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1.
PLoS One ; 17(2): e0263677, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35143580

RESUMO

Spodoptera frugiperda (J.E. Smith) is a highly invasive noctuid pest first reported in northern Australia during early 2020. To document current status of resistance in S. frugiperda in Australia, insecticide toxicity was tested in field populations collected during the first year of establishment, between March 2020 and March 2021. Dose-response was measured by larval bioassay in 11 populations of S. frugiperda and a susceptible laboratory strain of Helicoverpa armigera. Emamectin benzoate was the most efficacious insecticide (LC50 0.023µg/ml) followed by chlorantraniliprole (LC50 0.055µg/ml), spinetoram (LC50 0.098µg/ml), spinosad (LC50 0.526µg/ml), and methoxyfenozide (1.413µg/ml). Indoxacarb was the least toxic selective insecticide on S. frugiperda (LC50 3.789µg/ml). Emamectin benzoate, chlorantraniliprole and methoxyfenozide were 2- to 7-fold less toxic on S. frugiperda compared with H. armigera while spinosyns were equally toxic on both species. Indoxacarb was 28-fold less toxic on S. frugiperda compared with H. armigera. There was decreased sensitivity to Group 1 insecticides and synthetic pyrethroids in S. frugiperda compared with H. armigera: toxicity was reduced up to 11-fold for methomyl, 56 to 199-fold for cyhalothrin, and 44 to 132-fold for alpha cypermethrin. Synergism bioassays with metabolic inhibitors suggest involvement of mixed function oxidase in pyrethroid resistance. Recommended diagnostic doses for emamectin benzoate, chlorantraniliprole, spinetoram, spinosad, methoxyfenozide and indoxacarb are 0.19, 1.0, 0.75, 6, 12 and 48µg/µl, respectively.


Assuntos
Resistência a Inseticidas , Inseticidas/toxicidade , Oxigenases de Função Mista/metabolismo , Spodoptera/crescimento & desenvolvimento , Animais , Austrália , Combinação de Medicamentos , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Hidrazinas/toxicidade , Proteínas de Insetos/metabolismo , Ivermectina/análogos & derivados , Ivermectina/toxicidade , Hormônios Juvenis/toxicidade , Larva/efeitos dos fármacos , Larva/enzimologia , Larva/crescimento & desenvolvimento , Dose Letal Mediana , Macrolídeos/toxicidade , Oxazinas/toxicidade , Vigilância da População , Spodoptera/efeitos dos fármacos , Spodoptera/enzimologia , ortoaminobenzoatos/toxicidade
2.
Toxins (Basel) ; 14(1)2022 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-35051032

RESUMO

The insecticidal Vip3 proteins, secreted by Bacillus thuringiensis (Bt) during its vegetative growth phase, are currently used in Bt crops to control insect pests, and are genetically distinct from known insecticidal Cry proteins. Compared with Cry toxins, the mechanisms of Vip3 toxins are still poorly understood. Here, the responses of Spodoptera frugiperda larvae after Vip3Aa challenge are characterized. Using an integrative analysis of transcriptomics and proteomics, we found that Vip3Aa has enormous implications for various pathways. The downregulated genes and proteins were mainly enriched in metabolic pathways, including the insect hormone synthesis pathway, whereas the upregulated genes and proteins were mainly involved in the caspase-mediated apoptosis pathway, along with the MAPK signaling and endocytosis pathways. Moreover, we also identified some important candidate genes involved in apoptosis and MAPKs. The present study shows that exposure of S. frugiperda larvae to Vip3Aa activates apoptosis pathways, leading to cell death. The results will promote our understanding of the host response process to the Vip3Aa, and help us to better understand the mode of action of Vip3A toxins.


Assuntos
Proteínas de Bactérias/fisiologia , Proteínas de Insetos/genética , Proteoma/genética , Spodoptera/genética , Transcriptoma , Animais , Sistema Digestório/metabolismo , Proteínas de Insetos/metabolismo , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Larva/microbiologia , Proteoma/metabolismo , Spodoptera/efeitos dos fármacos , Spodoptera/crescimento & desenvolvimento , Spodoptera/microbiologia
3.
Proc Natl Acad Sci U S A ; 118(43)2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34675080

RESUMO

Plant secondary (or specialized) metabolites mediate important interactions in both the rhizosphere and the phyllosphere. If and how such compartmentalized functions interact to determine plant-environment interactions is not well understood. Here, we investigated how the dual role of maize benzoxazinoids as leaf defenses and root siderophores shapes the interaction between maize and a major global insect pest, the fall armyworm. We find that benzoxazinoids suppress fall armyworm growth when plants are grown in soils with very low available iron but enhance growth in soils with higher available iron. Manipulation experiments confirm that benzoxazinoids suppress herbivore growth under iron-deficient conditions and in the presence of chelated iron but enhance herbivore growth in the presence of free iron in the growth medium. This reversal of the protective effect of benzoxazinoids is not associated with major changes in plant primary metabolism. Plant defense activation is modulated by the interplay between soil iron and benzoxazinoids but does not explain fall armyworm performance. Instead, increased iron supply to the fall armyworm by benzoxazinoids in the presence of free iron enhances larval performance. This work identifies soil chemistry as a decisive factor for the impact of plant secondary metabolites on herbivore growth. It also demonstrates how the multifunctionality of plant secondary metabolites drives interactions between abiotic and biotic factors, with potential consequences for plant resistance in variable environments.


Assuntos
Benzoxazinas/metabolismo , Herbivoria , Solo/química , Spodoptera/crescimento & desenvolvimento , Zea mays/metabolismo , Animais , Ecossistema , Homeostase , Ferro/metabolismo , Larva/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Zea mays/parasitologia
4.
Molecules ; 26(18)2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34577165

RESUMO

Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm.


Assuntos
Beauveria/metabolismo , Agentes de Controle Biológico/farmacologia , Dípteros/efeitos dos fármacos , Hypocreales/metabolismo , Phaseolus/metabolismo , Extratos Vegetais/farmacologia , Spodoptera/efeitos dos fármacos , Animais , Dípteros/crescimento & desenvolvimento , Endófitos/metabolismo , Larva/efeitos dos fármacos , Metanol/química , Cloreto de Metileno/química , Controle Biológico de Vetores/métodos , Phaseolus/microbiologia , Doenças das Plantas/prevenção & controle , Pupa/efeitos dos fármacos , Spodoptera/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
5.
Insect Biochem Mol Biol ; 138: 103646, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34469782

RESUMO

The genus Spodoptera (Lepidoptera: Noctuidae) comprises some of the most polyphagous and destructive agricultural pests worldwide. The success of many species of this genus is due to their striking abilities to adapt to a broad range of host plants. Superfamilies of detoxification genes play a crucial role in the adaption to overcome plant defense mechanisms mediated by numerous secondary metabolites and toxins. Over the past decade, a substantial amount of expression data in Spodoptera larvae was produced for those genes in response to xenobiotics such as plant secondary metabolites, but also insecticide exposure. However, this information is scattered throughout the literature and in most cases does not allow to clearly identify candidate genes involved in host-plant adaptation and insecticide resistance. In the present review, we analyzed and compiled information on close to 600 pairs of inducers (xenobiotics) and induced genes from four main Spodoptera species: S. exigua, S. frugiperda, S. littoralis and S. litura. The cytochrome P450 monooxygenases (P450s; encoded by CYP genes) were the most upregulated detoxification genes across the literature for all four species. Most of the data was provided from studies on S. litura, followed by S. exigua, S. frugiperda and S. littoralis. We examined whether these detoxification genes were reported for larval survival under xenobiotic challenge in forward and reverse genetic studies. We further analyzed whether biochemical assays were carried out showing the ability of corresponding enzymes and transporters to breakdown and excrete xenobiotics, respectively. This revealed a clear disparity between species and the lack of genetic and biochemical information in S. frugiperda. Finally, we discussed the biological importance of detoxification genes for this genus and propose a workflow to study the involvement of these enzymes in an ecological and agricultural context.


Assuntos
Inativação Metabólica/genética , Spodoptera/genética , Xenobióticos/farmacologia , Animais , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Expressão Gênica/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Especificidade da Espécie , Spodoptera/efeitos dos fármacos , Spodoptera/crescimento & desenvolvimento , Regulação para Cima
6.
Insect Biochem Mol Biol ; 138: 103648, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34536505

RESUMO

Baculoviruses are double-stranded DNA entomopathogenic viruses that infect predominantly insects of the order Lepidoptera. Research in the last decade has started to disentangle the mechanisms underlying the insect-virus interaction, particularly focusing on the effects of the baculovirus infection in the host's physiology. Among crucial physiological functions, olfaction has a key role in reproductive tasks, food source detection and enemy avoidance. In this work, we describe that Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) induces expression changes in some odorant receptors (ORs) - the centrepiece of insect's olfaction - when infecting larvae from its natural host Spodoptera exigua (Lepidoptera: Noctuidae). Different ORs are up-regulated in larvae after SeMNPV infection, and two of them, SexiOR35 and SexiOR23, were selected for further functional characterization by heterologous expression in empty neurons of Drosophila melanogaster coupled to single-sensillum recordings. SexiOR35 appears to be a broadly tuned receptor able to recognise multiple and different chemical compounds. SexiOR23, although correctly expressed in Drosophila neurons, did not display any significant response to a panel of 58 stimuli. Behavioural experiments revealed that larvae infected by SeMNPV exhibit altered olfactory-driven behaviour to diet when it is supplemented with the plant volatiles linalool or estragole, two of the main SexiOR35 ligands, supporting the hypothesis that viral infection triggers changes in host perception through changes in the expression level of specific ORs.


Assuntos
Proteínas de Insetos/fisiologia , Nucleopoliedrovírus/fisiologia , Receptores Odorantes/fisiologia , Spodoptera/fisiologia , Animais , Drosophila melanogaster/fisiologia , Drosophila melanogaster/virologia , Larva/crescimento & desenvolvimento , Larva/fisiologia , Larva/virologia , Neurônios/fisiologia , Neurônios/virologia , Spodoptera/crescimento & desenvolvimento , Spodoptera/virologia
7.
J Invertebr Pathol ; 185: 107657, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34487747

RESUMO

Bacillus thuringiensis (Bt) has been used globally as a biopesticide for effective and environmentally friendly pest control. Research has intensified following the development of resistance by lepidopteran species to Bt insecticidal crystal proteins. Discovering new Bt strains with novel toxin properties which can overcome resistance is one of the strategies to improve pesticide sustainability. The genome of the Bacillus thuringiensis LTS290 strain was sequenced and assembled in 252 contigs containing a total of 6,391,328 bp. The novel cry79Aa1 gene from this strain was identified and cloned. Cry79Aa1 contains 729 amino acid residues and a molecular mass of 84.8 kDa by SDS-PAGE analysis. Cry79Aa1 was found to be active against the lepidopteran larvae of Spodoptera exigua, Helicoverpa armigera, and Plutella xylostella with LC50 values of 13.627 µg/mL, 42.8 µg/mL, and 38.086 µg/mL, respectively. However, Cry79Aa1 protein showed almost no insecticidal activity against Leguminivora glycinivorella, although some degree of growth retardation was observed.


Assuntos
Toxinas de Bacillus thuringiensis/genética , Bacillus thuringiensis/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Mariposas/efeitos dos fármacos , Animais , Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Controle de Insetos , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores , Spodoptera/efeitos dos fármacos , Spodoptera/crescimento & desenvolvimento
8.
J Chem Ecol ; 47(8-9): 799-809, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34347233

RESUMO

Fall armyworm (Spodoptera frugiperda) is a major global pest of many crops, including maize (Zea mays). This insect is known to use host plant-derived volatile organic compounds to locate suitable hosts during both its adult and larval stages, yet the function of individual compounds remains mostly enigmatic. In this study, we use a combination of volatile profiling, electrophysiological assays, pair-wise choice behavioral assays, and chemical supplementation treatments to identify and assess specific compounds from maize that influence S. frugiperda host location. Our findings reveal that methyl salicylate and (E)-alpha-bergamotene are oviposition attractants for adult moths but do not impact larval behavior. While geranyl acetate can act as an oviposition attractant or repellent depending on the host volatile context and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) is an oviposition deterrent. These compounds can also be attractive to the larvae when applied to specific maize inbreds. These data show that S. frugiperda uses different plant volatile cues for host location in its adult and larval stage and that the background volatile context that specific volatiles are perceived in, alters their impact as behavioral cues.


Assuntos
Herbivoria/efeitos dos fármacos , Oviposição/efeitos dos fármacos , Spodoptera/fisiologia , Compostos Orgânicos Voláteis/farmacologia , Zea mays/química , Animais , Compostos Bicíclicos com Pontes/isolamento & purificação , Compostos Bicíclicos com Pontes/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Larva/fisiologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Análise de Componente Principal , Salicilatos/isolamento & purificação , Salicilatos/farmacologia , Spodoptera/crescimento & desenvolvimento , Terpenos/isolamento & purificação , Terpenos/farmacologia , Compostos Orgânicos Voláteis/química , Zea mays/metabolismo
9.
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
10.
J Insect Sci ; 21(4)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34233003

RESUMO

Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) is a pest of great economic importance which can feed on more than 300 plant species. As it is polyphagous, its host plants may have variable physical and chemical constitutions. This may influence larval development, as protein and carbohydrate levels are important factors for adequate biological development. The aim of this study was to evaluate insect developmental parameters as well as to compare the food consumption of S. frugiperda larvae reared using diets with different protein levels under laboratory conditions. Three artificial diet formulations were used: one typically used for routine laboratory rearing, based on bean, wheat germ and brewer's yeast (D1); one containing half the original amount of protein (D2), and the other with twice the original amount of protein (D3). The relative consumption rate (RCR), relative growth rate (RGR), and efficiency of conversion of ingested food (ECI) for S. frugiperda fourth instar larvae varied among diets. The protein present in the diet influenced the duration of larval and pupal periods and pupal weight, but did not affect larval survival, fecundity and longevity of adults. The different protein levels in the diets did not negatively influence population growth, so these three diet variations can be used for mass rearing in the laboratory. However, the influence of these diets on successive generations of the insect remains untested.


Assuntos
Ração Animal , Spodoptera/crescimento & desenvolvimento , Animais , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento
11.
PLoS One ; 16(7): e0253122, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34270565

RESUMO

The invasion and wide spread of Spodoptera frugiperda represent real impediments to food security and the livelihood of the millions of maize and sorghum farming communities in the sub-Saharan and Sahel regions of Africa. Current management efforts for the pest are focused on the use of synthetic pesticides, which are often economically unviable and are extremely hazardous to the environment. The use of biological control offers a more economically and environmentally safer alternative. In this study, the performance of the recently described parasitoid, Cotesia icipe, against the pest was elucidated. We assessed the host stage acceptability by and suitability for C. icipe, as well as its ovigenic status. Furthermore, the habitat suitability for the parasitoid in the present and future climatic conditions was established using Maximum Entropy (MaxEnt) algorithm and the Genetic Algorithm for Rule-set Prediction (GARP). Cotesia icipe differentially accepted the immature stages of the pest. The female acceptance of 1st and 2nd instar larvae for oviposition was significantly higher with more than 60% parasitism. No oviposition on the egg, 5th and 6th larval instars, and pupal stages was observed. Percentage of cocoons formed, and the number of emerged wasps also varied among the larval stages. At initial parasitism, parasitoid progenies, time to cocoon formation and overall developmental time were significantly affected by the larval stage. Egg-load varied significantly with wasp age, with six-day-old wasps having the highest number of mature eggs. Ovigeny index of C. icipe was 0.53. Based on the models, there is collinearity in the ecological niche of the parasitoid and the pest under current and future climate scenarios. Eastern, Central and parts of coastal areas of western Africa are highly suitable for the establishment of the parasitoid. The geographic distribution of the parasitoid would remain similar under future climatic conditions. In light of the findings of this study, we discuss the prospects for augmentative and classical biological control of S. frugiperda with C. icipe in Africa.


Assuntos
Spodoptera/parasitologia , Vespas , Animais , Ecossistema , Etiópia , Feminino , Interações Hospedeiro-Parasita , Espécies Introduzidas , Quênia , Larva/parasitologia , Masculino , Oviposição , Controle Biológico de Vetores/métodos , Spodoptera/crescimento & desenvolvimento
12.
J Chem Ecol ; 47(7): 707-718, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34125370

RESUMO

Flooding is a major plant abiotic stress factor that is frequently experienced by plants simultaneously with other biotic stresses, including herbivory. How plant volatile emissions, which mediate interactions with a wide range of organisms, are influenced by flooding and by multiple co-occurring stress factors remains largely unexplored. Using Spodoptera frugiperda (Lepidoptera: Noctuidae) (fall armyworm) as the insect pest and two maize (Zea mays, L. Poaceae) hybrids differentially marketed for conventional and organic production, we assessed the effects of flooding, herbivory, and both stress factors on the composition of blends of emitted volatiles. Headspace volatiles were collected from all treatment combinations seven days after flooding. We documented metrics indicative of biomass allocation to determine the effects of individual and combined stressors on plant growth. We also evaluated relationships between volatile emissions and indicators of soil chemical characteristics as influenced by treatment factors. Flooding and herbivory induced the emission of volatile organic compounds (VOCs) in similar ways on both maize hybrids, but the interaction of both stress factors produced significantly larger quantities of emitted volatiles. Thirty-eight volatile compounds were identified, including green leaf volatiles, monoterpenes, an aldehyde, a benzoate ester, sesquiterpenes, a diterpene alcohol, and alkane hydrocarbons. The hybrid marketed for organic production was a stronger VOC emitter. As expected, plant biomass was detrimentally affected by flooding. Soil chemical properties were less responsive to the treatment factors. Taken together, the results suggest that flooding stress and the interactions of flooding and insect attack can shape the emission of plant volatiles and further influence insect-plant interactions.


Assuntos
Inundações , Spodoptera/fisiologia , Compostos Orgânicos Voláteis/química , Zea mays/química , Animais , Quimera , Cromatografia Gasosa-Espectrometria de Massas , Herbivoria , Larva/fisiologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Solo/química , Spodoptera/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/análise , Zea mays/metabolismo
13.
J Chem Ecol ; 47(8-9): 768-776, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34185213

RESUMO

In natural and agricultural ecosystems, plants are often simultaneously or sequentially exposed to combinations of stressors. Here we tested whether limited water availability (LWA) affects plant response to insect herbivory using two populations of Eruca sativa from desert and Mediterranean habitats that differ in their induced defenses. Considering that such differences evolved as responses to biotic and possibly abiotic stress factors, the two populations offered an opportunity to study ecological aspects in plant response to combined stresses. Analysis of chemical defense mechanisms showed that LWA significantly induced total glucosinolate concentrations in the Mediterranean plants, but their concentrations were reduced in the desert plants. However, LWA, with and without subsequent jasmonate elicitation, significantly induced the expression of proteinase inhibitor in the desert plants. Results of a no-choice feeding experiment showed that LWA significantly increased desert plant resistance to Spodoptera littoralis larvae, whereas it did not affect the relatively strong basal resistance of the Mediterranean plants. LWA and subsequent jasmonate elicitation increased resistance against the generalist insect in Mediterranean plants, possibly due to both increased proteinase inhibitor expression and glucosinolate accumulation. The effect of LWA on the expression of genes involved in phytohormone signaling, abscisic acid (ABA-1) and jasmonic acid (AOC1), and the jasmonate responsive PDF1.2, suggested the involvement of abscisic acid in the regulation of defense mechanisms in the two populations. Our results indicate that specific genotypic responses should be considered when estimating general patterns in plant response to herbivory under water deficiency conditions.


Assuntos
Brassicaceae/metabolismo , Ecossistema , Spodoptera/fisiologia , Água/química , Ácido Abscísico/metabolismo , Animais , Brassicaceae/química , Ciclopentanos/metabolismo , Defensinas/genética , Defensinas/metabolismo , Clima Desértico , Inibidores Enzimáticos/metabolismo , Expressão Gênica/efeitos dos fármacos , Glucosinolatos/análise , Glucosinolatos/metabolismo , Glucosinolatos/farmacologia , Herbivoria/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Região do Mediterrâneo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Spodoptera/crescimento & desenvolvimento , Estresse Fisiológico , Água/metabolismo
14.
PLoS One ; 16(5): e0251134, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33945577

RESUMO

The efficacy and non-target arthropod effects of transgenic DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 Bt cotton, expressing proteins Cry1Ac, Cry1F and Vip3Aa19, was examined through field trials in Brazil. Fifteen field efficacy experiments were conducted from 2014 through the 2020 growing season across six different states in Brazil to evaluate performance against key lepidopteran pests through artificial infestations of Chrysodeixis includens (Walker), Spodoptera frugiperda (J.E. Smith,1797), Spodoptera cosmioides (Walker, 1858) and Chloridea virescens (F., 1781), and natural infestations of Alabama argillacea (Hübner) and S. frugiperda. The impact of this Bt cotton technology on the non-target arthropod community in Brazilian cotton production systems was also assessed in a multi-site experiment. DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton significantly reduced the feeding damage caused by S. frugiperda, S. cosmioides, C. includens, C. virescens and A. argillacea, causing high levels of mortality (greater than 99%) to all target lepidopteran pests evaluated during vegetative and/or reproductive stages of crop development. Non-target arthropod community-level analyses confirmed no unintended effects on the arthropod groups monitored. These results demonstrate the value of transgenic Bt cotton containing event DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 for consideration as part of an integrated approach for managing key lepidopteran pests in Brazilian cotton production systems.


Assuntos
Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/análogos & derivados , Artrópodes/crescimento & desenvolvimento , Gossypium/metabolismo , Gossypium/parasitologia , Ácido 4-Acetamido-4'-isotiocianatostilbeno-2,2'-dissulfônico/metabolismo , Animais , Brasil , Controle de Insetos , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Controle Biológico de Vetores/métodos , Folhas de Planta/parasitologia , Plantas Geneticamente Modificadas/parasitologia , Spodoptera/crescimento & desenvolvimento
15.
J Chem Ecol ; 47(7): 689-706, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34056671

RESUMO

A large percentage of crop loss is due to insect damage, especially caterpillar damage. Plant chitinases are considered excellent candidates to combat these insects since they can degrade chitin in peritrophic matrix (PM), an important protective structure in caterpillar midgut. Compared to chemical insecticides, chitinases could improve host plant resistance and be both economically and environmentally advantageous. The focus of this research was to find chitinase candidates that could improve plant resistance by effectively limiting caterpillar damage. Five classes of endochitinase (I-V) genes were characterized in the maize genome, and we isolated and cloned four chitinase genes (chitinase A, chitinase B, chitinase I, and PRm3) present in two maize (Zea mays L.) inbred lines Mp708 and Tx601, with different levels of resistance to caterpillar pests. We also investigated the expression of these maize chitinases in response to fall armyworm (Spodoptera frugiperda, FAW) attack. The results indicated that both chitinase transcript abundance and enzymatic activity increased in response to FAW feeding and mechanical wounding. Furthermore, chitinases retained activity inside the caterpillar midgut and enzymatic activity was detected in the food bolus and frass. When examined under scanning electron microscopy, PMs from Tx601-fed caterpillars showed structural damage when compared to diet controls. Analysis of chitinase transcript abundance after caterpillar feeding and proteomic analysis of maize leaf trichomes in the two inbreds implicated chitinase PRm3 found in Tx601 as a potential insecticidal protein.


Assuntos
Quitinases/farmacologia , Proteínas de Plantas/farmacologia , Spodoptera/efeitos dos fármacos , Zea mays/metabolismo , Sequência de Aminoácidos , Animais , Quitinases/classificação , Quitinases/genética , Quitinases/metabolismo , Clonagem Molecular , DNA de Plantas/química , DNA de Plantas/genética , DNA de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas , Herbivoria/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/fisiologia , Filogenia , Folhas de Planta/metabolismo , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análise de Sequência de DNA , Spodoptera/crescimento & desenvolvimento , Spodoptera/fisiologia
16.
Sci Rep ; 11(1): 7760, 2021 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-33833345

RESUMO

Fall Armyworm (FAW), Spodoptera frugiperda, is a polyphagous pest capable of feeding over 80 plant species and was indigenous to the Western Hemisphere. Within a span of 4 years, FAW has established itself throughout most of the regions in Africa and Asia causing significant losses in maize production. Owing to its revamped distribution range, it would be prudent to analyze the ensuing genetic changes and study the emerging phylogeographic patterns across the world. In this regard, we would like to provide a current snapshot of genetic diversity of FAW in India 2 years after the initial introduction and compare it with the worldwide diversity in order to trace the origins and evolutionary trajectories of FAW in India. We have investigated around 190 FAW samples from different regions in India for strain identity and polymorphism analysis on the basis of partial mitochondrial cytochrome oxidase I (COI) gene sequences. Apart from the ancestral rice and corn strain haplotype, our study demonstrates the presence of 14 more haplotypes unique to India at a haplotype diversity of 0.356. We were also able to record inter-strain hybrid haplotypes of rice and corn strains in India. Regional heterogeneity within Indian populations seems to be quite low representative of extensive migration of FAW within India. Distribution analysis of pairwise differences and rejection of neutrality tests suggest that the FAW population in India might be undergoing expansion. Our data is consistent with the findings suggesting a recent and common origin for invasive FAW populations in Asia and Africa, and does not indicate multiple introductions to India. This study reports the highest genetic diversity for Indian FAW populations to date and will be useful to track the subsequent evolution of FAW in India. The findings would have important ramifications for FAW behavior and composition throughout the world.


Assuntos
Variação Genética , Spodoptera/crescimento & desenvolvimento , Animais , Haplótipos , Índia , Spodoptera/genética
17.
J Invertebr Pathol ; 183: 107562, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33652013

RESUMO

Host plays an important role in influencing virulence of a pathogen and efficacy of a biopesticide. The present study was aimed to characterize the possible factors present in Spodoptera litura that influenced pathogenecity of orally ingested S. marcescens strains, differing in their virulence. Fifth instar larvae of S. litura responded differently as challenged by two Serratia marcescens strains, SEN (virulent strain, LC50 7.02 103 cfu/ml) and ICC-4 (non-virulent strain, LC50 1.19 1012 cfu/ml). Considerable increase in activity of lytic enzymes protease and phospholipase was recorded in the gut and hemolymph of larvae fed on diet supplemented with S. marcescens strain ICC-4 as compared to the larvae treated with S. marcescens strain SEN. However, a significant up-regulation of antioxidative enzymes SOD (in foregut and midgut), CAT (in the midgut) and GST (in the foregut and hemolymph) was recorded in larvae fed on diet treated with the virulent S. marcescens strain SEN in comparison to larvae fed on diet treated with the non-virulent S. marcescens strain ICC-4. Activity of defense related enzymes lysozyme and phenoloxidase activity were also higher in the hemolymph of larvae fed with diet treated with S. marcescens strain SEN as compared to hemolymph of S. marcescens strain ICC-4 treated larvae. More number of over-expressed proteins was observed in the gut and hemolymph of S. marcescens strains ICC-4 and SEN treated larvae, respectively. Identification of the selected differentially expressed proteins indicated induction of proteins involved in insect innate immune response (Immunoglobulin I-set domain, Apolipophorin III, leucine rich repeat and Titin) in S. marcescens strain SEN treated larvae. Over-expression of two proteins, actin related protein and mt DNA helicase, were noted in S. marcescens treated larvae with very high levels observed in the non-virulent strain. Up-regulation of homeobox protein was noted only in S. marcescens strain ICC-4 challenged larvae. This study indicated that ingestion of non-virulent S. marcescens strain ICC-4 induced strong immune response in insect gut while there was weak response to the virulent S. marcescens strain SEN which probably resulted in difference in their virulence.


Assuntos
Agentes de Controle Biológico/farmacologia , Serratia marcescens/fisiologia , Serratia marcescens/patogenicidade , Spodoptera/virologia , Animais , Hemolinfa/virologia , Larva/crescimento & desenvolvimento , Larva/virologia , Spodoptera/crescimento & desenvolvimento , Virulência
18.
Int J Biol Macromol ; 180: 539-546, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33722622

RESUMO

To combat insect pests and vectors that are responsible for high losses in food and lives, insecticide discovery is of top priority. This study aimed to synthesize, characterize and investigate the insecticidal activity of 1,3,4-oxadiazole derivatives grafted on chitosan (CS) and modified polymethyl methacrylate (PMMA). 5-(pyridin-3-yl)-1,3,4-oxadiazole-2-thiol and 5-(pyridin-4-yl)-1,3,4-oxadiazole-2-thiol were respectively reacted with ethylchloroacetate and methyl-2-choloroacetoacetate. The resulted esters were grafted with CS and modified-PMMA. The products were characterized using FT-IR, 1H NMR, TGA, and XRD techniques. Four CS grafted ones were able to show good insecticidal activity against the cotton leafworm Spodoptera littoralis. Furthermore, the safety of these compounds was tested using MTT assay on a human cell line (WI-38). The results indicated that compounds 2a, 2b, 6a, and 6d are considered insecticide candidates to S. littoralis fourth-instar larvae. Cytotoxicity of 2b and 6d indicated that they are the least toxic to humans. It is concluded that both compounds may represent promising insecticide candidates.


Assuntos
Quitosana/química , Inseticidas/química , Oxidiazóis/química , Polimetil Metacrilato/química , Spodoptera/crescimento & desenvolvimento , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Gossypium/parasitologia , Humanos , Inseticidas/síntese química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Modelos Químicos , Estrutura Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
19.
Infect Genet Evol ; 90: 104749, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33540087

RESUMO

Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) represents a strong candidate to develop environmental-friendly pesticides against the fall armyworm (Spodoptera frugiperda), a widespread pest that poses a severe threat to different crops around the world. To date, SfMNPV genomic diversity of different isolates has been mainly studied by means of restriction pattern analyses and by sequencing of the egt region. Here, the genomic diversity present inside an isolate of SfMNPV was explored using high-throughput sequencing for the first time. We identified 704 intrahost single nucleotide variants, from which 184 are nonsynonymous mutations distributed among 82 different coding sequences. We detected several structural variants affecting SfMNPV genome, including two previously reported deletions inside the egt region. A comparative analysis between polymorphisms present in different SfMNPV isolates and our intraisolate diversity data suggests that coding regions with higher genetic diversity are associated with oral infectivity or unknown functions. In this context, through molecular evolution studies we provide evidence of diversifying selection acting on sf29, a putative collagenase which could contribute to the oral infectivity of SfMNPV. Overall, our results contribute to deepen our understanding of the coevolution between SfMNPV and the fall armyworm and will be useful to improve the applicability of this virus as a biological control agent.


Assuntos
Genoma Viral , Nucleopoliedrovírus/genética , Spodoptera/virologia , Animais , Argentina , Larva/genética , Larva/virologia , Nucleopoliedrovírus/classificação , Spodoptera/crescimento & desenvolvimento
20.
Ecotoxicol Environ Saf ; 213: 112076, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33639562

RESUMO

We executed a pot experiment to examine the differences of absorption, chemical forms, subcellular distribution, and toxicity of Cd between two cultivars of Chinese flowering cabbage Brassica campestris [Lvbao701 (low-Cd cultivar) and Chicaixin No.4 (high-Cd cultivar)]. Compared to Chicaixin No.4, the presence of Lvbao701 enhanced the proportion of insoluble Cd forms in soil, Lvbao701 roots and leaves had higher proportion of Cd converted into insoluble phosphate precipitates and pectate-or protein-bound forms and lower proportion of inorganic Cd, which result in low accumulation and toxicity of Cd to Lvbao701 and cutworm Spodoptera litura fed on Lvbao701 leaves. Instead of total Cd, Cd transfer and toxicity in B. campestris-S. litura system depend on chemical Cd forms in soil and cabbages and subcellular Cd distributions in cabbages and insects, and the proportions of them were not the highest among all chemical forms and subcellular distributions of Cd. Although exchangeable Cd was major Cd chemical form in cabbage planted soil, Cd bound to iron and manganese oxides and to organic matter were significantly correlated with growth indices and photosynthesis parameters of cabbages. Despite major part of Cd was precipitated in cell wall of roots, Cd in organelle fraction was closely associated with the fitness of cabbages. Metal-rich granules, not cytosolic fraction (the major subcellular Cd distribution), affected the food utilization of S. litura. Therefore, cabbage cultivars significantly affected Cd transfer and toxicity in B. campestris-S. litura system, and the use of Lvbao701 in Cd polluted soil could reduce potential risks for Cd entering food chains.


Assuntos
Brassica/fisiologia , Cádmio/toxicidade , Poluentes do Solo/toxicidade , Animais , Brassica/metabolismo , Cádmio/metabolismo , China , Cadeia Alimentar , Larva/metabolismo , Raízes de Plantas/metabolismo , Reprodução , Solo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Spodoptera/crescimento & desenvolvimento , Spodoptera/fisiologia
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