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1.
Molecules ; 26(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199500

RESUMO

In the search of new alternatives for weed control, spices appear as an option with great potential. They are rich in bioactive natural products and edible, which might minimize toxicity hazard. Marjoram (Origanum majorana L.) is an aromatic herb that has been widely employed as a seasoning herb in Mediterranean countries. Although marjoram boasts a plethora of therapeutic properties (painkiller, antibiotic, treatment for intestinal disorders, etc.), the potential for its extracts for weed control is still to be more thoroughly explored. In order to determine their phytotoxic potential, marjoram leaves were subjected to different bioguided extraction processes, using water, ethyl acetate, acetone or methanol. The most active extract (acetone) was sequentially fractionated to identify its most active compounds. This fractionation led to the isolation and identification of 25 compounds that were classified as monoterpenes, diterpenes or flavonoids. Among them, a new compound named majoradiol and several compounds are described in marjoram for the first time. The phytotoxicity of the major compounds to etiolated wheat coleoptiles was compared against that of the commercial herbicide (Logran®), with similar or higher activity in some cases. These results confirm the extraordinary potential of the extracts from this edible plant to develop safer and more environmentally friendly herbicides.


Assuntos
Herbicidas/farmacologia , Origanum/química , Compostos Fitoquímicos/farmacologia , Fracionamento Químico , Flavonoides/química , Flavonoides/farmacologia , Herbicidas/química , Região do Mediterrâneo , Estrutura Molecular , Compostos Fitoquímicos/química , Folhas de Planta/química , Compostos de Sulfonilureia/farmacologia , Terpenos/química , Terpenos/farmacologia , Controle de Plantas Daninhas
2.
J Agric Food Chem ; 69(30): 8415-8427, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34283603

RESUMO

In the present study, we have designed and synthesized a series of 42 novel sulfonylurea compounds with ortho-alkoxy substitutions at the phenyl ring and evaluated their herbicidal activities. Some target compounds showed excellent herbicidal activity against monocotyledon weed species. When applied at 7.5 g ha-1, 6-11 exhibited more potent herbicidal activity against barnyard grass (Echinochloa crus-galli) and crab grass (Digitaria sanguinalis) than commercial acetohydroxyacid synthase (AHAS; EC 2.2.1.6) inhibitors triasulfuron, penoxsulam, and nicosulfuron at both pre-emergence and postemergence conditions. 6-11 was safe for peanut for postemergence application at this ultralow dosage, suggesting that it could be considered a potential herbicide candidate for peanut fields. Although 6-11 and triasulfuron share similar chemical structures and have close Ki values for plant AHAS, a significant difference has been observed between their LUMO maps from DFT calculations, which might be a possible factor that leads to their different behaviors toward monocotyledon weed species.


Assuntos
Herbicidas , Álcoois , Digitaria , Herbicidas/farmacologia , Relação Estrutura-Atividade , Compostos de Sulfonilureia/farmacologia
3.
J Agric Food Chem ; 69(27): 7554-7564, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34196530

RESUMO

Iron is an essential microelement in plants that is involved in several growth processes. The use of herbicides may cause the abnormal aggregation of iron in leaves, but the regulatory mechanisms underlying this phenomenon remain unclear. Here, we show that chiral herbicide (R)-dichlorprop ((R)-DCPP) triggers ferroptosis-like death in Arabidopsis thaliana. (R)-DCPP led to reactive oxygen species (ROS) accumulation and iron aggregation, and these processes were iron dependent. Under (R)-DCPP treatment, ROS, lipid hydrogen peroxides, and malondialdehyde were significantly accumulated. In addition, (R)-DCPP induced the depletion of glutathione, ascorbic acid, and glutathione peroxidase as well as the accumulation of toxic lipid peroxides. Thus, oxidation imbalance led to cell death, and this mode of action could be inhibited by the ferroptosis inhibitor ferrostatin-1 or ciclopirox olamine. NADPH oxidases were found to be involved in herbicide-induced ROS accumulation, and lipoxygenase and NADPH cytochrome P450 oxidase were shown to positively regulate (R)-DCPP-induced lipid peroxidation. Overall, these results indicate that the iron- and ROS-dependent signaling cascades were involved in the (R)-DCPP-induced phytotoxicity pathway, which disrupted the structure of plant cell membranes and triggered ferroptosis. Generally, this study provides new insight into the mechanisms of pesticide phytotoxicity and suggests new therapeutic directions to protect nontarget plants.


Assuntos
Ferroptose , Herbicidas , Ácido 2,4-Diclorofenoxiacético/análogos & derivados , Herbicidas/farmacologia , Peroxidação de Lipídeos , Espécies Reativas de Oxigênio
4.
Pest Manag Sci ; 77(10): 4583-4592, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34087037

RESUMO

BACKGROUND: Wheat growers have limited herbicide options to manage Aegilops cylindrica Host (jointed goatgrass), with many relying on mesosulfuron or imazamox in Clearfield™ winter wheat. Both imazamox and mesosulfuron inhibit acetohydroxyacid synthase/acetolactate synthase (AHAS/ALS). In 2015, a suspected imazamox resistant biotype of Ae. cylindrica was found in eastern Washington. RESULTS: Imazamox and mesosulfuron were applied to the suspected resistant and susceptible Ae. cylindrica biotypes in increasing application rates to evaluate herbicide dose needed to cause 50% growth reduction (GR50 ). The imazamox resistant biotype had a GR50 of 308.5 g ai ha-1 and was more than 5000 times more resistant to imazamox than a known susceptible biotype with a GR50 of 0.06 g ai ha-1 . The Ae. cylindrica resistant biotype was also resistant to mesosulfuron, with an GR50 of 46.82 g ai ha-1 , which was five times more than the susceptible GR50 of 8.6 g ai ha-1 . Sequencing of the AHAS/ALS gene revealed an Ala122 Thr substitution in the herbicide binding region of the AHAS/ALS gene on the D genome of Ae. cylindrica. The resistance trait was inherited as a dominant trait, and the Ala122 Thr co-segregates with the resistance phenotype. CONCLUSIONS: An Ala122 Thr substitution in the AHAS/ALS gene on the D genome of Ae. cylindrica confers resistance to imazamox in Ae. cylindrica. © 2021 Society of Chemical Industry.


Assuntos
Acetolactato Sintase , Aegilops , Herbicidas , Acetolactato Sintase/genética , Esclerose Amiotrófica Lateral , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Imidazóis
5.
Pest Manag Sci ; 77(10): 4648-4657, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34092022

RESUMO

BACKGROUND: Ever since the beginning of agriculture, yields have been threatened by weeds. Chemical weed control is far more effective and economical than other methods. The frequent use of herbicides has led to environmental and human health concerns, resulting in the banning of several herbicides and challenges for the future of important active compounds such as glyphosate. RESULTS: The herbicidal activity of sustainable alternatives based on certain esters of fatty acids (FA), the action of which is unrelated to the free acid, on common weeds is assessed and reported. The 13 derivatives of FA showed better physicochemical properties than pelargonic acid-based herbicides. All the reported compounds have phytotoxic activity, the highest efficacy being displayed by the methyl end-capped polyethylene glycol (mPEG) ester of pelargonic acid having 6EO (ethylene oxide). This mPEG ester showed equal or better phytotoxicity than the pelargonic acid benchmark at reduced application rate and spray volume. The active compound is a liquid at ambient temperatures, has no bad smell and is not volatile, in contrast to pelargonic acid. Notably, this active compound can be the final product, can be sprayed without adjuvants and is relatively easy to co-formulate. CONCLUSION: A new lead substance is presented that is a sustainable alternative to current contact herbicides. In particular, it has potential application on railways, in precision agriculture and as a harvest aid. Its good performance and technical properties suggest this mPEG ester group may also overcome the volatility-related problems of other organic acids such as auxins. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Herbicidas , Controle de Plantas Daninhas , Ésteres , Ácidos Graxos , Resistência a Herbicidas , Herbicidas/farmacologia , Humanos , Plantas Daninhas , Polietilenoglicóis
6.
Pest Manag Sci ; 77(10): 4298-4302, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34148281

RESUMO

BACKGROUND: Hordeum glaucum Steud. is an important grass weed species in South Australia that has evolved resistance to glyphosate. This study investigated the mode of inheritance of glyphosate resistance in this species. RESULTS: Hand-pollination of glyphosate susceptible and resistant populations generated two F1 individuals, selfed to yield F2 progenies. In dose-response experiments, the F2 progenies showed intermediate response between the two parent populations. High variation in EPSPS gene copies was observed among F2 individuals, with some individuals possessing more gene copies than the resistant parent population. No evidence of a Mendelian single-gene pattern of inheritance was observed. CONCLUSION: Inheritance of gene amplification in H. glaucum is non-Mendelian. © 2021 Society of Chemical Industry.


Assuntos
Herbicidas , Hordeum , 3-Fosfoshikimato 1-Carboxiviniltransferase/genética , Amplificação de Genes , Glicina/análogos & derivados , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Hordeum/genética , Humanos , Austrália do Sul
7.
Pest Manag Sci ; 77(10): 4770-4784, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34148282

RESUMO

BACKGROUND: Low toxin doses that do not affect mean responses in plant populations can still change the growth of subpopulations. Studies covering vegetative stages ascribed fast-growing plants higher thresholds for growth stimulation and inhibition, compared with the rest of the population. We hypothesized that such selective effects also play a role after reproduction; that is, the offspring of glyphosate-treated tolerant, fast-growing phenotypes is more tolerant than the offspring of untreated plants. An experimental, high-density barley population was exposed to a range of glyphosate concentrations in the greenhouse, and reproduction and final growth were analyzed for selective effects. Therefore, F0, F1 treated and F1 non-treated offspring were re-exposed to glyphosate. RESULTS: Low doses of glyphosate inhibited the growth and reproduction of slow-growing plants at concentrations that did not change the population mean. Concentrations that inhibited average-sized plants hormetically increased the biomass and seed yield of fast-growing plants. Compared with F0 and F1 non-treated offspring, F1-treated offspring from hormetically stimulated fast-growing plants were more glyphosate tolerant. Hence, a pesticide can shape the reproductive pattern of a plant population and alter offspring tolerance at concentrations that have no effect on average yield. CONCLUSIONS: Toxin levels that do not change the population mean still alter the reproductive output of individuals. Sensitive phenotypes suffer, whereas the reproduction of tolerant phenotypes is boosted compared with toxin-free conditions. Because glyphosate is one of the leading herbicides in the world, tolerant phenotypes may benefit from current agricultural practices. If these results apply to other toxicants, low toxin doses may increase the fitness of tolerant phenotypes in a way not previously anticipated. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Herbicidas , Hordeum , Glicina/análogos & derivados , Glicina/toxicidade , Herbicidas/farmacologia , Humanos , Reprodução
8.
Pest Manag Sci ; 77(10): 4810-4817, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34161662

RESUMO

BACKGROUND: Glyphosate has been used for weed control in South China in various situations for four decades, and most Eleusine indica populations are suspected to have evolved resistance to glyphosate. This research investigated underling target-site glyphosate resistance mechanisms in six field-collected, putative glyphosate-resistant (R) E. indica populations. RESULTS: The six R E. indica populations were confirmed to be low (1.8 to 2.6-fold) to moderately (5.6- to 8.4-fold) resistant to glyphosate relative to the susceptible (S) population. Sixty-seven glyphosate-surviving plants from the six R populations were used to examine target-site resistance mechanisms. Target-site 5-enolpyruvylshikimate3-phosphate synthase (EPSPS) overexpression (OE) (plus further induction by glyphosate treatment) and gene copy number variation (CNV) occurred in 94% R plants, and among them, 16% had the P106A mutation and 49% had the heterozygous double TIPS (T102I + P106S) mutation (plus P381L). In addition, a low number of R plants (6%) only had the homologous TIPS (plus P381L) mutation. The (CT)6 insertion mutation in the EPSPS 5†-UTR always associates with EPSPS OE and CNV. Progeny plants possessing EPSPS OE/CNV (and P106A) displayed low level (up to 4.5-fold) glyphosate resistance. In contrast, plants homozygous for the TIPS mutation displayed higher (25-fold) resistance to glyphosate and followed by plants heterozygous for this mutation plus EPSPS OE/CNV (12-fold). CONCLUSIONS: Target-site glyphosate resistance in E. indica populations from South China is common with prevalence of EPSPS OE/induction/CNV conferring low level resistance. Individual plants acquiring both the TIPS mutation and EPSPS OE/CNV are favored due to evolutionary advantages. The role of (CT)6 insertion mutation in EPSPS CNV is worth further investigation. © 2021 Society of Chemical Industry.


Assuntos
Eleusine , Herbicidas , 3-Fosfoshikimato 1-Carboxiviniltransferase/genética , 3-Fosfoshikimato 1-Carboxiviniltransferase/metabolismo , Variações do Número de Cópias de DNA , Eleusine/genética , Eleusine/metabolismo , Regulação da Expressão Gênica de Plantas , Glicina/análogos & derivados , Resistência a Herbicidas/genética , Herbicidas/farmacologia
9.
Pest Manag Sci ; 77(10): 4785-4798, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34161678

RESUMO

BACKGROUND: In recent years, protoporphyrinogen oxidase (PPO, EC 1.3.3.4) inhibitors have been widely studied as important agricultural herbicides. Our research focused on the design and synthesis of novel PPO inhibitor herbicides, through linking of a diphenylether pyridine bioisostere structure to substituted coumarins, which aims to enhance environmental and crop safety while retaining high efficacy. RESULTS: A total of 21 compounds were synthesized via acylation reactions and all compounds were characterized using infrared, 1 H NMR, 13 C NMR, and high-resolution mass spectra. The respective configurations of compounds IV-6 and IV-12 were also confirmed using single crystal X-ray diffraction. The bioassay results showed that the title compounds displayed notable herbicidal activity, particularly compound IV-6 which displayed better herbicidal activity in greenhouse and field experiments, crop selectivity and safety for cotton and soybean compared with the commercial herbicide oxyfluorfen. CONCLUSION: The work revealed that compound IV-6 deserves further attention as a candidate structure for a novel and safe herbicide. © 2021 Society of Chemical Industry.


Assuntos
Produtos Biológicos , Herbicidas , Cumarínicos/farmacologia , Herbicidas/farmacologia , Protoporfirinogênio Oxidase/metabolismo , Relação Estrutura-Atividade
10.
J Agric Food Chem ; 69(23): 6414-6422, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34081453

RESUMO

The herbicide pyroxasulfone was widely introduced in 2012, and cases of evolved resistance in weeds such as annual ryegrass (Lolium rigidum Gaud.) and tall waterhemp [Amaranthus tuberculatus (Moq.) Sauer] have started to emerge. Pyroxasulfone is detoxified by tolerant crops, and by annual ryegrass that has been recurrently selected with pyroxasulfone, in a pathway that is hypothesized to involve glutathione conjugation. In the current study, it was confirmed that pyroxasulfone is conjugated to glutathione in vitro by glutathione transferases (GSTs) purified from susceptible and resistant annual ryegrass populations and from a tolerant crop species, wheat. The extent of conjugation corresponded to the pyroxasulfone resistance level. Pyroxasulfone-conjugating activity was higher in radicles, roots, and seeds compared to coleoptiles or expanded leaves. Among the GSTs purified from annual ryegrass radicles and seeds, an orthologue of Brachypodium distachyon GSTF13 was >20-fold more abundant in the pyroxasulfone-resistant population, suggesting that this protein could be responsible for pyroxasulfone conjugation.


Assuntos
Herbicidas , Lolium , Glutationa Transferase/genética , Resistência a Herbicidas , Herbicidas/farmacologia , Isoxazóis , Sulfonas
11.
J Agric Food Chem ; 69(23): 6423-6430, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34085526

RESUMO

Nicotinic acid, also known as niacin, is a natural product, which is widely found in plants and animals. To discover novel natural-product-based herbicides, a series of N-(arylmethoxy)-2-chloronicotinamides were designed and synthesized. Some of the new N-(arylmethoxy)-2-chloronicotinamides exhibited excellent herbicidal activity against Agrostis stolonifera (bentgrass) at 100 µM. Compound 5f (2-chloro-N-((3,4-dichlorobenzyl)oxy)nicotinamide) possessed excellent herbicidal activity against Lemna paucicostata (duckweed), with an IC50 value of 7.8 µM, whereas the commercial herbicides clomazone and propanil had values of 125 and 2 µM, respectively. The structure-activity relationships reported in this paper could be used for the development of new herbicides against monocotyledonous weeds.


Assuntos
Herbicidas , Niacina , Herbicidas/farmacologia , Niacina/farmacologia , Niacinamida/análogos & derivados , Plantas Daninhas , Relação Estrutura-Atividade
12.
J Environ Sci Health B ; 56(6): 532-539, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33950786

RESUMO

The addition of carbonaceous material such as cow bonechar to the soil can affect the availability of applied pre-emergent herbicides such as indaziflam. However, how cow bonechar affects the bioavailability of indaziflam is not yet known. The aim of this study was to evaluate the effect of cow bonechar on herbicidal activity of indaziflam on weeds in a tropical soil. Cow bonechar was added homogeneously to top soil, at 1, 2, 5, 10, and 20 t ha-1, in addition to treatment with unamended soil. At 21 days after indaziflam (75 g ha-1) application, injury weed levels, weed species that emerged spontaneously were identified and the weeds present in each sampling unit were collected. Only 1.4 t ha-1 cow bonechar added to soil was enough to reduce the weed injury level by 50%. From the addition of 2 t ha-1 cow bonechar the application of indaziflam was not efficient to weed control, being equivalent to treatments without herbicide application. Eight weed species (3 monocots and 5 dicots) were identified in all treatments. Eleusine indica and Digitaria horizontalis accounted for about 99.7% of the entire infestation of the weed community. Cow bonechar decreases indaziflam pre-emergence herbicidal activity in tropical soil for weed control, most likely due to the high sorption and unavailability of the product in the soil solution.


Assuntos
Osso e Ossos , Herbicidas/química , Herbicidas/farmacologia , Indenos/química , Indenos/farmacologia , Plantas Daninhas/efeitos dos fármacos , Triazinas/química , Triazinas/farmacologia , Animais , Bovinos , Solo , Clima Tropical , Controle de Plantas Daninhas
13.
Pest Manag Sci ; 77(7): 3036-3041, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33942963

RESUMO

While herbicides are the most effective and widely adopted weed management approach, the evolution of multiple herbicide resistance in damaging weed species threatens the yield and profitability of many crops. Weeds accumulate multiple resistance mechanisms through sequential selection and/or gene flow, with long-range and international transport of herbicide-resistant weeds proving to be a serious issue. Metabolic resistance mechanisms can confer resistance across multiple sites of action and even to herbicides not yet discovered. When a new site of action herbicide is introduced to control a key driver weed, it likely will be one of very few effective available herbicide options for that weed in a specific crop due to the continuous use of herbicides over the years and the resulting accumulation of resistance mechanisms, placing it at even higher risk to be rapidly lost to resistance due to the high selection pressure it will experience. The number of available, effective herbicides for certain driver weeds is decreasing over time because the rate of resistance evolution is faster than the rate of new herbicide discovery. Effective monitoring for species movement and diagnostics for resistance should be deployed to rapidly identify emerging resistance to any new site of action. While innovation in herbicide discovery is urgently needed to combat the pressing issue of resistance in weeds, the rate of selection for herbicide resistance in weeds must be slowed through changes in the patterns of how herbicides are used. © 2021 Society of Chemical Industry. © 2021 Society of Chemical Industry.


Assuntos
Herbicidas , Produtos Agrícolas/genética , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Plantas Daninhas/genética , Controle de Plantas Daninhas
14.
J Agric Food Chem ; 69(21): 5830-5839, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34011154

RESUMO

Fenclorim (Fen) is a safener developed for pretilachlor (Pre) that can protect rice from injury caused by Pre but does not lower the weed control effects of Pre. Unfortunately, the mechanism of selective action of Fen between rice and weeds, such as Echinochloa crusgalli (barnyard grass), has not been clarified. In this study, the differences in physiology, biochemistry, and gene transcription between rice and E. crusgalli response to Fen were compared. Comparing the protection effects of Fen on plant growth, it was found that Fen significantly protected rice from Pre, but did not protect E. crusgalli. The detection of malondialdehyde (MDA) content and activities of antioxidant enzymes showed that Pre induced significant oxidative damage both in rice and E. crusgalli; however, Fen reduced oxidative damage in rice but not in E. crusgalli. Transcriptome analysis revealed that Fen induced more genes related to herbicide metabolism in rice than in E. crusgalli, especially the glutathione-S-transferase (GST) genes, with six upregulated in rice but no genes upregulated in E. crusgalli. Accordingly, the GST activity analysis showed that Fen increased the activity of rice instead of E. crusgalli. These results indicate that the elevation of detoxifying enzyme activities and antioxidative defense may be the mechanism of selective action of Fen in rice but not in E. crusgalli.


Assuntos
Echinochloa , Herbicidas , Oryza , Antioxidantes , Echinochloa/genética , Herbicidas/farmacologia , Oryza/genética , Pirimidinas
15.
J Agric Food Chem ; 69(20): 5734-5745, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-33999624

RESUMO

Exploring novel p-hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) inhibitors has become one of the most promising research directions in herbicide innovation. On the basis of our tremendous interest in exploiting more powerful HPPD inhibitors, we designed a family of benzyl-containing triketone-aminopyridines via a structure-based drug design (SBDD) strategy and then synthesized them. Among these prepared derivatives, the best active 3-hydroxy-2-(3,5,6-trichloro-4-((4-isopropylbenzyl)amino)picolinoyl)cyclohex-2-en-1-one (23, IC50 = 0.047 µM) exhibited a 5.8-fold enhancement in inhibiting Arabidopsis thaliana (At) HPPD activity over that of commercial mesotrione (IC50 = 0.273 µM). The predicted docking models and calculated energy contributions of the key residues for small molecules suggested that an additional π-π stacking interaction with Phe-392 and hydrophobic contacts with Met-335 and Pro-384 were detected in AtHPPD upon the binding of the best active compound 23 compared with that of the reference mesotrione. Such a molecular mechanism and the resulting binding affinities coincide with the proposed design scheme and experimental values. It is noteworthy that inhibitors 16 (3-hydroxy-2-(3,5,6-trichloro-4-((4-chlorobenzyl)amino)picolinoyl)cyclohex-2-en-1-one), 22 (3-hydroxy-2-(3,5,6-trichloro-4-((4-methylbenzyl)amino)picolinoyl)cyclohex-2-en-1-one), and 23 displayed excellent greenhouse herbicidal effects at 150 g of active ingredient (ai)/ha after postemergence treatment. Furthermore, compound 16 showed superior weed-controlling efficacy against Setaria viridis (S. viridis) versus that of the positive control mesotrione at multiple test dosages (120, 60, and 30 g ai/ha). These findings imply that compound 16, as a novel lead of HPPD inhibitors, possesses great potential for application in specifically combating the malignant weed S. viridis.


Assuntos
4-Hidroxifenilpiruvato Dioxigenase , Herbicidas , 4-Hidroxifenilpiruvato Dioxigenase/metabolismo , Aminopiridinas , Inibidores Enzimáticos/farmacologia , Herbicidas/farmacologia , Ácidos Fenilpirúvicos , Plantas Daninhas/metabolismo , Relação Estrutura-Atividade
16.
Pest Manag Sci ; 77(9): 4109-4116, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33914407

RESUMO

BACKGROUND: Beckmannia syzigachne (Steud.) Fernald has become a dominant weed that has evolved resistance to major herbicides used in the wheat fields of rice-wheat double cropping areas of the middle and lower reaches of the Yangtze River, China. Seed dispersal occurs over long distances via irrigation water. As mechanical harvesting services popularize, there is concern that combine harvesters could play an increasing role in B. syzigachne seed dispersal. RESULTS: Random sampling of 30 combine harvesters at wheat harvest determined that an average of 8000 B. syzigachne seeds remain in the combine after wheat harvesting, predominantly on the metal plate. These seeds could potentially be transported into adjacent fields. A double exponential model predicted that seeds remaining on the metal plate could be dispersed over 7885 m2 into the next field. Within a field, the number of fallen seeds and their dispersal distance were positively correlated to panicle density. Combines spread seeds away from the source potentially creating new weed patches. During irrigation and rotary tillage ploughing, 70% of B. syzigachne seeds scattered in the field floated on the water surface and were moved away by the wind. CONCLUSION: Both wheat combine harvesters and water flow effectively spread B. syzigachne seeds. Areas with high B. syzigachne population density should be carefully harvested separately, and the metal plate should be carefully cleaned to prevent spreading the weed across fields and region. Floating B. syzigachne seeds displaced to field edges by water can be physically removed with nets to prevent further distribution by water.


Assuntos
Herbicidas , Dispersão de Sementes , Resistência a Herbicidas , Herbicidas/farmacologia , Poaceae , Sementes , Triticum
17.
J Agric Food Chem ; 69(26): 7388-7398, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-33909432

RESUMO

Weeds are one of the main factors that affect the yield and quality of rice. The combination of glyphosate-resistant transgenic crops and glyphosate is regarded as an important strategy for weed management in modern agriculture. In this study, a codon-optimized glyphosate oxidase gene WBceGO-B3S1 from a variant BceGO-B3S1 and a glyphosate-tolerant gene I. variabilis-EPSPS* from the bacterium Isoptericola variabilis were transformed into an Oryza sativa subsp. geng rice variety Zhonghua11 by Agrobacterium-mediated genetic transformation. Molecular detection and field agronomic trait analysis contributed to the selection of three homozygous lines with stable expression of a single copy of the transferred genes integrated into the intergenic region. Under the treatment of glyphosate at a test amount in the field, transgenic lines exhibited no differences in agronomic traits. Under the treatment by 3600 g ha-1 glyphosate, the glyphosate residues in the aboveground tissues of the three candidate transgenic homozygous lines were significantly lower than those in the transgenic homozygous line with I. variabilis-EPSPS* alone at 1, 5, and 10 days. The transgenic line coexpressing I. variabilis-EPSPS* and WBceGO-B3S1 has great application value in breeding of transgenic rice varieties with high glyphosate resistance and low glyphosate residues. This study is a step forward in solving the problem of herbicide residues in food crops by taking advantage of genes that degrade glyphosate.


Assuntos
Herbicidas , Oryza , 3-Fosfoshikimato 1-Carboxiviniltransferase/genética , Actinobacteria , Glicina/análogos & derivados , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Oryza/genética , Melhoramento Vegetal , Plantas Geneticamente Modificadas/genética
18.
Pest Manag Sci ; 77(7): 3042-3048, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33817955

RESUMO

Farmers need to manage weeds to grow and harvest crops that are essential to our food and energy supply, and herbicides are the most important tool in the farmers' armory to combat weeds. There is now a crisis in agriculture that has been brought about by herbicides being rendered ineffective by resistant weeds or withdrawn from the market due to safety concerns. Efficacious herbicides with novel modes of action (MoAs) and chemotypes are urgently needed to control resistant weeds and satisfy public and regulators' stringent requirements for safe and sustainable products. This article explores the main strategies being deployed by academic and industrial institutions to discover the next generation of commercial herbicides: phenotypic and in vitro target based approaches. There are early signs that much needed innovation and herbicidal products with novel MoAs are on the horizon from start-ups and established agrochemical companies. © 2021 Society of Chemical Industry. © 2021 Society of Chemical Industry.


Assuntos
Herbicidas , Produtos Agrícolas , Resistência a Herbicidas , Herbicidas/farmacologia , Plantas Daninhas , Controle de Plantas Daninhas
19.
Pest Manag Sci ; 77(7): 3049-3056, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33821561

RESUMO

Herbicides are the largest category of pesticides used in global agriculture, which is reflected in the rate of increase in the number of unique cases of herbicide-resistant weed biotypes since the late 1950s. Recommended herbicide resistance management strategies and tactics have evolved over the past 50 years through cumulative research and experience and have been regularly reviewed. Nevertheless, new perspectives may be gained by viewing current recommended strategies through the lens of insecticide, fungicide, and antibiotic resistance management. What commonalities exist and what is the basis for disparate strategies? Although pesticide and antibiotic mixtures (or combinations) are generally more effective than rotations (or alternations) in mitigating or managing resistance, the latter strategy is often employed because of greater ease of implementation and other reasons. We conclude that there are more common than different strategies for mitigating or managing pesticide and antibiotic resistance. Overall, a reduction in selection pressure for resistance evolution through diverse multi-tactic management programmes, and disruption or mitigation of the dispersal or transmission of problematic genotypes are needed to sustain the longevity of current and future mode-of-action products for crop and human health protection. © 2021 Society of Chemical Industry. © 2021 Society of Chemical Industry.


Assuntos
Fungicidas Industriais , Herbicidas , Inseticidas , Antibacterianos/farmacologia , Fungicidas Industriais/farmacologia , Resistência a Herbicidas , Herbicidas/farmacologia , Humanos , Plantas Daninhas , Controle de Plantas Daninhas
20.
Pestic Biochem Physiol ; 174: 104811, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33838713

RESUMO

Isoxazole, nicotinic acid and benzoic acid are important components in many natural products and useful synthons to build macrostructures having valuable biological activities. In continuation of our effort to discover 4-hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) inhibitors and search for active fragments from natural products, a series of substituted aryl-formyl piperidinone derivatives with natural product fragments was rationally designed, synthesized and tested for their herbicidal activity. Compound I-9 was considered the most effective candidate with an IC50 value of 0.260 µM. The molecular docking results showed that the triketone group of compound I-9 forms a bidentate complex with a metal ion, and the benzene ring interacted with Phe424 and Phe381 via π-π stacking, which was similar to the mechanisms of mesotrione. The present work indicates that compound I-9 may serve as a potential lead compound for further development of green HPPD inhibitors.


Assuntos
Herbicidas , Inibidores Enzimáticos/farmacologia , Herbicidas/farmacologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade
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