivatives were designed on the basis of active subunit combination. Forty-four novel compounds were synthesized by an efficient one-pot procedure under microwave irradiation. The bioactivity was evaluated as herbicide safener against the injury of chlorsulfuron. It was found that most of the synthesized compounds displayed remarkable protection against chlorsulfuron via enhanced glutathione content and glutathione S transferase activity. Especially compound I-11 exhibited better bioactivity than the safeners isoxadifen-ethyl and R-28725. Molecular docking simulations suggested that the target compounds could compete with chlorsulfuron in the active site of acetolactate synthase, which could explain the protective effects of safeners. The present work demonstrates that the target compounds containing oxazole isoxazole groups could be considered as potential candidates for developing novel safeners in the future.


Assuntos
Herbicidas/química , Herbicidas/farmacologia , Isoxazóis/química , Oxazóis/química , Sulfonamidas/farmacologia , Triazinas/farmacologia , Acetolactato Sintase/genética , Acetolactato Sintase/metabolismo , Ativação Enzimática/efeitos dos fármacos , Glutationa/metabolismo , Glutationa Transferase/metabolismo , Relação Estrutura-Atividade , Zea mays/enzimologia
18.
J Environ Sci Health B ; 54(7): 615-621, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31116075

RESUMO

The application of minimal doses of herbicides is very popular due to concerns about the negative impacts of herbicides on the environment and public health. Studies were conducted to estimate the possibility of using quick and non- destructive methods to investigate Chenopodium album L. and Abutilon theophrasti Medik. response to mesotrione. The studies were conducted in a controlled environment to determine the response of C. album and A. theophrasti to mesotrione using dose-response curves created based on plant dry weight, chlorophyll fluorescence parameters and chlorophyll content. The obtained effective dose values showed that the studied weeds were susceptible to reduced doses of mesotrione. ED95 values estimated for both species for dry weight and chlorophyll fluorescence parameters were lower than the recommended dose rate (120 g a.i. ha-1), with less than 85 g a.i. ha-1 needed to achieve a reduction of 95%, compared with untreated plants, while ED95 value (A. theophrasti: 182 g a.i. ha-1 and C. album: 180 g a.i. ha-1) for chlorophyll content for both species was above the recommended dose rates. Consequently, dry weight and the chlorophyll fluorescence parameters are suitable for estimating the plant response to mesotrione, while chlorophyll content is not.


Assuntos
Chenopodium album/efeitos dos fármacos , Cicloexanonas/farmacologia , Herbicidas/farmacologia , Malvaceae/efeitos dos fármacos , Chenopodium album/metabolismo , Clorofila/metabolismo , Cicloexanonas/administração & dosagem , Relação Dose-Resposta a Droga , Herbicidas/administração & dosagem , Malvaceae/metabolismo , Plantas Daninhas/efeitos dos fármacos
19.
J Agric Food Chem ; 67(31): 8431-8440, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067047

RESUMO

Glufosinate-resistant Lolium perenne L. spp. multiflorum biotypes from Oregon exhibited resistance levels up to 2.8-fold the field rate. One resistant biotype (MG) had an amino acid substitution in glutamine synthetase 2 (GS2), whereas the other (OR) exhibited the wild-type genotype. We hypothesized that the amino acid substitution in GS2 is involved in the resistance mechanism in MG and that non-target site resistance mechanisms are present in OR. OR metabolized glufosinate faster than the other two biotypes, with >75% of the herbicide metabolized in comparison to 50% in MG and the susceptible biotype. A mutation in GS2 co-segregating with resistance in MG did not reduce the enzyme activity, with results further supported by our enzyme homology models. This research supports the conclusion that a metabolism mechanism of glufosinate resistance is present in OR and that glufosinate resistance in MG is not due to an altered target site.


Assuntos
Aminobutiratos/metabolismo , Glutamato-Amônia Ligase/metabolismo , Resistência a Herbicidas , Herbicidas/metabolismo , Lolium/enzimologia , Proteínas de Plantas/metabolismo , Substituição de Aminoácidos , Aminobutiratos/farmacologia , Glutamato-Amônia Ligase/genética , Herbicidas/farmacologia , Isoenzimas/genética , Isoenzimas/metabolismo , Lolium/efeitos dos fármacos , Lolium/genética , Lolium/metabolismo , Mutação , Oregon , Proteínas de Plantas/genética
20.
J Agric Food Chem ; 67(20): 5736-5745, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31042035

RESUMO

As a potent herbicide capable of contaminating water and soil environments, paraquat, which is still widely used worldwide, is toxic to mammals, algae, aquatic animals, etc. Paraquat was loaded on novel nanoparticles composed of pectin, chitosan, and sodium tripolyphosphate (PEC/CS/TPP). The size, polydispersity index, and ζ potential of nanoparticles were characterized. Further assessments were carried out by SEM, AFM, FT-IR, and DSC. The encapsulation was highly efficient, and there was a delayed release pattern of paraquat. The encapsulated herbicide was less toxic to alveolar and mouth cell lines. Moreover, the mutagenicity of the formulation was significantly lower than those of pure or commercial forms of paraquat in a Salmonella typhimurium strain model. The soil sorption of paraquat and the deep soil penetration of the nanoparticle-associated herbicide were also decreased. The herbicidal activity of paraquat for maize or mustard was not only preserved but also enhanced after encapsulation. It was concluded that paraquat encapsulation with PEC/CS/TPP nanoparticles is highly efficient and the formulation has significant herbicide activity. It is less toxic to human environment and cells, as was evidenced by less soil sorption, cytotoxicity, and mutagenicity. Hence, paraquat-loaded PEC/CS/TPP nanoparticles have potential advantages for future use in agriculture.


Assuntos
Quitosana/química , Composição de Medicamentos/métodos , Herbicidas/química , Mutagênicos/química , Nanopartículas/química , Paraquat/química , Pectinas/química , Polifosfatos/química , Adsorção , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Herbicidas/farmacologia , Herbicidas/toxicidade , Humanos , Cinética , Mostardeira/efeitos dos fármacos , Mostardeira/crescimento & desenvolvimento , Mutagênicos/farmacologia , Mutagênicos/toxicidade , Paraquat/farmacologia , Paraquat/toxicidade , Tamanho da Partícula , Solo/química , Poluentes do Solo/química , Poluentes do Solo/farmacologia , Poluentes do Solo/toxicidade , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento
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