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1.
PLoS One ; 14(11): e0221646, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31743338

RESUMO

Plant allelochemicals are a group of secondary metabolites produced by plants to defend against herbivore. The mortality of two plant allelochemicals (tannic acid and gossypol) on the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), were investigated using feeding assays and the sublethal effects were evaluated using the age-stage, two-sex life table approach. Tannic acid and gossypol have deleterious effects on A. gossypii, and as the concentrations increased, the mortality of cotton aphid increased. The life history traits of A. gossypii including the developmental duration of each nymph stage, the longevity, oviposition days, total preadult survival rate and adult pre-oviposition period were not significantly affected by sublethal concentration of tannic acid (20 mg/L) and gossypol (50 mg/L), while the population parameters (r, λ and R0) were significantly affected by these two plant allelochemicals. Furthermore, tannic acid can increase the pre-adult duration time and TPOP but reduce the fecundity of A. gossypii significantly compared to the control and gossypol treatment groups. These results are helpful for comprehensively understanding the effects of plant allelochemicals on A. gossypii.

2.
Chemosphere ; 219: 961-970, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30572243

RESUMO

Cytochrome P450 monooxygenases play a key role in herbivorous pest adaptation to host plants by the detoxification against plant allelochemicals. A new P450 gene (CYP4CJ1) was identified from Aphis gossypii, which displayed a positive response to plant allelochemicals. The transcript levels of CYP4CJ1 could be significantly induced by both gossypol and tannic acid. Knockdown of CYP4CJ1 increased the sensitivity of A. gossypii to these two plant allelochemicals. These results suggest that CYP4CJ1 could be involved in the tolerance of A. gossypii to some plant allelochemicals. Subsequently, we examined the regulatory mechanism of CYP4CJ1 based on the transcriptional and post-transcriptional level. A promoter region from -1422 to -1166 of CYP4CJ1 was identified, which was an essential plant allelochemical responsive region. In addition, miR-4133-3p was found to participate in the regulation of CYP4CJ1 post-transcriptionally. Our results suggest that the transcript abundance of CYP4CJ1, following the exposure of A. gossypii to gossypol and tannic acid can be attributed to both the transcriptional and post-transcriptional regulation mechanisms. These results are important for understanding the roles of P450s in the plant allelochemical tolerance of A. gossypii.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Gossipol/química , Taninos/química , Animais
3.
J Econ Entomol ; 112(2): 852-858, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30590572

RESUMO

The cosmopolitan pest Aphis gossypii (Glover) causes considerable economic losses on various crops by its feeding damage and transmitting diseases around the world. Flupyradifurone is a novel butenolide pesticide; its toxicity on A. gossypii parent generation (F0) was estimated following treatment with LC25 concentration for 48 h. The adult longevity and fecundity of the F0 individuals treated by flupyradifurone showed no significant decrease in comparison with the control. Life table method was used to evaluate the sublethal effects on progeny population (F1). Results showed that the development time of the fourth instar and the preadult as well as the total pre-reproductive period were significantly prolonged, while their fecundity was significantly decreased compared with the control. Additionally, the intrinsic rate of increase (r), the finite rate of increase (λ), and the net reproductive rate (R0) of F1 were all significantly lower in the group treated by LC25 than in the control group. These results reveal that the sublethal concentration of flupyradifurone could suppress the population growth of A. gossypii and indicate that this novel insecticide may be as a useful tool in pest management.


Assuntos
Afídeos , Inseticidas , 4-Butirolactona/análogos & derivados , Animais , Fertilidade , Piridinas
4.
Pestic Biochem Physiol ; 141: 1-8, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28911734

RESUMO

Aphis gossypii Glover is a destructive pest of numerous crops throughout the world. Although the expansion of Bt cotton cultivation has helped to control some insect pests, the damage from cotton aphids has not been mitigated. The evolution of aphid resistance to imidacloprid has made its chemical control more difficult since its introduction in 1991. Field populations of A. gossypii that were collected from different transgenic (Bt) cotton planting areas of China in 2014 developed different levels of resistance to imidacloprid. The IMI_R strain has developed high resistance to imidacloprid with the resistance ratio >1200-fold. Compared with the susceptible IMI_S strain, the IMI_R strain also developed a high level cross resistance to sulfoxaflor and acetamiprid. The limited synergism with either PBO or DEF suggests that resistance may be due to the site mutation of molecular target rather than to enhanced detoxification. Three target-site mutations within the nicotinic acetylcholine receptor (nAChR) ß1 subunit were detected in the IMI_R strain. The R81T mutation has been reported to be responsible for imidacloprid resistance in A. gossypii and M. persicae. Both V62I and K264E were first detected in A. gossypii. These point mutations are also present in field populations, suggesting that they play a role in the resistance to imidacloprid. Furthermore, the expression level of transcripts encoding ß1 subunit was decreased significantly in the IMI_R strain compared with the IMI_S strain, suggesting that both point mutations and the down-regulation of nAChR ß1 subunit expression may be involved in the resistance mechanism for imidacloprid in A. gossypii. These results should be useful for the management of imidacloprid-resistant cotton aphids in Bt cotton fields in China.


Assuntos
Afídeos/efeitos dos fármacos , Afídeos/genética , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Mutação Puntual/genética , Receptores Nicotínicos/genética , Sequência de Aminoácidos , Animais , Afídeos/metabolismo , Bioensaio , China , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos
5.
Pest Manag Sci ; 73(11): 2353-2359, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28544677

RESUMO

BACKGROUND: The cotton aphid, Aphis gossypii (Glover), is a destructive pest that affects numerous crops throughout the world. Pyrethroid resistance has become endemic in A. gossypii populations in the cotton growing areas of China due to wide- spread application of insecticides. To assess the extent of pyrethroid resistance, bioassays were conducted on field populations collected from several cotton cultivation areas from 2010 to 2015. The frequency of a known resistance-associated sodium channel mutation (M918 L) in A. gossypii was evaluated and the bioassay of bifenthrin with or without the synergist was performed to illuminate the mechanisms underlying resistance to pyrethroids. RESULTS: The field populations exhibited very high levels of resistance to both beta-cypermethrin and deltamethrin. Pretreatment with synergists, DEF and PBO, significantly increased the toxicity of bifenthrin to cotton aphid populations collected from Bt cotton fields in China. Further, 96.8-100% of individuals with the M918 L mutation (including both RR and RS individuals) were observed in various populations, and only 2.8-3.2% of individuals with wild-type homozygotes (SS) were detected. CONCLUSION: The mutation M918 L in the voltage-gated sodium channel along with detoxifying metabolism was contributed to the pyrethroid resistance in the field populations of Aphis gossypii from cotton growing regions of China. And insecticides with different modes of action should be recommended for the control of A. gossypii in the future. © 2017 Society of Chemical Industry.


Assuntos
Afídeos/efeitos dos fármacos , Resistência a Inseticidas , Inseticidas/farmacologia , Nitrilos/farmacologia , Piretrinas/farmacologia , Animais , Afídeos/enzimologia , Afídeos/genética , Bacillus thuringiensis/genética , China , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Inativação Metabólica , Mutação , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento
6.
Pestic Biochem Physiol ; 138: 71-75, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28456307

RESUMO

Plant allelochemicals are a group of important defensive agents of plants, which have been documented to be deleterious to insect herbivores. In the present study, we found that the expression level of Dicer-1 was significantly increased when Aphis gossypii adults fed on plant allelochemicals (tannic acid and gossypol) incorporated artificial diets. Consider that miRNAs play great regulatory roles in various biological processes, this suggested that miRNAs may be related to the regulation of enzymes involved in metabolism of plant allelochemicals in A. gossypii. To further reveal the roles of miRNAs in the response of A. gossypii against plant allelochemicals, both Dicer-1 and Argonaute-1, an important component of the RNA-induced silencing complex (RISC) in miRNA pathway, were silenced using systemic RNA interference (RNAi). The results indicated that silence of Dicer-1 reduced the expression of miRNAs, and resulted in a high mortality of A. gossypii when fed on both tannic acid and gossypol. The silencing of Argonaute-1 resulted in the mortality of A. gossypii by the treatment of tannic acid significantly increased compared with control, however, the sensitivity of A. gossypii to gossypol was not significantly changed. It suggested that miRNAs play potential regulatory roles in the response of A. gossypii to plant allelochemicals. These results should be useful to understand the molecular mechanisms of the cotton aphid adaption to plant allelochemicals.


Assuntos
Afídeos/metabolismo , Proteínas Argonauta/metabolismo , Proteínas de Insetos/metabolismo , Feromônios/toxicidade , RNA Helicases/metabolismo , Ribonuclease III/metabolismo , Adaptação Fisiológica , Animais , Afídeos/genética , Proteínas Argonauta/genética , Regulação Enzimológica da Expressão Gênica , Proteínas de Insetos/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Estrutura Molecular , Feromônios/química , RNA Helicases/genética , Interferência de RNA , Ribonuclease III/genética
7.
J Econ Entomol ; 110(2): 624-631, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28334129

RESUMO

Aphis gossypii Glover (Hemiptera: Aphididae) can damage a variety of agricultural crops, so it is very important for cotton aphids to evolve adaptive mechanisms to various allelochemicals from host plants. Our results aim to provide a fundamental and rich resource for exploring aphid functional genes in A. gossypii. A transcriptome data set and five expression profile data sets of A. gossypii samples were analyzed by Illumina sequencing platform. In total, 53,763,866 reads were assembled into 1,963,516 contigs and 28,555 unigenes. Compared with the control, 619 genes were significantly up- or downregulated in the treatment group by 2-tridecanone. There were 516, 509, and 717 of differential expression genes in tannic acid, quercetin, and gossypol treatment groups, respectively. Furthermore, there were 4 of 54 putative cytochrome P450 genes and 1 of 7 putative carboxylesterases downregulated in all treatment groups by four plant allelochemicals. When aphids fed on 2-tridecanone, tannic acid, and quercetin, only one P450 gene was upregulated. These results show that plant allelochemical stress can induce differential gene expression in A. gossypii. The differential response information of gene expression based on a large-scale sequence would be useful to reveal molecular mechanisms of adaptation for A. gossypii to plant allelochemicals.


Assuntos
Afídeos/efeitos dos fármacos , Afídeos/genética , Genes de Insetos , Inativação Metabólica/genética , Feromônios/farmacocinética , Animais , Afídeos/fisiologia , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Enzimas/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Inativação Metabólica/efeitos dos fármacos , Anotação de Sequência Molecular , Filogenia , Transcriptoma
8.
BMC Mol Biol ; 18(1): 5, 2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-28202045

RESUMO

BACKGROUND: MicroRNAs (miRNAs) are a group of short non-coding RNAs involved in the inhibition of protein translation or in mRNA degradation. Although the regulatory roles of miRNAs in various biological processes have been investigated, there is as yet an absence of studies about the regulatory roles of miRNAs involved in the metabolism of plant allelochemicals in insects. RESULTS: We constructed five small RNA libraries from apterous Aphis gossypii adults that had fed on an artificial diet containing various allelochemicals. Using Illumina sequencing, a total of 73.27 million clean reads was obtained, and 292 miRNAs were identified from A. gossypii. Comparative analysis of read counts indicated that both conserved and novel miRNAs were differently expressed among the five libraries, and the differential expression was validated via qRT-PCR. We found that the transcript levels of several miRNAs were increased or decreased in all of the allelochemical treatment libraries compared to the control. The putative target genes of the miRNAs were predicted using in silico tools, and the target genes of several miRNAs were presumed to be involved in the metabolism of xenobiotic compounds. Furthermore, the target prediction results were confirmed using dual luciferase reporter assay, and Ago-miR-656a-3p was demonstrated to regulate the expression of CYP6J1 post-transcriptionally through binding to the 3' UTR of CYP6J1. CONCLUSION: Our research results indicate that miRNAs may be involved in the metabolism of plant allelochemicals in A. gossypii, and these results also represent an important new small RNA genomics resource for further studies on this topic.


Assuntos
Afídeos/genética , Regulação da Expressão Gênica , MicroRNAs/genética , Feromônios/metabolismo , Plantas/metabolismo , Animais , Afídeos/fisiologia , Estresse Fisiológico
9.
Ecotoxicology ; 25(10): 1841-1848, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27670668

RESUMO

Sulfoxaflor is a novel insecticide belonging to sulfoximine chemical class that can be used to control sap-feeding insects, notably Aphis gossypii Glover. In addition to its acute toxicity, it is also important to consider the possible sublethal effects when establishing a comprehensive understanding of the toxicity of a new insecticide. We assessed the effects of a low lethal concentration (LC25) of sulfoxaflor on biological parameters of A. gossypii adults (F0) and subsequent transgenerational effects, i.e., on the progeny (F1 generation). The data were analyzed using an age-stage life table procedure. The results showed that the longevity and fecundity were not significantly affected by the LC25 of sulfoxaflor in the F0 or F1 generations. In addition, no significant differences were observed on the developmental time of each instar, the adult pre-oviposition period, and on the longevity of F1 individuals. However, the duration of their pre-adult stage and total pre-oviposition period, as well as their mean generation time were significantly increased. These observed effects affected aphid demographic traits; the survival rate, the intrinsic rate of increase (r i ), the finite rate of increase (λ), the net reproductive rate (R0), and the gross reproduction rate (GRR) of the F1 individuals (i.e., from F0 mothers) were significantly lower compared to the control. Our results showed that sublethal effects of sulfoxaflor significantly slowed down A. gossypii population growth; they indicated that effects of sulfoxaflor might be increased (beyond lethal effect) through sublethal effects when concentrations decreased in sulfoxaflor-treated areas after initial application in field.


Assuntos
Afídeos/efeitos dos fármacos , Inseticidas/toxicidade , Piridinas/toxicidade , Compostos de Enxofre/toxicidade , Testes de Toxicidade , Animais , Fertilidade , Longevidade , Reprodução
10.
J Insect Sci ; 16(1)2016.
Artigo em Inglês | MEDLINE | ID: mdl-28076279

RESUMO

To obtain accurate and reliable results from quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analysis, it is necessary to select suitable reference genes as standards for normalizing target gene expression data. QRT-PCR is a popular analytical methodology for studying gene expression and it has been used widely in studies of Aphis gossypii Glover in recent years. However, there is absence of study on the stability of the expression of reference genes in A. gossypii. In this study, eight commonly used candidate reference genes, including 18S, 28S, ß-ACT, GAPDH, EF1α, RPL7, α-TUB, and TBP, were evaluated under various experimental conditions to assess their suitability for use in the normalization of qRT-PCR data. The optimal number of reference genes was determined using the geNorm program, and the suitability of particular reference genes was empirically validated by performing normalizations of expression data for the HSP70 gene. The results showed the most suitable combinations of reference genes for the different experimental conditions. For experiments based on divergent developmental stages, EF1α, ß-ACT, and RPL7 are the optimal reference gene combination, both EF1α and ß-ACT are the optimal combination used in the experiments of different geographical populations, whereas for experiments of the temperature changes, the combination of GAPDH and RPL7 is optimal, both 18S and ß-ACT are an optimal combination for feeding assay experiments. These research results should be useful for the selection of the suitable reference genes to obtain reliable qRT-PCR data in the gene expression study of A. gossypii.


Assuntos
Afídeos/genética , Perfilação da Expressão Gênica/métodos , Expressão Gênica , Proteínas de Insetos/genética , Animais , Afídeos/crescimento & desenvolvimento , Afídeos/metabolismo , Perfilação da Expressão Gênica/normas , Proteínas de Insetos/metabolismo , Ninfa/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
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