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1.
Artigo em Inglês | MEDLINE | ID: mdl-31669662

RESUMO

Tetranychus cinnabarinus (Boisduval) is a major pest that harms crops and vegetables worldwide. Scopoletin is a promising acaricidal compound. Our previous study demonstrated that the acaricidal mechanism of scopoletin may be via disrupting intracellular Ca2+ homeostasis and calcium signaling pathway. However, the mechanism underlying the specific target location of scopoletin against T. cinnabarinus remains unclear. In this study, the full-length cDNA of the calcium channel (TcT-VDCC) gene from T. cinnabarinus was cloned and characterized. The TcT-VDCC gene is expressed at all developmental stages of T. cinnabarinus but is highly expressed in the larval and nymphal stages. The TcT-VDCC gene was significantly upregulated after treatment with scopoletin, and the RNAi method was used to feed the dsRNA in T. cinnabarinus to silence the TcT-VDCC gene and reduce its sensitivity to scopoletin. The results showed that the acaricidal mechanism of scopoletin on T. cinnabarinus may be related to TcT-VDCC.


Assuntos
Acaricidas/farmacologia , Canais de Cálcio/metabolismo , Resistência a Medicamentos/genética , Interferência de RNA , Escopoletina/farmacologia , Tetranychidae/efeitos dos fármacos , Animais , Feminino
2.
J Agric Food Chem ; 67(49): 13544-13549, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31725276

RESUMO

With the ultimate goal of addressing pest-related constraints on global agricultural production, we used combination principles to design and synthesize 2,4-diphenyl-1,3-oxazolines containing a sulfonate moiety at the para-position of the 4-phenyl group. The target compounds, which have strong affinity for lipids and can be expected to traverse cell membranes, were characterized by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry. Their activities against the larvae and eggs of carmine spider mites (Tetranychus cinnabarinus) were determined by a leaf-dipping method and compared with the activity of the commercial acaricide etoxazole. Most of the test compounds displayed good ovicidal and larvicidal activities. In particular, a tert-butylphenyl-substituent compound possessed better larvicidal activity (LC50 = 0.022 ± 0.009 mg/L) and ovicidal activity (0.044 ± 0.020 mg/L) than etoxazole (0.091 ± 0.051 and 0.095 ± 0.059 mg/L, respectively). Given its outstanding bioactivities, this compound deserves further attention as a pesticide candidate.


Assuntos
Acaricidas/química , Acaricidas/farmacologia , Oxazóis/química , Oxazóis/farmacologia , Acaricidas/síntese química , Animais , Desenho de Drogas , Larva/efeitos dos fármacos , Dose Letal Mediana , Estrutura Molecular , Oxazóis/síntese química , Relação Estrutura-Atividade , Ácidos Sulfônicos/química , Tetranychidae/efeitos dos fármacos
3.
J Agric Food Chem ; 67(44): 12182-12190, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31609606

RESUMO

In continuation of our program to develop natural-product-based pesticidal candidates, matrinic/oxymatrinic amides were obtained through structural optimization of matrine. N'-(4-Fluoro)phenyl-N-(4-bromo)phenylsulfonyloxymatrinic amide (IIm) showed potent insecticidal activity against Mythimna separata. N-(Un)substituted phenylsulfonylmatrinic acids (3a-c) exhibited promising acaricidal activity against Tetranychus cinnabarinus. By qRT-PCR analysis of nAChR subunits and AChE genes and determination of AChE activity of (un)treated T. cinnabarinus, it suggested that the open lactam ring of matrine and carboxyl group and (4-methyl)phenylsulfonyl of N-(4-methyl)phenylsulfonylmatrinic acid (3b) were necessary for action with α2, α4, α5, and ß3 nAChR subunits; compound 3b was an inhibitor of AChE in T. cinnabarinus, and AChE was one possible target of action in T. cinnabarinus against 3b; and compound 3b may be an antagonist of nAChR and AChE in T. cinnabarinus.


Assuntos
Acaricidas/química , Alcaloides/química , Amidas/química , Inseticidas/química , Quinolizinas/química , Acaricidas/síntese química , Acaricidas/farmacologia , Acetilcolinesterase/genética , Acetilcolinesterase/metabolismo , Alcaloides/farmacologia , Amidas/farmacologia , Animais , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Inseticidas/síntese química , Inseticidas/farmacologia , Estrutura Molecular , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Quinolizinas/farmacologia , Relação Estrutura-Atividade , Tetranychidae/efeitos dos fármacos , Tetranychidae/genética , Tetranychidae/crescimento & desenvolvimento , Tetranychidae/metabolismo
4.
Artigo em Inglês | MEDLINE | ID: mdl-31254664

RESUMO

Spider mites are destructive arthropod pests on many crops and they have developed resistance to nearly all acaricides. In recent years, along with the application of high throughput sequencing, the molecular mechanisms of mite resistance had made a series of progress. But, the response in molecular level of mite exposure to acaricides, as well as the original mechanism of resistance development was still unclear. To disclose the deeply mechanisms, we used RNA sequencing to analyze the responses of mite exposure to a sublethal concentration (LC30) treatment of the three different action mode acaricides (Abamectin, Fenpropathrin, and Tebufenpyrad). A high number of differentially expressed genes may well be involved in detoxification and regulatory, with extensive overlap in differentially expressed genes between the three insecticide treatments. Two cytochrome P450 genes were co-up-regulated and one glutathione S-transferase genes were co-down-regulated in all the treatments, while carboxylesterase genes only had a response to abamectin. This interesting phenomenon revealed that P450 enzymes play an important role in the early stage of mite exposure to acaricide. Moreover, a P8 nuclear receptor gene was in response to stress caused by exposure to acaricides and RNA interference (RNAi) experiment indicated P8 nuclear receptor regulates the P450 enzyme activity and susceptibility of mites to acaricide. The differential response information of gene expression based on a large-scale sequence would provide some useful clues for studying the molecular mechanisms of mite resistance formation and development.


Assuntos
Acaricidas/toxicidade , Sistema Enzimático do Citocromo P-450/genética , Resistência a Medicamentos/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Tetranychidae/efeitos dos fármacos , Transcrição Genética/efeitos dos fármacos , Acaricidas/metabolismo , Animais , Proteínas de Artrópodes/metabolismo , Inativação Metabólica/genética , Ivermectina/análogos & derivados , Ivermectina/metabolismo , Ivermectina/toxicidade , Proteínas Nucleares/metabolismo , Pirazóis/metabolismo , Pirazóis/toxicidade , Piretrinas/metabolismo , Piretrinas/toxicidade , Receptores Citoplasmáticos e Nucleares/genética , Tetranychidae/genética
5.
Exp Appl Acarol ; 78(3): 343-360, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31250237

RESUMO

Tetranychus urticae Koch is one of the most common and harmful pests in vegetable production areas. Similar to other countries, control of T. urticae is mainly based on acaricides in Turkey. However, T. urticae rapidly develops resistance and failures in chemical control have occurred frequently. The toxicity of various acaricides was investigated in ten T. urticae populations collected from vegetable crops in Turkey. In addition, populations were screened for the presence of currently known target-site resistance mutations. It was shown that resistance to bifenthrin was the most widespread, but also half of the populations were resistant to abamectin and hexythiazox. Resistance mutations in the voltage-gated sodium channel (VGSC) and chitin synthase 1 were found in various populations. Moreover, for the first time, F1538I and L1024V VGSC mutations were reported for Turkish populations. Mutations that confer resistance to abamectin, bifenazate and METI-I acaricides such as pyridaben were not detected. These results will contribute to the design of an effective resistance management program in Turkey.


Assuntos
Acaricidas/farmacologia , Resistência a Medicamentos/genética , Ivermectina/análogos & derivados , Piretrinas/farmacologia , Tetranychidae/efeitos dos fármacos , Tiazolidinas/farmacologia , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Cadeia Alimentar , Ivermectina/farmacologia , Mutação , Tetranychidae/genética , Turquia , Verduras/crescimento & desenvolvimento
6.
J Agric Food Chem ; 67(24): 6708-6715, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31140799

RESUMO

This is the first systemic assessment of the stereoselectivity of etoxazole enantiomers. Etoxazole's stereoselective bioactivity was assessed against target organisms ( Tetranychus urticae eggs and Tetranychus cinnabarinus eggs), and its acute toxicity was assessed toward nontarget aquatic organisms ( Daphnia magna and Danio rerio). Additionally, stereoselective elimination was investigated in three species of fruits (grape and strawberry grown in a greenhouse and apple grown in an open field) and in field soil. The ovicidal activity of (+)-( S)-etoxazole against Tetranychus urticae and Tetranychus cinnabarinus eggs was about 16 and 24 times higher, respectively, than that of (-)-( R)-etoxazole. Inconsistent order of etoxazole isomer toxicity was found toward different aquatic organisms: (+)-( S)-etoxazole showed nearly 8.7 times higher acute toxicity than (-)-( R)-etoxazole toward Daphnia magna, whereas (-)-( R)-etoxazole was ∼4.5 times more toxic to Danio rerio than (+)-( S)-etoxazole. Stereoselective degradation of etoxazole enantiomers showed significant variation in various fruits and field soil. The (+)-( S)-etoxazole was preferentially dissipated in grape and strawberry fruits grown under greenhouse condition, whereas (-)-( R)-etoxazole degraded faster than its antipode in apple fruits and soils under open-field condition. Overall, the stereoselectivity of etoxazole enantiomers should be fully considered in comprehensive environmental health risk in future work.


Assuntos
Acaricidas/química , Acaricidas/toxicidade , Frutas/química , Oxazóis/química , Oxazóis/toxicidade , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Animais , Fragaria/química , Fragaria/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Malus/química , Malus/crescimento & desenvolvimento , Solo/química , Estereoisomerismo , Tetranychidae/efeitos dos fármacos , Vitis/química , Vitis/crescimento & desenvolvimento
7.
Pestic Biochem Physiol ; 156: 105-115, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31027569

RESUMO

Six natural monoterpenes (1,8-cineole, (-)-citronellal, limonene, α-pinene, pulegone and 4-terpineol) showed high acaricidal activity by fumigant and contact actions against adult females of the two-spotted spider mite, Tetranychus urticae Koch. The monoterpenes exhibited varying degrees of acaricidal potency using contact toxicity test after 24 and 48 h of treatment, where the LC50 values were <160 and 45 mg/L, respectively. In fumigation test, of these six monoterpenes, pulegone exhibited the highest toxicity (LC50 = 3.81 mg/L air), while (-)-citronellal had the lowest fumigant toxicity (LC50 = 15.20 mg/L air). All compounds had high inhibitory effect on acetylcholinesterase (AChE) and gama amino butyric acid transaminase (GABA-T) activities. Pulegone was the most AChE inhibitor (IC50 = 8.79 mg/L), while 4-terpineol revealed the lowest inhibitory effect (IC50 = 32.82 mg/L). However, limonene caused the highest inhibition of GABA-T (IC50 = 11.37 mg/L). The molecular docking studies revealed that the compounds displayed different binding interactions with the amino acid residues at the catalytic sites of AChE and GABA-T enzymes. Noncovalent interactions especially van der Waals, hydrogen bonding as well as hydrophobic was found between the compounds and the enzymes. A significant relationship was found between the docking score and the biological activity of monoterpenes compared to the standard acaricide pyridaben. In silico ADMET properties were also performed and displayed potential for the development of good acaricidal candidates.


Assuntos
Monoterpenos/farmacologia , Tetranychidae/efeitos dos fármacos , Animais , Inibidores da Colinesterase/farmacologia , Limoneno/farmacologia , Simulação de Acoplamento Molecular
8.
Exp Appl Acarol ; 77(4): 545-554, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30997606

RESUMO

The acaricide bifenazate acts as complex III inhibitor whereas cyenopyrafen and SYP-9625 act as complex II inhibitors. All these acaricides are commonly used to control two-spotted spider mite (TSSM), Tetranychus urticae Koch. We examined field-evolved and laboratory-selected resistance of TSSM to these three acaricides and determined cross-resistance among them. Six field populations of TSSM showed low levels of resistance to bifenazate with resistance ratios ranging from 2.20 to 10.65 compared to a susceptible strain. SYP-9625, structurally similar to cyenopyrafen, showed slightly higher activity to TSSMs but significant cross-resistance in both field populations and a laboratory-selected strain by SYP-9625. However, low levels of resistance to these two chemicals were found in field populations even when used for short time periods. Cross-resistance was not found between bifenazate and Complex II inhibitors, cyenopyrafen and SYP-9625, in both field populations and the laboratory-selected strain. Field-evolved resistance of TSSM to the tested acaricides is still low and should be delayed by the implementation of resistance management practices. Cross-resistance between cyenopyrafen and SYP-9625 is obvious, so they should not be used together in resistance management strategies based on mode of action rotation.


Assuntos
Acaricidas/farmacologia , Evolução Biológica , Resistência a Medicamentos , Tetranychidae/efeitos dos fármacos , Acrilonitrila/análogos & derivados , Acrilonitrila/farmacologia , Animais , Carbamatos/farmacologia , China , Hidrazinas/farmacologia , Pirazóis/farmacologia , Tetranychidae/fisiologia
9.
Pest Manag Sci ; 75(12): 3226-3234, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30972909

RESUMO

BACKGROUND: A key element of conservation biocontrol is identifying and limiting the use of pesticides that have substantial non-target effects on natural enemies to prevent biocontrol disruption. The Phytoseiidae (predatory mites) are one of the most studied natural enemy groups in the field of pesticide non-target effects. Although there is substantial research on the non-target effects of insecticides on arthropod natural enemies, research on herbicide impacts is limited. Natural enemies, including phytoseiids, associate with weeds due to the presence of alternative prey, shelter, or floral resources. Therefore, a whole-systems approach to integrated pest management should integrate weed management with biocontrol. We conducted a study to examine the non-target effects of vegetable herbicides on Phytoseiulus persimilis Athias-Henriot, and the primary pest that it controls, Tetranychus urticae Koch. Two assays were used to assess the effects of direct application and walking on residues. RESULTS: In both assays, S-metolachlor was highly toxic to P. persimilis (80-90% mortality) and had minimal effect on T. urticae. Dicamba, oxyfluorfen, and napropamide also caused moderate levels of P. persimilis mortality (21-74%). Check mortality of P. persimilis was higher in the direct contact assay (19%) than the residue assay (3%). CONCLUSIONS: Halosulfuron-methyl, flumioxazin, and mesotrione were the most compatible herbicides with biocontrol by P. persimilis, whereas S-metolachlor and napropamide were the least compatible. We also determined that the residue assay may be more useful than direct contact slide-dips for future assessment of herbicide non-target effects. Future efforts should continue to examine the impacts of weed management on natural enemies to better integrate pest management practices. © 2019 Society of Chemical Industry.


Assuntos
Cadeia Alimentar , Herbicidas/efeitos adversos , Herbivoria , Ácaros/efeitos dos fármacos , Comportamento Predatório/efeitos dos fármacos , Animais , Feminino , Resíduos de Praguicidas/efeitos adversos , Tetranychidae/efeitos dos fármacos
10.
J Agric Food Chem ; 67(17): 4782-4792, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30973721

RESUMO

Polyketides represent an important class of biologically active and structurally diverse compounds found in nature. They are biosynthesized from acyl CoA precursors by polyketide synthases (PKSs). The use of combinatorial biosynthesis to form hybrid PKSs is considered to be an excellent approach for the development of novel polyketides. Here, 10 new 16-membered macrolide compounds were isolated from the broth of the genetically engineered strain Streptomyces avermitilis TM24, in which the PKS gene aveA3 was seamlessly replaced by the milbemycin PKS gene milA3. Their structures were elucidated on the basis of NMR and MS spectroscopic analyses. The acaricidal and nematicidal activities of them against Tetranychus cinnabarinus and Bursaphelenchus xylophilus were tested. The results indicated that compound 1 had potent acaricidal activity against adult mites with an LC50 value of 0.0022 mg L-1, while compounds 5 and 7 possessed potent nematicidal activity with LC50 values of 4.56 and 4.30 mg L-1, respectively.


Assuntos
Acaricidas/farmacologia , Antinematódeos/farmacologia , Proteínas de Bactérias/genética , Macrolídeos/farmacologia , Streptomyces/química , Streptomyces/genética , Acaricidas/química , Acaricidas/isolamento & purificação , Acaricidas/metabolismo , Animais , Antinematódeos/química , Antinematódeos/isolamento & purificação , Antinematódeos/metabolismo , Proteínas de Bactérias/metabolismo , Feminino , Engenharia Genética , Macrolídeos/química , Macrolídeos/isolamento & purificação , Macrolídeos/metabolismo , Masculino , Estrutura Molecular , Streptomyces/metabolismo , Tetranychidae/efeitos dos fármacos , Tylenchida/efeitos dos fármacos
11.
Insect Biochem Mol Biol ; 110: 19-33, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31022513

RESUMO

Arthropod herbivores cause dramatic crop losses, and frequent pesticide use has led to widespread resistance in numerous species. One such species, the two-spotted spider mite, Tetranychus urticae, is an extreme generalist herbivore and a major worldwide crop pest with a history of rapidly developing resistance to acaricides. Mitochondrial Electron Transport Inhibitors of complex I (METI-Is) have been used extensively in the last 25 years to control T. urticae around the globe, and widespread resistance to each has been documented. METI-I resistance mechanisms in T. urticae are likely complex, as increased metabolism by cytochrome P450 monooxygenases as well as a target-site mutation have been linked with resistance. To identify loci underlying resistance to the METI-I acaricides fenpyroximate, pyridaben and tebufenpyrad without prior hypotheses, we crossed a highly METI-I-resistant strain of T. urticae to a susceptible one, propagated many replicated populations over multiple generations with and without selection by each compound, and performed bulked segregant analysis genetic mapping. Our results showed that while the known H92R target-site mutation was associated with resistance to each compound, a genomic region that included cytochrome P450-reductase (CPR) was associated with resistance to pyridaben and tebufenpyrad. Within CPR, a single nonsynonymous variant distinguished the resistant strain from the sensitive one. Furthermore, a genomic region linked with tebufenpyrad resistance harbored a non-canonical member of the nuclear hormone receptor 96 (NHR96) gene family. This NHR96 gene does not encode a DNA-binding domain (DBD), an uncommon feature in arthropods, and belongs to an expanded family of 47 NHR96 proteins lacking DBDs in T. urticae. Our findings suggest that although cross-resistance to METI-Is involves known detoxification pathways, structural differences in METI-I acaricides have also resulted in resistance mechanisms that are compound-specific.


Assuntos
Acaricidas/farmacologia , Resistência a Medicamentos/genética , Locos de Características Quantitativas/genética , Tetranychidae/genética , Animais , Mapeamento Cromossômico , Feminino , Locos de Características Quantitativas/efeitos dos fármacos , Seleção Genética , Tetranychidae/efeitos dos fármacos
12.
J Agric Food Chem ; 67(15): 4224-4231, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30905158

RESUMO

Sulfimides and sulfoximines are highly relevant for medicinal chemistry and crop protection, as the resulting products can reveal interesting bioactivities. Herein, we report the design and synthesis of a series of novel 2,4-diphenyl-1,3-oxazolines containing sulfiliminyl and sulfoximinyl moieties. The acaricidal and insecticidal activities of the new compounds were evaluated and indicated that these compounds exhibited excellent acaricidal activities against spider mite larvae and eggs. The LC50 values of 6a-7, 6b-3, 6b-4, 6c-2, and 6c-4 against spider mite larvae were about 4 to 6 times lower than that of the commercial insecticide etoxazole (0.0221 mg L-1), and the LC50 value of 6a-4 against spider mite eggs was 0.0006 mg L-1, which was 10 times lower than that of etoxazole (0.0063 mg L-1). At the same time, most of the compounds showed insecticidal activity though their structure-activity relationships that were different. Oxazolines containing an N-cyano sulfiliminyl moiety at the para position of the 4-phenyl group exhibited better insecticidal activities against cotton bollworm and corn borer than etoxazole, whereas the compounds containing groups derived from sulfiliminyl and sulfoximinyl had weak insecticidal activities. This research again proved that the substituent type at the para site of the 4-phenyl moiety has a decisive role on the biological activity and insecticidal spectrum.


Assuntos
Acaricidas/síntese química , Inseticidas/síntese química , Acaricidas/química , Acaricidas/farmacologia , Animais , Desenho de Drogas , Avaliação de Medicamentos , Inseticidas/química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Estrutura Molecular , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tetranychidae/efeitos dos fármacos , Tetranychidae/crescimento & desenvolvimento
13.
Pest Manag Sci ; 75(10): 2598-2609, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30740869

RESUMO

BACKGROUND: To discover novel natural product-based pesticidal agents for crop protection, a series of N-acyl/sulfonyl derivatives of 5(3,5)-(di)halogenocytisines/cytisine were prepared by structural modifications of cytisine. Their pesticidal activities were evaluated against three typically crop-threatening agricultural pests, Mythimna separata Walker, Tetranychus cinnabarinus Boisduval, and Sitobion avenae Fabricius. RESULTS: Compound 5f exhibited the promising pesticidal activities against three tested pests. All N-phenylsulfonylcytisine derivatives showed potent acaricidal activity. Compound 5j exhibited 2.5-fold more potent acaricidal activity than cytisine, and showed good control effects. Intermediates 2, and 3/3' displayed pronounced aphicidal activity. Some interesting results of structure-activity relationships were also obtained. CONCLUSION: These results demonstrate that compounds 5f and 5j could be further modified as pesticidal agents. © 2019 Society of Chemical Industry.


Assuntos
Acaricidas/farmacologia , Afídeos/efeitos dos fármacos , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Tetranychidae/efeitos dos fármacos , Acaricidas/síntese química , Alcaloides/química , Animais , Azocinas/química , Feminino , Inseticidas/síntese química , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Estrutura Molecular , Mariposas/crescimento & desenvolvimento , Quinolizinas/química
14.
Pest Manag Sci ; 75(10): 2802-2809, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30809924

RESUMO

BACKGROUND: Cyflumetofen is an outstanding acaricide with a novel mode of action. Tetranychus cinnabarinus, an important agricultural pest, is notorious for developing resistance to most classes of acaricides rapidly and results in enormous loss for the economy. Our previous study had pointed out glutathione S-transferase (GSTs) significantly contributed to the cyflumetofen-resistance formation in T. cinnabarinus, but the more specific mechanism needed to be further investigated. RESULTS: The unstable resistance was observed in cyflumetofen-resistant strain (CyR)under acaricide-free condition. The activity of GSTs increased along with the development of resistance. The expressions of 13 GST genes were detected in CyR and susceptible strain (SS), of which six genes were overexpressed in CyR and the TcGSTm02 was selected as the representative for functional study. The expression of TcGSTm02 changed along with the resistant level of CyR with the same trend. Recombinant protein of TcGSTm02 with high activity was successfully obtained by E. coli expression system, whose activity could be inhibited by cyflumetofen (IC50 = 0.23 mM). Recombinant TcGSTm02 could effectively decompose cyflumetofen, and catalyze GS- to conjugate with cyflumetofen. CONCLUSION: All clues confirmed that GSTs strongly associated with cyflumetofen-resistance and a representative gene, TcGSTm02, showed function on contributing the evolution of cyflumetofen-resistance in T. cinnabarinus. © 2019 Society of Chemical Industry.


Assuntos
Acaricidas/farmacologia , Resistência a Medicamentos/genética , Expressão Gênica/efeitos dos fármacos , Glutationa Transferase/genética , Propionatos/farmacologia , Tetranychidae/efeitos dos fármacos , Animais , Feminino , Glutationa Transferase/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Tetranychidae/enzimologia , Tetranychidae/genética
15.
Int J Mol Sci ; 20(3)2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30759791

RESUMO

Neonicotinoids are widely used systemic insecticides that have been associated with spider mite outbreaks on diverse plants. These insecticides have complex effects on plant physiology, which have been speculated to drive enhanced performance of spider mites. We used RNA-Seq to explore how neonicotinoids modify gene expression in soybean thereby lowering plant resistance. We exposed soybean (Glycine max L.) to two neonicotinoid insecticides, thiamethoxam applied to seeds and imidacloprid applied as a soil drench, and we exposed a subset of these plants to spider mites (Tetranychus cinnabarinus). Applications of both insecticides downregulated genes involved in plant-pathogen interactions, phytohormone pathways, phenylpropanoid pathway, and cell wall biosynthesis. These effects were especially pronounced in plants exposed to thiamethoxam. Introduction of spider mites restored induction of genes in these pathways in plants treated with imidacloprid, while expression of genes involved in phenylpropanoid synthesis, in particular, remained downregulated in thiamethoxam-treated plants. Our outcomes indicate that both insecticides suppress genes in pathways relevant to plant⁻arthropod interactions, and suppression of genes involved in cell wall synthesis may explain lower plant resistance to spider mites, cell-content feeders. These effects appear to be particularly significant when plants are exposed to neonicotinoids applied to soybean seeds.


Assuntos
Inseticidas/farmacologia , Neonicotinoides/farmacologia , Soja/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Animais , Parede Celular/efeitos dos fármacos , Parede Celular/genética , Fabaceae/genética , Nitrocompostos/farmacologia , Sementes/genética , Tetranychidae/efeitos dos fármacos , Tiametoxam/farmacologia
16.
Genetics ; 211(4): 1409-1427, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30745439

RESUMO

Pesticide resistance arises rapidly in arthropod herbivores, as can host plant adaptation, and both are significant problems in agriculture. These traits have been challenging to study as both are often polygenic and many arthropods are genetically intractable. Here, we examined the genetic architecture of pesticide resistance and host plant adaptation in the two-spotted spider mite, Tetranychus urticae, a global agricultural pest. We show that the short generation time and high fecundity of T. urticae can be readily exploited in experimental evolution designs for high-resolution mapping of quantitative traits. As revealed by selection with spirodiclofen, an acetyl-CoA carboxylase inhibitor, in populations from a cross between a spirodiclofen-resistant and a spirodiclofen-susceptible strain, and which also differed in performance on tomato, we found that a limited number of loci could explain quantitative resistance to this compound. These were resolved to narrow genomic intervals, suggesting specific candidate genes, including acetyl-CoA carboxylase itself, clustered and copy variable cytochrome P450 genes, and NADPH cytochrome P450 reductase, which encodes a redox partner for cytochrome P450s. For performance on tomato, candidate genomic regions for response to selection were distinct from those responding to the synthetic compound and were consistent with a more polygenic architecture. In accomplishing this work, we exploited the continuous nature of allele frequency changes across experimental populations to resolve the existing fragmented T. urticae draft genome to pseudochromosomes. This improved assembly was indispensable for our analyses, as it will be for future research with this model herbivore that is exceptionally amenable to genetic studies.


Assuntos
Adaptação Fisiológica , Evolução Molecular , Genoma de Inseto , Resistência a Inseticidas/genética , Tetranychidae/genética , 4-Butirolactona/análogos & derivados , 4-Butirolactona/toxicidade , Acetil-CoA Carboxilase/genética , Animais , Especificidade de Hospedeiro , Proteínas de Insetos/genética , Lycopersicon esculentum/parasitologia , NADPH-Ferri-Hemoproteína Redutase/genética , Seleção Genética , Compostos de Espiro/toxicidade , Tetranychidae/efeitos dos fármacos , Tetranychidae/patogenicidade
17.
Pest Manag Sci ; 75(8): 2166-2173, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30653811

RESUMO

BACKGROUND: Increased expression or point mutations of carboxyl/cholinesterases (CCEs) have been involved in many cases of insecticide and acaricide resistance. However, it has been only rarely documented that downregulation of CCE genes is associated with resistance, although many insecticides and acaricides need hydrolytic activation in vivo. Previously, expression analysis of a laboratory-selected cyflumetofen-resistant strain of Tetranychus cinnabarinus indicated that resistance was associated with increased expression of a CCE gene of TcCCE04, but also the downregulation of two CCE genes, TcCCE12 and TcCCE23. RESULTS: Synergism experiments revealed the importance of ester hydrolysis in cyflumetofen toxicity, because treatment with S,S,S-tributylphosphorotrithioate (DEF) caused strong inhibition of cyflumetofen hydrolysis, in both the susceptible and resistant strains. Moreover, silencing expression of TcCCE12 and TcCCE23 via RNAi further decreased the susceptibility of mites to cyflumetofen significantly, suggesting that downregulated CCE genes could be involved in cyflumetofen resistance. In addition, it was shown that recombinant TcCCE12 protein could hydrolyze cyflumetofen effectively. CONCLUSION: Decreased esterase activity via downregulation of specific CCE genes most likely contributes to cyflumetofen resistance by decreased activation of cyflumetofen to its active metabolite. Mixtures of cyflumetofen and esterase-inhibition acaricides (e.g. organophosphates or carbamates) should be avoided in field applications. © 2019 Society of Chemical Industry.


Assuntos
Acaricidas/farmacologia , Resistência a Medicamentos/genética , Propionatos/farmacologia , Tetranychidae/efeitos dos fármacos , Tetranychidae/genética , Animais , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Carboxilesterase/genética , Carboxilesterase/metabolismo , Regulação para Baixo , Feminino
18.
Pest Manag Sci ; 75(7): 1855-1865, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30653814

RESUMO

BACKGROUND: Botanical compounds from plant species are known to have pesticidal activity and have been used in integrated pest management programs. The varied spectrum of the pesticidal action of these compounds can also avoid selection of resistance in pest populations. In this study, mixtures of the botanical compounds geraniol, eugenol and cinnamaldehyde were encapsulated in zein nanoparticles to improve their stability and efficiency. Biological effects of the nano-scale formulations of the botanical compounds were evaluated against two agricultural pests: the two-spotted spider mite (Tetranychus urticae) and the soybean looper (Chrysodeixis includes). RESULTS: The formulations were stable over time (120 days) with a high encapsulation efficiency (>90%). Nanoencapsulation also provided protection against degradation of the compounds during storage and led to a decrease in toxicity to non-target organisms. The release of the compounds (especially eugenol and cinnamaldehyde) from the nanoparticles was directly influenced by temperature, and the main mechanism of release was through a diffusion-based process. Nanoencapsulated compounds also showed superior efficiency compared to the emulsified compounds in terms of repellency and insecticidal activity. CONCLUSION: The findings of this study indicate that the convergence of botanical compounds with nano-scale formulation has the potential to improve efficacy for their sustainable use in integrated pest management in agriculture. © 2019 Society of Chemical Industry.


Assuntos
Acaricidas , Inseticidas , Mariposas/efeitos dos fármacos , Nanopartículas/química , Tetranychidae/efeitos dos fármacos , Zeína/química , Acroleína/análogos & derivados , Acroleína/química , Acroleína/farmacologia , Animais , Linhagem Celular , Cricetulus , Portadores de Fármacos , Eugenol/química , Eugenol/farmacologia , Larva/efeitos dos fármacos , Camundongos , Temperatura Ambiente , Terpenos/química , Terpenos/farmacologia
19.
Pest Manag Sci ; 75(1): 252-261, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29877064

RESUMO

BACKGROUND: Carboxylesterases (CarEs) are important in pesticide resistance. Four overexpressed CarE genes with inducible character were screened out in fenpropathrin-resistant Tetranychus cinnabarinus, but their functional roles remained to be further analyzed by RNAi and protein expression. RESULTS: Feeding a single double-stranded (ds)RNA of each of four genes led to gene-specific downregulation of mRNA, decreased esterase activity and diminished resistance in T. cinnabarinus. More interestingly, feeding four dsRNAs simultaneously led to a more significant decrease in enzymatic activity and fold resistance than feeding a single dsRNA individually, suggesting that these CarE genes were involved in fenpropathrin-resistance and had cooperative roles. The gene CarE6 was regarded as the primary and representative candidate to be functionally expressed, because silencing of CarE6 led to the most significant decrease in resistance level. The activity of CarE6 protein was competitively inhibited by fenpropathrin. It could effectively decompose 41.7 ± 0.09% of fenpropathrin within 3 h, proving that CarE6 protein was capable of metabolizing fenpropathrin effectively in T. cinnabarinus. CONCLUSION: The results confirm that four CarE genes are cooperatively involved in fenpropathrin resistance and the metabolic enzymes encoded by these overexpressed genes do indeed metabolize acaricide in resistant T. cinnabarinus in the evolution of acaricide resistance. © 2018 Society of Chemical Industry.


Assuntos
Acaricidas/farmacologia , Proteínas de Artrópodes/genética , Hidrolases de Éster Carboxílico/genética , Resistência a Medicamentos , Piretrinas/farmacologia , Tetranychidae/genética , Sequência de Aminoácidos , Animais , Proteínas de Artrópodes/química , Proteínas de Artrópodes/metabolismo , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Expressão Gênica , Interferência de RNA , RNA de Cadeia Dupla/farmacologia , Tetranychidae/efeitos dos fármacos , Tetranychidae/fisiologia , Regulação para Cima
20.
Braz J Biol ; 79(2): 273-277, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30088526

RESUMO

The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a'), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.


Assuntos
Acaricidas/farmacologia , Ivermectina/análogos & derivados , Ácaros , Controle Biológico de Vetores/métodos , Tetranychidae , Animais , Ivermectina/farmacologia , Ácaros/efeitos dos fármacos , Ácaros/parasitologia , Ácaros/patogenicidade , Ácaros/fisiologia , Tetranychidae/efeitos dos fármacos , Tetranychidae/parasitologia
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