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1.
J Agric Food Chem ; 69(45): 13425-13435, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34748318

RESUMO

Adaptation to phytochemicals in herbivorous insects can influence tolerance to insecticides. However, it is unclear how insects use phytochemicals as cues to activate their metabolic detoxification systems. In this study, we found that dietary exposure to xanthotoxin enhanced tolerance of Spodoptera litura larvae to λ-cyhalothrin. Xanthotoxin ingestion significantly elevated the mRNA levels of 35 detoxification genes as well as the transcription factors Cap 'n' collar isoform-C (CncC) and its binding factor small muscle aponeurosis fibromatosis isoform-K (MafK). Additionally, xanthotoxin exposure increased the levels of reactive oxygen species (ROS), while ROS inhibitor N-acetylcysteine (NAC) treatment blocked xanthotoxin-induced expression of CncC, MafK, and detoxification genes and also prevented xanthotoxin-enhanced larval tolerance to λ-cyhalothrin. The 20-hydroxyecdysone (20E) signaling pathway was effectively activated by xanthotoxin, while blocking of 20E signaling transduction prevented xanthotoxin-enhanced larval tolerance to λ-cyhalothrin. Application of 20E induced the expression of multiple xanthotoxin-induced detoxification genes and enhanced λ-cyhalothrin tolerance in S. litura. NAC treatment blocked xanthotoxin-induced 20E synthesis, while the CncC agonist curcumin activated the 20E signaling pathway. These results indicate that the ROS/CncC pathway controls the induction of metabolic detoxification upon exposure to xanthotoxin, at least in part, through its regulation of the 20E signaling pathway.


Assuntos
Ecdisterona , Inseticidas , Animais , Proteínas de Insetos/metabolismo , Inseticidas/farmacologia , Larva/genética , Larva/metabolismo , Metoxaleno , Nitrilas , Piretrinas , Espécies Reativas de Oxigênio , Transdução de Sinais , Spodoptera/genética , Spodoptera/metabolismo
2.
J Vis Exp ; (175)2021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-34633386

RESUMO

Stable insertion of genetic cargo into insect genomes using transposable elements is a powerful tool for functional genomic studies and developing genetic pest management strategies. The most used transposable element in insect transformation is piggyBac, and piggyBac-based germline transformation has been successfully conducted in model insects. However, it is still challenging to employ this technology in non-model insects that include agricultural pests. This paper reports on germline transformation of a global agricultural pest, the fall armyworm (FAW), Spodoptera frugiperda, using the hyperactive piggyBac transposase (hyPBase). In this work, the hyPBase mRNA was produced and used in place of helper plasmid in embryo microinjections. This change led to the successful generation of transgenic FAW. Furthermore, the methods of screening transgenic animals, PCR-based rapid detection of transgene insertion, and thermal asymmetric interlaced PCR (TAIL-PCR)-based determination of the integration site, are also described. Thus, this paper presents a protocol to produce transgenic FAW, which will facilitate piggyBac-based transgenesis in FAW and other lepidopteran insects.


Assuntos
Elementos de DNA Transponíveis , Transposases , Animais , Elementos de DNA Transponíveis/genética , Células Germinativas/metabolismo , Plasmídeos , Spodoptera/genética , Spodoptera/metabolismo , Transposases/genética , Transposases/metabolismo
3.
Arch Insect Biochem Physiol ; 108(3): e21844, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34519097

RESUMO

Animals maintain homeostasis of cell numbers, constantly creating new cells and eliminating others. Programmed cell death, apoptosis, is a mechanism of cell elimination and it acts in many aspects of animal biology. Drawing on the biomedical background, several signals launch the apoptosis mechanisms, including prostaglandins (PGs). Based on this information, we posed the hypothesis that PGs similarly induce apoptosis in insect cell lines. We used three Spodoptera frugiperda cell lines, including two newly established, BCIRL-SfNS-0518B-YL derived from the central nervous system and BCIRL-Sf4FB-0614-SGS derived from fat body, and the commercially available Sf9 cells. Using a kinetic apoptosis kit, we found treating SfNS cells for 18 h with 15 or 20 µM PGA2 led to decreases in cell numbers, coupled with increased numbers of apoptotic and dead cells. Similar exposures to 10 µM PGA2 (24 h) led to substantial increases in apoptotic cells, confirmed by a terminal deoxynucleotidyl transferase dUTP nick end labeling assay on a flow cytometer. The influence of PGA2 treatments increased with dosage, as we recorded about 20% apoptosis at 24 h post-PGA2 treatments (10 µM) and about 34% apoptosis at 24 h post-30 µM treatments. PGA2 treatments led to 10- to 30-fold increases in messenger RNAs (mRNAs) encoding apoptosis-specific caspases-1, -2, -3, and -5 at 12 h and 40- to 60-fold increases in mRNAs encoding caspases-1 and -2, 10-fold increases for caspases-3 and -5 at 24 h. These findings strongly support our hypothesis that PGs induce apoptosis in an insect cell line and confirm an additional PG action in insect biology.


Assuntos
Caspases , Prostaglandinas A/farmacologia , Células Sf9/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Caspases/efeitos dos fármacos , Caspases/metabolismo , Spodoptera/metabolismo
4.
DNA Repair (Amst) ; 106: 103193, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34339948

RESUMO

The nonhomologous DNA end joining pathway is required for repair of most double-strand breaks in the mammalian genome. Here we use a purified biochemical NHEJ system to compare the joining of free DNA with recombinant mononucleosomal and dinucleosomal substrates to investigate ligation and local DNA end resection. We find that the nucleosomal state permits ligation in a manner dependent on the presence of free DNA flanking the nucleosome core particle. Local resection at DNA ends by the Artemis:DNA-PKcs nuclease complex is completely suppressed in all mononucleosome substrates regardless of flanking DNA up to a length of 14 bp. Like mononucleosomes, dinucleosomes lacking flanking free DNA are not joined. Therefore, the nucleosomal state imposes severe constraints on NHEJ nuclease and ligase activities.


Assuntos
Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Proteína Quinase Ativada por DNA/metabolismo , Nucleossomos/metabolismo , Animais , Linhagem Celular , DNA/metabolismo , DNA Ligases/metabolismo , Células HeLa , Humanos , Spodoptera/metabolismo , Xenopus/metabolismo
5.
Cell Mol Life Sci ; 78(19-20): 6593-6603, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34448011

RESUMO

The concept of reverse chemical ecology (exploitation of molecular knowledge for chemical ecology) has recently emerged in conservation biology and human health. Here, we extend this concept to crop protection. Targeting odorant receptors from a crop pest insect, the noctuid moth Spodoptera littoralis, we demonstrate that reverse chemical ecology has the potential to accelerate the discovery of novel crop pest insect attractants and repellents. Using machine learning, we first predicted novel natural ligands for two odorant receptors, SlitOR24 and 25. Then, electrophysiological validation proved in silico predictions to be highly sensitive, as 93% and 67% of predicted agonists triggered a response in Drosophila olfactory neurons expressing SlitOR24 and SlitOR25, respectively, despite a lack of specificity. Last, when tested in Y-maze behavioral assays, the most active novel ligands of the receptors were attractive to caterpillars. This work provides a template for rational design of new eco-friendly semiochemicals to manage crop pest populations.


Assuntos
Mariposas/efeitos dos fármacos , Mariposas/metabolismo , Receptores Odorantes/metabolismo , Animais , Drosophila/efeitos dos fármacos , Drosophila/metabolismo , Proteínas de Insetos/metabolismo , Repelentes de Insetos/farmacologia , Aprendizado de Máquina , Odorantes , Feromônios/farmacologia , Olfato/efeitos dos fármacos , Spodoptera/efeitos dos fármacos , Spodoptera/metabolismo
6.
Sci Rep ; 11(1): 15885, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-34354173

RESUMO

Given the new spread and potential damage of the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in Asia, it has become imperative to understand the development biology of this invasive species on selected vegetable crops in newer geographical regions. In this study, we investigated the ovipositional preference of FAW females on different host plants, under choice- and non-choice tests. In addition, using the age-stage, two-sex life table theory, we assessed the performance of immature FAW individuals fed and reared on selected vegetable crops to get information related to development time, survival, reproduction and longevity. Fall armyworm females had an oviposition preference on maize compared to other vegetable crops, including cabbage and soybean, and reluctance for tomato, which was confirmed during the choice and non-choice tests. In contrast to the oviposition preference, our results also suggest that despite low preference for cabbage, soybean, and tomato, these crops seemed to provide a high benefit for an appropriate offspring performance, exceeding in some cases the benefits from a maize-based diet. Information from this study was discussed in terms of FAW ecology and how female's decision affects their reproductive fitness, and the survival and performance of its offspring.


Assuntos
Oviposição/fisiologia , Spodoptera/crescimento & desenvolvimento , Spodoptera/metabolismo , Animais , Produtos Agrícolas , Larva/crescimento & desenvolvimento , Reprodução/fisiologia , Estações do Ano , Spodoptera/fisiologia , Taiwan , Verduras , Zea mays
7.
Science ; 373(6554): 535-541, 2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34326235

RESUMO

Interkingdom competition occurs between hymenopteran parasitoids and insect viruses sharing the same insect hosts. It has been assumed that parasitoid larvae die with the death of the infected host or as result of competition for host resources. Here we describe a gene family, parasitoid killing factor (pkf), that encodes proteins toxic to parasitoids of the Microgastrinae group and determines parasitism success. Pkfs are found in several entomopathogenic DNA virus families and in some lepidopteran genomes. We provide evidence of equivalent and specific toxicity against endoparasites for PKFs found in entomopoxvirus, ascovirus, baculovirus, and Lepidoptera through a mechanism that elicits apoptosis in the cells of susceptible parasitoids. This highlights the evolutionary arms race between parasitoids, viruses, and their insect hosts.


Assuntos
Entomopoxvirinae/fisiologia , Proteínas de Insetos/toxicidade , Lepidópteros/parasitologia , Lepidópteros/virologia , Proteínas Virais/toxicidade , Vespas/fisiologia , Animais , Apoptose , Evolução Biológica , Transferência Genética Horizontal , Genoma de Inseto , Interações Hospedeiro-Parasita , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Vírus de Insetos/fisiologia , Larva/genética , Larva/parasitologia , Larva/virologia , Lepidópteros/genética , Lepidópteros/metabolismo , Nucleopoliedrovírus/fisiologia , Spodoptera/genética , Spodoptera/metabolismo , Spodoptera/parasitologia , Spodoptera/virologia , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vespas/crescimento & desenvolvimento
8.
PLoS Genet ; 17(7): e1009680, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34252082

RESUMO

The evolution of insecticide resistance represents a global constraint to agricultural production. Because of the extreme genetic diversity found in insects and the large numbers of genes involved in insecticide detoxification, better tools are needed to quickly identify and validate the involvement of putative resistance genes for improved monitoring, management, and countering of field-evolved insecticide resistance. The avermectins, emamectin benzoate (EB) and abamectin are relatively new pesticides with reduced environmental risk that target a wide number of insect pests, including the beet armyworm, Spodoptera exigua, an important global pest of many crops. Unfortunately, field resistance to avermectins recently evolved in the beet armyworm, threatening the sustainable use of this class of insecticides. Here, we report a high-quality chromosome-level assembly of the beet armyworm genome and use bulked segregant analysis (BSA) to identify the locus of avermectin resistance, which mapped on 15-16 Mbp of chromosome 17. Knockout of the CYP9A186 gene that maps within this region by CRISPR/Cas9 gene editing fully restored EB susceptibility, implicating this gene in avermectin resistance. Heterologous expression and in vitro functional assays further confirm that a natural substitution (F116V) found in the substrate recognition site 1 (SRS1) of the CYP9A186 protein results in enhanced metabolism of EB and abamectin. Hence, the combined approach of coupling gene editing with BSA allows for the rapid identification of metabolic resistance genes responsible for insecticide resistance, which is critical for effective monitoring and adaptive management of insecticide resistance.


Assuntos
Sistema Enzimático do Citocromo P-450/genética , Resistência a Inseticidas/genética , Spodoptera/genética , Animais , Mapeamento Cromossômico/métodos , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Edição de Genes/métodos , Genoma/genética , Inseticidas/farmacologia , Ivermectina/análogos & derivados , Ivermectina/farmacologia , Larva/genética , Spodoptera/metabolismo
9.
Insect Biochem Mol Biol ; 135: 103608, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34119653

RESUMO

Bacillus thuringiensis (Bt) bacteria produce Cry toxins that kill insect pests. Insect specificity of Cry toxins relies on their binding to larval gut membrane proteins such as cadherin and ATP-binding cassette (ABC) transporter proteins. Mutations in ABC transporters have been implicated in high levels of resistance to Cry toxins in multiple pests. Spodoptera frugiperda is an insect pest susceptible to Cry1Fa and Cry1Ab toxins while Mythimna separata is tolerant to Cry1Fa and less susceptible to Cry1Ab. Here, we analyzed the potential role of ABCC2 in determining the susceptibility of S. frugiperda to Cry1Fa and Cry1Ab, by expressing SfABCC2 or MsABCC2 in Hi5 insect cell line and by the systematic replacements of extracellular loops (ECLs) between these two proteins. Expression of SfABCC2 in Hi5 conferred susceptibility to both Cry1Fa and Cry1Ab, in contrast to the expression of MsABCC2 that mediated low toxicity to Cry1Ab and no toxicity to Cry1Fa in agreement with their larvicidal toxicities. The SfABCC2 and MsABCC2 amino acid sequences showed differential residues among ECL1, ECL2, ECL4 and ECL6 loops, while ECL3 and ECL5 share the same primary sequence. The exchange of ECLs between SfABCC2 and MsABCC2 demonstrated that ECL4 and ECL2 contribute to Cry1Fa toxicity, where ECL4 plays a major role. The medium region (named M2) of ECL4 was identified as the most important region of SfABCC2 involved in Cry1Fa toxicity as shown by point mutations in this region. These findings will be helpful to understand the mechanisms of action of Bt toxins in S. frugiperda.


Assuntos
Toxinas de Bacillus thuringiensis/farmacologia , Resistência a Inseticidas/genética , Mariposas , Proteínas Associadas à Resistência a Múltiplos Medicamentos , Animais , Proteínas de Bactérias/farmacologia , Linhagem Celular , Endotoxinas/farmacologia , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/química , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/metabolismo
10.
Pest Manag Sci ; 77(10): 4758-4769, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34148283

RESUMO

BACKGROUND: AcMNPV is a model organism of baculovirus, and Spodoptera frugiperda is one of its hosts. Disclosing the role of ac106/107 in AcMNPV infecting Spodoptera frugiperda 9 (Sf9) cells is of great significance for modifying AcMNPV as a microbial insecticide. This work constructed recombinant baculovirus that knocking out, repairment and overexpression of ac106/107 and explored the effects of Ac106/107 on the proliferation of progeny viruses. Moreover, the potential mechanism and targets of ac106/107 were further revealed. RESULTS: First, compared with the Bacmid-EGFP transfection group, the progeny virus does not proliferate after knocking out of ac106/107, and the proliferation ability increases by 14.5% at 72 h post transfection (h p.t.) when overexpression of ac106/107. However, knockout, repairment and overexpression of ac106/107 have no effect on viral DNA replication. Secondly, Ac106/107-EGFP was located in the cytoplasm and nucleus. Transcription level of late viral genes and viral RNA polymerase subunit genes in the Bacmidac106/107KO -EGFP transfection group and Bacmid-Ac106/107-EGFP transfection group was reduced and increased, respectively. Thirdly, AcMNPV would increase the glucose utilization and lactate consumption of the host Sf9 cells, and Bacmidac106/107KO -EGFP transfection group had lower glucose consumption and lactic acid accumulation than Bacmid-EGFP, Bacmidac106/107KO -Ac106/107(rep)-EGFP and Bacmid-Ac106/107-EGFP transfection groups. CONCLUSION: Ac106/107 can enter the nucleus and affect transcription of viral RNA polymerase subunit genes, which in turn affects the transcription of late genes, and ultimately affects virus proliferation and energy metabolism in host cells. © 2021 Society of Chemical Industry.


Assuntos
Nucleopoliedrovírus , Animais , Replicação do DNA , DNA Viral , Metabolismo Energético , Genes Virais , Nucleopoliedrovírus/genética , Spodoptera/genética , Spodoptera/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo , Replicação Viral
11.
Insect Mol Biol ; 30(4): 400-409, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33837597

RESUMO

Proteins containing nuclear localization signals (NLSs) are actively transported into the nucleus via the classic importin-α/ß-mediated pathway, and NLSs are recognized by members of the importin-α family. Most studies of insect importin-αs have focused on Drosophila to date, little is known about the importin-α proteins in Lepidoptera insects. In this study, we identified four putative importin-α homologues, Spodoptera frugiperda importin-α1 (SfIMA1), SfIMA2, SfIMA4 and SfIMA7, from Sf9 cells. Immunofluorescence analysis showed that SfIMA2, SfIMA4 and SfIMA7 localized to the nucleus, while SfIMA1 distributed in cytoplasm. Additionally, SfIMA4 and SfIMA7 were also detected in the nuclear membrane of Sf9 cells. SfIMA1, SfIMA4 and SfIMA7, but not SfIMA2, were found to associate with the C terminus of AcMNPV DNA polymerase (DNApol) that harbours a typical monopartite NLS and a classic bipartite NLS. Further analysis of protein-protein interactions revealed that SfIMA1 specifically recognizes the bipartite NLS, while SfIMA4 and SfIMA7 bind to both monopartite and bipartite NLSs. Together, our results suggested that SfIMA1, SfIMA4 and SfIMA7 play important roles in the nuclear import of AcMNPV DNApol C terminus in Sf9 cells.


Assuntos
DNA Polimerase Dirigida por DNA/metabolismo , Nucleopoliedrovírus , Spodoptera , alfa Carioferinas/metabolismo , Transporte Ativo do Núcleo Celular/fisiologia , Animais , Núcleo Celular/metabolismo , Núcleo Celular/virologia , Proteínas de Insetos/metabolismo , Sinais de Localização Nuclear/metabolismo , Nucleopoliedrovírus/genética , Nucleopoliedrovírus/metabolismo , Domínios e Motivos de Interação entre Proteínas , Células Sf9/metabolismo , Células Sf9/virologia , Spodoptera/metabolismo , Spodoptera/virologia , Proteínas Virais/metabolismo
12.
PLoS Pathog ; 17(3): e1009467, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33765093

RESUMO

Xenorhabdus hominickii, an entomopathogenic bacterium, inhibits eicosanoid biosynthesis of target insects to suppress their immune responses by inhibiting phospholipase A2 (PLA2) through binding to a damage-associated molecular pattern (DAMP) molecule called dorsal switch protein 1 (DSP1) from Spodoptera exigua, a lepidopteran insect. However, the signalling pathway between DSP1 and PLA2 remains unknown. The objective of this study was to determine whether DSP1 could activate Toll immune signalling pathway to activate PLA2 activation and whether X. hominickii metabolites could inhibit DSP1 to shutdown eicosanoid biosynthesis. Toll-Spätzle (Spz) signalling pathway includes two Spz (SeSpz1 and SeSpz2) and 10 Toll receptors (SeToll1-10) in S. exigua. Loss-of-function approach using RNA interference showed that SeSpz1 and SeToll9 played crucial roles in connecting DSP1 mediation to activate PLA2. Furthermore, a deletion mutant against SeToll9 using CRISPR/Cas9 abolished DSP1 mediation and induced significant immunosuppression. Organic extracts of X. hominickii culture broth could bind to DSP1 at a low micromolar range. Subsequent sequential fractionations along with binding assays led to the identification of seven potent compounds including 3-ethoxy-4-methoxyphenol (EMP). EMP could bind to DSP1 and prevent its translocation to plasma in response to bacterial challenge and suppress the up-regulation of PLA2 activity. These results suggest that X. hominickii inhibits DSP1 and prevents its DAMP role in activating Toll immune signalling pathway including PLA2 activation, leading to significant immunosuppression of target insects.


Assuntos
Alarminas/metabolismo , Proteínas de Bactérias/metabolismo , Infecções por Bactérias Gram-Negativas/metabolismo , Spodoptera/metabolismo , Xenorhabdus/metabolismo , Animais , Infecções por Bactérias Gram-Negativas/imunologia , Proteínas de Insetos/metabolismo , Fosfolipases A2/metabolismo , Salicilatos/metabolismo , Transdução de Sinais/fisiologia , Spodoptera/imunologia
13.
Commun Biol ; 4(1): 286, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33674721

RESUMO

Voracious feeding, trans-continental migration and insecticide resistance make Spodoptera litura among the most difficult Asian agricultural pests to control. Larvae exhibit strong circadian behavior, feeding actively at night and hiding in soil during daytime. The daily pattern of larval metabolism was reversed, with higher transcription levels of genes for digestion (amylase, protease, lipase) and detoxification (CYP450s, GSTs, COEs) in daytime than at night. To investigate the control of these processes, we annotated nine essential clock genes and analyzed their transcription patterns, followed by functional analysis of their coupling using siRNA knockdown of interlocked negative feedback system core and repressor genes (SlituClk, SlituBmal1 and SlituCwo). Based on phase relationships and overexpression in cultured cells the controlling mechanism seems to involve direct coupling of the circadian processes to E-boxes in responding promoters. Additional manipulations involving exposure to the neonicotinoid imidacloprid suggested that insecticide application must be based on chronotoxicological considerations for optimal effectiveness.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Ritmo Circadiano , Comportamento Alimentar , Proteínas de Insetos/metabolismo , Spodoptera/metabolismo , Animais , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Inativação Metabólica , Proteínas de Insetos/genética , Inseticidas/farmacologia , Larva/genética , Larva/metabolismo , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Interferência de RNA , RNA-Seq , Spodoptera/efeitos dos fármacos , Spodoptera/embriologia , Spodoptera/genética , Fatores de Tempo , Transcriptoma
14.
Bull Entomol Res ; 111(4): 454-463, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33632348

RESUMO

The tobacco cutworm Spodoptera litura (Lepidoptera: Noctuidae) is a polyphagous pest with a highly selective and sensitive chemosensory system involved in complex physiological behaviors such as searching for food sources, feeding, courtship, and oviposition. However, effective management strategies for controlling the insect pest populations under threshold levels are lacking. Therefore, there is an urgent need to formulate eco-friendly pest control strategies based on the disruption of the insect chemosensory system. In this study, we identified 158 putative chemosensory genes based on transcriptomic and genomic data for S. litura, including 45 odorant-binding proteins (OBPs, nine were new), 23 chemosensory proteins (CSPs), 60 odorant receptors (ORs, three were new), and 30 gustatory receptors (GRs, three were new), a number higher than those reported by previous transcriptome studies. Subsequently, we constructed phylogenetic trees based on these genes in moths and analyzed the dynamic expression of various genes in head capsules across larval instars using quantitative real-time polymerase chain reaction. Nine genes-SlitOBP8, SlitOBP9, SlitOBP25, SlitCSP1, SlitCSP7, SlitCSP18, SlitOR34, SlitGR240, and SlitGR242-were highly expressed in the heads of 3- to 5-day-old S. litura larvae. The genes differentially expressed in olfactory organs during larval development might play crucial roles in the chemosensory system of S. litura larvae. Our findings substantially expand the gene inventory for S. litura and present potential target genes for further studies on larval feeding in S. litura.


Assuntos
Genes de Insetos , Proteínas de Insetos/genética , Receptores Odorantes/genética , Spodoptera/genética , Animais , Feminino , Cabeça , Proteínas de Insetos/metabolismo , Larva/metabolismo , Masculino , Receptores Odorantes/metabolismo , Spodoptera/metabolismo , Transcriptoma
15.
Biochim Biophys Acta Gene Regul Mech ; 1864(3): 194687, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33561559

RESUMO

A dataset of gene expression from Spodoptera frugiperda, a highly generalist pest moth, was used to understand how gene regulation is related to larval host plant preference. Transcriptomic data of corn and rice strains of S. frugiperda larvae, reared on different diets, were analysed with three different approaches of gene network inference, namely co-expression, weighted co-expression and Bayesian networks, since each methodology provides a different visualization of the data. Using these approaches, it was possible to identify two loosely interconnected co-expression networks, one of them responsible for fast response to herbivory and anti-herbivory mechanisms and the other related to housekeeping genes, which present slower response to environmental variations. Integrating different levels of information such as gene expression patterns, gene assembly, transcriptomics, relationship among genes and phenotypes, functional relationships, among other information, enabled a wider visualization of S. frugiperda response to diet stimuli. The biological properties in the proposed networks are here described and discussed, as well as patterns of gene expression related to larval performance attributes.


Assuntos
Comportamento Alimentar/fisiologia , Regulação da Expressão Gênica/fisiologia , Oryza/parasitologia , Spodoptera/metabolismo , Transcriptoma/fisiologia , Zea mays/parasitologia , Animais , Perfilação da Expressão Gênica , Larva/genética , Larva/metabolismo , Spodoptera/genética
16.
Insect Sci ; 28(3): 611-626, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33629522

RESUMO

The evolutionary success of phytophagous insects depends on their ability to efficiently exploit plants as a source of energy for survival. Herbivorous insects largely depend on the efficiency, flexibility, and diversity of their digestive physiology and sophistication of their detoxification system to use chemically diverse host plants as food sources. The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a polyphagous pest of many commercially important crops. To elucidate the ability of this insect pest to adapt to host plant mechanisms, we evaluated the impact of primary (corn) and alternate (rice) host plants after 11 generations on gut digestive enzymatic activity and expression profiles of related genes. Results indicated that the total protease and class-specific trypsin- and chymotrypsin-like protease activity of S. frugiperda significantly differed among host plant treatments. The class-specific protease profiles greatly differed in S. frugiperda midguts upon larval exposure to different treatments with inhibitors compared with treatments without inhibitors. Similarly, the single and cumulative effects of the enzyme-specific inhibitors TLCK, TPCK, and E-64 significantly increased larval mortality and reduced larval growth/mass across different plant treatments. Furthermore, the quantitative reverse transcription polymerase chain reaction results revealed increased transcription of two trypsin (SfTry-3, SfTry-7) and one chymotrypsin gene (Sfchym-9), which indicated that they have roles in host plant adaptation. Knockdown of these genes resulted in significantly reduced mRNA expression levels of the trypsin genes. This was related to the increased mortality observed in treatments compared with the dsRED control. This result indicates possible roles of S. frugiperda gut digestive enzymes and related genes in host plant adaptation.


Assuntos
Adaptação Fisiológica/genética , Sistema Digestório/metabolismo , Endopeptidases , Herbivoria , Spodoptera , Animais , Quimotripsina/genética , Produtos Agrícolas , Digestão/efeitos dos fármacos , Sistema Digestório/efeitos dos fármacos , Endopeptidases/efeitos dos fármacos , Endopeptidases/genética , Endopeptidases/metabolismo , Genes de Insetos , Herbivoria/efeitos dos fármacos , Herbivoria/genética , Herbivoria/fisiologia , Larva/efeitos dos fármacos , Larva/genética , Larva/metabolismo , Oryza , Controle de Pragas , Inibidores de Proteases/farmacologia , Interferência de RNA , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/metabolismo , Transcriptoma , Tripsina/genética , Zea mays
17.
Insect Biochem Mol Biol ; 128: 103515, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33387638

RESUMO

The diverse colors and patterns found in Lepidoptera are important for success of these species. Similar to the wings of adult butterflies, lepidopteran larvae exhibit diverse color variations to adapt to their habitats. Compared with butterfly wings, however, less attention has been paid to larval body colorations and patterns. In the present study, we focus on the yellow-y gene, which participates in the melanin synthesis pathway. We conducted CRISPR/Cas9-mediated targeted mutagenesis of yellow-y in the tobacco cutworm Spodoptera litura. We analyzed the role of S. litura yellow-y in pigmentation by morphological observation and discovered that yellow-y is necessary for normal black pigmentation in S. litura. We also showed species- and tissue-specific requirements of yellow-y in pigmentation in comparison with those of Bombyx mori yellow-y mutants. Furthermore, we found that almost none of the yellow-y mutant embryos hatched unaided. We provide evidence that S. litura yellow-y has a novel important function in egg hatching, in addition to pigmentation. The present study will enable a greater understanding of the functions and diversification of the yellow-y gene in insects.


Assuntos
Lepidópteros , Melaninas/metabolismo , Pigmentação/genética , Spodoptera , Animais , Evolução Biológica , Bombyx/genética , Bombyx/metabolismo , Sistemas CRISPR-Cas , Genes de Insetos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Lepidópteros/genética , Lepidópteros/metabolismo , Mutagênese , Spodoptera/genética , Spodoptera/metabolismo
18.
Insect Sci ; 28(3): 639-648, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33386702

RESUMO

Spodoptera frugiperda (Lepidoptera: Noctuidae) is a widely distributed pest of corn. Since it invaded China in 2018, it has caused serious damage to local corn production. Chlorantraniliprole, an anthranilic diamide insecticide, has been widely used to control lepidopteran pests. Tetrachloropyramid is a new allosteric modulator insecticide developed based on chlorantraniliprole, so it has a similar mechanism and insecticidal effect. In this study, we investigated resistance levels to chlorantraniliprole and tetrachloropyramid in S. frugiperda from 13 populations in China. Among the populations tested, the relative highest resistance to chlorantraniliprole occurred in the Guangzhou population, and the most susceptible to chlorantraniliprole was found in the Wuhan population. The lethal dosage LD50 value of the Guangzhou population against chlorantraniliprole was 27.8-fold higher than that of the Wuhan population. Minimal differences were observed among S. frugiperda populations in terms of sensitivity to tetrachloropyramid. Heterozygous mutations at the I4734 site of the ryanodine receptor (RyR) were found, while no mutations were found in the G4891 site. The mutations were detected in only two of the 786 individuals analyzed, one from the Qinzhou population and other from the Anshun population (frequency below 2% in both cases). There were no significant differences in the expression levels of RyR between Guangzhou and Wuhan populations. In summary, our results indicate that: (i) S. frugiperda has low resistance levels to diamide insecticides in China; and (ii) the differences in relative resistance among the 13 populations analyzed are not caused by the mutations in RyR or the expression of RyR.


Assuntos
Resistência a Inseticidas/genética , Mutação , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Spodoptera , ortoaminobenzoatos/farmacologia , Animais , China , Diamida/farmacologia , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/genética , Larva/metabolismo , Spodoptera/efeitos dos fármacos , Spodoptera/genética , Spodoptera/metabolismo , ortoaminobenzoatos/análise
19.
Arch Insect Biochem Physiol ; 106(1): e21748, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33038048

RESUMO

Polytrophic ovarioles of Spodoptera exigua, a lepidopteran insect, begins with the development of oocytes and differentiation of nurse cells followed by vitellogenesis and choriogenesis. Compared with previtellogenic and vitellogenic developments, choriogenesis has not been clearly understood yet in endocrine control. This study investigated the expression and function of a mucin-like structural protein of S. exigua called Se-Mucin1 in choriogenesis. It was highly expressed in ovarioles containing chorionated oocytes. The expression level of Se-Mucin1 was increased during adult stage as early as 18 h after adult emergence, reaching the maximal level at 24 h and later. Interestingly, DNA amount of Se-Mucin1 was increased by almost four folds during early adult stage while other genes (hexokinase and glyceraldehyde-3-phosphate dehydrogenase) not directly associated with chorion formation did not show genomic DNA increase, suggesting specific gene amplification of Se-Mucin1. RNA interference (RNAi) suppressed Se-Mucin1 expression by injecting 1 µg of double-strand RNA to teneral females (<5 h after emergence), which exhibited significantly impaired fecundity and egg hatching rate. Eggs laid by RNAi-treated females were malformed in eggshell structures with loss of mesh-like fibers. Treatment with aspirin, a prostaglandin (PG) biosynthesis inhibitor, suppressed the induction of Se-Mucin1 expression during early adult stage and impaired egg development. An addition of PGE2 significantly rescued such impairment in Se-Mucin1 expression and subsequent egg development. These results suggest that PGs mediate choriogenesis of S. exigua by activating the expression of chorion-associated genes including Se-Mucin1.


Assuntos
Dinoprostona/metabolismo , Mucinas/metabolismo , Ovário/metabolismo , Spodoptera , Animais , Aspirina/farmacologia , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Insetos , Mucinas/efeitos dos fármacos , Mucinas/genética , Interferência de RNA , Transdução de Sinais , Spodoptera/genética , Spodoptera/metabolismo , Vitelogênese/fisiologia
20.
Pest Manag Sci ; 77(3): 1492-1501, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33145907

RESUMO

BACKGROUND: The fall armyworm Spodoptera frugiperda is a major agricultural pest that has invaded the East Hemisphere since 2016, generating a serious threat to food security worldwide including Africa and Asia. The Cry toxins produced by Bacillus thuringiensis (Bt) have been shown to be effective against this insect pest. In different insect ABC transporters (ABCC2 or ABCC3) have been shown to be involved as receptors of some Cry1 toxins. Here we analyzed the role of SfABCC2 and SfABCC3 in the toxicity of Cry1Fa and Cry1Ab toxins in this insect pest. RESULTS: Two S. frugiperda SfABCC2 and SfABCC3 knockout strains, coding for potential functional Bt receptors, were created using CRISPR/Cas9 genome editing system. Both knockout strains showed resistance to both Cry1Fa and Cry1Ab toxins compared with the susceptible strain. SfABCC2 knockout strain showed higher resistance to both Cry toxins than SfABCC3 knockout strain, suggesting a major role of SfABCC2 in the mode of action of these Cry toxins. In addition, expression of SfABCC2 and SfABCC3 genes in Trichoplusia ni Hi5 cells also increased the susceptibility to Cry1Ab and Cry1Fa toxins, in agreement with the genome editing results. The double knockout of SfABCC2 and SfABCC3 strain was not viable in contrast to other lepidopteran species. Furthermore, we report here that SfABCC2 or SfABCC3 knockout strains increased their susceptibility to abamectin and spinosad insecticides. CONCLUSION: We provide functional evidence that in S. frugiperda these two ABCC transporters serve as receptors of Bt Cry1Fa and Cry1Ab toxins. © 2020 Society of Chemical Industry.


Assuntos
Bacillus thuringiensis , Transportadores de Cassetes de Ligação de ATP , África , Animais , Ásia , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endotoxinas/genética , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Larva/genética , Larva/metabolismo , Spodoptera/genética , Spodoptera/metabolismo
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