Evaluation of the inhibitory potential of pro-peptide region as the inhibitor of the digestive chymotrypsin of cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae), based on in silico studies

Spodoptera frugiperda (J.E. Smith) is an invasive pest in agriculture. It can potentially damage yield resulting severe crop losses and subsequently significant economic damage each year. S. frugiperda is predominantly managed using traditional chemical pesticides. Accordingly, sustainable alternatives such as digestive enzymes inhibitors can be used as an efficient pest management that protects the environment. This contribution aims to examine the pro-region of S. frugiperda trypsin as specific inhibitor of the pest protease enzyme. Structural modeling in conjunction with molecular docking simulations were conducted to design a peptide sequence with the best docking scores and strong binding energy to the target enzyme. The structural models of six pro-peptides were produced based on modification of 7-amino acids of the pro-region of S. frugiperda trypsin. VERIFY_3D, ERRAT, PROCHECK, PROSA and WHAT-IF scores validated the reliability of the predicted model of S. frugiperda trypsin. Molecular docking studies between the six designed inhibitor peptides and the predicted model structure at three different pH conditions were carried out. Data revealed that VPSNPQR at pH 11.0 with the best docking score, the lowest binding energy (ΔG) and dissociation constant (Kd) indicated a potent binding affinity towards S. frugiperda trypsin’s active site. Moreover, the peptide showed a weak potential for interaction with the human trypsin. The results indicated the importance of computational studies in design and selection of inhibitor peptides against target enzymes. Such inhibitors can be used for S. frugiperda control, which can be further applied in other pest management programs. Docking simulations between the pro-peptide inhibitor and Spodoptera frugiperda midgut trypsin confirmed the capacity of the designed pro-region in inhibiting the insect trypsin.

PDF HTML阅读 XML下载 导出引用 引用提醒 新疆北部棉铃虫寄主来源与转基因棉区庇护所评估 DOI: 10.5846/stxb201402160266 作者: 作者单位: 石河子大学,中国科学院新疆生态与地理研究所,中国科学院干旱区生物地理与生物资源重点实验室,121团农机推广站,147团农业科植保站,147团农业科植保站,石河子大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家国际科技合作专项(2011DFA33170);中国科学院院地合作专项(XBXJ-2011-029) Analysis of Larval host types of Cotton Bollworm (Helicoverpa armigera) Populations for Evaluation of Bt Refuges in Northern Xinjiang Author: Affiliation: Shihezi University,Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences,,The 121th Production and Construction Crops Agricultural Technology Extension Station,The 147th plant protection station of Agricultration Department,The 147th plant protection station of Agricultration Department,Shihezi University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:转Bt基因抗虫棉长期大规模种植后,棉铃虫对其存在抗性风险,庇护所是延缓抗性上升的策略之一。但在新疆北部转基因棉区,庇护所提供敏感棉铃虫的生态功能尚未见评估。2013年5-9月期间在新疆北部石河子地区147团、121团利用棉田边缘的智能测报灯收集棉铃虫成虫,应用碳稳定同位素技术从群体水平(混合翅膀)分析虫源性质,从个体水平(雌蛾翅膀和对应精包)确定交配类型;同时通过解剖雌性棉铃虫体内的精包数量评估交配频率。结果表明:来源于C4植物的棉铃虫主要出现在5月下旬和8-9月期间,比例占到50%左右;6-7月接近100%的棉铃虫来自于C3植物上;经测定不同寄主来源棉铃虫的有效交配比例为10%左右;两个地方的棉铃虫交配频率一般在0.9-2.1 次,但121团的第一代和第二代均高于147团。玉米是新疆北部地区重要的庇护所,但C3和C4来源棉铃虫同存的时间比较短,有效交配比例相对比较低,影响了庇护所的抗性稀释能力。在转基因棉区的抗性管理中不仅要考虑庇护所提供敏感棉铃虫数量大小,同时需要考虑有效交配比率,这将有利深刻理解庇护所生态功能。 Abstract:Transgenic cotton, expressing an insecticidal toxin from Bacillus thuringiensis (Bt cotton), has been widely cultivated for a long period in some areas of China. Therefore, there is the potential for the cotton bollworm, Helicoverpa armigera, to develop resistance to Bt cotton toxins. The United States Environmental Protection Agency (US EPA) is rethinking the requirement for some regions to delay developing natural refuge crops where Bt cotton growth has been highly successful. The policy of establishing refuges was intended to delay pest population development of Bt-toxin resistance. Bt cotton is widely grown in Xinjiang Province, which is the largest cotton-producing area in China, but no studies have been conducted on potential refuges in this region of China. In recent years, stable carbon isotope techniques (δ13C) have been used to identify the larval host-types (i.e., whether the hosts are C3 or C4 plants) of cotton bollworm. These methods have been used to evaluate the Bt refuge function of non-cotton crops. In this study, intelligent forecast light traps were established to collect adult cotton bollworms from May to September 2013, from the 147th and 121st regiments of the Shihezi reclamation area located in northern Xinjiang. The captured moths were placed into bottles and preserved in 95% alcohol until analysis. At each of the sites, 50 males and 30 females moths were selected on the day of capture, their wings combined into two bulked samples respectively to analyze their host type (C3 or C4) using δ13C analysis. At the same time, 30 female's wings and corresponding spermatophore were separated to one single sample to analyze the mating type and percentage of mating frequency between C3 and C4 host. A total of 23 bulked samples from the 147th regiment and 25 bulked samples from the 121st regiment were tested. The proportions of C3 and C4 hosts were calculated according to a standard curve constructed in 2012. Approximately 50% of cotton bollworms were derived from C4 hosts, and approximately 50% from C3 hosts in late May and from early August to September. From June to July, 100% of cotton bollworms were derived from C4 hosts. To evaluate the mating frequency of cotton bollworms at the two sites, we selected 210 anatomically adult females in the 1st and 2nd generations from the 147th and 121st regiments. The percentage of effective mating between the two larval host-types (C3 and C4) was approximately 10%. Mating frequency ranged from 0.9 to 2.1 per adult female at the two sites, and was higher at the 121st regiment site than at the 147th regiment site. Maize is considered to be the most important natural refuge for Bt-susceptible cotton bollworms in northern Xinjiang, since maize is the main C4 host plant in this area. Thus, maize may provide refuges for susceptible cotton bollworms in the autumn of one year and the spring of the following year. There is a short period in which cotton bollworms derived from C3 and C4 hosts simultaneously co-exist, and there is a very small percentage of effective mating between cotton bollworms derived from C3 and C4 hosts. This will affect the capacity to dilute the Bt-resistance in cotton bollworms, and may be related to the non-synchronization of C3 and C4 crops and male and female cotton bollworms. 参考文献 相似文献 引证文献

Cotton production nationally is low due to various constraints, including pests. Two main pests commonly found in cotton plantation in rain fed fields are cotton leafhopper (Amrasca biguttula) and cotton bollworm (Helicoverpa armigera). The study aimed to evaluate four packages of integrated pest management (IPM) techniques to control cotton leafhopper and cotton bollworm in rain fed fields. The experiment was conducted in farmers’ fields at Asembagus, East Java, between January and July 2012. Four packages of IPM evaluated were cotton varieties, i.e. Kanesia 10 or Kanesia 13, and seed treatment with synthetic insecticide (imidacloprid) before sowing or spraying molasses (10 ml L-1 water) as food for natural enemies. The cotton plants were intercropped with groundnut and sprayed with neem seed extract (NSE) at the action threshold level for pest control. These packages were compared among themselves and also with the methods usually used by farmers, i.e. planting cotton variety Kanesia 8 intercropped with groundnut and pest control using synthetic chemical insecticides. Twenty five plants were sampled randomly per plot and measured for their growth, leafhopper and bollworm populations, as well as cotton seed yield per plot. Observations were made weekly, starting at 30 days after planting (DAP) until 120 DAP. The results showed that the use of Kanesia 10 or Kanesia 13 intercropped with groundnut and spraying molasses to conserve natural enemies was the best pest management practice and superior to farmers’ practices. Conserving natural enemies is not only profitable (saving production cost of IDR1,150,000 to IDR1,500,000 ha-1 season-1), but also safe for the environment (no need to spray chemical insecticides).

Goal. To establish the effectiveness of the use of modern insecticides in corn crops against the cotton bollworm. Methods. Determination of the technical efficiency of insecticides was carried out in field conditions. Treatment with chemical insecticides was carried out on the 3rd day after the mass flight of H. armigera once, with biological preparations — twice, during the period of mass revival of caterpillars. Observation of the pest after treatment with drugs was carried out on the 3rd, 7th and 14th day at the rate of ex./100 plants in four repetitions, by counting them on cobs, panicles and leaves. For the experiments, the Paradiz corn hybrid (mid-early) was used, the seeds of which were pre-treated at the plant with a fungicide Maksym XL 035 FS (fludioxonil, 25 g/l, metalaxyl-M, 10 g/l) — 1 l/t. The beginning and intensity of the flight of cotton bollworm adults was determined using pheromone traps. The collection of male imagos was carried out every three days after the start of the flight. Data on crop losses were based on the actually calculated indicators of each variant of the experiment. The reliability of the obtained results was determined using the mathematical and statistical method. Results. In 2021—2022, when testing insecticides against cotton bollworm caterpillars on corn crops, the highest technical efficiency was provided by: Koragen 20 KS (chlorantraniliprole, 200 g/l) — 82.1% and Ampliho 150 ZC, FC (chlorantraniliprole 150 g/l, lambda-cyhalothrin 50 g/l) — 77.7%. The biological preparations of Lepidotsyd-BTU, r. (Bacillus thuringiensis var. Kurstaki, serotype 3, titer 1.0 ќ 10 9 CFU/cm3) had the lowest technical efficiency — 48.2% and Bitoksybatsylin-BTU, r. (Bacilius thuringiensis var Thuringiensis, endospores — titer 1.0 ќ 10 9 CFU/ cm3) — 53.7%. When using the tested insecticides, the productivity of the Paradiz hybrid was higher compared to the control. When treated with Koragen 20 KS and Ampligo 150 ZC, FC, the yield increased by 0.480 and 0.320 t/ha. When treated with Radiant, CS (spinetoram, 120 g/l) and Belt 480 SC, CS (flubendiamide, 480 g∕l), — by 0.250 and 0.280 t/ha, respectively more. With the use of Liufoks 105 ES, e.c. (75 g/l fenoxycarb, 30 g/l lufenuron), Lepidotsyd-BTU, r. and Bitoksybatsylin-BTU, r., the amount of preserved corn grain yield was 0.190, 0.110 and 0.140 t/ha, respectively. Conclusions. It was found that Koragen 20 KS (82.1%) and Ampligo 150 ZC, FK (7.7%) were the most effective insecticides against cotton bollworm caterpillars in the Left Bank Forest Steppe of Ukraine. The specified drugs are used in low concentrations, and with the help of phytosanitary and instrumental monitoring in corn crops, treatment is recommended to be carried out once, which in turn allows to reduce the pesticide load on the ecosystem and prevents the development of resistance in phytophagous plants.

Cotton production nationally is low due to various constraints, including pests. Two main pests commonly found in cotton plantation in rain fed fields are cotton leafhopper (Amrasca biguttula) and cotton bollworm (Helicoverpa armigera). The study aimed to evaluate four packages of integrated pest management (IPM) techniques to control cotton leafhopper and cotton bollworm in rain fed fields. The experiment was conducted in farmers’ fields at Asembagus, East Java, between January and July 2012. Four packages of IPM evaluated were cotton varieties, i.e. Kanesia 10 or Kanesia 13, and seed treatment with synthetic insecticide (imidacloprid) before sowing or spraying molasses (10 ml L-1 water) as food for natural enemies. The cotton plants were intercropped with groundnut and sprayed with neem seed extract (NSE) at the action threshold level for pest control. These packages were compared among themselves and also with the methods usually used by farmers, i.e. planting cotton variety Kanesia 8 intercropped with groundnut and pest control using synthetic chemical insecticides. Twenty five plants were sampled randomly per plot and measured for their growth, leafhopper and bollworm populations, as well as cotton seed yield per plot. Observations were made weekly, starting at 30 days after planting (DAP) until 120 DAP. The results showed that the use of Kanesia 10 or Kanesia 13 intercropped with groundnut and spraying molasses to conserve natural enemies was the best pest management practice and superior to farmers’ practices. Conserving natural enemies is not only profitable (saving production cost of IDR1,150,000 to IDR1,500,000 ha-1 season-1), but also safe for the environment (no need to spray chemical insecticides).

The cotton bollworm (Helicoverpa armigera, Lepidoptera: Noctuidae) poses significant risks to maize. Changes in the maize plant, such as its phenology, influence the short-distance movement and oviposition of cotton bollworm adults and, thus, the distribution of the subsequent larval damage. We aim to provide an overview of future approaches to the surveillance of maize ear damage by cotton bollworm larvae based on remote sensing. We focus on finding a near-optimal combination of Landsat 8 or Sentinel-2 spectral bands, vegetation indices, and maize phenology to achieve the best predictions. The study areas were 21 sweet and grain maze fields in Hungary in 2017, 2020, and 2021. Correlations among the percentage of damage and the time series of satellite images were explored. Based on our results, Sentinel-2 satellite imagery is suggested for damage surveillance, as 82% of all the extremes of the correlation coefficients were stronger, and this satellite provided 20–64% more cloud-free images. We identified that the maturity groups of maize are an essential factor in cotton bollworm surveillance. No correlations were found before canopy closure (BBCH 18). Visible bands were the most suitable for damage surveillance in mid–late grain maize (|rmedian| = 0.49–0.51), while the SWIR bands, NDWI, NDVI, and PSRI were suitable in mid–late grain maize fields (|rmedian| = 0.25–0.49) and sweet maize fields (|rmedian| = 0.24–0.41). Our findings aim to support prediction tools for cotton bollworm damage, providing information for the pest management decisions of advisors and farmers.

Emergence rates and timing of emergence of cotton bollworm (CBW), Heliothis zea (Boddie), and tobacco budworm (TBW), H. virescens (F.), each reared concurrently in field cages erected over three host crops, differed characteristically among hosts. Sorghum produced the highest total number of CBW moths, followed by cotton, and then corn; pigeon pea yielded the highest number of TBW, followed by cotton; sesame failed to support TBW development. Sex ratios differed between the TBW and CBW (1:0.99 and 1:0.90 male/female, respectively; P < 0.01; t test, df = 3), but were consistent across all hosts per species. Emergence patterns of females and males for each host were significantly correlated; however, females frequently began to emerge first and reached 50% emergence 24–72 h prior to males.

Allocation of defensive compounds of transgenic Bt cotton grown under conditions of elevated CO2 in response to infestation by cotton bollworm, Helicoverpa armigera (Hübner) was studied in two successive years (2004 and 2005). Both CO2 levels and bollworm infestation affected allocation of defensive compounds of non-transgenic cotton and transgenic Bt cotton. Both significantly higher foliar condensed tannin and a higher carbon/nitrogen ratio for non-transgenic cotton and transgenic Bt cotton were recorded under elevated CO2 compared to ambient CO2. This result accords with the Carbon Nutrient Balance hypothesis linking limiting nitrogen and excess carbon in cotton plants in response to elevated CO2. Furthermore, significantly higher levels of catalase (CAT) and superoxide dismutase (SOD) and a significantly lower level of true choline esterase (TChE) were also observed in H. armigera fed on transgenic Bt cotton compared with those fed on non-transgenic cotton. Also, there were significant interactions between cotton variety and bollworm infestation time on CAT and SOD activities. Our results indicate that plant allocation to defensive compounds will be affected sufficiently to affect plant–herbivore populations interactions.

The beet armyworm, Spodoptera exigua, is a significant agricultural pest managed primarily through chemical insecticides, which present environmental concerns and promote resistance. Genetics-based sterile insect technique (gSIT) provides an alternative by inducing male sterility without irradiation. In this study, we cloned the S. exigua boule gene (Sebol), a 741-nucleotide open reading frame encoding a 246-amino-acid protein with an RNA recognition motif. Phylogenetic analysis confirmed its conservation across Lepidoptera and high similarity to orthologs in Spodoptera litura and Helicoverpa armigera. Sebol is predominantly expressed in adult males, particularly in the testis. CRISPR/Cas9-mediated deletion of 190 bp in exon 1 generated a truncated Sebol protein, resulting in complete male sterility. Transcriptome analysis revealed 2069 differentially expressed genes associated with sperm development, with potential interactions involving syf1 and ZNFX1. Our findings suggest that Sebol is crucial for spermatogenesis, making it a promising target for gSIT-based pest control.

Tomato (Solanum lycopersicum) polyphenol oxidases (PPOs), enzymes that oxidize phenolics to quinones, have been implicated in plant resistance to insects. The role of PPO in resistance to cotton bollworm [Helicoverpa armigera (Hübner)] and beet armyworm [Spodoptera exigua (Hübner)] (Lepidoptera: Noctuidae) was evaluated. Consumption, weight gains, and mortality of larvae feeding on foliage of transgenic tomato lines overexpressing PPO (OP lines) and of larvae feeding on foliage of transgenic tomato lines with suppressed PPO (SP lines) were compared with consumption, weight gains, and mortality of larvae feeding on non-transformed (NT) plants. Increases in foliage consumption and weight gains were observed for cotton bollworms feeding on leaves of SP plants compared to NT and OP plants. PPO activity was negatively correlated with both weight gains and foliar consumption of cotton bollworm, substantiating the defensive role of PPO against this insect. Similarly, beet armyworm consumed less foliage (both young and old leaves) from OP plants than SP plants. Larvae feeding on OP leaves generally exhibited lower weight gains than those feeding on SP leaves. These results indicate that tomato PPO plays a role in resistance to both cotton bollworm and beet armyworm.

'Helicoverpa armigera' Hubner (H. armigera) is significant pest to corn crops and a constant problem for farmers. The objective of this research was to obtain a more effective insecticide for suppressing the population and intensity of 'H. armigera', as well as providing high economic value for sweet corn crops. The following experiment uses a randomized block design, consisting of 4 treatments and 6 replications, the treatments are a control (P0 = without insecticides), P1 = biological insecticide (Beauveria bassiana 5 g.l-1) , P2 = botanic insecticide (pandan wangi leaf extracts 5 ml.l-1), and P3 = chemical insecticide (Deltamethrin synthetic 3 ml.l-1). The results show that the application of various types of insecticides has a significant effect on population density of larvae, intensity of 'H. armigera' presence, and sweet-corn crop yield. All types of insecticides applied are highly effective but the effectiveness of 'Beauveria bassiana' 5 g.l-1 tends to be greater in comparison to others. The highest cost-benefit ratio was obtained from the application of the biological insecticide followed by the botanic insecticide and the chemical insecticide.

The cotton bollworm, Helicoverpa armigera is a highly polyphagous pest infesting a number of economically important crops, annually causing enormous crop losses. Management of this pest is challenging over the years due to various factors including development of resistance to wide spectrum of chemical insecticides. RNA interference (RNAi) has tremendous potential to combat insect pests. However, RNAi mediated silencing efficiency varies from gene to gene, hence successful RNAi mediated pest control requires selection of suitable target gene(s), which are effectively silenced by the exogenous delivery of cognate double-stranded RNA (dsRNA) through midgut. Therefore, we have evaluated the effect of two concentrations of dsRNA delivered through semi-synthetic diet in silencing five important genes, viz. glutathione-S-transferase, cytochrome P450 (both involved in detoxification of host allelochemicals); trypsin, chymotrypsin (both involved in digestion of proteins) and juvenile hormone acid methyl transferase (jhamt) (involved in larval metamorphosis). Extent of silencing was assessed by quantitative real-time PCR (qRT-PCR). Results revealed that above target genes were silenced variably, 20 μg dsRNA treatment having a more pronounced effect than 10 μg in reducing the transcript levels, larval, pupal weight, and pupation. Silencing of chymotrypsin had a more pronounced effect on larval and pupal weight compared to other target genes, while jhamt severely affected pupation. This study demonstrated that target genes have varied sensitivity to RNAi, chymotrypsin, and jhamt were shown to be suitable candidate genes that could be utilized for RNAi mediated management of H. armigera.

The study assesses farmers’ perceptions and willingness to pay for a biopesticide developed from Metarhizium anisopliae a fungi. A sample of 400 conventional and organic cotton producers was randomly selected in cotton producing zones in Benin and interviewed for their perceptions on the efficacy of the biopesticide and the likely prices they are willing to pay for the product to control a major pest like Helicoverpa armigera or cotton bollworm causing substantial crop losses. An econometric model (Logit) is used to identify factors highly likely to affect farmer’s willingness to purchase the product. The results show that Helicoverpa armigera or cotton bollworm is perceived by farmers as the most severe pest with losses reaching up to 100%. Farmers attribute the current pest intensity to a number of factors including ineffectiveness of chemical pesticides, delay in access to input mainly fertilizers and the development of refuge host plants for cotton pests. The results also show that most cotton producers and their households members are exposed to chemical insecticides without adequate protection devices during the pest control sprays. Both organic and conventional cotton producers have expressed a significant interest in the use of Metarhizium to control Helicoverpa on cotton. Both types of farmers willing to pay more for any pest control product that would improve cotton product quality for higher cotton price. Three variables influencing farmers’ willing to pay for biopesticides from Metarhizium were efficacy, agro-ecological zone and broad spectrum.

The cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) is a polyphagous pest that exist all over the world. It is also very destructive in Turkey on various agricultural products. In this study, we have detected an alphabaculovirus from Helicoverpa armigera larvae collected from cotton field. The virus isolate was named as Helicoverpa armigera nucleopolyhedrovirus (HearNPV-O1) based on morphological and molecular properties. This is the first record of baculovirus from H. armigera in Eurasia region. Scanning electron microscopy examinations of polyhedral inclusion bodies (PIBs) showed their irregular morphology with average diameter of 0.85 to 1.25 μm. Transmission electron microscopy studies revealed that the nucleocapsids were multiple enveloped and bacilliform shaped. The size of nucleocapsid was found as 279 nm with a width of 56 nm. Digestion of viral genome by PstI generated 8 fragments with total size of 130.9 kbp. According to the phylogenetic analysis of the partial polyhedrin (polh), late expression factor 8 (lef8) and late expression factor 9 (lef9) genes, HearNPV-O1 isolate is very close to H. armigera MNPV Indian isolate-443. Five different concentrations of HearNPV-O1 between 103 and 107 were used in dose-response test on neonate, 3rd and 5th instars larvae of H. armigera. The highest dose (107) showed 92%, 88% and 57% mortality, respectively within 14 days. LC50 values of HearNPV-O1 isolate were calculated as 6 × 104, 7 × 104 and 8 × 106 PIBs/mL−1 against neonate, 3rd and 5th instars larval stages, respectively. These results demonstrate that HearNPV-O1 isolate may be a potential biocontrol agent to be utilized against H. armigera.

The cotton bollworm (Helicoverpa armigera Hübner), which migrated in the Carpathian-basin from Mediterraneum in the last decades, is becoming an increasingly serious problem for maize producers in Hungary. In several regions the damage it causes has reached the threshold of economic loss, especially in the case of the sweet maize cultivation. The aim of the research was to determine the changing of ears weights and in-kernel accumulation and alteration in grain as a function of cotton bollworm mastication.Our investigation confirmed that there is an in-kernel and protein pattern change of maize grain by cotton bollworm. Our results proved the significant damaging of each part of ears by cotton bollworm masticating (the average weight loss of ears: 13.99%; the average weight loss of grains: 14.03%; the average weight loss of cobs: 13.74%), with the exception of the increasing of the grain-cob ratio. Our examinations did not prove the water loss - that is the "forced maturing" - caused by the damage. Decreasing of raw fat (control: 2.8%; part-damaged: 2.6%; damaged: 2.4%) and starch content (control: 53.1%; part-damaged: 46.6%; damaged: 44.7%) were registered as a function of injury. In contrast, the raw protein content was increased (control: 4.7%; part-damaged: 5.3%; damaged: 7.4%) by maize ear masticating. The most conspicuous effect on protein composition changing was proved by comparison of damaged grain samples by SDS PAGE. Increased amounts of 114, 50, 46 and 35 kDa molecular mass proteins were detected which explained the more than 50% elevation of raw protein content. The statistical analysis of molecular weights proved the protein realignment as a function of the pest injuries, too.