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During their co-evolution with herbivorous insects, plants have developed multiple defense strategies that resist pests, such as releasing a blend of herbivory-induced plant volatiles (HIPVs) that repel pests or recruit their natural enemies. However, the responses of insects to HIPVs in maize (Zea mays L.) are not well understood. Here, we demonstrate that the Asian corn borer (ACB, Ostrinia furnacalis), a major insect pest of maize, shows a preference for maize pre-infested with ACB larvae rather than being repelled by these plants. Through combined transcriptomic and metabolomics analysis of ACB-infested maize seedlings, we identified two substances that explain this behavior: (E)-4,8-dimethylnona-1,3,7-triene (DMNT) and (3E,7E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). DMNT and TMTT attracted ACB larvae, and knocking out the maize genes responsible for their biosynthesis via gene editing impaired this attraction. External supplementation with DMNT/TMTT hampered the larvae's ability to locate pre-infested maize. These findings uncover a novel role for DMNT and TMTT in driving the behavior of ACB. Genetic modification of maize to make it less detectable by ACB might be an effective strategy for developing maize germplasm resistant to ACB and for managing this pest effectively in the field.
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Lateralisation is a well-established phenomenon observed in an increasing number of insect species. This study aims to obtain basic details on lateralisation in courtship and mating behaviour in Ostrinia furnacalis, the Asian corn borer. We conducted laboratory investigations to observe lateralisation in courtship and mating behaviours in adult O. furnacalis. Our goal was also to detect lateralised mating behaviour variations during sexual interactions and to elucidate how these variances might influence the mating success of males. Our findings reveal two distinct lateralised traits: male approaches from the right or left side of the female and the direction of male turning displays. Specifically, males approaching females from their right side predominantly exhibited left-biased 180° turning displays, while males approaching females from the left-side primarily displayed right-biased 180° turning displays. Notably, left-biased males, executing a 180° turn for end-to-end genital contact, initiated copulation with fewer attempts and began copulation earlier than their right-biased approaches with left-biased 180° turning displays. Furthermore, mating success was higher when males subsequently approached the right side of females during sexual encounters. Left-biased 180° turning males exhibited a higher number of successful mating interactions. These observations provide the first report on lateralisation in the reproductive behaviour of O. furnacalis under controlled laboratory conditions and hold promise for establishing reliable benchmarks for assessing and monitoring the quality of mass-produced individuals in pest control efforts.
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OfChtI and OfChi-h are considered potential targets for the control of Asian corn borer (Ostrinia furnacalis). In this work, the previously reported OfChtI inhibitor 5f was found to show certain inhibitory activity against OfChi-h (Ki = 5.81 µM). Two series of novel butenolide derivatives based on lead compound 5f were designed with the conjugate skeleton, contributing to the π-binding interaction to chitinase, and then synthesized. Compounds 4a-l and 7a-p displayed excellent inhibitory activities against OfChtI and OfChi-h, respectively, at a concentration of 10 µM. Compound 4h was found to be a good dual-Chitinase inhibitor, with Ki values of 1.82 and 2.00 µM against OfChtI and OfChi-h, respectively. The inhibitory mechanism studies by molecular docking suggested that π-π stacking interactions were crucial to the inhibitory activity of novel butenolide derivatives against two different chitinases. A preliminary bioassay indicated that 4h exhibited certain growth inhibition effects against O. furnacalis. Butenolide-like analogues should be further studied as promising novel dual-chitinase inhibitor candidates for the control of O. furnacalis.
Assuntos
4-Butirolactona/análogos & derivados , Quitinases , Mariposas , Animais , Zea mays , Simulação de Acoplamento Molecular , Quitinases/química , Crescimento e DesenvolvimentoRESUMO
Interspecific competition is an important factor in the population dynamics and geographical distribution of insect populations. Fall armyworm (FAW), Spodoptera frugiperda, an invasive species, and the Asian corn borer (ACB), Ostrinia furnacalis, a native pest species are major pests on maize in China, posing a threat to maize yield and grain quality. A series of laboratory, greenhouse, and field experiments were conducted to elucidate the competitive interactions between FAW and ACB. In the laboratory experiments, FAW exhibited aggressive behaviors more frequently when compared with ACB, while the latter species exhibited defense behaviors more frequently. Higher intraspecific competition was recorded in the FAW conspecific rather than in ACB, particularly in the 6th larval stage. FAW had a higher interspecific competitive advantage through intraguild predation over ACB, resulting in partial or complete displacement ACB when initially the ratio of the 2 species was 1 : 1. The interspecific competition also had significantly influenced on the population parameters, defensive enzymes, and nutrient of these 2 species. Competitive interaction proved that the response of superoxide, catalase, and soluble protein in FAW were significantly increased, whereas the total sugar content in both species was substantially decreased. Survival rate, and the plant damage that co-infested by both species varied significantly among the sequential combinations under greenhouse and field conditions. FAW consistently exhibited stronger intraspecific aggression than ACB under laboratory and field conditions when co-existing on the same feeding guild. These findings contribute to efforts toward the improvement of integrated pest management programs for FAW, in decision making for invasive and native pests' management strategies to reduce the high risks of FAW and ACB outbreaks.
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Genetically modified MON 89034 corn (Zea mays L.) expressing Bacillus thuringiensis (Bt) insecticidal proteins, viz. Cry1A.105 and Cry2Ab2, is a biotechnological option being considered for the management of the major corn pest in Indonesia, the Asian corn borer (Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae)). As a part of a proactive resistance-management program for MON 89034 corn in Indonesia, we assessed the baseline susceptibility of field-collected populations of O. furnacalis to Cry1A.105 and Cry2Ab2 proteins. Dose-response bioassays using the diet-dipping method indicated that the lethal concentration (LC50) values of Cry1A.105 and Cry2Ab2 in 24 different field populations of O. furnacalis ranged from 0.006 to 0.401 µg/mL and from 0.044 to 4.490 µg/mL, respectively, while the LC95 values ranged from 0.069 to 15.233 µg/mL for Cry1A.105 and from 3.320 to 277.584 µg/mL for Cry2Ab2. The relative resistance ratios comparing the most tolerant field populations and an unselected laboratory population were 6.0 for Cry1A.105 and 2.0 for Cry2Ab2 based on their LC50 values. Some field populations were more susceptible to both proteins than the unselected laboratory population. The LC99 and its 95% fiducial limits across the field populations were calculated and proposed as candidate diagnostic concentrations. These data provide a basis for resistance monitoring in Bt Corn and further support building resistance-management strategies in Indonesia.
Assuntos
Bacillus thuringiensis , Mariposas , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Indonésia , Endotoxinas/genética , Endotoxinas/metabolismo , Proteínas de Bactérias/farmacologia , Proteínas de Bactérias/toxicidade , Toxinas de Bacillus thuringiensis/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Proteínas Hemolisinas/farmacologia , Proteínas Hemolisinas/toxicidade , Mariposas/genética , Mariposas/metabolismo , Zea mays/genética , Zea mays/metabolismo , Resistência a Inseticidas/genética , Larva/metabolismoRESUMO
The Asian corn borer (Ostrinia furnacalis, Lepidoptera, Crambidae) and Oriental armyworm (Mythimna separata, Lepidoptera, Noctuidae) are 2 major lepidopteran pests of the maize plant, especially the whorls and tassels. The aim of this study was to investigate competition between 2 lepidopteran pests of maize. Intraspecific and interspecific competition occurs when O. furnacalis and M. separata larvae interact with various stages of the maize plant. Therefore, determining whether this competition can decrease larval damage by causing adverse effects on larval growth is crucial. During the maize growing season of 2022, the interaction of these species was assessed in the experimental field of Jilin Agricultural University, China. Interspecific and intraspecific competition of larvae in different maize tissues and the influence of competition on larval development was determined in the fields. The results showed that first, probing behavior was significantly frequent in O. furnacalis larvae; intraspecific and interspecific attack was significant at 4th instar (with leaf, silk, and kernel). Interspecific defense behavior was significant at 3rd instar (without food). O. furnacalis larvae showed attack behavior toward M. separata larvae frequently. Second, competition increased the mortality rate of O. furnacalis larvae (intraspecific, 67%; interspecific, 33%) and decreased pupation emergence rate. Thus, intraspecific and interspecific competition might affect the competitive displacement of pest species sharing the same ecological niche, as well as the prevalence and population dynamics of pests, and help to develop integrated pest management strategies.
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Mariposas , Humanos , Animais , Larva , Dinâmica Populacional , Zea mays , ChinaRESUMO
Asion corn borer (Ostrinia furnacalis (Guenee)) is one of the most important factors affecting the normal growth and yield of corn. However, chemical control methods currently in use cause severe pollution. In the present study, aminated mesoporous silica nanoparticles (MSNs-NH2) and polylactic acid (PLA) were used as the carrier and capping agent respectively to construct an insect gut microenvironment nano-response system that loaded spinosad, a biopesticide used to control O. furnacalis. The resulting spinosad@MSNs-PLA demonstrated high loading capacity (38.6 %) and improved photostability of spinosad. Moreover, this delivery system could intelligently respond to the intestinal microenvironment of the corn borer's gut and achieve the smart release of spinosad. Compared with the conventional pesticide, spinosad@MSNs-PLA exhibited superior efficacy in controlling the O. furnacalis and could uptake and transport in maize plants without adverse effects on their growth. Furthermore, the toxicity of spinosad@MSNs-PLA on zebrafish was reduced by over 50 times. The prepared spinosad@MSNs-PLA has great potential and could be widely applied in agricultural production in the future. This approach could improve the utilization of pesticide and reduce environmental pollution. In addition, MSNs-PLA nano vectors provide new ideas for the control of other borer pests.
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Nanopartículas , Praguicidas , Animais , Zea mays , Dióxido de Silício , Peixe-Zebra , Poliésteres , PorosidadeRESUMO
Maize seedlings contain high amounts of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), and the effect of DIMBOA is directly associated with multiple insect-resistance against insect pests such as Asian corn borer and corn leaf aphids. Although numerous genetic loci for multiple insect-resistant traits have been identified, little is known about genetic controls regarding DIMBOA content. In this study, the best linear unbiased prediction (BLUP) values of DIMBOA content in two ecological environments across 310 maize inbred lines were calculated; and their phenotypic data and BLUP values were used for marker-trait association analysis. We identified nine SSRs that were significantly associated with DIMBOA content, which explained 4.30-20.04% of the phenotypic variation. Combined with 47 original genetic loci from previous studies, we detected 19 hot loci and approximately 11 hot loci (in Bin 1.04, Bin 2.00-2.01, Bin 2.03-2.04, Bin 4.00-4.03, Bin 5.03, Bin 5.05-5.07, Bin 8.01-8.03, Bin 8.04-8.05, Bin 8.06, Bin 9.01, and Bin 10.04 regions) supported pleiotropy for their association with two or more insect-resistant traits. Within the 19 hot loci, we identified 49 candidate genes, including 12 controlling DIMBOA biosynthesis, 6 involved in sugar metabolism/homeostasis, 2 regulating peroxidases activity, 21 associated with growth and development [(auxin-upregulated RNAs (SAUR) family member and v-myb avian myeloblastosis viral oncogene homolog (MYB)], and 7 involved in several key enzyme activities (lipoxygenase, cysteine protease, restriction endonuclease, and ubiquitin-conjugating enzyme). The synergy and antagonism interactions among these genes formed the complex defense mechanisms induced by multiple insect pests. Moreover, sufficient genetic variation was reported for DIMBOA performance and SSR markers in the 310 tested maize inbred lines, and 3 highly (DIMBOA content was 402.74-528.88 µg g-1 FW) and 15 moderate (DIMBOA content was 312.92-426.56 µg g-1 FW) insect-resistant genotypes were major enriched in the Reid group. These insect-resistant inbred lines can be used as parents in maize breeding programs to develop new varieties.
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Melhoramento Vegetal , Zea mays , Animais , Zea mays/genética , Insetos/genética , Variação Genética , Estudos de Associação GenéticaRESUMO
The Asian corn borer (ACB) Ostrinia furnacalis (Guenée) can occur in one to seven generations annually from cool (48°00' N) to warm (18°10' N) region of corn cultivation in China. Although ACB is commonly known as a facultative larval diapause insect, the co-existence of various voltinism suggests that intra-population variation may have evolved for the nature of diapause, i.e., voltinism plasticity. Here, we conducted recurrent selection efforts to establish three strains of, respectively, univoltine (with obligate diapause), multivoltine (with facultative diapause), and non-diapausing ACB under various temperature and photoperiod environments. The univoltine (Lu) strain has evolved a stable univoltinism under a diapause suppressing condition (16 h daylength at 28 °C), with the diapause incidence constantly over 80% after three generations of selection. The multivoltine strain (Lm) under the high temperature (28 °C) was shown to have a typical facultative diapause induced by a range of short-day lengths (11-13.5 h). Diapause incidence was constantly <2.6% under the long day length (16 h) when the temperature was from 18 to 28 °C, i.e., low temperature could not enhance the diapause response in the Lm strain. However, the development was prolonged from 14.2 ± 0.3 d to 46.0 ± 0.8 d when the temperature was reduced from 28 °C to 18 °C. The majority (94.4%) of the developed Ln strain still maintained the non-diapausing nature under a diapause enhancing condition, i.e., a short (13 h) daylength at a low temperature (22 °C). Lm and Ln were able to complete their second generation in Heihe (50°14' N) if the first-generation moth oviposits before 18 June. The study suggests that ACB has evolutionary intra-population variation in voltinism. Under the climate change scenario warmer spring and summer might affect the proportion of sympatric voltine biotype populations that evolve toward being multivoltine.
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Asian corn borer (ACB) is a destructive insect pest of corn and causes up to 80% yield reduction in the Philippines. Synthetic insecticides have been used to control ACB but they pose a risk to human health and the environment. The use of synergists increases insecticide effectiveness and decreases the frequency of insecticide application. In line with this principle, we performed in silico screening of phytochemicals from bayati against glutathione-s-transferase (GST), one of the important detoxifying enzymes of ACB. Homology modeling was done to generate an acceptable three-dimensional protein structure (OfGST). Through ensemble molecular docking, we found that three phytosterols (stigmasterol, lupeol, and gamma-sitosterol) from bayati have a higher binding affinity to OfGST than glutathione, its natural substrate. Molecular dynamics simulation revealed that lupeol and gamma-sitosterol have a greater stabilizing effect on OfGST than stigmasterol, as supported by the RMSD, radius of gyration, and SASA plots of all complexes.Communicated by Ramaswamy H. Sarma.
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Cocculus , Inseticidas , Mariposas , Animais , Humanos , Zea mays , Glutationa Transferase/metabolismo , Simulação de Acoplamento Molecular , Estigmasterol/farmacologiaRESUMO
Asian corn borer (Ostrinia furnacalis) is one of the most destructive pests in agriculture. Three chitinases OfChtI, OfChtII, and OfChi-h are regarded as potential targets for discovering novel agrochemicals to control O. furnacalis. In this study, piperine (Ki = 43.78â¼83.03 µM) was first shown to exhibit inhibitory activities against all three chitinases. Subsequently, 19 novel piperine derivatives were rationally designed based on the conserved aromatic residues of three chitinases and then synthesized. Among them, Compound 5k (Ki = 11.78â¼22.82 µM) was identified as the most effective multichitinase inhibitor and indeed displayed higher insecticidal activity against O. furnacalis than dual- or single-chitinase inhibitors. Molecular mechanism studies clarified that Compound 5k interacted with two conserved TRP and TYR of three chitinases in identical modes through hydrogen bonds, hydrophobic, and π-π interactions. Moreover, the microinjection experiment indicated that Compound 5k exhibited substantial sublethal effects against O. furnacalis by regulating its growth and development. This study provides evidence of multichitinase inhibitors to be applied in the control of O. furnacalis.
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Quitinases , Mariposas , Alcaloides , Animais , Benzodioxóis/farmacologia , Quitinases/química , Piperidinas , Alcamidas Poli-Insaturadas/farmacologiaRESUMO
AIMS: This study aimed to isolate and identify entomopathogenic fungi (EPF) from fungus-infected Ostrinia furnacalis larvae, screen their bio-efficacy against O. furnacalis, and select the most suitable virulent native EPF for biocontrol agent development. METHODS AND RESULTS: The occurrence of EPF isolated from various maize production regions in Xinjiang was investigated. Of 13,864 O. furnacalis cadavers surveyed, 536 were selected, and of 136 fungal specimens collected, 14 species were identified. Four fungal isolates were highly pathogenic to O. furnacalis: Aspergillus sp., Lecanicillium attenuatum, Beauveria bassiana and Penicillium polonicum. The Aspergillus sp. was the most abundant (42.25% distribution frequency). Bioassay results revealed that it was as pathogenic as B. bassiana (positive control), with 96.58% lethality against O. furnacalis (LC50 : 1.40 × 104 conidia ml-1 , LT50 : 3.41 days). Through morphological examination and rDNA-benA and rDNA-CaM homogeneity analyses, the isolate was identified as Aspergillus nomius. CONCLUSIONS: Four EPF species were highly pathogenic, with A. nomius being the most prevalent in Xinjiang. A. nomius is a potential biocontrol agent. SIGNIFICANCE AND IMPACT OF STUDY: For sustainable prevention and control of O. furnacalis infestation, identifying biocontrol agents with high virulence against O. furnacalis is crucial. The findings of this study support the development of EPF-based biocontrol approaches.
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Beauveria , Mariposas , Animais , Zea mays/genética , Larva/microbiologia , Beauveria/genética , DNA RibossômicoRESUMO
The Asian corn borer, Ostrinia furnacalis (Guenée, 1854), is a highly damaging pest in Asia and the Pacific islands, and larvae feed mainly from corn crops. To determine the suitability of Bt-corn technology for the future control of this pest, understanding the potential to develop resistance to Cry1Ab and the basis of cross-resistance to other Cry1 proteins is of great interest. Here, we have explored the binding of Cry1A proteins to brush border membrane vesicles from two O. furnacalis colonies, one susceptible (ACB-BtS) and one laboratory-selected with Cry1Ab (ACB-AbR). The insects developed resistance to Cry1Ab and showed cross-resistance to Cry1Aa, Cry1Ac, and Cry1F. Binding assays with radiolabeled Cry1Ab and brush border membrane vesicles from susceptible insects showed that Cry1A proteins shared binding sites, though the results were not conclusive for Cry1F. The results were confirmed using radiolabeled Cry1Aa. The resistant insects showed a reduction of the specific binding of both Cry1Ab and Cry1Aa, suggesting that part of the binding sites were lost or altered. Competition binding assays showed full competition between Cry1Ab and Cry1Aa proteins in the susceptible colony but only partial competition in resistant insects, confirming the alteration of some, but not all, binding sites for these two proteins. The binding site model for Cry1A proteins in O. furnacalis is in agreement with the occurrence of multiple membrane receptors for these proteins.
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Toxinas de Bacillus thuringiensis/efeitos adversos , Resistência a Inseticidas/genética , Larva/efeitos dos fármacos , Larva/genética , Mariposas/efeitos dos fármacos , Mariposas/genética , Zea mays/parasitologia , Animais , Sítios de Ligação/efeitos dos fármacos , Sítios de Ligação/genética , China , Controle Biológico de Vetores/métodosRESUMO
Clarification of the interactions between engineered nanomaterials and multiple generations of insects is crucial to understanding the impact of nanotechnology on the environment and agriculture, particularly in toxicity management, pest management and genetic engineering. To date, there has been very limited information about nanoparticle-insect interactions at the genetic and proteomic levels. Here, we examined the phenotypic responses and potential mechanism of a lepidopteran insect Asian corn borer (ACB) to graphene oxide (GO). It was demonstrated that GO could significantly promote the growth of ACB. The transcriptomic and proteomic results consistently verified that GO might activate trypsin-like serine protease, glutathione S-transferase, heat shock protein and glycosyltransferase to further influence the development of ACB. RNA interference results indicated that the trypsin gene was one of the critical genes to accelerate the growth of ACB fed with GO diet. Moreover, physiological analysis showed potential alterations of the expression levels of genes and proteins, and more cholesterol (CE), triacylglycerides (TG) and lipids were accumulated in GO-exposed ACB. Our findings may help to reveal the phenotypic, physiological and genetic responses of insects under exposure to nanomaterials and to assess the environmental risks of other nanomaterials.
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Transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal proteins have been extensively planted for insect pest control, but the evolution of Bt resistance in target pests threatens the sustainability of this approach. Mutations of cadherin in the midgut brush border membrane was associated with Cry1Ac resistance in several lepidoptera species, including the Asian corn borer, Ostrinia furnacalis, a major pest of maize in Asian-Western Pacific countries. However, the causality of O. furnacalis cadherin (OfCad) with Cry1Ac resistance remains to be clarified. In this study, in vitro and in vivo approaches were employed to examine the involvement of OfCad in mediating Cry1Ac toxicity. Sf9 cells transfected with OfCad showed significant immunofluorescent binding with Cry1Ac toxin and exhibited a concentration-dependent mortality effect when exposed to Cry1Ac. The OfCad knockout strain OfCad-KO, bearing homozygous 15.4 kb deletion of the OfCad gene generated by CRISPR/Cas9 mutagenesis, exhibited moderate-level resistance to Cry1Ac (14-fold) and low-level resistance to Cry1Aa (4.6-fold), but no significant changes in susceptibility to Cry1Ab and Cry1Fa, compared with the original NJ-S strain. The Cry1Ac resistance phenotype was inherited as autosomal, recessive mode, and significantly linked with the OfCad knockout in the OfCad-KO strain. These results demonstrate that the OfCad protein is a functional receptor for Cry1Ac, and disruption of OfCad confers a moderate Cry1Ac resistance in O. furnacalis. This study provides new insights into the mode of action of the Cry1Ac toxin and useful information for designing resistance monitoring and management strategies for O. furnacalis.
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Toxinas de Bacillus thuringiensis/metabolismo , Toxinas de Bacillus thuringiensis/toxicidade , Caderinas/metabolismo , Resistência à Doença/efeitos dos fármacos , Insetos/metabolismo , Resistência a Inseticidas/efeitos dos fármacos , Zea mays/metabolismo , Zea mays/parasitologia , Animais , Bacillus thuringiensis/químicaRESUMO
The Asian corn borer, Ostrinia furnacalis (Guenée), is the most devastating maize pest in Myanmar. The damage caused by this pest has become a significant obstacle to farmers' income and the national economy. Control of O. furnacalis is challenging due to its protected feeding sites and the crop's height during later phases of the pest's attack. Trichogramma (Hymenoptera: Trichogrammatidae) parasitoids have been used successfully against corn borers in other countries, but knowledge on the species composition in Myanmar is limited. As a first step for potential biological control of Asian corn borer in Myanmar, Trichogramma were collected from major maize growing regions. Identification was performed based on both morphological and molecular techniques. The majority of collected specimens were identified as Trichogramma ostriniae Pang and Chen, T. chilonis Ishii, and T. dendrolimi Matsumura. This is the first report on the composition of Trichogramma species, and an important step towards the establishment of biological control against O. furnacalis in Myanmar.
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Himenópteros , Lepidópteros , Mariposas , Vespas , Animais , Mianmar , Controle Biológico de Vetores , Zea maysRESUMO
This study assessed the farm-level economic and environmental impacts from the use of genetically modified (GM) corn in Vietnam (resistant to Lepidopteran pests of corn and tolerant to the herbicide glyphosate). It was largely based on a farmer survey conducted in 2018-19. The GM varieties out-performed conventional varieties in terms of yield by +30.4% (+15.2% if the yield comparison is with only the nearest performing equivalent conventional varieties) and reduced the cost of production by between US $26.47 per ha and US $31.30 per ha. For every extra US $1 spent on GM seed relative to conventional seed, farmers gained between an additional US $6.84 and US $12.55 in extra income. The GM maize technology also reduced insecticide and herbicide use. The average amount of herbicide active ingredient applied to the GM crop area was 26% lower (1.66 kg per ha) than the average value for the conventional corn area (2.26 kg/ai per ha) and in terms of the associated environmental impact of the herbicide use, as measured by the Environmental Impact Quotient (EIQ) indicator, it was lower by 36% than the average value applicable to the conventional corn area. Insecticides were used on a significantly lower GM crop area and, when used, in smaller amounts. The average amount of insecticide applied to the GM corn crop was significantly lower by 78% (0.08 kg/ai per ha) than the average value for the conventional corn area (0.36 kg/ai per ha) and in terms of the associated environmental impact of the insecticide use, as measured by the EIQ indicator, it was also lower by 77% than the average value for conventional corn (14.06 per ha).
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Produtos Agrícolas/genética , Zea mays/genética , Fazendas , Plantas Geneticamente Modificadas/genética , Inquéritos e Questionários , VietnãRESUMO
Evolution of insect resistance to Bt toxins challenges the use of Cry toxins to control agricultural pests. In lepidopterans, Cry toxin affinity towards multiple midgut epithelial receptors has become a matter of dispute. Cry1Ah toxin-binding proteins were identified in the larval midgut of susceptible (ACB-BtS) and resistant (ACB-AhR) strains of the Asian corn borer (ACB). A pull-down assay was performed using biotinylated Cry1Ah toxin, and the binding proteins were identified by employing liquid chromatography-tandem mass spectrometry (LC-MS/MS). This study aimed to find the binding consistency of the midgut epithelial protein to the Cry1Ah toxin. The binding proteins from different fractions of SDS-PAGE showed a different pattern. We observed an isoform of prophenoloxidase PPO1b (UniProt Acc No. A0A1Q1MKI0), which was found only in the ACB-AhR fractions. Prophenoloxidase (proPO) is an extraordinary defense molecule activated in insect species during pathogen invasion and the wound healing process. Importantly, this prophenoloxidase might have direct/indirect interaction with the Cry1Ah toxin. Our data also suggest that factors like techniques, enrichment of binding proteins in the sample and the reversible and irreversible nature of the brush border membrane vesicles (BBMVs) to Cry toxins could cause the inconsistency in the protein-protein interactions. Moreover, inside the larva midgut, the influence of the Cry toxins under physiological conditions might be different from the laboratory procedures.
Assuntos
Toxinas de Bacillus thuringiensis/metabolismo , Sistema Digestório/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Proteínas de Insetos/metabolismo , Lepidópteros/metabolismo , Proteínas de Membrana/metabolismo , Zea mays/parasitologia , Animais , Toxinas de Bacillus thuringiensis/farmacologia , Sistema Digestório/embriologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Resistência a Inseticidas , Larva/metabolismo , Lepidópteros/efeitos dos fármacos , Lepidópteros/embriologia , Ligação ProteicaRESUMO
The adoption of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal crystalline (Cry) proteins has reduced insecticide application, increased yields, and contributed to food safety worldwide. However, the efficacy of transgenic Bt crops is put at risk by the adaptive resistance evolution of target pests. Previous studies indicate that resistance to Bacillus thuringiensis Cry1A and Cry1F toxins was genetically linked with mutations of ATP-binding cassette (ABC) transporter subfamily C gene ABCC2 in at least seven lepidopteran insects. Several strains selected in the laboratory of the Asian corn borer, Ostrinia furnacalis, a destructive pest of corn in Asian Western Pacific countries, developed high levels of resistance to Cry1A and Cry1F toxins. The causality between the O. furnacalisABCC2 (OfABCC2) gene and resistance to Cry1A and Cry1F toxins remains unknown. Here, we successfully generated a homozygous strain (OfC2-KO) of O. furnacalis with an 8-bp deletion mutation of ABCC2 by the CRISPR/Cas9 approach. The 8-bp deletion mutation results in a frame shift in the open reading frame of transcripts, which produced a predicted protein truncated in the TM4-TM5 loop region. The knockout strain OfC2-KO showed much more than a 300-fold resistance to Cry1Fa, and low levels of resistance to Cry1Ab and Cry1Ac (<10-fold), but no significant effects on the toxicities of Cry1Aa and two chemical insecticides (abamectin and chlorantraniliprole), compared to the background NJ-S strain. Furthermore, we found that the Cry1Fa resistance was autosomal, recessive, and significantly linked with the 8-bp deletion mutation of OfABCC2 in the OfC2-KO strain. In conclusion, in vivo functional investigation demonstrates the causality of the OfABCC2 truncating mutation with high-level resistance to the Cry1Fa toxin in O. furnacalis. Our results suggest that the OfABCC2 protein might be a functional receptor for Cry1Fa and reinforces the association of this gene to the mode of action of the Cry1Fa toxin.
Assuntos
Toxinas de Bacillus thuringiensis/metabolismo , Bacillus thuringiensis/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Proteínas de Insetos/genética , Mariposas/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/parasitologia , Zea mays/parasitologia , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis/genética , Sistemas CRISPR-Cas , Endotoxinas/genética , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Proteínas Hemolisinas/genética , Proteínas de Insetos/deficiência , Resistência a Inseticidas/genética , Mariposas/metabolismo , Proteína 2 Associada à Farmacorresistência Múltipla , Proteínas Associadas à Resistência a Múltiplos Medicamentos/deficiência , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Zea mays/genética , Zea mays/metabolismoRESUMO
Phenoloxidase (PO) is a crucial enzyme in the Arthropods melanization process, in which synthesized melanin rapidly acts at the site of injury and infection. In this study, we observed significant changes in humoral and cellular responses after exposing susceptible and resistant strains to a sub-lethal concentration of Cry1Ah toxin. Based on STRING v 11.0 computational protein-protein interaction analysis, we selected seven immune genes namely Prophenoloxidase PPO1b, PP03, Serpin-3, Serpin-5, Beta-1,3-glucan recognition protein, Immulectin-3 and Serine protease SP105 reported in Asian corn borer. Quantitative real-time PCR gene expression studies showed Cry1Ah resistant strain had higher expression of PPO1b, PP03, Serpin-3, Beta-1,3-glucan recognition protein, Immulectin-3 and Serine protease SP105 genes in midgut and hemocyte samples. This study also investigated and found that the level of prophenoloxidation (proPO) activity in Cry1Ah resistant strains was significantly higher than susceptible strains. Cry1Ah toxin significantly increased the resistant strain's immune responses, the difference was observed through assays of bacterial agglutination and phagocytosis. Additionally, immune response induced by Cry1Ah toxin influences the microbiome composition associated with the host system. These parameters seem to explain the contribution of PO/PO regulating proteins render the host to resist the Cry1Ah toxin.