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1.
Ecotoxicol Environ Saf ; 203: 111033, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888611

RESUMO

Diamide insecticides, such as chlorantraniliprole, cyantraniliprole, and tetrachlorantraniliprole, are a new class of insecticides that selectively target insects by affecting calcium homeostasis. While this class of insecticides are effective on a wide range of insect pests, the toxicities of diamide insecticides vary among species and life stages. In this study, we addressed the mechanism underlying the different responses of Plutella xylostella and Pieris rapae to diamide insecticides. The susceptibility to insecticides of P. xylostella and P. rapae larvae was assessed 2 and 4 days after exposure to chlorantraniliprole, cyantraniliprole, and tetrachlorantraniliprole. P. xylostella larvae treated with distilled water (Group A), chlorantraniliprole (Group B), cyantraniliprole (Group C), and tetrachlorantraniliprole (Group D) and P. rapae larvae treated with distilled water (Group E), chlorantraniliprole (Group F), cyantraniliprole (Group G) and tetrachlorantraniliprole (Group H) were subjected to metabolomics analysis. The differential metabolites in the B vs. F, C vs. G, and D vs. H groups were analyzed, followed by pathway enrichment analysis. Chlorantraniliprole, cyantraniliprole, and tetrachlorantraniliprole all showed high toxicities for P. xylostella and P. rapae larvae. P. rapae larvae were more sensitive to the diamide insecticides than P. xylostella larvae. There were 65 overlapped differential metabolites between P. xylostella and P. rapae larvae treated with these three diamide insecticides. Pathway analysis showed that the differential metabolites were closely related with fatty acid biosynthesis and metabolism-related pathways. The differential regulation of fatty acid biosynthesis and metabolism may contribute to the different response to diamide insecticides in P. xylostella and P. rapae.


Assuntos
Borboletas/efeitos dos fármacos , Diamida/farmacologia , Inseticidas/farmacologia , Metaboloma/efeitos dos fármacos , Mariposas/efeitos dos fármacos , Animais , Borboletas/metabolismo , Larva/efeitos dos fármacos , Larva/metabolismo , Mariposas/metabolismo , Especificidade da Espécie
2.
Pestic Biochem Physiol ; 169: 104668, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32828374

RESUMO

Diamondback moth (DBM), Plutella xylostella, is an important pest of crucifers worldwide. The extensive use of flubendiamide has led to the development of resistance in field populations and reports of control failures. In this study, the lab-selected (Rf) and field-collected (Rb) flubendiamide-resistant strains of P. xylostella with LC50 resistance ratios of 1890-fold and 1251-fold, respectively, were used, as well as a lab-reared flubendiamide-susceptible strain (S). The results showed that the fecundity of the Rf and Rb-resistant strains was significantly lower than that of S strain. The contents of vitellin and transcripts of P. xylostella vitellogenin (PxVg) and P. xylostella vitellogenin receptor (PxVgR) genes in the Rf and Rb strains were significantly higher than those of S strains at 0-48 h after adult eclosion. At 96 h after eclosion, the content of vitellin in the Rf and Rb strains did not differ significantly from those of S strains, whereas transcripts of the PxVg and PxVgR genes in the Rf and Rb strains were significantly lower than that of the S strain. The content of the juvenile hormone III (JH III), ß-ecdysone (20E), and the gene expression level of P. xylostella methoprene tolerant (PxMet) in the Rf and Rb strains were significantly higher than that of the S strain. The activity of trehalase was significantly higher in the Rf and Rb strains than that of the S strain in the first to the third instar larvae, whereas in the fourth instar larvae, there was no significantly difference in the three strains. At different times after adult eclosion, the differences in trehalase activity were erratic between the strains. The transcripts of P. xylostella trehalase (PxTre) gene in the Rf and Rb strains were significantly higher than that of the S strain in most developmental stages. Here, we report differences in fecundity between flubendiamide-resistant and susceptible strains of P. xylostella and discuss gene expression of several reproductive factors, which provides a possible explanation for the mechanism of fecundity reduction concurrent with flubendiamide-resistance in P. xylostella.


Assuntos
Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Animais , Benzamidas , Fertilidade/efeitos dos fármacos , Resistência a Inseticidas/efeitos dos fármacos , Larva/efeitos dos fármacos , Sulfonas
3.
PLoS Pathog ; 16(8): e1008697, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776976

RESUMO

The diamondback moth, Plutella xylostella, is a cosmopolitan pest and the first species to develop field resistance to toxins from the gram-positive bacterium Bacillus thuringiensis (Bt). Although previous work has suggested that mutations of ATP-binding cassette transporter subfamily C2 (ABCC2) or C3 (ABCC3) genes can confer Cry1Ac resistance, here we reveal that P. xylostella requires combined mutations in both PxABCC2 and PxABCC3 to achieve high-level Cry1Ac resistance, rather than simply a mutation of either gene. We identified natural mutations of PxABCC2 and PxABCC3 that concurrently occurred in a Cry1Ac-resistant strain (Cry1S1000) of P. xylostella, with a mutation (RA2) causing the mis-splicing of PxABCC2 and another mutation (RA3) leading to the premature termination of PxABCC3. Genetic linkage analysis showed that RA2 and RA3 were tightly linked to Cry1Ac resistance. Introgression of RA2 and RA3 enabled a susceptible strain (G88) of P. xylostella to obtain high resistance to Cry1Ac, confirming that these genes confer resistance. To further support the role of PxABCC2 and PxABCC3 in Cry1Ac resistance, frameshift mutations were introduced into PxABCC2 and PxABCC3 singly and in combination in the G88 strain with CRISPR/Cas9 mediated mutagenesis. Bioassays of CRISPR-based mutant strains, plus genetic complementation tests, demonstrated that the deletion of PxABCC2 or PxABCC3 alone provided < 4-fold tolerance to Cry1Ac, while disruption of both genes together conferred >8,000-fold resistance to Cry1Ac, suggesting the redundant/complementary roles of PxABCC2 and PxABCC3. This work advances our understanding of Bt resistance in P. xylostella by demonstrating mutations within both PxABCC2 and PxABCC3 genes are required for high-level Cry1Ac resistance.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Bactérias/farmacologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Proteínas de Insetos/metabolismo , Resistência a Inseticidas , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/genética , Sequência de Aminoácidos , Animais , Bacillus thuringiensis , Proteínas de Insetos/química , Proteínas de Insetos/genética , Mariposas/química , Mariposas/genética , Mariposas/metabolismo , Mutação , Alinhamento de Sequência
4.
Pestic Biochem Physiol ; 168: 104636, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32711770

RESUMO

Synergism and metabolic studies were conducted to identify the resistance mechanism against indoxacarb in two Choristoneura rosaceana (Harris) field populations compared to a susceptible population. The synergism study was carried out using diet incorporation bioassay for indoxacarb and the three synergists PBO, DEM, and DEF. The metabolic study consists of indoxacarb in vitro reaction with fifth instar larvae 12,000 g midgut supernatant or with pre-inhibited (in vivo by the esterases inhibitor DEF) fifth instar larvae 12,000 g midgut supernatant at different incubation times. In both susceptible and cherry populations, only DEF significantly synergized indoxacarb with a synergism ratio (SR) of 6.5 and 22.6-fold respectively indicating an involvement of esterases in the both populations. In the apple population, all synergists PBO, DEM, and DEF significantly synergized indoxacarb with SR of 9.6, 7.7, and 285.6-fold respectively indicating a complex resistance case with the possible involvement of all three metabolic resistance mechanisms with the central role of esterase enzymes. In vitro, the indoxacarb (DPX-JW062) was very rapidly metabolized within 5 min into small molecules in the lower portion of the metabolic pathway when it reacted with the midgut supernatant of each population. None of the metabolites in the upper portion of the metabolic pathway were detected at any incubation time including the potent sodium channel blocker DCJW metabolite. The two field populations showed significantly higher rates of metabolism of DPX-JW062 compared to the susceptible population at five min of incubation and that may explain the presence of indoxacarb resistance. In the second part of the in vitro study, the bio-transformation of DPX-JW062 was remarkably decreased when it reacted with the pre-inhibited (by DEF) midgut supernatant of each population. Additionally, the degradation of metabolites in the upper portion of the metabolic pathway remarkably decreased, which resulted in accumulation of DCJW and MP819 metabolites. The accumulation of DCJW metabolite under the pre-inhibited midgut supernatants treatment provided a persuasive explanation of the synergistic impact of esterase inhibitor DEF on indoxacarb in C. rosaceana.


Assuntos
Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Animais , Resistência a Inseticidas/efeitos dos fármacos , Oxazinas
5.
Ecotoxicol Environ Saf ; 201: 110828, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531576

RESUMO

Toosendanin (TSN), which is extracted from the root bark of Melia toosendan Siebold and Zuccarini, has multiple modes of action against insects. Especially, this compound has a potent stomach poisoning activity against several lepidoptera pests. In this paper, the signs of toxicity, digestive enzymes activity, the histopathological changes and immuno-electron microscopic localization of TSN in the midgut epithelium of Mythimna separate Walker larvae were investigated for better understanding its action mechanism against insects. The bioassay results indicated that TSN has strong stomach poisoning against the fifth-instar larvae of M. separata (LC50 = 252.23 µg/mL). The typical poisoned symptom were regurgitation and paralysis. Activities of digestive enzymes had no obvious changes after treatment with LC80 dose of TSN. The midgut epithelial cells of insect were damaged by TSN, showing the degeneration of microvilli, hyperplasia of smooth endoplasmic reticulum and condensation of chromatin. Immunohistochemical analysis revealed that the gold particles existed on the microvilli of columnar cells and goblet cells, and gradually accumulated with the exacerbation of poisoning symptoms, showing that TSN targets on the microvilli of the midgutcells. Therefore, TSN acts on digestive system and locates in the microvilli of midgutcells of M. separata.


Assuntos
Sistema Digestório/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Células Epiteliais/efeitos dos fármacos , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Microvilosidades/efeitos dos fármacos , Mariposas/efeitos dos fármacos , Animais , Sistema Digestório/ultraestrutura , Células Epiteliais/ultraestrutura , Microscopia Eletrônica de Transmissão , Microvilosidades/ultraestrutura , Mariposas/crescimento & desenvolvimento
6.
Chemosphere ; 256: 127103, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32447114

RESUMO

The effects of Ajwain essential oil and its major constituents were investigated against newly fourth instar larvae of Tuta absoluta, a major pest of tomato cropping in Iran and other parts of the world. The study included individual efficacy of each compound and determination of their synergistic or antagonistic efficacy. We also determined the activities of detoxifying enzymes in treated insects. According to the results, the Ajwain essential oil and thymol showed the highest toxicity against T. absoluta larvae (LC50 = 6.14 and 7.72 µL/mL, respectively, and LC30 = 3.05 and 3.57 µL/mL, respectively). The ɤ-terpinene and p-cymene had lesser toxicity compared to other compounds. The larvicidal potency increased by binary mixtures of active constituents, such as thymol + p-cymene and thymol + É¤-terpinene. On the other hand, ɤ-terpinene + p-cymene mixture demonstrated antagonistic effect on the larvae. The esterases and glutathione S-transferases were significantly increased in all treatments. Finally, our results revealed a significant inhibition of AChE activity in the treated larvae by all treatments except for ɤ-terpinene + p-cymene. In vitro experiments representing AChE inhibition with IC50 values were recorded 0.370, 0.457, 0.528, 1.094 and 1.323 µL/mL for thymol + p-cymene, thymol + É¤-terpinene, thymol, ɤ-terpinene and p-cymene, respectively. Thymol demonstrated significant potential as a controlling agent of T. absoluta larvae, both larvicidal, compatible with other compounds with strong AChE inhibition properties. These finding could pave the way for development of new botanicals based on EO constituents which should be completed with preparation of an efficient formulation and field trials.


Assuntos
Apiaceae , Lepidópteros/efeitos dos fármacos , Óleos Voláteis/toxicidade , Animais , Carum , Cimenos , Irã (Geográfico) , Larva/efeitos dos fármacos , Lycopersicon esculentum , Mariposas/efeitos dos fármacos , Timol/toxicidade
7.
World J Microbiol Biotechnol ; 36(5): 78, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32409941

RESUMO

Bacillus thuringiensis (Bt) and entomopathogenic fungi (EPF) are in use for management of insect pests. Continuous use of Bt can lead to problem of resistance development in insect pests. Hence use of combination formulations (CF) of microbials with diverse modes of action has been attempted to slow down the process of resistance development. Suspension concentrate (SC) formulations of a local strain of Bt var. kurstaki DOR Bt-127 were developed singly and in combination with conidia of the EPF Nomuraea rileyi (Nr) and Beauveria bassiana (Bb). Electron microscopy of Bt + Bb CF treated larvae of Helicoverpa armigera revealed simultaneous infection by both microbials indicating their compatibility. Endotoxin contents in Bt-SC, Bt + Bb and Bt + Nr CFs were 5.0, 4.7 and 4.7%, respectively. These formulations were effective against larvae of Spodoptera litura, H. armigera and Achaea janata coupled with a lowering of the effective requirement of Bt and EPF. In multi-location field trials, Bt-SC and Bt + Nr CF were highly effective against S. litura and A. janata on castor as well as H. armigera and Thysanoplusia orichalcea on sunflower. However, Bt + Bb CF was highly effective only on sunflower against H. armigera and T. orichalcea. All formulations had 24 months shelf-life at room temperature. DOR Bt-127 based SC formulations developed singly and in combination with Nr and Bb were effective against major lepidopteran pests of castor and sunflower and did not lose viability under storage at room temperature. The CFs of Bt with EPF could prove promising for mitigating resistance development to Bt.


Assuntos
Bacillus thuringiensis/fisiologia , Endotoxinas/farmacologia , Insetos/efeitos dos fármacos , Larva/efeitos dos fármacos , Mariposas/efeitos dos fármacos , Controle Biológico de Vetores/métodos , Animais , Proteínas de Bactérias/farmacologia , Beauveria/fisiologia , Relação Dose-Resposta a Droga , Composição de Medicamentos , Proteínas Hemolisinas/farmacologia , Metarhizium/fisiologia , Esporos Fúngicos
8.
Arch Insect Biochem Physiol ; 104(3): e21676, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32323892

RESUMO

The gut microbiota plays an important role in pheromone production, pesticide degradation, vitamin synthesis, and pathogen prevention in the host animal. Therefore, similar to gut morphology and digestive enzyme activity, the gut microbiota may also get altered under plant defensive compound-induced stress. To test this hypothesis, Dendrolimus superans larvae were fed either aconitine- or nicotine-treated fresh leaves of Larix gmelinii, and Lymantria dispar larvae were fed either aconitine- or nicotine-treated fresh leaves of Salix matsudana. Subsequently, the larvae were sampled 72hr after diet administration and DNA extracted from larval enteric canals were employed for gut microbial 16S ribosomal RNA gene sequencing (338 F and 806 R primers). The sequence analysis revealed that dietary nicotine and aconitine influenced the dominant bacteria in the larval gut and determined their abundance. Moreover, the effect of either aconitine or nicotine on D. superans and L. dispar larvae had a greater dependence on insect species than on secondary plant metabolites. These findings further our understanding of the interaction between herbivores and host plants and the coevolution of plants and insects.


Assuntos
Aconitina/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Mariposas/microbiologia , Nicotina/farmacologia , Animais , Bactérias/classificação , Bactérias/genética , Larix , Larva/efeitos dos fármacos , Larva/microbiologia , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Folhas de Planta , RNA Ribossômico 16S , Salix
9.
Arch Insect Biochem Physiol ; 104(3): e21684, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32329117

RESUMO

The Indian meal moth Plodia interpunctella is a pest of stored products worldwide. Plant-derived essential oils with insecticidal activity could be safe products to control this species. The scarce information about the mode of action of most plant-derived products limits their use for the control of insect pests. Here, we demonstrate that an essential oil distilled from Lippia turbinata ("poleo") has insecticidal activity on P. interpunctella larvae. Furthermore, we performed a comprehensive characterization of P. interpunctella neuroendocrine system, in comparison with other lepidopteran species.


Assuntos
Lippia/química , Mariposas/efeitos dos fármacos , Óleos Vegetais/toxicidade , Animais , Inseticidas , Larva/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Mariposas/fisiologia , Sistemas Neurossecretores
10.
Bull Environ Contam Toxicol ; 104(6): 864-870, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32342111

RESUMO

Fraxinellone is an important botanical lactone compound and has been demonstrated to have insecticidal activity. To provide theoretical support to the assessment on the safety of utilizing fraxinellone as a natural insecticidal agent, the interactions between fraxinellone and armyworm DNA, salmon sperm DNA and calf thymus DNA were investigated using UV-Vis absorption spectroscopy, isothermal titration calorimetry, and molecular docking. Results showed that there were two types of combinations between fraxinellone and three kinds of DNA. Type I combination had an equilibrium constant of combination (Ka1) of about 105 and binding sites (n1) of 0.40-0.70, while type II combination had an equilibrium constant of combination (Ka2) of 103 and binding sites (n2) of 1.35-3.15. Results of molecular docking showed that there were non-classical embedding type interactions between fraxinellone and three kinds of DNA, with the reaction taking place in small groove areas of the DNA structure, resulting in relatively weak interactive forces.


Assuntos
Benzofuranos/química , Agentes de Controle Biológico/química , DNA/química , Inseticidas/química , Animais , Calorimetria , Simulação de Acoplamento Molecular , Mariposas/efeitos dos fármacos , Análise Espectral , Termodinâmica
11.
Arch Insect Biochem Physiol ; 104(3): e21687, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32342573

RESUMO

The economic loss in soybean crops caused by the Lepidoptera insects has encouraged the search for new strategies to control this pest, which are currently based on synthetic insecticides. This paper evaluated the ability of ApTI (Adenanthera pavonina trypsin inhibitor) to inhibit trypsin-like proteins from Anticarsia gemmatalis by docking, molecular dynamics, and enzymatic and survival assay. The docking and molecular dynamic simulation between trypsin and ApTI were performed using the program CLUSPRO and NAMD, respectively. The inhibitory constant Ki and the inhibition type were determined through chromogenic assays. The survival assay of neonatal larvae under treatment with artificial diet supplemented with ApTI was also performed. The ApTI binding site was predicted to block substrate access to trypsin due to four interactions with the enzyme, producing a complex with a surface area of 1,183.7 Å2 . The kinetic analysis revealed a noncompetitive tight-binding mechanism. The survival curves obtained using Kaplan-Meier estimators indicated that the highest larvae mortality was 60%, using 1.2 mg of ApTI per 100 ml of artificial diet. The in vitro, in vivo, and in silico studies demonstrated that ApTI is a strong noncompetitive inhibitor of trypsin with biotechnological potential for the control of A. gemmatalis insect.


Assuntos
Mariposas/efeitos dos fármacos , Proteínas de Plantas/farmacologia , Inibidores da Tripsina/farmacologia , Animais , Fabaceae/química , Larva/efeitos dos fármacos , Larva/enzimologia , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Mariposas/enzimologia , Mariposas/crescimento & desenvolvimento , Tripsina/metabolismo
12.
World J Microbiol Biotechnol ; 36(4): 56, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-32211973

RESUMO

PirAB toxin was initially found in the Photorhabdus luminescens TT01 strain and is a demonstrated binary toxin with high insecticidal activity. In this paper, we co-expressed the pirAB gene of Xenorhabdus nematophila HB310 in a prokaryotic expression system, and we found that the PirAB protein showed high hemocoel insecticidal activity against Galleria mellonella, Helicoverpa armigera and Spodoptera exigua. LD50 values were 1.562, 2.003 and 2.17 µg/larvae for G. mellonella, H. armigera, and S. exigua, respectively (p > 0.05). Additionally, PirAB-interaction proteins were identified from G. mellonella by 6 × His Protein Pulldown combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Of which, arylphorin of G. mellonella showed the highest matching rate. A protein domain conservative structure analysis indicated that arylphorin has three domains including Hemocyanin-N, Hemocyanin-M, and Hemocyanin-C. Among these protein domains, Hemocyanin-C has immune and recognition functions. Further, Hemocyanin-C domain of arylphorin was identified to interact with PirA but not PirB by Yeast two-hybrid system. These findings reveal, for the first time, new host protein interacting with PirAB. The identification of interaction protein may serve as the foundation for further study on the function and insecticidal mechanism of this binary toxin from Xenorhabdus.


Assuntos
Toxinas Bacterianas/farmacologia , Proteínas de Insetos/metabolismo , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Xenorhabdus/metabolismo , Animais , Toxinas Bacterianas/genética , Sítios de Ligação , Cromatografia Líquida , Clonagem Molecular , Proteínas de Insetos/química , Mariposas/classificação , Mariposas/metabolismo , Ligação Proteica , Domínios Proteicos , Espectrometria de Massas em Tandem , Técnicas do Sistema de Duplo-Híbrido , Xenorhabdus/genética
13.
J Insect Sci ; 20(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32061083

RESUMO

Plant tannins, polyphenolic plant secondary metabolites are involved in important chemical defense processes in plants. In this study, tannic acid was used as the standard of plant tannins to determine the effects on nutritional indices and activities of glutathione S-transferases (GSTs), cytochrome P450 monooxygenase (CYP450), carboxylesterase (CarE), and acetylcholinesterase (AChE) in fourth-instar larvae of Hyphantria cunea (Drury) by feeding on an artificial diet containing tannic acid under different treatments. We found that tannic acid significantly affected the digestive capacity and food utilization rate of H. cunea larvae. A tannic acid concentration of less than 2.0% promoted feeding and the utilization of undesirable food by H. cunea larvae, while inhibitory effects were observed at high concentrations (>2.5%). Tannic acid had a significant effect on the activity of detoxification enzymes and AChE in H. cunea larvae in concentration-dependent and time-dependent manners (P < 0.05). These results provide new insights into the potential mechanisms underlying detoxification in H. cunea larvae against tannic acid in host plants.


Assuntos
Mariposas/efeitos dos fármacos , Taninos/farmacologia , Acetilcolinesterase/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Carboxilesterase/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Glutationa Transferase/metabolismo , Inativação Metabólica , Larva/efeitos dos fármacos , Larva/enzimologia , Mariposas/enzimologia , Mariposas/crescimento & desenvolvimento
14.
J Chem Ecol ; 46(3): 308-316, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32016775

RESUMO

Polyphenol oxidases (PPOs) as inducible defense proteins, contribute to tea (Camellia sinensis) resistance against tea geometrid larvae (Ectropis grisescens), and this resistance has been associated with the jasmonic acid (JA) signaling by testing geometrid performance in our previous work. However, the regulation of PPO-based defense by JA and other hormone signaling underlying these defense responses is poorly understood. Here, we investigated the role of phytohormones in regulating the PPO response to tea geometrids. We profiled levels of defense hormones, PPO activity and CsPPO genes in leaves infested with tea geometrids. Then, hormone levels were manipulated by exogenous application of methyl jasmonate (MeJA), gibberellin acid (GA3), abscisic acid (ABA), JA biosynthesis inhibitors (sodium diethyldithiocarbamate trihydrate, DIECA and salicylhydroxamic acid, SHAM) and GA inhibitor (uniconazole, UNI). Upon geometrid attack, JA levels significantly increased, whereas GA levels notably decreased and ABA level was slightly decreased. And the PPO activity significantly increased in line with the transcript levels of CsPPO2 and CsPPO4 but not CsPPO1. There were an obvious antagonistic cross-talk between JA and GA signals and an association among JA signals, PPO response and herbivore resistance in tea plants. Pretreatment with MeJA increased PPO activity by activating the transcripts of CsPPO2 and CsPPO4, whereas application of JA inhibitor DIECA suppressed PPO activity. GA3 strongly enhanced PPO activity, but ABA did not alter PPO activity. These findings strongly suggest that JA is a central player in PPO-mediated tea resistance against tea geometrids in a manner that prioritizes defense over growth.


Assuntos
Antibiose , Camellia sinensis/metabolismo , Catecol Oxidase/metabolismo , Ciclopentanos/metabolismo , Mariposas/fisiologia , Oxilipinas/metabolismo , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismo , Acetatos/metabolismo , Animais , Antibiose/efeitos dos fármacos , Camellia sinensis/efeitos dos fármacos , Ciclopentanos/antagonistas & inibidores , Giberelinas/antagonistas & inibidores , Giberelinas/metabolismo , Herbivoria/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/fisiologia , Mariposas/efeitos dos fármacos , Oxilipinas/antagonistas & inibidores , Transdução de Sinais
15.
Arch Insect Biochem Physiol ; 104(1): e21661, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32011765

RESUMO

Polycalin has been confirmed as a binding protein of the Cry toxins in a few Lepidoptera insects, but its function in the action mechanism of Cry1Ac and whether it is involved in resistance evolution are still unclear. In this study, Ligand blot and enzyme-linked immunosorbent assays showed that Helicoverpa armigera polycalin could specifically interact with Cry1Ac with a high affinity (Kd = 118.80 nM). Importantly, antisera blocking polycalin in H. armigera larvae decreased the toxicity of Cry1Ac by 31.84%. Furthermore, the relative gene and protein expressions were lower in Cry1Ac-resistant strain (LF60) than that in Cry1Ac-susceptible strain (LF). These findings indicated that H. armigera polycalin was a possible receptor of Cry1Ac and may be contributed to the resistance to Cry1Ac.


Assuntos
Inseticidas/farmacologia , Lipocalinas/metabolismo , Mariposas/efeitos dos fármacos , Mariposas/fisiologia , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Endotoxinas/metabolismo , Endotoxinas/farmacologia , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/farmacologia , Proteínas de Insetos , Resistência a Inseticidas/genética , Inseticidas/metabolismo , Mariposas/metabolismo
16.
J Agric Food Chem ; 68(6): 1731-1740, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31951399

RESUMO

Diamide insecticides targeting ryanodine receptors (RyRs) are a major class of pesticides used to control a wide range of agricultural pests, but their efficacies have been reduced dramatically by the recent emergence of resistance mutations. There is a pressing need to develop novel insecticides, targeting distinct and novel binding sites within insect RyRs to overcome the resistance crisis; however, the limited structural information on insect RyRs is a major roadblock to our understanding of their molecular mechanisms. Here, we report the crystal structure of the RyR SPRY2 domain from the diamondback moth (DBM), Plutella xylostella, a destructive agricultural pest worldwide that has developed resistance to all classes of insecticide at 2.06 Å resolution. The overall fold of DBM SPRY2 is similar to its mammalian homolog, but it shows distinct conformations in several loops. Docking it into the recently published cryo-electron microscope structure of the full-length RyR reveals that two insect-specific loops interact with the BSol domain from the neighboring subunit. The SPRY2-BSol interface will change the conformation upon channel gating, indicating that it might be a potential targeting site for insect-specific insecticides. Interestingly, several previously identified disease-causing mutations also lie in the same interface, implying that this interface is important for channel gating. Another insect-specific loop located in the SPRY2-SPRY3 interface might indirectly affect another gating interface between SPRY3 and Repeat34.


Assuntos
Diamida/química , Proteínas de Insetos/química , Inseticidas/química , Mariposas/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/química , Animais , Diamida/farmacologia , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Inseticidas/farmacologia , Simulação de Acoplamento Molecular , Mariposas/química , Mariposas/efeitos dos fármacos , Mariposas/genética , Domínios Proteicos , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo
17.
J Agric Food Chem ; 68(4): 982-988, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31909997

RESUMO

Cycloxaprid (CYC) is effective in the control of hemipteran pests, but its bioactivity against lepidopteran pests is still unclear. Here, the bioactivity of CYC against lepidopteran pests was found to be much worse than that against hemipteran insects. To reveal the mechanism, the transcriptomes of CYC-treated and untreated Ostrinia furnacalis larvae were compared. Among the top 20 differentially expressed genes, 11 encode proteins involved in cuticle formation, while only one encodes a detoxifying enzyme. Thus, the cuticle appears to be important for the insensitivity of O. furnacalis to CYC. A pretreatment of O. furnacalis larvae with methoprene enhanced the bioactivity of CYC by 1.12-fold. Moreover, mixtures of CYC with graphene oxide increased the bioactivity of CYC by 1.88-fold. Because lepidopteran and hemipteran insects often harm crops at the same time, the work can help make full use of CYC and reduce the environmental impacts of using multiple pesticides.


Assuntos
Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/farmacologia , Inseticidas/química , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Piridinas/química , Piridinas/farmacologia , Sequência de Aminoácidos , Animais , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Estrutura Molecular , Mariposas/química , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Alinhamento de Sequência
18.
J Agric Food Chem ; 68(10): 2861-2871, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-31369255

RESUMO

Brazilian organic propolis (BOP) is an unexplored Brazilian propolis that is produced organically and certified according to international legislation. Our results showed that BOP has strong anti-inflammatory effects and acts by reducing nuclear factor κB activation, tumor necrosis factor α release, and neutrophil migration. In addition, BOP6 exhibited antifungal activity on planktonic and biofilm cultures of Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei, and Candida parapsisolis and reduced in vitro yeast cell adhesion to human keratinocytes at sub-inhibitory concentrations. BOP demonstrated significantly low toxicity in Galleria melonella larvae at antifungal doses. Lastly, a chemical analysis revealed the presence of caffeoyltartaric acid, 3,4-dicaffeoylquinic acid, quercetin, and gibberellins A7, A9, and A20, which may be responsible for the biological properties observed. Thus, our data indicate that BOP is a promising source of anti-inflammatory and antifungal molecules that may be used as a functional food.


Assuntos
Anti-Inflamatórios/farmacologia , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Alimento Funcional/análise , Própole/farmacologia , Animais , Anti-Inflamatórios/química , Antifúngicos/química , Biofilmes/efeitos dos fármacos , Brasil , Candida/fisiologia , Testes de Sensibilidade Microbiana , Mariposas/efeitos dos fármacos , Própole/química
19.
Insect Biochem Mol Biol ; 117: 103283, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31759051

RESUMO

Cry protein toxins produced by Bacillus thuringiensis (Bt) are now widely used in sprays and transgenic crops to control insect pests. Most recently, ATP-binding cassette transporter proteins (ABC transporter), including ABCC2, ABCC3, ABCG1, ABCA2 and ABCB1, were reported as putative receptors for different Cry toxins. However, little is known about the regulatory mechanism involved in the expression of these ABC transporter genes. In the present study, a conserved target site of miR-998-3p was identified from the coding sequence (CDS) of ABCC2 in diverse lepidopteran insects. Luciferase reporter assays demonstrated that miR-998-3p could bind to the CDS of ABCC2 and down-regulate its expression through a conserved site and several non-conserved sites in three representative lepidopteran pests, including Helicoverpa armigera, Spodoptera exigua and Plutella xylostella. Injection of miR-998-3p agomir significantly reduced the abundance of ABCC2, accompanied by increased tolerance to Cry1Ac toxin in H. armigera, S. exigua and P. xylostella (Cry-S) larvae, while injection of miR-998-3p antagomir increased the abundance of ABCC2 dramatically, and thereby reduced the Cry1Ac resistance in a Cry1Ac resistant population of P. xylostella (GX-R). These results give a better understanding of the mechanisms of post-transcriptional regulation of ABCC2, and will be helpful for further studies on the role of miRNAs in the regulation of Cry1Ac resistance in lepidopteran pests.


Assuntos
Proteínas de Bactérias/farmacologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , MicroRNAs/metabolismo , Mariposas/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Animais , Proteínas de Insetos/metabolismo , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/crescimento & desenvolvimento , Spodoptera/metabolismo
20.
Arch Insect Biochem Physiol ; 103(4): e21638, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31702074

RESUMO

Clostera anachoreta is one of the important Lepidoptera insect pests in forestry, especially in poplars woods in China, Europe, Japan, and India, and so forth, and also the target insect of Cry1Ac toxin and Bt plants. Six genes, HSC70, GNB2L/RACK1, PNLIP, BI1-like, arylphorin type 2, and PKM were found in this study, and they might be associated with the response to the Cry1Ac toxin, found by analyzing the transcriptome data. And the PI3K-Akt pathway was highly enriched in differentially expressed unigenes and linked to several crucial pathways, including the B-cell receptor signaling pathway, toll-like receptor pathway, and mitogen-activated protein kinase signaling pathway. They might be involved in the recovery stage of the damaged midgut during the response to sublethal doses of Cry1Ac toxin. This is the first study conducted to specifically investigate C. anachoreta response to Cry toxin stress using large-scale sequencing technologies, and the results highlighted some important genes and pathways that could be involved in Btcry1Ac resistance development or could serve as targets for biologically based control mechanisms of this insect pest.


Assuntos
Proteínas de Bactérias/efeitos adversos , Endotoxinas/efeitos adversos , Proteínas Hemolisinas/efeitos adversos , Resistência a Inseticidas/genética , Mariposas/genética , Transcriptoma , Animais , Bacillus thuringiensis/química , China , Trato Gastrointestinal/metabolismo , Perfilação da Expressão Gênica , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo
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