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Sample records for helicoverpa armigera nucleopolyhedrovirus

  1. Genetic variation and virulence of nucleopolyhedroviruses isolated worldwide from the heliothine pests Helicoverpa armigera, Helicoverpa zea, and Heliothis virescens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A PCR-based method was used to classify 90 samples of nucleopolyhedrovirus (NPV; Baculoviridae: Alphabaculovirus) obtained worldwide from larvae of Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Partial nucleotide sequencing and phylogenetic analysis of three highly conserved genes...

  2. Classification, genetic variation, and biological activity of nucleopolyhedrovirus samples from larvae of the heliothine pests heliothis virescens, helicoverpa zea, and helicoverpa armigera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A PCR-based method was used to classify 109 isolates of nucleopolyhedrovirus (NPV; Baculoviridae: Alphabaculovirus) collected worldwide from larvae of Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Partial nucleotide sequencing and phylogenetic analysis of three highly conserved ge...

  3. Ubiquitins of Bombyx mori nucleopolyhedrovirus and Helicoverpa armigera nucleopolyhedrovirus show distinct subcellular localization in infected cells.

    PubMed

    Guo, Z J; Zhu, Y M; Li, G H; Chen, K P; Zhang, C X

    2011-01-01

    Ubiquitin (UB) is a conserved protein that regulates a number of processes in eukaryotic cells. Nearly all lepidopteran baculoviruses encode UB homologs showing a partial sequence identity with human UB (Hu-UB). In this study, the sequence, predicted 3D-structure and subcellular localization of UB homologs encoded by two different nucleopolyhedroviruses of Bombyx mori (BmNPV) and Helicoverpa armigera (HaNPV) were compared. UBs of BmNPV and HaNPV (Bm-UB, Ha-UB, respectively) shared only 73% of sequence identity of the different aa in relation to Hu-UB being localized in non-conserved parts, namely in two heterogeneous regions of aa 15-32 and aa 53-60. Interestingly, Bm-UB and Ha-UB share the same seven lysines except for an additional Lys54 in Bm-UB. However, in spite of the sequence heterogeneity, Bm-UB and Ha-UB have a similar predicted 3D-structure. A difference in their subcellular localization during virus growth in insect cell lines was found in the late stage of formation of occlusion-derived virus (ODV). In particular Bm-UB was localized mainly and evenly in the nucleus, while Ha-UB on the nuclear membrane. These data suggest that (i) UBs, besides being engaged in various cellular processes, have a role in specific processes of virus growth, and (ii) Bm-UB and Ha-UB may show certain different activities associated with the virus growth. PMID:21692557

  4. Characterization of the viral fibroblast growth factor homolog of Helicoverpa armigera single nucleopolyhedrovirus.

    PubMed

    Yin, Feifei; Du, Ruikun; Kuang, Wenhua; Yang, Guang; Wang, Hualin; Deng, Fei; Hu, Zhihong; Wang, Manli

    2016-06-01

    Fibroblast growth factor (FGF) is found throughout multicellular organisms; however, fgf homologs (vfgf) have only been identified among viruses in lepidopteran baculoviruses. The function of vFGFs from Group I alphabaculoviruses, including Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Bombyx mori nucleopolyhedrovirus (BmNPV), involves accelerated killing of infected larvae by both viruses. The vFGF of Group II alphabaculovirus is structurally different from that of Group I alphabaculovirus, with a larger C-terminal region and additional N-linked glycosylation sites. In this study, we characterized the Group II alphabaculovirus vFGF of Helicoverpa armigera single nucleopolyhedrovirus (HearNPV). The transcription and expression of vfgf was detected at 3 h and 16 h post-infection in HearNPV-infected cells. To further study vFGF function, we constructed vfgf-knockout and -repaired HearNPV bacmids and investigated their affect in both cultured cells and insects. Deletion of vfgf had no effect on budded-virus production or viral DNA replication in cultured HzAM1 cells. However, bioassays showed that HearNPV vfgf deletion significantly increased the median lethal dose and delayed the median lethal time by ∼12 h in the host insect when the virus was delivered orally. These results suggested that vFGF is an important virulent factor for HearNPV infection and propagation in vivo. PMID:27142667

  5. Characterization of a new Helicoverpa armigera nucleopolyhedrovirus variant causing epizootic on a previously unreported host, Helicoverpa gelotopoeon (Lepidoptera: Noctuidae).

    PubMed

    Ferrelli, M L; Taibo, C; Fichetti, P; Sciocco-Cap, A; Arneodo, J D

    2016-07-01

    This paper reports the first biological and molecular characterization of a nucleopolyhedrovirus isolated from the soybean and cotton pest Helicoverpa gelotopoeon. Studies were performed following a virus outbreak in a rearing facility and in wild H. gelotopoeon populations in Córdoba, Argentina. Host identity was corroborated by partial sequencing of the COI gene. Scanning electron microscope observations of purified OBs revealed their polyhedral morphology and an average diameter of 0.89±0.14μm. Ultrathin sections of infected larvae examined by transmission electron microscopy showed the intranuclear occurrence of polyhedra and virus particles in fat body cells. Nucleocapsids were singly enveloped. Phylogenetic analysis of lef-8, lef-9, polh, orf5/5b and hr3-orf62 viral sequences identified this new NPV isolate (hereafter HegeSNPV) as a variant of Helicoverpa armigera nucleopolyhedrovirus (HearNPV). Furthermore, HegeSNPV was closely related to the so-called "HzSNPV Group" within HearNPV, although having particular characteristics. PMID:26296927

  6. Genomic sequencing and analyses of HearMNPV—a new Multinucleocapsid nucleopolyhedrovirus isolated from Helicoverpa armigera

    PubMed Central

    2012-01-01

    Background HearMNPV, a nucleopolyhedrovirus (NPV), which infects the cotton bollworm, Helicoverpa armigera, comprises multiple rod-shaped nucleocapsids in virion(as detected by electron microscopy). HearMNPV shows a different host range compared with H. armigera single-nucleocapsid NPV (HearSNPV). To better understand HearMNPV, the HearMNPV genome was sequenced and analyzed. Methods The morphology of HearMNPV was observed by electron microscope. The qPCR was used to determine the replication kinetics of HearMNPV infectious for H. armigera in vivo. A random genomic library of HearMNPV was constructed according to the “partial filling-in” method, the sequence and organization of the HearMNPV genome was analyzed and compared with sequence data from other baculoviruses. Results Real time qPCR showed that HearMNPV DNA replication included a decreasing phase, latent phase, exponential phase, and a stationary phase during infection of H. armigera. The HearMNPV genome consists of 154,196 base pairs, with a G + C content of 40.07%. 162 putative ORFs were detected in the HearMNPV genome, which represented 90.16% of the genome. The remaining 9.84% constitute four homologous regions and other non-coding regions. The gene content and gene arrangement in HearMNPV were most similar to those of Mamestra configurata NPV-B (MacoNPV-B), but was different to HearSNPV. Comparison of the genome of HearMNPV and MacoNPV-B suggested that HearMNPV has a deletion of a 5.4-kb fragment containing five ORFs. In addition, HearMNPV orf66, bro genes, and hrs are different to the corresponding parts of the MacoNPV-B genome. Conclusions HearMNPV can replicate in vivo in H. armigera and in vitro, and is a new NPV isolate distinguished from HearSNPV. HearMNPV is most closely related to MacoNPV-B, but has a distinct genomic structure, content, and organization. PMID:22913743

  7. Efficacy of spiracular infection of Helicoverpa armigera with its nucleopolyhedrovirus and its role in virus production.

    PubMed

    Jeyarani, S; Rabindra, R J; Sathiah, N; Karuppachamy, P; Subramanian, S

    2007-06-01

    Baculoviruses are important microbial control agents of insects, with per os mode of infectivity. However, recently the spiracular infection of this virus group was suggested as an optimum method for virus production in grown up larvae. In this regard, a detailed evaluation of the spiracular infection with intact polyhedral inclusion bodies (PIB), alkali liberated virions and alkali liberated filtered virions of Helicoverpa armigera (Hubner) nucleopolyhedrovirus at 1 x 10(8), 1 x 10(7) and 2 x 10(6)PIB/ml concentrations was undertaken and compared with the standard diet surface treatment method. All the spiracle treatments resulted in larval death due to virus infection with alkali liberated virions causing higher mortality of larvae than alkali liberated filtered virions and intact PIB. Diet surface treatment method resulted in very high mortality as compared to spiracle treatment and among the different inoculum tested the intact PIB resulted in higher larval mortality. The PIB yield/larva in spiracle treatment was comparable with the diet surface treatment method, but due to very low larval mortality it resulted in low virus yield/100 inoculated larvae. Diet surface treatment with 5 x 10(7)PIB/ml concentration of virus resulted in the maximum yield of PIB/100 inoculated larvae. Low mortality, higher labour requirement and low amenability for mechanization for spiracle treatment method make it unviable for mass production of the virus in large scale compared to the standard diet surface treatment method. PMID:17316835

  8. Putative phosphorylation sites on WCA domain of HA2 is essential for Helicoverpa armigera single nucleopolyhedrovirus replication.

    PubMed

    Lv, Yi-pin; Wang, Qian; Wu, Chun-chen; Pei, Rong-juan; Zhou, Yuan; Wang, Yun; Chen, Xin-wen

    2011-08-01

    Protein phosphorylation is one of the most common post-translational modification processes that play an essential role in regulating protein functionality. The Helicoverpa armigera single nucleopolyhedrovirus (HearNPV) orf2-encoded nucleocapsid protein HA2 participates in orchestration of virus-induced actin polymerization through its WCA domain, in which phosphorylation status are supposed to be critical in respect to actin polymerization. In the present study, two putative phosphorylation sites ((232)Thr and (250)Ser) and a highly conserved Serine ((245)Ser) on the WCA domain of HA2 were mutated, and their phenotypes were characterized by reintroducing the mutated HA2 into the HearNPV genome. Viral infectivity assays demonstrated that only the recombinant HearNPV bearing HA2 mutation at (245)Ser can produce infectious virions, both (232)Thr and (250)Ser mutations were lethal to the virus. However, actin polymerization assay demonstrated that all the three viruses bearing HA2 mutations were still capable of initiating actin polymerization in the host nucleus, which indicated the putative phosphorylation sites on HA2 may contribute to HearNPV replication through another unidentified pathway. PMID:21847755

  9. A Novel Binary Mixture of Helicoverpa armigera Single Nucleopolyhedrovirus Genotypic Variants Has Improved Insecticidal Characteristics for Control of Cotton Bollworms

    PubMed Central

    Arrizubieta, Maite; Simón, Oihane; Williams, Trevor

    2015-01-01

    The genotypic diversity of two Spanish isolates of Helicoverpa armigera single nucleopolyhedrovirus (HearSNPV) was evaluated with the aim of identifying mixtures of genotypes with improved insecticidal characteristics for control of the cotton bollworm. Two genotypic variants, HearSP1A and HearSP1B, were cloned in vitro from the most pathogenic wild-type isolate of the Iberian Peninsula, HearSNPV-SP1 (HearSP1-wt). Similarly, six genotypic variants (HearLB1 to -6) were obtained by endpoint dilution from larvae collected from cotton crops in southern Spain that died from virus disease during laboratory rearing. Variants differed significantly in their insecticidal properties, pathogenicity, speed of kill, and occlusion body (OB) production (OBs/larva). HearSP1B was ∼3-fold more pathogenic than HearSP1-wt and the other variants. HearLB1, HearLB2, HeaLB5, and HearLB6 were the fastest-killing variants. Moreover, although highly virulent, HearLB1, HearLB4, and HearLB5 produced more OBs/larva than did the other variants. The co-occluded HearSP1B:LB6 mixture at a 1:1 proportion was 1.7- to 2.8-fold more pathogenic than any single variant and other mixtures tested and also killed larvae as fast as the most virulent genotypes. Serial passage resulted in modified proportions of the component variants of the HearSP1B:LB6 co-occluded mixture, suggesting that transmissibility could be further improved by this process. We conclude that the improved insecticidal phenotype of the HearSP1B:LB6 co-occluded mixture underlines the utility of the genotypic variant dissection and reassociation approach for the development of effective virus-based insecticides. PMID:25841011

  10. A Novel Neurotoxin Gene ar1b Recombination Enhances the Efficiency of Helicoverpa armigera Nucleopolyhedrovirus as a Pesticide by Inhibiting the Host Larvae Ability to Feed and Grow.

    PubMed

    Yu, Huan; Meng, Jiao; Xu, Jian; Liu, Tong-Xian; Wang, Dun

    2015-01-01

    A recombinant Helicoverpa armigera nucleopolyhedrovirus (HearNPV), Ar1b-HearNPV, was constructed and identified as an improved bio-control agent of Helicoverpa armigera larvae. The HearNPV polyhedrin promoter was used to express the insect-specific neurotoxin gene, ar1b, which was originally isolated from the Australian funnel-web spider (Atrax robustus). RT-PCR and Western blotting analysis showed that both the ar1b transcript and protein were produced successfully in Ar1b-HearNPV-infected HzAM1 cells. In order to investigate the influence of foreign gene insertion in HearNPV, including the ar1b gene, chloramphenicol resistance gene, lacZ, kanamycin resistance gene, and the gentamicin resistance gene, two virus strains (HZ8-HearNPV and wt-HearNPV) were used as controls in the cell transfection analysis. As expected, foreign gene insertion had no impact on budded virus production and viral DNA replication. Both optical microscopy and electron microscopy observations indicated that the formation of the occlusion bodies of recombinant virus was similar to wild type virus. The Ar1b-HearNPV-infected H. armigera larvae exhibited paralysis and weight loss before dying. This recombinant virus also showed a 32.87% decrease in LT50 assays compared with the wild type virus. Besides, Ar1b-HearNPV also inhibited host larval growth and diet consumption. This inhibition was still significant in the older instar larvae treated with the recombinant virus. All of these positive properties of this novel recombinant HearNPV provide a further opportunity to develop this virus strain into a commercial product to control the cotton bollworm. PMID:26296090

  11. A Novel Neurotoxin Gene ar1b Recombination Enhances the Efficiency of Helicoverpa armigera Nucleopolyhedrovirus as a Pesticide by Inhibiting the Host Larvae Ability to Feed and Grow

    PubMed Central

    Yu, Huan; Meng, Jiao; Xu, Jian; Liu, Tong-xian; Wang, Dun

    2015-01-01

    A recombinant Helicoverpa armigera nucleopolyhedrovirus (HearNPV), Ar1b-HearNPV, was constructed and identified as an improved bio-control agent of Helicoverpa armigera larvae. The HearNPV polyhedrin promoter was used to express the insect-specific neurotoxin gene, ar1b, which was originally isolated from the Australian funnel-web spider (Atrax robustus). RT-PCR and Western blotting analysis showed that both the ar1b transcript and protein were produced successfully in Ar1b-HearNPV-infected HzAM1 cells. In order to investigate the influence of foreign gene insertion in HearNPV, including the ar1b gene, chloramphenicol resistance gene, lacZ, kanamycin resistance gene, and the gentamicin resistance gene, two virus strains (HZ8-HearNPV and wt-HearNPV) were used as controls in the cell transfection analysis. As expected, foreign gene insertion had no impact on budded virus production and viral DNA replication. Both optical microscopy and electron microscopy observations indicated that the formation of the occlusion bodies of recombinant virus was similar to wild type virus. The Ar1b-HearNPV-infected H. armigera larvae exhibited paralysis and weight loss before dying. This recombinant virus also showed a 32.87% decrease in LT50 assays compared with the wild type virus. Besides, Ar1b-HearNPV also inhibited host larval growth and diet consumption. This inhibition was still significant in the older instar larvae treated with the recombinant virus. All of these positive properties of this novel recombinant HearNPV provide a further opportunity to develop this virus strain into a commercial product to control the cotton bollworm. PMID:26296090

  12. Proteomics Analysis of Helicoverpa armigera Single Nucleocapsid Nucleopolyhedrovirus Identified Two New Occlusion-Derived Virus-Associated Proteins, HA44 and HA100▿

    PubMed Central

    Deng, Fei; Wang, Ranran; Fang, Minggang; Jiang, Yue; Xu, Xushi; Wang, Hanzhong; Chen, Xinwen; Arif, Basil M.; Guo, Lin; Wang, Hualin; Hu, Zhihong

    2007-01-01

    Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry were used to analyze the structural proteins of the occlusion-derived virus (ODV) of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearNPV), a group II NPV. Twenty-three structural proteins of HearNPV ODV were identified, 21 of which have been reported previously as structural proteins or ODV-associated proteins in other baculoviruses. These include polyhedrin, P78/83, P49, ODV-E18, ODV-EC27, ODV-E56, P74, LEF-3, HA66 (AC66), DNA polymerase, GP41, VP39, P33, ODV-E25, helicase, P6.9, ODV/BV-C42, VP80, ODV-EC43, ODV-E66, and PIF-1. Two proteins encoded by HearNPV ORF44 (ha44) and ORF100 (ha100) were discovered as ODV-associated proteins for the first time. ha44 encodes a protein of 378 aa with a predicted mass of 42.8 kDa. ha100 encodes a protein of 510 aa with a predicted mass of 58.1 kDa and is a homologue of the gene for poly(ADP-ribose) glycohydrolase (parg). Western blot analysis and immunoelectron microscopy confirmed that HA44 is associated with the nucleocapsid and HA100 is associated with both the nucleocapsid and the envelope of HearNPV ODV. HA44 is conserved in group II NPVs and granuloviruses but does not exist in group I NPVs, while HA100 is conserved only in group II NPVs. PMID:17581982

  13. Complete Genome Sequences of Helicoverpa armigera Single Nucleopolyhedrovirus Strains AC53 and H25EA1 from Australia

    PubMed Central

    Noune, Christopher

    2015-01-01

    We report here the genome sequences of two alphabaculoviruses of Helicoverpa spp. from Australia: AC53, used in the biopesticides ViVUS and ViVUS Max, and H25EA1, used in in vitro production studies. PMID:26404605

  14. Sequence analysis, expression profiles and function of thioredoxin 2 and thioredoxin reductase 1 in resistance to nucleopolyhedrovirus in Helicoverpa armigera

    PubMed Central

    Zhang, Songdou; Li, Zhen; Nian, Xiaoge; Wu, Fengming; Shen, Zhongjian; Zhang, Boyu; Zhang, Qingwen; Liu, Xiaoxia

    2015-01-01

    The thioredoxin system, including NADPH, thioredoxin (Trx), and thioredoxin reductase (TrxR), plays significant roles in maintaining intracellular redox homeostasis and protecting organisms against oxidative damage. In this study, the characteristics and functions of H. armigera HaTrx2 and HaTrxR1 were identified. Sequence analysis showed that HaTrx2 and HaTrxR1 were both highly conserved and shared high sequence identity with other insect counterparts. The mRNA of HaTrx2 was expressed the highest in 5th instar 96 h and was mainly detected in heads and epidermis. The expression of HaTrxR1 was highly concentrated in 5th instar 72 h and 96 h, and higher in malpighian tube, midgut and hemocyte than other examined tissues. HaTrx2 and HaTrxR1 were markedly induced by various types of stress. HaTrx2- or HaTrxR1-knockdown increased ROS production in hemocytes and also increased the lipid damage in NPV infected H. armigera larvae. Furthermore, interference with expression of HaTrx2 or HaTrxR1 transcripts in H. armigera larvae resulted in increased sensitivity to NPV infection and shortened LT50 values. Our findings indicated that HaTrx2 and HaTrxR1 contribute to the susceptibility of H. armigera to NPV and also provided the theoretical basis for the in-depth study of insect thioredoxin system. PMID:26502992

  15. Ha83, a Chitin Binding Domain Encoding Gene, Is Important to Helicoverpa armigera Nucleopolyhedrovirus Budded Virus Production and Occlusion Body Assembling.

    PubMed

    Yu, Huan; Xu, Jian; Liu, Qiang; Liu, Tong-Xian; Wang, Dun

    2015-01-01

    Helicoerpa armigera nucleopolyhedrovirus (HearNPV) ha83 is a late expressed gene that encodes a chitin binding protein. Chitin domain truncation studies revealed that the cysteine at the 128 amino acid position probably played an important role in both chitin binding ability and protein transmission of Ha83. In order to study the function of ha83 in the HearNPV infection cycle, an ha83 knockout HearNPV (Ha83KO) was constructed via homologous recombination. Viral growth and viral DNA replication curves showed that fewer budded virions were produced in Ha83KO transfected cells, while viral DNA replication was increased. Electron microscopy revealed that fewer nucleocapsids were transmitted from virogenic stroma in the Ha83KO transfected cell nucleus, and the morphology of occlusion bodies was prominently larger and cube-shaped. Furthermore, DNA quantity in occlusion bodies of Ha83KO was significantly lower than the occlusion bodies of HaWT. The transcription analysis indicated that these changes may be due to the decreased expression level of viral structural associated genes, such as polyhedrin, p10, pif-2, or cg30 in Ha83KO infected cells. Above results demonstrated that the cysteine at the 128 amino acid position in Ha83 might be the key amino acid, and Ha83 plays an important role in BVs production and OBs assembling. PMID:26057202

  16. Ha83, a Chitin Binding Domain Encoding Gene, Is Important to Helicoverpa armigera Nucleopolyhedrovirus Budded Virus Production and Occlusion Body Assembling

    PubMed Central

    Yu, Huan; Xu, Jian; Liu, Qiang; Liu, Tong-Xian; Wang, Dun

    2015-01-01

    Helicoerpa armigera nucleopolyhedrovirus (HearNPV) ha83 is a late expressed gene that encodes a chitin binding protein. Chitin domain truncation studies revealed that the cysteine at the 128 amino acid position probably played an important role in both chitin binding ability and protein transmission of Ha83. In order to study the function of ha83 in the HearNPV infection cycle, an ha83 knockout HearNPV (Ha83KO) was constructed via homologous recombination. Viral growth and viral DNA replication curves showed that fewer budded virions were produced in Ha83KO transfected cells, while viral DNA replication was increased. Electron microscopy revealed that fewer nucleocapsids were transmitted from virogenic stroma in the Ha83KO transfected cell nucleus, and the morphology of occlusion bodies was prominently larger and cube-shaped. Furthermore, DNA quantity in occlusion bodies of Ha83KO was significantly lower than the occlusion bodies of HaWT. The transcription analysis indicated that these changes may be due to the decreased expression level of viral structural associated genes, such as polyhedrin, p10, pif-2, or cg30 in Ha83KO infected cells. Above results demonstrated that the cysteine at the 128 amino acid position in Ha83 might be the key amino acid, and Ha83 plays an important role in BVs production and OBs assembling. PMID:26057202

  17. Genomic sequence analysis of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genome of a granulovirus isolated from the Old World bollworm, Helicoverpa armigera, was completely sequenced. The size of the Helicoverpa armigera granulovirus (HearGV) genome is 169,794 nt containing 179 open reading frames (ORFs), making it the second largest baculovirus genome analyzed to d...

  18. Proteomic analysis of novel Cry1Ac binding proteins in Helicoverpa armigera (Hübner)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aminopeptidase N (APN) and cadherin-like proteins have been previously identified as Cry1Ac-binding proteins in Helicoverpa armigera (Hübner). In this study, a proteomic approach was used to identify novel Cry1Ac-binding proteins in H. armigera. Brush border membrane vesicles (BBMV) of H. armigera w...

  19. Host plant induced variation in gut bacteria of Helicoverpa armigera.

    PubMed

    Priya, Natarajan Gayatri; Ojha, Abhishek; Kajla, Mayur K; Raj, Anand; Rajagopal, Raman

    2012-01-01

    Helicoverpa are important polyphagous agricultural insect pests and they have a worldwide distribution. In this study, we report the bacterial community structure in the midgut of fifth instar larvae of Helicoverpa armigera, a species prevalent in the India, China, South Asia, South East Asia, Southern & Eastern Africa and Australia. Using culturable techniques, we isolated and identified members of Bacillus firmus, Bacillus niabense, Paenibacillus jamilae, Cellulomonas variformis, Acinetobacter schindleri, Micrococcus yunnanesis, Enterobacter sp., and Enterococcus cassiliflavus in insect samples collected from host plants grown in different parts of India. Besides these the presence of Sphingomonas, Ralstonia, Delftia, Paracoccus and Bacteriodetes was determined by culture independent molecular analysis. We found that Enterobacter and Enterococcus were universally present in all our Helicoverpa samples collected from different crops and in different parts of India. The bacterial diversity varied greatly among insects that were from different host plants than those from the same host plant of different locations. This result suggested that the type of host plant greatly influences the midgut bacterial diversity of H. armigera, more than the location of the host plant. On further analyzing the leaf from which the larva was collected, it was found that the H. armigera midgut bacterial community was similar to that of the leaf phyllosphere. This finding indicates that the bacterial flora of the larval midgut is influenced by the leaf surface bacterial community of the crop on which it feeds. Additionally, we found that laboratory made media or the artificial diet is a poor bacterial source for these insects compared to a natural diet of crop plant. PMID:22292034

  20. Densovirus Is a Mutualistic Symbiont of a Global Crop Pest (Helicoverpa armigera) and Protects against a Baculovirus and Bt Biopesticide

    PubMed Central

    Xu, Pengjun; Liu, Yongqiang; Graham, Robert I.; Wilson, Kenneth; Wu, Kongming

    2014-01-01

    Mutualistic associations between symbiotic bacteria and their hosts are common within insect systems. However, viruses are often considered as pathogens even though some have been reported to be beneficial to their hosts. Herein, we report a novel densovirus, Helicoverpa armigera densovirus-1 (HaDNV-1) that appears to be beneficial to its host. HaDNV-1 was found to be widespread in wild populations of H. armigera adults (>67% prevalence between 2008 and 2012). In wild larval populations, there was a clear negative interaction between HaDNV-1 and H. armigera nucleopolyhedrovirus (HaNPV), a baculovirus that is widely used as a biopesticide. Laboratory bioassays revealed that larvae hosting HaDNV-1 had significantly enhanced resistance to HaNPV (and lower viral loads), and that resistance to Bacillus thuringiensis (Bt) toxin was also higher at low doses. Laboratory assays indicated that the virus was mainly distributed in the fat body, and could be both horizontally- and vertically-transmitted, though the former occurred only at large challenge doses. Densovirus-positive individuals developed more quickly and had higher fecundity than uninfected insects. We found no evidence for a negative effect of HaDNV-1 infection on H. armigera fitness-related traits, strongly suggesting a mutualistic interaction between the cotton bollworm and its densovirus. PMID:25357125

  1. Complete Genome Sequences of Seven Helicoverpa armigera SNPV-AC53-Derived Strains

    PubMed Central

    2016-01-01

    Wild-type baculovirus isolates typically consist of multiple strains. We report the full genome sequences of seven alphabaculovirus strains derived by passage through tissue culture from Helicoverpa armigera SNPV-AC53 (KJ909666). PMID:27151787

  2. Efficacy of Venom from Tentacle of Jellyfish Stomolophus meleagris (Nemopilema nomurai) against the Cotton Bollworm Helicoverpa armigera

    PubMed Central

    Yu, Huahua; Li, Rongfeng; Dong, Xiangli; Xing, Ronge; Liu, Song; Li, Pengcheng

    2014-01-01

    Efficacy of venom from tentacle of jellyfish Stomolophus meleagris against the cotton bollworm Helicoverpa armigera was determined. Venom from tentacle of jellyfish Stomolophus meleagris could inhibit the growth of Helicoverpa armigera and the weight inhibiting rate of sample NFr-2 was 60.53%. Of the six samples, only NFr-2 had high insecticidal activity against Helicoverpa armigera and the corrected mortality recorded at 7 d was 74.23%. PMID:25162008

  3. Olfactory perception and behavioral effects of sex pheromone gland components in Helicoverpa armigera and Helicoverpa assulta

    PubMed Central

    Xu, Meng; Guo, Hao; Hou, Chao; Wu, Han; Huang, Ling-Qiao; Wang, Chen-Zhu

    2016-01-01

    Two sympatric species Helicoverpa armigera and Helicoverpa assulta use (Z)-11-hexadecenal and (Z)-9-hexadecenal as sex pheromone components in reverse ratio. They also share several other pheromone gland components (PGCs). We present a comparative study on the olfactory coding mechanism and behavioral effects of these additional PGCs in pheromone communication of the two species using single sensillum recording, in situ hybridization, calcium imaging, and wind tunnel. We classify antennal sensilla types A, B and C into A, B1, B2, C1, C2 and C3 based on the response profiles, and identify the glomeruli responsible for antagonist detection in both species. The abundance of these sensilla types when compared with the number of OSNs expressing each of six pheromone receptors suggests that HarmOR13 and HassOR13 are expressed in OSNs housed within A type sensilla, HarmOR14b within B and C type sensilla, while HassOR6 and HassOR16 within some of C type sensilla. We find that for H. armigera, (Z)-11-hexadecenol and (Z)-11-hexadecenyl acetate act as behavioral antagonists. For H. assulta, instead, (Z)-11-hexadecenyl acetate acts as an agonist, while (Z)-9-hexadecenol, (Z)-11-hexadecenol and (Z)-9-hexadecenyl acetate are antagonists. The results provide an overall picture of intra- and interspecific olfactory and behavioral responses to all PGCs in two sister species. PMID:26975244

  4. Olfactory perception and behavioral effects of sex pheromone gland components in Helicoverpa armigera and Helicoverpa assulta.

    PubMed

    Xu, Meng; Guo, Hao; Hou, Chao; Wu, Han; Huang, Ling-Qiao; Wang, Chen-Zhu

    2016-01-01

    Two sympatric species Helicoverpa armigera and Helicoverpa assulta use (Z)-11-hexadecenal and (Z)-9-hexadecenal as sex pheromone components in reverse ratio. They also share several other pheromone gland components (PGCs). We present a comparative study on the olfactory coding mechanism and behavioral effects of these additional PGCs in pheromone communication of the two species using single sensillum recording, in situ hybridization, calcium imaging, and wind tunnel. We classify antennal sensilla types A, B and C into A, B1, B2, C1, C2 and C3 based on the response profiles, and identify the glomeruli responsible for antagonist detection in both species. The abundance of these sensilla types when compared with the number of OSNs expressing each of six pheromone receptors suggests that HarmOR13 and HassOR13 are expressed in OSNs housed within A type sensilla, HarmOR14b within B and C type sensilla, while HassOR6 and HassOR16 within some of C type sensilla. We find that for H. armigera, (Z)-11-hexadecenol and (Z)-11-hexadecenyl acetate act as behavioral antagonists. For H. assulta, instead, (Z)-11-hexadecenyl acetate acts as an agonist, while (Z)-9-hexadecenol, (Z)-11-hexadecenol and (Z)-9-hexadecenyl acetate are antagonists. The results provide an overall picture of intra- and interspecific olfactory and behavioral responses to all PGCs in two sister species. PMID:26975244

  5. Rapid Identification of Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) Using Ribosomal RNA Internal Transcribed Spacer 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rapid identification of invasive species is crucial for deploying management strategies to prevent establishment. Recent Helicoverpa armigera (Hübner) invasions and subsequent establishment in some countries of South America has increased the risk of this species invading North America. Differentiat...

  6. Carbon dioxide receptor genes in cotton bollworm Helicoverpa armigera

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Anderson, Alisha

    2015-04-01

    Carbon dioxide (CO2) is important in insect ecology, eliciting a range of behaviours across different species. Interestingly, the numbers of CO2 gustatory receptors (GRs) vary among insect species. In the model organism Drosophila melanogaster, two GRs (DmelGR21a and DmelGR63a) have been shown to detect CO2. In the butterfly, moth, beetle and mosquito species studied so far, three CO2 GR genes have been identified, while in tsetse flies, four CO2 GR genes have been identified. In other species including honeybees, pea aphids, ants, locusts and wasps, no CO2 GR genes have been identified from the genome. These genomic differences may suggest different mechanisms for CO2 detection exist in different insects but, with the exception of Drosophila and mosquitoes, limited attention has been paid to the CO2 GRs in insects. Here, we cloned three putative CO2 GR genes from the cotton bollworm Helicoverpa armigera and performed phylogenetic and expression analysis. All three H. armigera CO2 GRs (HarmGR1, HarmGR2 and HarmGR3) are specifically expressed in labial palps, the CO2-sensing tissue of this moth. HarmGR3 is significantly activated by NaHCO3 when expressed in insect Sf9 cells but HarmGR1 and HarmGR2 are not. This is the first report characterizing the function of lepidopteran CO2 receptors, which contributes to our general understanding of the molecular mechanisms of insect CO2 gustatory receptors.

  7. Bioactivity of non-edible oil seed extracts and purified extracts against Helicoverpa armigera (Hubner).

    PubMed

    Pawar, Pushpa; Joseph, Mary; Tungikar, Vijay; Joshi, Swati

    2004-01-01

    Extracts and purified extracts of seeds of two plant species, Madhuca latifolia and Calophyllum inophyllum when evaluated against the 2nd instar larvae of Helicoverpa armigera reared on synthetic diet, exhibited high larval mortality, prolongation of developmental period, morphological deformities and highly significant reduction in adult emergence. The reduction in larval weights in the treatments was also highly significant. PMID:15274488

  8. Prediction of cotton resistance to Helicoverpa armigera based on the percent (+)-gossypol in mature seed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various Uzbek commercial varieties were grown in the field and these were exposed to cotton bollworm (Helicoverpa armigera) larvae. A significant negative correlation coefficient (r = -0.89) and linear regression (Y = 109.69-5.26X) was observed between the concentration of (+)-gossypol in cotton se...

  9. Rapid identification of Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) using ribosomal RNA internal transcribed spacer 1.

    PubMed

    Perera, Omaththage P; Allen, Kerry C; Jain, Devendra; Purcell, Matthew; Little, Nathan S; Luttrell, Randall G

    2015-01-01

    Rapid identification of invasive species is crucial for deploying management strategies to prevent establishment. Recent Helicoverpa armigera (Hübner) invasions and subsequent establishment in South America has increased the risk of this species invading North America. Morphological similarities make differentiation of H. armigera from the native Helicoverpa zea (Boddie) difficult. Characteristics of adult male genitalia and nucleotide sequence differences in mitochondrial DNA are two of the currently available methods to differentiate these two species. However, current methods are likely too slow to be employed as rapid detection methods. In this study, conserved differences in the internal transcribed spacer 1 (ITS1) of the ribosomal RNA genes were used to develop species-specific oligonucleotide primers that amplified ITS1 fragments of 147 and 334 bp from H. armigera and H. zea, respectively. An amplicon (83 bp) from a conserved region of 18S ribosomal RNA subunit served as a positive control. Melting temperature differences in ITS1 amplicons yielded species-specific dissociation curves that could be used in high resolution melt analysis to differentiate the two Helicoverpa species. In addition, a rapid and inexpensive procedure for obtaining amplifiable genomic DNA from a small amount of tissue was identified. Under optimal conditions, the process was able to detect DNA from one H. armigera leg in a pool of 25 legs. The high resolution melt analysis combined with rapid DNA extraction could be used as an inexpensive method to genetically differentiate large numbers of H. armigera and H. zea using readily available reagents. PMID:26516166

  10. Rapid Identification of Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) Using Ribosomal RNA Internal Transcribed Spacer 1

    PubMed Central

    Perera, Omaththage P.; Allen, Kerry C.; Jain, Devendra; Purcell, Matthew; Little, Nathan S.; Luttrell, Randall G.

    2015-01-01

    Rapid identification of invasive species is crucial for deploying management strategies to prevent establishment. Recent Helicoverpa armigera (Hübner) invasions and subsequent establishment in South America has increased the risk of this species invading North America. Morphological similarities make differentiation of H. armigera from the native Helicoverpa zea (Boddie) difficult. Characteristics of adult male genitalia and nucleotide sequence differences in mitochondrial DNA are two of the currently available methods to differentiate these two species. However, current methods are likely too slow to be employed as rapid detection methods. In this study, conserved differences in the internal transcribed spacer 1 (ITS1) of the ribosomal RNA genes were used to develop species-specific oligonucleotide primers that amplified ITS1 fragments of 147 and 334 bp from H. armigera and H. zea, respectively. An amplicon (83 bp) from a conserved region of 18S ribosomal RNA subunit served as a positive control. Melting temperature differences in ITS1 amplicons yielded species-specific dissociation curves that could be used in high resolution melt analysis to differentiate the two Helicoverpa species. In addition, a rapid and inexpensive procedure for obtaining amplifiable genomic DNA from a small amount of tissue was identified. Under optimal conditions, the process was able to detect DNA from one H. armigera leg in a pool of 25 legs. The high resolution melt analysis combined with rapid DNA extraction could be used as an inexpensive method to genetically differentiate large numbers of H. armigera and H. zea using readily available reagents. PMID:26516166

  11. Reduction of Bacillus thuringiensis Cry1Ac Toxicity Against Helicoverpa armigera by a Soluble Toxin-Binding Cadherin Fragment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A cadherin-like protein has been identified as a putative receptor for Bacillus thuringiensis (Bt) Cry1Ac toxin in Helicoverpa armigera and plays a key role in Bt insecticidal action. In this study, we produced a fragment from this H. armigera Cry1Ac toxin-binding cadherin that included the predict...

  12. A brave new world for an old world pest: Helicoverpa armigera (Lepidoptera: Noctuidae) in Brazil.

    PubMed

    Tay, Wee Tek; Soria, Miguel F; Walsh, Thomas; Thomazoni, Danielle; Silvie, Pierre; Behere, Gajanan T; Anderson, Craig; Downes, Sharon

    2013-01-01

    The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. armigera is thought to have colonised the American continents around 1.5 to 2 million years ago, leading to the current H. zea populations on the American continents. The relatively recent species divergence history is evident in mating compatibility between H. zea and H. armigera under laboratory conditions. Despite periodic interceptions of H. armigera into North America, this pest species is not believed to have successfully established significant populations on either continent. In this study, we provide molecular evidence via mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and cytochrome b (Cyt b) partial gene sequences for the successful recent incursion of H. armigera into the New World, with individuals being detected at two sites (Primavera do Leste, Pedra Preta) within the State of Mato Grosso in Brazil. The mtDNA COI and Cyt b haplotypes detected in the Brazilian H. armigera individuals are common throughout the Old World, thus precluding identification of the founder populations. Combining the two partial mtDNA gene sequences showed that at least two matrilines are present in Brazil, while the inclusion of three nuclear DNA Exon-Primed Intron-Crossing (EPIC) markers identified a further two possible matrilines in our samples. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas. PMID:24260345

  13. A Brave New World for an Old World Pest: Helicoverpa armigera (Lepidoptera: Noctuidae) in Brazil

    PubMed Central

    Walsh, Thomas; Thomazoni, Danielle; Silvie, Pierre; Behere, Gajanan T.; Anderson, Craig; Downes, Sharon

    2013-01-01

    The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. armigera is thought to have colonised the American continents around 1.5 to 2 million years ago, leading to the current H. zea populations on the American continents. The relatively recent species divergence history is evident in mating compatibility between H. zea and H. armigera under laboratory conditions. Despite periodic interceptions of H. armigera into North America, this pest species is not believed to have successfully established significant populations on either continent. In this study, we provide molecular evidence via mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and cytochrome b (Cyt b) partial gene sequences for the successful recent incursion of H. armigera into the New World, with individuals being detected at two sites (Primavera do Leste, Pedra Preta) within the State of Mato Grosso in Brazil. The mtDNA COI and Cyt b haplotypes detected in the Brazilian H. armigera individuals are common throughout the Old World, thus precluding identification of the founder populations. Combining the two partial mtDNA gene sequences showed that at least two matrilines are present in Brazil, while the inclusion of three nuclear DNA Exon-Primed Intron-Crossing (EPIC) markers identified a further two possible matrilines in our samples. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas. PMID:24260345

  14. Developmental and Digestive Flexibilities in the Midgut of a Polyphagous Pest, the Cotton Bollworm, Helicoverpa armigera

    PubMed Central

    Sarate, P.J.; Tamhane, V.A.; Kotkar, H.M.; Ratnakaran, N.; Susan, N.; Gupta, V.S.; Giri, A.P.

    2012-01-01

    Developmental patterns and survival of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), a polyphagous insect pest, have been studied with reference to the effect of diet on major gut digestive enzymes (amylases, proteases, and lipases). Significant correlations between nutritional quality of the diet and larval and pupal mass were observed when H. armigera larvae were fed on various host plants viz. legumes (chickpea and pigeonpea), vegetables (tomato and okra), flowers (rose and marigold), and cereals (sorghum and maize). Larvae fed on diets rich in proteins and/or carbohydrates (pigeonpea, chickpea, maize, and sorghum) showed higher larval mass and developed more rapidly than larvae fed on diets with low protein and carbohydrate content (rose, marigold, okra, and tomato). Low calorific value diets like rose and marigold resulted in higher mortality (25–35%) of H. armigera. Even with highly varying development efficiency and larval/pupal survival rates, H. armigera populations feeding on different diets completed their life cycles. Digestive enzymes of H. armigera displayed variable expression levels and were found to be regulated on the basis of macromolecular composition of the diet. Post—ingestive adaptations operating at the gut level, in the form of controlled release of digestive enzymes, might be a key factor contributing to the physiological plasticity in H. armigera. PMID:22954360

  15. THE ENDOPARASITOID Campoletis chlorideae INDUCES A HEMOLYTIC FACTOR IN THE HERBIVOROUS INSECT Helicoverpa armigera.

    PubMed

    Wang, Xiong-Ya; Bai, Su-Fen; Li, Xin; Yin, Xin-Ming; Li, Xian-Chun

    2015-09-01

    Although lysis of invading organisms is a major innate form of immunity used by invertebrates, it remains unclear whether herbivorous insects have hemolysin or not. To address this general question, we tested the hemolytic (HL) activity of the hemolymph and tissue extracts from various stages of the polyphagous insect Helicoverpa armigera (Hübner) against the erythrocytes from chicken, duck, and rabbit. An HL activity was identified in the hemolymph of H. armigera larvae. Further studies demonstrated that the HL activity is proteinaceous as it was precipitable by deproteinizing agents. Hemolysins were found in Helicoverpa egg, larva, pupa, and adult, but the activity was higher in feeding larvae than in molting or newly molted larvae. Hemolysins were distributed among a variety of larval tissues including salivary gland, fat body, epidermis, midgut, or testes, but the highest activity was found in salivary gland and fat body. Relative to nonparasitized larvae, parasitization of H. armigera larvae by the endoparasitoid Campoletis chlorideae Uchida induced a 3.4-fold increase in the HL activity in the plasma of parasitized host at day two postparasitization. The present study shows the presence of a parasitoid inducible HL factor in the parasitized insect. The HL activity increased significantly in H. armigera larvae at 12 and 24 h postinjection with Escherichia coli. We infer the HL factor(s) is inducible or due to de novo synthesis, which means that the HL factor(s) is associated with insect immune response by inhibiting or clearance of invading organisms. PMID:25929852

  16. Data of in vitro synthesized dsRNAs on growth and development of Helicoverpa armigera.

    PubMed

    Chikate, Yojana R; Dawkar, Vishal V; Barbole, Ranjit S; Tilak, Priyadarshini V; Gupta, Vidya S; Giri, Ashok P

    2016-06-01

    The data presented in this article is related to the research article "RNAi of selected candidate genes interrupts growth and development of Helicoverpa armigera" (Chikate et al., 2016) [1]. RNA interference (RNAi) is emerging as a potent insect pest control strategy over current methods and their resistance by pest. In this study we tested 15 different in vitro synthesized dsRNAs for gene silencing in Helicoverpa armigera. These dsRNAs were specific against H. armigera enzymes/proteins such as proteases like trypsins (HaTry2, 3, 4 and 6), chymotrypsin (HaChy4) and cysteine proteases such as cathepsin (HaCATHL); glutathione S-transferases (HaGST1a, 6 and 8); esterases (HaAce4, HaJHE); catalase (HaCAT); super-oxide-dismutase (HaCu/ZnSOD); fatty acid binding protein (HaFabp) and chitin deacetylase (HaCda5b). These dsRNAs were fed to second instar larvae at an optimized dose (60 µg/day) for 3 days separately. Effects of dsRNA feeding were observed in terms of larval mass gain, percentage mortality and phenotypic abnormalities in later developmental stages of H. armigera. These findings might provide potential new candidates for designing sequence-specific dsRNA as pesticide in crop protection. PMID:27222861

  17. Bioinsecticidal activity of Murraya koenigii miraculin-like protein against Helicoverpa armigera and Spodoptera litura.

    PubMed

    Gahloth, Deepankar; Shukla, Umesh; Birah, Ajanta; Gupta, Gorakh P; Kumar, P Ananda; Dhaliwal, Harcharan S; Sharma, Ashwani K

    2011-11-01

    Miraculin-like proteins, belonging to the Kunitz superfamily, are natural plant defense agents against pests and predators, and therefore are potential biopesticides for incorporation into pest-resistant crops. Here, a miraculin-like protein from Murraya koenigii was assessed for its in vitro and in vivo effects against two polyphagous lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura. M. koenigii miraculin-like protein (MKMLP) inhibited the trypsin-like activity and total protease activity of H. armigera gut proteinases (HGP) by 78.5 and 40%, respectively, and S.litura gut proteinases (SGP) by 81 and 48%, respectively. The inhibitor was stable and actively inhibited the proteolysis of both HGP and SGP enzymes for up to 72 h. Incorporation of MKMLP into artificial diet adversely affected the growth and development of pests in a dose-dependent manner. After 10 days of feeding on diets containing 200 µM MKMLP, larval weight was reduced to 69 and 44.8% and larval mortality was increased to 40 and 43.3% for H. armigera and S litura, respectively. The LC(50) of MKMLP was 0.34 and 0.22% of the diet for H.armigera and S. litura, respectively. These results demonstrate the efficacy of MKMLP as a potential plant defense agent against H. armigera and S. litura. PMID:21948662

  18. Data of in vitro synthesized dsRNAs on growth and development of Helicoverpa armigera

    PubMed Central

    Chikate, Yojana R.; Dawkar, Vishal V.; Barbole, Ranjit S.; Tilak, Priyadarshini V.; Gupta, Vidya S.; Giri, Ashok P.

    2016-01-01

    The data presented in this article is related to the research article “RNAi of selected candidate genes interrupts growth and development of Helicoverpa armigera” (Chikate et al., 2016) [1]. RNA interference (RNAi) is emerging as a potent insect pest control strategy over current methods and their resistance by pest. In this study we tested 15 different in vitro synthesized dsRNAs for gene silencing in Helicoverpa armigera. These dsRNAs were specific against H. armigera enzymes/proteins such as proteases like trypsins (HaTry2, 3, 4 and 6), chymotrypsin (HaChy4) and cysteine proteases such as cathepsin (HaCATHL); glutathione S-transferases (HaGST1a, 6 and 8); esterases (HaAce4, HaJHE); catalase (HaCAT); super-oxide-dismutase (HaCu/ZnSOD); fatty acid binding protein (HaFabp) and chitin deacetylase (HaCda5b). These dsRNAs were fed to second instar larvae at an optimized dose (60 µg/day) for 3 days separately. Effects of dsRNA feeding were observed in terms of larval mass gain, percentage mortality and phenotypic abnormalities in later developmental stages of H. armigera. These findings might provide potential new candidates for designing sequence-specific dsRNA as pesticide in crop protection. PMID:27222861

  19. Genetic basis of sex pheromone blend difference between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae).

    PubMed

    Wang, Hong-Lei; Ming, Qing-Lei; Zhao, Cheng-Hua; Wang, Chen-Zhu

    2008-05-01

    The two closely related moth species, Helicoverpa armigera and H. assulta, are sympatric in China. Both species use a mixture of (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as their sex pheromones but in widely different ratios. Hybridization and backcrossing experiments between H. armigera and H. assulta were conducted and sex pheromone compositions of the parent species, their F(1) hybrids and backcrosses were compared to study the genetic basis of the production of their sex pheromone blend composition. Results show that the difference in sex pheromone blend ratios of these Helicoverpa species is mainly controlled by an autosomal locus with two alleles, with the allele from H. armigera being almost completely dominant over that derived from H. assulta. PMID:18405915

  20. Seasonal migration of Helicoverpa armigera (Lepidoptera: Noctuidae) over the Bohai Sea.

    PubMed

    Feng, Hongqiang; Wu, Xianfu; Wu, Bo; Wu, Kongming

    2009-02-01

    The seasonal migration of the Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) over the Bohai Sea was observed with a searchlight trap and an entomological radar located on a small island in the center of the sea, and through a network of light-traps around the Bohai region. The H. armigera moths were observed to migrate over the sea at least as early as May and light trapping through a network suggested migration might start as early as April, as soon as the moths had emerged from overwintering pupae. H. armigera moths migrated toward the north in southerly winds during spring and summer, and returned south on nights with northerly winds, or at altitudes where the wind was northerly, during fall. The passage of a weather front (cold or warm) or trough at approximately 1700 hours provokes migration of H. armigera over the sea. The H. armigera generally flew at altitudes of below 1,500 m above sea level (asl) with layer concentrations at 200-500 m asl, where the wind direction, wind speed, and temperature were optimum. During fall migration, H. armigera tended to orient toward the southwest and was able to compensate for the wind drift by turning clockwise when the downwind direction was < 225 degrees but counterclockwise when it was > 225 degrees. The displacement speed measured with the radar was 24-41 km/h, the duration of flight was 8-11 h and the maximum migration rate was 1,894 moths per km per h. PMID:19253623

  1. Significance of Penicillium ochrochloron chitinase as a biocontrol agent against pest Helicoverpa armigera.

    PubMed

    Patil, Nilambari S; Jadhav, Jyoti P

    2015-06-01

    Penicillium ochrochloron chitinase purified by DEAE-cellulose ion exchange chromatography was evaluated for its antifeedant and growth inhibitory activities against Helicoverpa armigera at different concentrations of 2000, 1000, 500, 250 and 100 U mL(-1). It reduced the successful pupation and increased larval and pupal mortality, adult emergence in a dosage-dependent manner when applied topically. The highest mortalities were recorded for groups treated with 2000 U mL(-1) chitinase activity. The studies showed P.ochrochloron chitinase can affect the growth of H.armigera larvae. Since this insect pest species has developed resistance and resurgence to chemical insecticides, only alternate is the usage of enzyme-based pesticide formulations as an environmentally friendly pest management tool. PMID:25723715

  2. Toxicity of Bacillus thuringiensis Cry proteins to Helicoverpa armigera (Lepidoptera: Noctuidae) in South Africa.

    PubMed

    Li, Hua; Bouwer, Gustav

    2012-01-01

    The susceptibility of one of the most important pests in southern Africa, Helicoverpa armigera (Lepidoptera: Noctuidae), to Bacillus thuringiensis Cry proteins was evaluated by bioassay. Cry proteins were produced in Escherichia coli BL21 cells that were transformed with plasmids containing one of six cry genes. The toxicity of each Cry protein to H. armigera larvae was determined by the diet contamination method for second instar larvae and the droplet feeding method for neonate larvae. For each of the proteins, dose-mortality and dose-growth inhibition responses were analyzed and the median lethal dose (LD(50)) and median inhibitory dose (ID(50)) determined. Second instar larvae were consistently less susceptible to the evaluated Cry proteins than neonate larvae. The relative toxicity of Cry proteins ranked differently between neonate larvae and second instar larvae. On the basis of the LD(50) and ID(50) values, Cry1Ab, Cry1Ac, and Cry2Aa were the most toxic of the evaluated proteins to H. armigera larvae. The study provides an initial benchmark of the toxicity of individual Cry proteins to H. armigera in South Africa. PMID:22019386

  3. Differential Induction of Flavonoids in Groundnut in Response to Helicoverpa armigera and Aphis craccivora Infestation.

    PubMed

    War, Abdul Rashid; Sharma, Suraj Prasad; Sharma, Hari Chand

    2016-01-01

    Flavonoids are important plant secondary metabolites, which protect plants from various stresses, including herbivory. Plants differentially respond to insects with different modes of action. High performance liquid chromatography (HPLC) fingerprinting of phenols of groundnut (Arachis hypogaea) plants with differential levels of resistance was carried out in response to Helicoverpa armigera (chewing insect) and Aphis craccivora (sucking pest) infestation. The genotypes used were ICGV 86699, ICGV 86031, ICG 2271 (NCAc 343), ICG 1697 (NCAc 17090), and JL 24. Most of the identified compounds were present in H. armigera- and A. craccivora-infested plants of ICGV 86699. Syringic acid was observed in all the genotypes across the treatments, except in the uninfested control plants of ICG 2271 and aphid-infested plants of ICG 1697. Caffeic acid and umbelliferone were observed only in the H. armigera-infested plants of ICGV 86699. Similarly, dihydroxybenzoic acid and vanillic acid were observed in H. armigera- and aphid-infested plants of ICG 2271 and JL 24, respectively. The peak areas were transformed into the amounts of compounds by using internal standard peak areas and were expressed in nanograms. Quantities of the identified compounds varied across genotypes and treatments. The common compounds observed were chlorogenic, syringic, quercetin, and ferulic acids. These results suggest that depending on the mode of feeding, flavonoids are induced differentially in groundnut plants. PMID:27398031

  4. Rab3 is involved in cellular immune responses of the cotton bollworm, Helicoverpa armigera.

    PubMed

    Li, Jie; Song, Cai-Xia; Li, Yu-Ping; Li, Li; Wei, Xiu-Hong; Wang, Jia-Lin; Liu, Xu-Sheng

    2015-06-01

    Rab3, a member of the Rab GTPase family, has been found to be involved in innate immunity. However, the precise function of this GTPase in innate immunity remains unknown. In this study, we identified a Rab3 gene (Ha-Rab3) from the cotton bollworm, Helicoverpa armigera and studied its roles in innate immune responses. Expression of Ha-Rab3 was upregulated in the hemocytes of H. armigera larvae after the injection of Escherichia coli or chromatography beads. The dsRNA-mediated knockdown of Ha-Rab3 gene in H. armigera larval hemocytes led to significant reduction in the phagocytosis and nodulation activities of hemocytes against E. coli, significant increase in the bacterial load in larval hemolymph, and significant reduction in the encapsulation activities of hemocytes toward invading chromatography beads. Furthermore, Ha-Rab3 knockdown significantly suppressed spreading of plasmatocytes. These results suggest that Ha-Rab3 plays important roles in H. armigera cellular immune responses, possibly by mediating spreading of hemocytes. PMID:25662061

  5. Assimilatory potential of Helicoverpa armigera reared on host (Chickpea) and nonhost (Cassia tora) diets.

    PubMed

    Dawkar, Vishal V; Chikate, Yojana R; Gupta, Vidya S; Slade, Susan E; Giri, Ashok P

    2011-11-01

    Adaptation to plant allelochemicals is a crucial aspect of herbivore chemical ecology. To understand an insect ecology, we studied an effect of nonhost Cassia tora seed-based diet (Ct) on growth, development, and molecular responses in Helicoverpa armigera. We employed a comparative approach to investigate the proteomic differences in gut, hemolymph, and frass of H. armigera reared on a normal (chickpea seed-based, Cp) and Ct diet. In this study, a total of 46 proteins were identified by nano-LC-MS(E). Among them, 17 proteins were up-regulated and 29 proteins were down-regulated when larvae were exposed to the Ct diet. Database searches combined with GO analysis revealed that gut proteases engrossed in digestion, proteins crucial for immunity, adaptive responses to stress, and detoxification were down-regulated in the Ct fed larvae. Proteins identified in H. armigera hemolymph were found to be involved in defense mechanisms. Moreover, proteins found in frass of the Ct fed larvae were observed to participate in energy metabolism. Biochemical and quantitative real-time PCR analysis of selected candidate proteins showed differential gene expression patterns and corroborated with the proteomic data. Our results suggest that the Ct diet could alter expression of proteins related to digestion, absorption of nutrients, adaptation, defense mechanisms, and energy metabolism in H. armigera. PMID:21936543

  6. Differential Induction of Flavonoids in Groundnut in Response to Helicoverpa armigera and Aphis craccivora Infestation

    PubMed Central

    War, Abdul Rashid; Sharma, Suraj Prasad; Sharma, Hari Chand

    2016-01-01

    Flavonoids are important plant secondary metabolites, which protect plants from various stresses, including herbivory. Plants differentially respond to insects with different modes of action. High performance liquid chromatography (HPLC) fingerprinting of phenols of groundnut (Arachis hypogaea) plants with differential levels of resistance was carried out in response to Helicoverpa armigera (chewing insect) and Aphis craccivora (sucking pest) infestation. The genotypes used were ICGV 86699, ICGV 86031, ICG 2271 (NCAc 343), ICG 1697 (NCAc 17090), and JL 24. Most of the identified compounds were present in H. armigera- and A. craccivora-infested plants of ICGV 86699. Syringic acid was observed in all the genotypes across the treatments, except in the uninfested control plants of ICG 2271 and aphid-infested plants of ICG 1697. Caffeic acid and umbelliferone were observed only in the H. armigera-infested plants of ICGV 86699. Similarly, dihydroxybenzoic acid and vanillic acid were observed in H. armigera- and aphid-infested plants of ICG 2271 and JL 24, respectively. The peak areas were transformed into the amounts of compounds by using internal standard peak areas and were expressed in nanograms. Quantities of the identified compounds varied across genotypes and treatments. The common compounds observed were chlorogenic, syringic, quercetin, and ferulic acids. These results suggest that depending on the mode of feeding, flavonoids are induced differentially in groundnut plants. PMID:27398031

  7. Genome sequence of Acinetobacter sp. strain HA, isolated from the gut of the polyphagous insect pest Helicoverpa armigera.

    PubMed

    Malhotra, Jaya; Dua, Ankita; Saxena, Anjali; Sangwan, Naseer; Mukherjee, Udita; Pandey, Neeti; Rajagopal, Raman; Khurana, Paramjit; Khurana, Jitendra P; Lal, Rup

    2012-09-01

    In this study, Acinetobacter sp. strain HA was isolated from the midgut of a fifth-instar larva of Helicoverpa armigera. Here, we report the draft genome sequence (3,125,085 bp) of this strain that consists of 102 contigs, 2,911 predicted coding sequences, and a G+C content of 41%. PMID:22933775

  8. Genome Sequence of Acinetobacter sp. Strain HA, Isolated from the Gut of the Polyphagous Insect Pest Helicoverpa armigera

    PubMed Central

    Malhotra, Jaya; Dua, Ankita; Saxena, Anjali; Sangwan, Naseer; Mukherjee, Udita; Pandey, Neeti; Rajagopal, Raman; Khurana, Paramjit; Khurana, Jitendra P.

    2012-01-01

    In this study, Acinetobacter sp. strain HA was isolated from the midgut of a fifth-instar larva of Helicoverpa armigera. Here, we report the draft genome sequence (3,125,085 bp) of this strain that consists of 102 contigs, 2,911 predicted coding sequences, and a G+C content of 41%. PMID:22933775

  9. F1 Screening for Resistance Gene Alleles to Bt Cotton in Helicoverpa armigera: How to Differentiate S and R Genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The F1 screening method relies on the availability in the laboratory of an insecticide-resistant insect strain that is used to detect resistance alleles at the same loci in field populations. This technique was used in this study to survey a field population of Helicoverpa armigera for Bt-resistant ...

  10. The Potential Distribution of Invading Helicoverpa armigera in North America: Is It Just a Matter of Time?

    PubMed Central

    Kriticos, Darren J.; Ota, Noboru; Hutchison, William D.; Beddow, Jason; Walsh, Tom; Tay, Wee Tek; Borchert, Daniel M.; Paula-Moreas, Silvana V.; Czepak, Cecília; Zalucki, Myron P.

    2015-01-01

    Helicoverpa armigera has recently invaded South and Central America, and appears to be spreading rapidly. We update a previously developed potential distribution model to highlight the global invasion threat, with emphasis on the risks to the United States. The continued range expansion of H. armigera in Central America is likely to change the invasion threat it poses to North America qualitatively, making natural dispersal from either the Caribbean islands or Mexico feasible. To characterise the threat posed by H. armigera, we collated the value of the major host crops in the United States growing within its modelled potential range, including that area where it could expand its range during favourable seasons. We found that the annual value of crops that would be exposed to H. armigera totalled approximately US$78 billion p.a., with US$843 million p.a. worth growing in climates that are optimal for the pest. Elsewhere, H. armigera has developed broad-spectrum pesticide resistance; meaning that if it invades the United States, protecting these crops from significant production impacts could be challenging. It may be cost-effective to undertake pre-emptive biosecurity activities such as slowing the spread of H. armigera throughout the Americas, improving the system for detecting H. armigera, and methods for rapid identification, especially distinguishing between H. armigera, H. zea and potential H. armigera x H. zea hybrids. Developing biological control programs, especially using inundative techniques with entomopathogens and parasitoids could slow the spread of H. armigera, and reduce selective pressure for pesticide resistance. The rapid spread of H. armigera through South America into Central America suggests that its spread into North America is a matter of time. The likely natural dispersal routes preclude aggressive incursion responses, emphasizing the value of preparatory communication with agricultural producers in areas suitable for invasion by H

  11. The potential distribution of invading Helicoverpa armigera in North America: is it just a matter of time?

    PubMed

    Kriticos, Darren J; Ota, Noboru; Hutchison, William D; Beddow, Jason; Walsh, Tom; Tay, Wee Tek; Borchert, Daniel M; Paula-Moraes, Silvana V; Paula-Moreas, Silvana V; Czepak, Cecília; Zalucki, Myron P

    2015-01-01

    Helicoverpa armigera has recently invaded South and Central America, and appears to be spreading rapidly. We update a previously developed potential distribution model to highlight the global invasion threat, with emphasis on the risks to the United States. The continued range expansion of H. armigera in Central America is likely to change the invasion threat it poses to North America qualitatively, making natural dispersal from either the Caribbean islands or Mexico feasible. To characterise the threat posed by H. armigera, we collated the value of the major host crops in the United States growing within its modelled potential range, including that area where it could expand its range during favourable seasons. We found that the annual value of crops that would be exposed to H. armigera totalled approximately US$78 billion p.a., with US$843 million p.a. worth growing in climates that are optimal for the pest. Elsewhere, H. armigera has developed broad-spectrum pesticide resistance; meaning that if it invades the United States, protecting these crops from significant production impacts could be challenging. It may be cost-effective to undertake pre-emptive biosecurity activities such as slowing the spread of H. armigera throughout the Americas, improving the system for detecting H. armigera, and methods for rapid identification, especially distinguishing between H. armigera, H. zea and potential H. armigera x H. zea hybrids. Developing biological control programs, especially using inundative techniques with entomopathogens and parasitoids could slow the spread of H. armigera, and reduce selective pressure for pesticide resistance. The rapid spread of H. armigera through South America into Central America suggests that its spread into North America is a matter of time. The likely natural dispersal routes preclude aggressive incursion responses, emphasizing the value of preparatory communication with agricultural producers in areas suitable for invasion by H

  12. Expression of Cry1Aa in cassava improves its insect resistance against Helicoverpa armigera.

    PubMed

    Duan, Xiaoguang; Xu, Jia; Ling, Erjun; Zhang, Peng

    2013-09-01

    Lepidopteran insects affect cassava production globally, especially in intercropping system. The expression of Cry toxins in transgenic crops has contributed to an efficient control of insect pests, leading to a significant reduction in chemical insecticide usage. Helicoverpa armigera is a Lepidopteran pest that feeds on a wide range of plants like cotton and cassava. In the present study, transgenic cassava plants over-expressing Cry1Aa, which we named as Bt cassava, were developed and used to evaluate its efficacy against H. armigera as a model. Insect feeding assays were carried out to test the effects of Bt cassava leaves on the development and survival of H. armigera. Significant reduction (P < 0.05) in the survival and weight were detected on larvae fed with Bt cassava leaves in comparison with those fed with wild-type cassava leaves. The higher expression of Cry1Aa in transgenic cassava caused the lethal effect in larvae, in contrast to the normal growth and development of adults and pupation observed when fed with wild-type leaves. Morphological observation on the larval midguts showed that the consumption of Bt cassava affected the gut integrity of H. armigera. The columnar cells of the midgut epithelium were dramatically damaged and showed loose or disordered structure. Their cytoplasms become highly vacuolated and contained disorganized microvilli. Our study demonstrated that the transgenic cassava expressing the Cry1Aa is effective in controlling H. armigera. Our Bt transgenic cassava plant would provide a long-term beneficial effect on all crops in intercropping system, which in-turn, will be profitable to the farmers. PMID:23325479

  13. Relationships of Helicoverpa armigera, Ostrinia nubilalis and Fusarium verticillioides on MON 810 Maize

    PubMed Central

    Darvas, Béla; Bánáti, Hajnalka; Takács, Eszter; Lauber, Éva; Szécsi, Árpád; Székács, András

    2011-01-01

    MON 810 maize was developed against Ostrinia nubilalis and is suggested to indirectly decrease Fusarium spp. infestation in maize ears. To evaluate this effect, co-occurrence of insect and fungal pests on MON 810 maize was studied. During 2009, exceptionally high maize ear infestation occurred in Julianna-major (Hungary). From investigation of some thousands of maize ears, the majority of the larval damage originated from Helicoverpa armigera larvae, while O. nubilalis larvae contributed significant damage only at a single plot. Fusarium verticillioides infection appeared only in a small portion (∼20–30%) of the insect damaged cobs. H. armigera and O. nubilalis larvae feeding on F. verticillioides mycelia can distribute its conidia with their fecal pellets. MON 810 maize showed 100% efficacy against O. nubilalis in the stem, but lower efficacy against O. nubilalis and H. armigera in maize ears. The ∼Cry1Ab toxin content of maize silk, the entry site of H. armigera, was lower than that in the leaves/stem/husk leaves of MON 810. Fusarium-infected MON 810 cobs are rarely found and only after larval damage by O. nubilalis. H. armigera larvae could not tolerate well F. verticillioides infected food and attempted to move out from the infected cobs. For further feeding they re-entered the maize ears through the 8–12 husk leaves, but in the case of the MON 810 variety, they usually could not reach the kernels. Apical damage on cobs resulted in only a minor (about one-tenth of the cob) decrease in yield. PMID:26467495

  14. piggyBac-like elements in cotton bollworm, Helicoverpa armigera (Hübner).

    PubMed

    Sun, Z C; Wu, M; Miller, T A; Han, Z J

    2008-02-01

    Two piggyBac-like elements (PLEs) were identified in the cotton bollworm, Helicoverpa armigera, and were designated as HaPLE1 and HaPLE2. HaPLE1 is flanked by 16 bp inverted terminal repeats (ITRs) and the duplicated TTAA tetranucleotide, and contains an open reading frame (ORF) of 1794 bp with the presumed DDD domain, indicating that this element may be an active autonomously mobile element. HaPLE2 was found with the same ITRs, but lacks the majority of an ORF-encoding transposase. Thus, this element was thought to be a non-autonomous element. Transposable element displays and distribution of the two PLEs in individuals from three different H. armigera populations suggest that transmobilization of HaPLE2 by the transposase of HaPLE1 may be likely, and mobilization of HaPLE1 might occur not only within the same individual, but also among different individuals. In addition, horizontal transfer was probably involved in the evolution of PLEs between H. armigera and Trichoplusia ni. PMID:18237280

  15. Bacterial Expression and Kinetic Analysis of Carboxylesterase 001D from Helicoverpa armigera.

    PubMed

    Li, Yongqiang; Liu, Jianwei; Lu, Mei; Ma, Zhiqing; Cai, Chongling; Wang, Yonghong; Zhang, Xing

    2016-01-01

    Carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. A subgroup of Helicoverpa armigera esterases, known as Clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. In this work, a novel carboxylesterasegene 001D of H. armigera from China was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. We used a series of fusion proteins to successfully express carboxylesterase 001D in Escherichia coli. Three different fusion proteins were generated and tested. The enzyme kinetic assay towards 1-naphthyl acetate showed all three purified fusion proteins are active with a Kcat between 0.35 and 2.29 s(-1), and a Km between 7.61 and 19.72 μM. The HPLC assay showed all three purified fusion proteins had low but measurable hydrolase activity towards β-cypermethrin and fenvalerate insecticides (specific activities ranging from 0.13 to 0.67 μM·min(-1)·(μM(-1)·protein)). The enzyme was stable up to 40 °C and at pH 6.0-11.0. The results imply that carboxylesterase 001D is involved in detoxification, and this moderate insecticide hydrolysis may suggest that overexpression of the gene to enhance insecticide sequestration is necessary to allow carboxylesterases to confer resistance to these insecticides in H. armigera. PMID:27049381

  16. Bacterial Expression and Kinetic Analysis of Carboxylesterase 001D from Helicoverpa armigera

    PubMed Central

    Li, Yongqiang; Liu, Jianwei; Lu, Mei; Ma, Zhiqing; Cai, Chongling; Wang, Yonghong; Zhang, Xing

    2016-01-01

    Carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. A subgroup of Helicoverpa armigera esterases, known as Clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. In this work, a novel carboxylesterasegene 001D of H. armigera from China was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. We used a series of fusion proteins to successfully express carboxylesterase 001D in Escherichia coli. Three different fusion proteins were generated and tested. The enzyme kinetic assay towards 1-naphthyl acetate showed all three purified fusion proteins are active with a Kcat between 0.35 and 2.29 s−1, and a Km between 7.61 and 19.72 μM. The HPLC assay showed all three purified fusion proteins had low but measurable hydrolase activity towards β-cypermethrin and fenvalerate insecticides (specific activities ranging from 0.13 to 0.67 μM·min−1·(μM−1·protein)). The enzyme was stable up to 40 °C and at pH 6.0–11.0. The results imply that carboxylesterase 001D is involved in detoxification, and this moderate insecticide hydrolysis may suggest that overexpression of the gene to enhance insecticide sequestration is necessary to allow carboxylesterases to confer resistance to these insecticides in H. armigera. PMID:27049381

  17. X-ray radiation and development inhibition of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Kim, Junheon; Jung, Soon-Oh; Jang, Sin Ae; Kim, Jeongmin; Park, Chung Gyoo

    2015-10-01

    Effect of X-ray radiation on the development inhibition was evaluated for all stages of the life cycle of Helicoverpa armigera to determine a radiation dose for potential quarantine treatment against the insect. ED99 values for inhibition of hatching, pupation, and adult emergence from irradiated eggs were 413, 210, and 154 Gy, respectively. ED99 values for inhibition of pupation and adult emergence from irradiated larvae were 221 and 167 Gy, respectively. Pupa was the most tolerant to X-ray radiation. ED99 value for inhibition of adult emergence from irradiated pupae was as high as 2310 Gy, whereas that for inhibition of F1 egg hatching was only 66 Gy. ED99 value for inhibition of hatching of F1 eggs which were laid by irradiated adults was estimated to 194 Gy. X-ray irradiation against H. armigera is recommended as an alternative method to methyl bromide fumigation for phytosanitary treatments during quarantine. X-ray radiation dose of 200 Gy is proposed as a potential quarantine treatment dose for H. armigera eggs and larvae.

  18. Glomerular identification in the antennal lobe of the male moth Helicoverpa armigera.

    PubMed

    Zhao, Xin-Cheng; Chen, Qiu-Yan; Guo, Pei; Xie, Gui-Ying; Tang, Qing-Bo; Guo, Xian-Ru; Berg, Bente G

    2016-10-15

    This study investigates anatomical organization of the antennal lobe (AL) glomeruli of the male cotton bollworm Helicoverpa armigera by synaptic antibody staining combined with three-dimensional reconstruction. To identify all glomeruli, their boundaries were accurately determined by means of several additional staining techniques visualizing the neuron categories forming the characteristic spherical neuropils. In total, 78-80 glomeruli were identified in the male H. armigera. The number of glomeruli was considerably larger than that previously reported in this species. Thus, compared with previous studies, we identified 15 new glomeruli, G63-G77. Most of them are located in the posterior part of the AL, which was previously considered to be a part of the protocerebrum. From the general anatomical organization of the AL glomeruli of H. armigera, we classified these neuropil structures into four groups, the macroglomerular complex, posterior complex, labial-palp pit organ glomerulus, and ordinary glomeruli. The complete identification of glomeruli is important for future studies seeking to explore further the coding mechanisms residing within the primary olfactory center of the moth brain. J. Comp. Neurol. 524:2993-3013, 2016. © 2016 Wiley Periodicals, Inc. PMID:27018863

  19. Insecticidal Potential of Defense Metabolites from Ocimum kilimandscharicum against Helicoverpa armigera

    PubMed Central

    Thulasiram, Hirekodathakallu V.; Kulkarni, Mahesh J.; Giri, Ashok P.

    2014-01-01

    Genus Ocimum contains a reservoir of diverse secondary metabolites, which are known for their defense and medicinal value. However, the defense-related metabolites from this genus have not been studied in depth. To gain deeper insight into inducible defense metabolites, we examined the overall biochemical and metabolic changes in Ocimum kilimandscharicum that occurred in response to the feeding of Helicoverpa armigera larvae. Metabolic analysis revealed that the primary and secondary metabolism of local and systemic tissues in O. kilimandscharicum was severely affected following larval infestation. Moreover, levels of specific secondary metabolites like camphor, limonene and β-caryophyllene (known to be involved in defense) significantly increased in leaves upon insect attack. Choice assays conducted by exposing H. armigera larvae on O. kilimandscharicum and tomato leaves, demonstrated that O. kilimandscharicum significantly deters larval feeding. Further, when larvae were fed on O. kilimandscharicum leaves, average body weight decreased and mortality of the larvae increased. Larvae fed on artificial diet supplemented with O. kilimandscharicum leaf extract, camphor, limonene and β-caryophyllene showed growth retardation, increased mortality rates and pupal deformities. Digestive enzymes of H. armigera - namely, amylase, protease and lipase- showed variable patterns after feeding on O. kilimandscharicum, which implies striving of the larvae to attain required nutrition for growth, development and metamorphosis. Evidently, selected metabolites from O. kilimandscharicum possess significant insecticidal activity. PMID:25098951

  20. Insecticidal potential of defense metabolites from Ocimum kilimandscharicum against Helicoverpa armigera.

    PubMed

    Singh, Priyanka; Jayaramaiah, Ramesha H; Sarate, Priya; Thulasiram, Hirekodathakallu V; Kulkarni, Mahesh J; Giri, Ashok P

    2014-01-01

    Genus Ocimum contains a reservoir of diverse secondary metabolites, which are known for their defense and medicinal value. However, the defense-related metabolites from this genus have not been studied in depth. To gain deeper insight into inducible defense metabolites, we examined the overall biochemical and metabolic changes in Ocimum kilimandscharicum that occurred in response to the feeding of Helicoverpa armigera larvae. Metabolic analysis revealed that the primary and secondary metabolism of local and systemic tissues in O. kilimandscharicum was severely affected following larval infestation. Moreover, levels of specific secondary metabolites like camphor, limonene and β-caryophyllene (known to be involved in defense) significantly increased in leaves upon insect attack. Choice assays conducted by exposing H. armigera larvae on O. kilimandscharicum and tomato leaves, demonstrated that O. kilimandscharicum significantly deters larval feeding. Further, when larvae were fed on O. kilimandscharicum leaves, average body weight decreased and mortality of the larvae increased. Larvae fed on artificial diet supplemented with O. kilimandscharicum leaf extract, camphor, limonene and β-caryophyllene showed growth retardation, increased mortality rates and pupal deformities. Digestive enzymes of H. armigera - namely, amylase, protease and lipase- showed variable patterns after feeding on O. kilimandscharicum, which implies striving of the larvae to attain required nutrition for growth, development and metamorphosis. Evidently, selected metabolites from O. kilimandscharicum possess significant insecticidal activity. PMID:25098951

  1. Differential immunosuppression by Campoletis chlorideae eggs and ichnovirus in larvae of Helicoverpa armigera and Spodoptera exigua.

    PubMed

    Han, Li-Bin; Yin, Li-Hong; Huang, Ling-Qiao; Wang, Chen-Zhu

    2015-09-01

    The ichneumonid wasp, Campoletis chlorideae Uchida, successfully develops in the cotton bollworm Helicoverpa armigera (Hübner), but rarely survives in the beet armyworm Spodoptera exigua (Hübner) due to the encapsulation by host immunity. In this study, we investigated the role of C. chlorideae ichnovirus (CcIV) and eggs in the evasion of the host immune system. Washed eggs of different types, immature, mature, newly laid, or pretreated with protease K, were injected alone or with the calyx fluid containing CcIV into the larvae of H. armigera and S. exigua. In H. armigera, when injected with washed eggs alone, only 9.5% of the mature eggs were encapsulated at 24h post-injection. This is much lower than that of the immature eggs (100%), mature eggs pretreated with protease K (100%) and newly laid eggs (54.4%). No encapsulation was observed when the washed eggs were co-injected with calyx fluid at 24h post-injection. Conversely, the eggs in all treatments were encapsulated in S. exigua. Electron microscopic observations of parasitoid eggs showed structural differences between the surfaces of the mature and other kinds of eggs. The injected CcIV decreased the numbers of host hemocytes and suppressed the spreading ability of plasmatocytes and granulocytes in H. armigera, but had little effect on the hemocytes from S. exigua. In conclusion, the C. chlorideae egg provides a passive protection against encapsulation by itself, and CcIV supplies an active protection through disrupting host immune responses. These coordinated protections are host-specific, implying their role in host range determination. PMID:26183795

  2. Life Table and Consumption Capacity of Corn Earworm, Helicoverpa armigera, Fed Asparagus, Asparagus officinalis

    PubMed Central

    Jha, Ratna Kumar; Tuan, Shu-Jen; Chi, Hsin; Tang, Li-Cheng

    2014-01-01

    The life table and consumption rate of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) reared on asparagus, Asparagus officinalis L. (Asparagales: Asparagaceae) were studied under laboratory conditions to assess their interaction. Development, survival, fecundity, and consumption data were analyzed by the age-stage, two-sex life table. This study indicated that asparagus is a natural host of H. armigera. However, the poor nutritional content in asparagus foliage and the poor fitness of H. armigera that fed on asparagus indicated that asparagus is a suboptimal host in comparison to hybrid sweet corn. The uncertainty associated with life table parameters was estimated by using jackknife and bootstrap techniques, and the results were compared for statistical inference. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were estimated by the jackknife technique to be 0.0780 day-1, 1.0811 day-1, 67.4 offspring, and 54.8 days, respectively, while those estimated by the bootstrap technique were 0.0752 day-1, 1.0781 day-1, 68.0 offspring, and 55.3 days, respectively. The net consumption rate of H. armigera, as estimated by the jackknife and bootstrap technique, was 1183.02 and 1132.9 mg per individual, respectively. The frequency distribution of sample means obtained by the jackknife technique failed the normality test, while the bootstrap results fit the normal distribution well. By contrast, the relationship between the mean fecundity and the net reproductive rate, as estimated by the bootstrap technique, was slightly inconsistent with the relationship found by mathematical proof. The application of the jackknife and bootstrap techniques in estimating population parameters requires further examination. PMID:25373181

  3. Life table and consumption capacity of corn earworm, Helicoverpa armigera, fed asparagus, Asparagus officinalis.

    PubMed

    Jha, Ratna Kumar; Tuan, Shu-Jen; Chi, Hsin; Tang, Li-Cheng

    2014-01-01

    The life table and consumption rate of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) reared on asparagus, Asparagus officinalis L. (Asparagales: Asparagaceae) were studied under laboratory conditions to assess their interaction. Development, survival, fecundity, and consumption data were analyzed by the age-stage, twosex life table. This study indicated that asparagus is a natural host of H. armigera. However, the poor nutritional content in asparagus foliage and the poor fitness of H. armigera that fed on asparagus indicated that asparagus is a suboptimal host in comparison to hybrid sweet corn. The uncertainty associated with life table parameters was estimated by using jackknife and bootstrap techniques, and the results were compared for statistical inference. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were estimated by the jackknife technique to be 0.0780 day(-1), 1.0811 day(-1), 67.4 offspring, and 54.8 days, respectively, while those estimated by the bootstrap technique were 0.0752 day(-1), 1.0781 day(-1), 68.0 offspring, and 55.3 days, respectively. The net consumption rate of H. armigera, as estimated by the jackknife and bootstrap technique, was 1183.02 and 1132.9 mg per individual, respectively. The frequency distribution of sample means obtained by the jackknife technique failed the normality test, while the bootstrap results fit the normal distribution well. By contrast, the relationship between the mean fecundity and the net reproductive rate, as estimated by the bootstrap technique, was slightly inconsistent with the relationship found by mathematical proof. The application of the jackknife and bootstrap techniques in estimating population parameters requires further examination. PMID:25373181

  4. Pigeonpea genotypes influence parasitization preference and survival and development of the Helicoverpa armigera larval parasitoid, Campoletis chlorideae.

    PubMed

    Hugar, Shiddalingappa V; Sharma, Hari C; Basavan Goud, Kondikallu

    2014-01-01

    Studies were undertaken to identify pigeonpea, Cajanus cajan (L.) Millspaugh and the wild relative of pigeonpea, Cajanus scarabaeoides (L.) (accession ICPW 125,) genotypes that are hospitable to the pod borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larval parasitoid, Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) for the management of this pest in pigeonpea based cropping systems. Percentage parasitization of the H. armigera larvae by the C. chlorideae females was greater under no-choice conditions than under multi-choice conditions because of forced parasitization under no-choice conditions. Lowest parasitization was recorded on the wild relative, ICPW 125, which may be due to long nonglandular hairs and low survival of H. armigera larvae. Parasitization of H. armigera larvae was greater under no-choice, dual-choice and/or multi-choice conditions on ICPL 87, ICPL 87119 and ICPL 87091, which are susceptible to H. armigera, than on the pod borer-resistant genotypes ICPL 332WR, ICPL 84060 and ICPB 2042; while survival and development of the parasitoid was better on H. armigera larvae fed on ICPL 87, ICPL 87119, LRG 41, ICP 7035 and ICPL 87091 than on ICPL 332WR, ICPL 84060, ICPB 2042 and ICPW 125. The genotypes ICPL 87, ICPL 87119, LRG 42 and ICPL 87091 that are hospitable to C. chloridae, are better suited for use in integrated pest management to minimize the losses due to H. armigera in pigeonpea. PMID:25110629

  5. Interaction of salivary and midgut proteins of Helicoverpa armigera with soybean trypsin inhibitor.

    PubMed

    Upadhyay, Santosh Kumar; Chandrashekar, Krishnappa

    2012-03-01

    Feeding of Helicoverpa armigera larvae on semi-synthetic diet containing Soybean trypsin inhibitor (STI) resulted in disappearance of STI sensitive protease in salivary and midgut protease extract. This might be due to in situ inhibition by dietary STI. STI was largely degraded within 1 h of incubation with total salivary protease (1:1). Degradation was relatively low in midgut proteases. STI interacting proteins were isolated from saliva and midgut extracts of larvae fed on STI supplemented diet using affinity column. Most of the isolated proteins showed caseinolytic activity in zymogram. Denovo sequencing data of seven different peptides selected from trypsin digested total protein showed similarity to chymotrypsinogen, serine protease, aminopeptidase N, peroxidase, hypothetical protein and muscle specific protein. PMID:22415700

  6. Variation in resistance to pyrethroids in Helicoverpa armigera from Benin Republic, West Africa.

    PubMed

    Djihinto, Angelo C; Katary, André; Prudent, Patrick; Vassal, Jean-Michel; Vaissayre, Maurice

    2009-10-01

    Pyrethroid resistance in Helicoverpa armigera (Hübner) field populations was investigated in Benin over several years by using third- and fourth-instar larval topicalbioassays. H. armigera was resistant to pyrethroids tested as cypermethrin, deltamethrin, bifenthrin, and fenvalerate. Pretreatment with piperonyl butoxide significantly decreased the LD50 value of cypermethrin and deltamethrin, and the resistance suppression by this synergist effect was observed. No significant decrease in the LD50 value was obtained when S,S,S-tributyl phosphoro-trithioate was applied before deltamethrin. In the field, cypermethrin's LD50 value varied, and the highest LD50 values were observed during the rainy season, the cotton, Gossypium hirsutum L., crop period, when pyrethroids are extensively used. In the dry season when there was no cotton cultivation, the lowest LD50 values were obtained. However, reversion was never total in the field; resistance did not revert to the level we observed in the susceptible strain. In the laboratory, when field populations were reared in insecticide-free conditions, resistance decreased and total reversion was observed. Results are discussed with regard to insecticide resistance fitness cost and resistance management strategies. PMID:19886459

  7. Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae-A 2D NMR Metabolomics Study.

    PubMed

    Vergara, Fredd; Shino, Amiu; Kikuchi, Jun

    2016-01-01

    Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea). Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal), the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR) and principal component analysis (PCA). Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of ¹H-(13)C HSQC (Heteronuclear Single Quantum Coherence) signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae. PMID:27598144

  8. Functional validation of the carbon dioxide receptor in labial palps of Helicoverpa armigera moths.

    PubMed

    Ning, Chao; Yang, Ke; Xu, Meng; Huang, Ling-Qiao; Wang, Chen-Zhu

    2016-06-01

    Adult moths possess an organ in their labial palps, the labial-palp pit organ, which is specialized for sensing carbon dioxide (CO2). They use CO2 as a cue to detect healthy plants and find food or lay eggs on them. The molecular bases of the CO2 receptor in Drosophila melanogaster and Aedes aegypti have been reported, but the molecular mechanisms of the CO2 receptor in Lepidoptera remains elusive. In this study, we first re-examined three putative Helicoverpa armigera CO2 gustatory receptor genes (HarmGr1, HarmGr2, and HarmGr3), and then analyzed expression patterns of them. RT-PCR results verified they were predominantly expressed in the labial palps of H. armigera. Thus, we used in situ hybridization to localize the expression of three genes in the labial palps. We found that all three genes were co-expressed in the same cells of the labial palps. Next, we employed the Xenopus laevis oocyte expression system and the two-electrode voltage-clamp recording to study the function of the three genes. Results showed that only oocytes co-expressing HarmGr1 and HarmGr3 or co-expressing HarmGr1, HarmGr2 and HarmGr3 gave robust responses to NaHCO3. Finally, we confirmed that the sensory cells in labial palps of both females and males show dose dependent responses to CO2 stimuli by using single sensillum recording. Our work uncovers that HarmGr1 and HarmGr3 are indispensable and sufficient for CO2 sensing in labial palps of H. armigera. PMID:27060445

  9. Effect of storage temperature and duration on viability of eggs of Helicoverpa armigera (Lepidoptera: Noctuidae).

    PubMed

    Dhillon, M K; Sharma, H C

    2007-02-01

    The ability to store different insect stadia for prolonged periods provides considerable flexibility and ability to conduct experiments properly. Therefore, studies were undertaken to determine the effect of storage temperature and duration on viability of eggs of Helicoverpa armigera (Hübner). The percentage egg hatch and incubation period were significantly (P=0.01) influenced by egg age, storage temperature, and storage duration. Egg hatch ranged from 0.0 to 96.8% across temperatures and storage durations. None of the eggs hatched when stored at -20 and 0 degrees C. The regression model with the optimum Mallow Cp statistic for any of the identified linear and quadratic terms did not improve the precision of prediction in egg hatch beyond 67.0%. Forecasting of incubation period based on egg age, storage duration, and durationxtemperature was quite effective (R2=84.2%). Day degrees required for egg hatching decreased with an increase in temperature from 10 to 27 degrees C, and egg age from 0 to 3 days. The day degree requirements were highest for 0-day-old eggs at 10 degrees C, and lowest at 27 degrees C. Although the incubation period was higher, the hatchability was lower for 0- and 1-day-old eggs stored at constant 10 degrees C, these eggs can be stored for 10 days at 10 degrees C, with a hatchability of >75.0%. It was safer to store the H. armigera eggs for 10 days at 10 degrees C, which will hatch within 1.6 to 2.0 days after restoration at 27 degrees C with a hatchability of >75.0%. This information will be useful in planning and execution of experiments involving H. armigera on various aspects of research in entomology. PMID:17298682

  10. An overlooked component: (Z)-9-tetradecenal as a sex pheromone in Helicoverpa armigera.

    PubMed

    Zhang, Jin-Ping; Salcedo, Christian; Fang, Yu-Ling; Zhang, Ruo-Jian; Zhang, Zhong-Ning

    2012-09-01

    The sex pheromone blend of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a multi-component system, as is that of many other moths, and (Z)-11-hexadecenal 90-99%+(Z)-9-hexadecenal 10-1% was recommended as a standard blend for attracting the species. However, this fails to account for the significance of other compounds that exist in the sex gland. The aim of the present study was to investigate the function of other compounds present in the female sex gland of H. armigera. Extract of female sex glands were analysed by GC-MS combined with GC-EAD. Total 10 compounds were identified, which two novel were reported in female sex gland: heptanal and nonanal, and some previously identified compounds were confirmed. We developed bioassays to evaluate the potential roles of these 10 compounds. In Y-tube bioassays, the gland constituents hexadecanal, (Z)-7-hexadecenal and (Z)-9-tetradecenal increased male attractiveness when added as a three-compound admixture to the standard blend. Field trapping tests showed that (Z)-9-tetradecenal doubled trap catch in comparison with the standard blend, but that the addition of (Z)-7-hexadecenal and hexadecanal did not significantly increase trap catch. These results indicated that while (Z)-7-hexadecenal and hexadecanal function well only at short range, (Z)-9-tetradecenal plays a very important role at both short and long ranges. We suggest that that (Z)-9-tetradecenal as a previously overlooked sex pheromone component of H. armigera, it should be added to sex pheromone lure formulations to improve pheromone trap sensitivity and the efficacy of commercial mating disruption. PMID:22732233

  11. Feeding deterrent and growth inhibitory activities of PONNEEM, a newly developed phytopesticidal formulation against Helicoverpa armigera (Hubner)

    PubMed Central

    Packiam, Soosaimanickam Maria; Baskar, Kathirvelu; Ignacimuthu, Savarimuthu

    2014-01-01

    Objective To assess the feeding deterrent, growth inhibitory and egg hatchability effects of PONNEEM on Helicoverpa armigera (H. armigera). Methods Five oil formulations were prepared at different ratios to assess the feeding deterrent, growth inhibitory and egg hatchability effects on H. armigera. Results Invariably all the newly formulated phytopesticidal oil formulations showed the feeding deterrent and growth inhibitory activities against H. armigera. The maximum feeding deterrent activity of 88.44% was observed at 15 µL/L concentration of PONNEEM followed by formulation A (74.54%). PONNEEM was found to be effective in growth inhibitory activities and egg hatchability at 10 µL/L concentration. It exhibited statistically significant feeding deterrent activity and growth inhibitory activity compared with all the other treatments. Conclusions PONNEEM was found to be effective phytopesticidal formulation to control the larval stage of H. armigera. This is the first report for the feeding deterrent activity of PONNEEM against H. armigera. This newly formulated phytopesticide was patented in India. PMID:25183105

  12. Cross-species amplification and polymorphism of microsatellite loci in Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) in Brazilian cropping systems.

    PubMed

    Leite, N A; Corrêa, A S; Alves-Pereira, A; Campos, J B; Zucchi, M I; Omoto, C

    2016-01-01

    The Old World bollworm Helicoverpa armigera (Hübner) was recently discovered in Brazil. This species is closely related to the New World bollworm H. zea (Boddie), and mating between these species has already been reported under laboratory conditions. Here, we tested the cross-species amplification of 20 microsatellite (SSR) loci in field populations of H. armigera and H. zea collected from Brazilian cropping systems. Seven SSR loci were successfully amplified and polymorphic in both species except for the locus HaC14, which was monomorphic for H. zea. All SSR loci were in linkage equilibrium, and deviations from Hardy- Weinberg equilibrium were only observed for the locus HarSSR1 in the HaRS-2 population, where null alleles were present. A moderate level of polymorphism was detected in H. armigera and H. zea populations with a mean allele number of 4.14, and 2.24, respectively. Interestingly, most of the populations of the recent invader H. armigera showed higher genetic diversity and inbreeding coefficients than H. zea populations. The genetic identity of each species was recovered using a STRUCTURE analysis, where the populations formed two clusters (K = 2) according to their species. STRUCTURE also suggested the occurrence of potential hybrid offspring between H. armigera and H. zea individuals in natural conditions. These SSR loci will be valuable in characterizing population differentiation, invasion routes, adaptation, reproductive behavior, and intra- and interspecific gene flow in H. armigera and H. zea populations in Brazil, the USA, and other areas where these two pests occur. PMID:27173200

  13. Targeting chitinase gene of Helicoverpa armigera by host-induced RNA interference confers insect resistance in tobacco and tomato.

    PubMed

    Mamta; Reddy, K R K; Rajam, M V

    2016-02-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a devastating agricultural insect pest with broad spectrum of host range, causing million dollars crop loss annually. Limitations in the present conventional and transgenic approaches have made it crucial to develop sustainable and environmental friendly methods for crop improvement. In the present study, host-induced RNA interference (HI-RNAi) approach was used to develop H. armigera resistant tobacco and tomato plants. Chitinase (HaCHI) gene, critically required for insect molting and metamorphosis was selected as a potential target. Hair-pin RNAi construct was prepared from the conserved off-target free partial HaCHI gene sequence and was used to generate several HaCHI-RNAi tobacco and tomato plants. Northern hybridization confirmed the production of HaCHI gene-specific siRNAs in HaCHI-RNAi tobacco and tomato lines. Continuous feeding on leaves of RNAi lines drastically reduced the target gene transcripts and consequently, affected the overall growth and survival of H. armigera. Various developmental deformities were also manifested in H. armigera larvae after feeding on the leaves of RNAi lines. These results demonstrated the role of chitinase in insect development and potential of HI-RNAi for effective management of H. armigera. PMID:26659592

  14. Effect of electron beam irradiation on developmental stages of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Kim, Junheon; Chung, Soon-Oh; Jang, Sin Ae; Jang, Miyeon; Park, Chung Gyoo

    2015-07-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an economically important and polyphagous pest, which harms various kinds of food crops and important agricultural plants, such as cotton and paprika. Effects of electron beam irradiation at six dose levels between 50 and 350 Gy on the egg (24-48 h old), the larval (4-5th instar), and the pupal (7-d old for female, 5-d old for male) development, and on the adult (1-d old) reproduction were tested to identify a potential quarantine treatment dose. Increased doses of irradiation on eggs decreased egg hatchability, pupation and adult emergence and increased larval period. ED99 values for inhibition of hatching, pupation and emergence were 460.6, 236.9 and 197.8 Gy, respectively. When larvae were irradiated with more than 280 Gy, no larvae could develop into pupae. ED99 values for inhibition of pupation and adult emergence were 265.6 and 189.6 Gy, respectively. Even though the irradiation on pupa did not completely inhibit adult emergence, most of the pupae emerged to deformed adults. When adults were irradiated, fecundity was not affected. However, F1 egg hatching was completely inhibited at the dose of 350 Gy. ED99 value for inhibition of adult emergence was estimated at 366.5 Gy. Our results suggest that electron beam irradiation could be recommendable as an alternative to MB and as a phytosanitary treatment for quarantine. A treatment dose of less than or equal to 220 Gy is suggested as a potential quarantine treatment to H. armigera egg for prevention of pupation and to larva for prevention of adult emerge.

  15. NMR structure and function of Helicoverpa armigera sterol carrier protein-2, an important insecticidal target from the cotton bollworm

    PubMed Central

    Ma, Haihao; Ma, Yuemin; Liu, Xuehui; Dyer, David H.; Xu, Pingyong; Liu, Kaiyu; Lan, Que; Hong, Huazhu; Peng, Jianxin; Peng, Rong

    2015-01-01

    The cotton bollworm, Helicoverpa armigera, has developed strong resistance to many insecticides. Sterol Carrier Protein-2 (SCP-2) is an important non-specific lipid transfer protein in insects and appears to be a potential new target. In order to elucidate the structure and function of Helicoverpa armigera SCP-2 (HaSCP-2), NMR spectroscopy, docking simulations, mutagenesis and bioassays were performed. HaSCP-2 composed of five α-helices and four stranded β-sheets. The folds of α-helices and β-sheets interacted together to form a hydrophobic cavity with putative entrance and exit openings, which served as a tunnel for accommodating and transporting of lipids. Several sterols and fatty acids could interact with HaSCP-2 via important hydrophobic sites, which could be potential targets for insecticides. Mutagenesis experiments indicated Y51, F53, F89, F110, I117 and Q131 may be the key functional sites. HaSCP-2 showed high cholesterol binding activity and SCP-2 inhibitors (SCPIs) could inhibit the biological activity of HaSCP-2. SCPI-treated larvae at young stage showed a significant decrease of cholesterol uptake in vivo. Our study describes for the first time a NMR structure of SCP-2 in lepidopteran H. armigera and reveals its important function in cholesterol uptake, which facilitates the screening of effective insecticides targeting the insect cholesterol metabolism. PMID:26655641

  16. Cantharidin Impedes Activity of Glutathione S-Transferase in the Midgut of Helicoverpa armigera Hübner

    PubMed Central

    Khan, Rashid Ahmed; Liu, Ji Yuan; Rashid, Maryam; Wang, Dun; Zhang, Ya Lin

    2013-01-01

    Previous investigations have implicated glutathione S-transferases (GSTs) as one of the major reasons for insecticide resistance. Therefore, effectiveness of new candidate compounds depends on their ability to inhibit GSTs to prevent metabolic detoxification by insects. Cantharidin, a terpenoid compound of insect origin, has been developed as a bio-pesticide in China, and proves highly toxic to a wide range of insects, especially lepidopteran. In the present study, we test cantharidin as a model compound for its toxicity, effects on the mRNA transcription of a model Helicoverpa armigera glutathione S-transferase gene (HaGST) and also for its putative inhibitory effect on the catalytic activity of GSTs, both in vivo and in vitro in Helicoverpa armigera, employing molecular and biochemical methods. Bioassay results showed that cantharidin was highly toxic to H. armigera. Real-time qPCR showed down-regulation of the HaGST at the mRNA transcript ranging from 2.5 to 12.5 folds while biochemical assays showed in vivo inhibition of GSTs in midgut and in vitro inhibition of rHaGST. Binding of cantharidin to HaGST was rationalized by homology and molecular docking simulations using a model GST (1PN9) as a template structure. Molecular docking simulations also confirmed accurate docking of the cantharidin molecule to the active site of HaGST impeding its catalytic activity. PMID:23528854

  17. Cantharidin Impedes Activity of Glutathione S-Transferase in the Midgut of Helicoverpa armigera Hübner.

    PubMed

    Khan, Rashid Ahmed; Liu, Ji Yuan; Rashid, Maryam; Wang, Dun; Zhang, Ya Lin

    2013-01-01

    Previous investigations have implicated glutathione S-transferases (GSTs) as one of the major reasons for insecticide resistance. Therefore, effectiveness of new candidate compounds depends on their ability to inhibit GSTs to prevent metabolic detoxification by insects. Cantharidin, a terpenoid compound of insect origin, has been developed as a bio-pesticide in China, and proves highly toxic to a wide range of insects, especially lepidopteran. In the present study, we test cantharidin as a model compound for its toxicity, effects on the mRNA transcription of a model Helicoverpa armigera glutathione S-transferase gene (HaGST) and also for its putative inhibitory effect on the catalytic activity of GSTs, both in vivo and in vitro in Helicoverpa armigera, employing molecular and biochemical methods. Bioassay results showed that cantharidin was highly toxic to H. armigera. Real-time qPCR showed down-regulation of the HaGST at the mRNA transcript ranging from 2.5 to 12.5 folds while biochemical assays showed in vivo inhibition of GSTs in midgut and in vitro inhibition of rHaGST. Binding of cantharidin to HaGST was rationalized by homology and molecular docking simulations using a model GST (1PN9) as a template structure. Molecular docking simulations also confirmed accurate docking of the cantharidin molecule to the active site of HaGST impeding its catalytic activity. PMID:23528854

  18. Mis-splicing of the ABCC2 gene linked with Bt toxin resistance in Helicoverpa armigera

    PubMed Central

    Xiao, Yutao; Zhang, Tao; Liu, Chenxi; Heckel, David G.; Li, Xianchun; Tabashnik, Bruce E.; Wu, Kongming

    2014-01-01

    Toxins from the bacterium Bacillus thuringiensis (Bt) are used widely for insect control in sprays and transgenic plants, but their efficacy is reduced when pests evolve resistance. Previous work showed that mutations in a gene encoding the transporter protein ABCC2 are linked with resistance to Bt toxins Cry1Ab, Cry1Ac or both in four species of Lepidoptera. Here we compared the ABCC2 gene of Helicoverpa armigera (HaABCC2) between susceptible strains and a laboratory-selected strain with >1,000-fold resistance to Cry1Ac relative its susceptible parent strain. We discovered a 73-base pair (bp) insertion in the cDNA of the resistant strain that generates a premature stop codon expected to yield a truncated ABCC2 protein. Sequencing of genomic DNA revealed that this insertion is an intron that is not spliced out because of a 6-bp deletion at its splicing site. Analysis of progeny from crosses revealed tight genetic linkage between HaABCC2 and resistance to Cry1Ac. These results provide the first evidence that mis-splicing of a gene encoding an ABCC2 protein confers resistance to a Bt toxin. PMID:25154974

  19. A transferrin gene associated with development and 2-tridecanone tolerance in Helicoverpa armigera

    PubMed Central

    Zhang, L; Shang, Q; Lu, Y; Zhao, Q; Gao, X

    2015-01-01

    The full-length cDNA (2320 bp) encoding a putative iron-binding transferrin protein from Helicoverpa armigera was cloned and named HaTrf. The putative HaTrf sequence included 670 amino acids with a molecular mass of approximately 76 kDa. Quantitative PCR results demonstrated that the transcriptional level of HaTrf was significantly higher in the sixth instar and pupa stages as compared with other developmental stages. HaTrf transcripts were more abundant in fat bodies and in the epidermis than in malpighian tubules. Compared with the control, the expression of HaTrf increased dramatically 24 h after treatment with 2-tridecanone. Apparent growth inhibition with a dramatic body weight decrease was observed in larvae fed with HaTrf double-stranded RNA (dsRNA), as compared with those fed with green fluorescent protein dsRNA. RNA interference of HaTrf also significantly increased the susceptibility of larvae to 2-tridecanone. These results indicate the possible involvement of HaTrf in tolerance to plant secondary chemicals. PMID:25430818

  20. Characterization of protein phosphatase 5 from three lepidopteran insects: Helicoverpa armigera, Mythimna separata and Plutella xylostella.

    PubMed

    Chen, Xi'en; Lü, Shumin; Zhang, Yalin

    2014-01-01

    Protein phosphatase 5 (PP5), a unique member of serine/threonine phosphatases, regulates a variety of biological processes. We obtained full-length PP5 cDNAs from three lepidopteran insects, Helicoverpa armigera, Mythimna separata and Plutella xylostella, encoding predicted proteins of 490 (55.98 kDa), 490 (55.82 kDa) and 491 (56.07 kDa) amino acids, respectively. These sequences shared a high identity with other insect PP5s and contained the TPR (tetratricopeptide repeat) domains at N-terminal regions and highly conserved C-terminal catalytic domains. Tissue- and stage-specific expression pattern analyses revealed these three PP5 genes were constitutively expressed in all stages and in tested tissues with predominant transcription occurring at the egg and adult stages. Activities of Escherichia coli-produced recombinant PP5 proteins could be enhanced by almost 2-fold by a known PP5 activator: arachidonic acid. Kinetic parameters of three recombinant proteins against substrate pNPP were similar both in the absence or presence of arachidonic acid. Protein phosphatases inhibitors, okadaic acid, cantharidin, and endothall strongly impeded the activities of the three recombinant PP5 proteins, as well as exerted an inhibitory effect on crude protein phosphatases extractions from these three insects. In summary, lepidopteran PP5s share similar characteristics and are all sensitive to the protein phosphatases inhibitors. Our results also imply protein phosphatase inhibitors might be used in the management of lepidopteran pests. PMID:24823652

  1. Influence of CO2 and Temperature on Metabolism and Development of Helicoverpa armigera (Noctuidae: Lepidoptera).

    PubMed

    Akbar, S Md; Pavani, T; Nagaraja, T; Sharma, H C

    2016-02-01

    Climate change will have a major bearing on survival and development of insects as a result of increase in CO2 and temperature. Therefore, we studied the direct effects of CO2 and temperature on larval development and metabolism in cotton bollworm, Helicoverpa armigera (Hübner). The larvae were reared under a range of CO2 (350, 550, and 750 ppm) and temperature (15, 25, 35, and 45°C) regimes on artificial diet. Elevated CO2 negatively affected the larval survival, larval weight, larval period, pupation, and adult emergence, but showed a positive effect on pupal weight, pupal period, and fecundity. Increase in temperature exhibited a negative effect on larval survival, larval period, pupal weights, and pupal period, but a positive effect on larval growth. Pupation and adult emergence were optimum at 25°C. Elevated CO2 and temperature increased food consumption and metabolism of larvae by enhancing the activity of midgut proteases, carbohydrases (amylase and cellulase), and mitochondrial enzymes and therefore may cause more damage to crop production. Elevated CO2 and global warming will affect insect growth and development, which will change the interactions between the insect pests and their crop hosts. Therefore, there is need to gain an understanding of these interactions to develop strategies for mitigating the effects of climate change. PMID:26363173

  2. Multicopper oxidase-1 is required for iron homeostasis in Malpighian tubules of Helicoverpa armigera

    PubMed Central

    Liu, Xiaoming; Sun, Chengxian; Liu, Xiaoguang; Yin, Xinming; Wang, Baohai; Du, Mengfang; An, Shiheng

    2015-01-01

    Multicopper oxidases (MCOs) are enzymes that contain 10 conserved histidine residues and 1 cysteine residue. MCO1 has been extensively investigated in the midgut because this MCO is implicated in ascorbate oxidation, iron homeostasis and immune responses. However, information regarding the action of MCO1 in Malpighian tubules is limited. In this study, Helicoverpa armigera was used as a model to investigate the function of MCO1 in Malpighian tubules. Sequence analysis results revealed that HaMCO1 exhibits typical MCO characteristics, with 10 histidine and 1 cysteine residues for copper ion binding. HaMCO1 was also found to be highly abundant in Malpighian tubules. Temporal expression patterns indicated that HaMCO1 is mainly expressed during larval molting stages. Hormone treatments [the molting hormone 20-hydroxyecdysone (20E) and juvenile hormone (JH)] revealed that 20E inhibits HaMCO1 transcript expression via its heterodimer receptor, which consists of ecdysone receptor (EcR) and ultraspiracle (USP), and that JH counteracts the action of 20E to activate HaMCO1 transcript expression via its intracellular receptor methoprene-tolerant (Met). HaMCO1 knockdown caused a significant decrease in iron accumulation and also significantly reduced transferrin and ferritin transcript expression. Therefore, HaMCO1 is coordinately regulated by 20E and JH and is required for iron homeostasis in Malpighian tubules. PMID:26437857

  3. Multicopper oxidase-1 is required for iron homeostasis in Malpighian tubules of Helicoverpa armigera.

    PubMed

    Liu, Xiaoming; Sun, Chengxian; Liu, Xiaoguang; Yin, Xinming; Wang, Baohai; Du, Mengfang; An, Shiheng

    2015-01-01

    Multicopper oxidases (MCOs) are enzymes that contain 10 conserved histidine residues and 1 cysteine residue. MCO1 has been extensively investigated in the midgut because this MCO is implicated in ascorbate oxidation, iron homeostasis and immune responses. However, information regarding the action of MCO1 in Malpighian tubules is limited. In this study, Helicoverpa armigera was used as a model to investigate the function of MCO1 in Malpighian tubules. Sequence analysis results revealed that HaMCO1 exhibits typical MCO characteristics, with 10 histidine and 1 cysteine residues for copper ion binding. HaMCO1 was also found to be highly abundant in Malpighian tubules. Temporal expression patterns indicated that HaMCO1 is mainly expressed during larval molting stages. Hormone treatments [the molting hormone 20-hydroxyecdysone (20E) and juvenile hormone (JH)] revealed that 20E inhibits HaMCO1 transcript expression via its heterodimer receptor, which consists of ecdysone receptor (EcR) and ultraspiracle (USP), and that JH counteracts the action of 20E to activate HaMCO1 transcript expression via its intracellular receptor methoprene-tolerant (Met). HaMCO1 knockdown caused a significant decrease in iron accumulation and also significantly reduced transferrin and ferritin transcript expression. Therefore, HaMCO1 is coordinately regulated by 20E and JH and is required for iron homeostasis in Malpighian tubules. PMID:26437857

  4. A transferrin gene associated with development and 2-tridecanone tolerance in Helicoverpa armigera.

    PubMed

    Zhang, L; Shang, Q; Lu, Y; Zhao, Q; Gao, X

    2015-04-01

    The full-length cDNA (2320 bp) encoding a putative iron-binding transferrin protein from Helicoverpa armigera was cloned and named HaTrf. The putative HaTrf sequence included 670 amino acids with a molecular mass of approximately 76 kDa. Quantitative PCR results demonstrated that the transcriptional level of HaTrf was significantly higher in the sixth instar and pupa stages as compared with other developmental stages. HaTrf transcripts were more abundant in fat bodies and in the epidermis than in malpighian tubules. Compared with the control, the expression of HaTrf increased dramatically 24 h after treatment with 2-tridecanone. Apparent growth inhibition with a dramatic body weight decrease was observed in larvae fed with HaTrf double-stranded RNA (dsRNA), as compared with those fed with green fluorescent protein dsRNA. RNA interference of HaTrf also significantly increased the susceptibility of larvae to 2-tridecanone. These results indicate the possible involvement of HaTrf in tolerance to plant secondary chemicals. PMID:25430818

  5. 20-hydroxyecdysone activates Forkhead box O to promote proteolysis during Helicoverpa armigera molting.

    PubMed

    Cai, Mei-Juan; Zhao, Wen-Li; Jing, Yu-Pu; Song, Qian; Zhang, Xiao-Qian; Wang, Jin-Xing; Zhao, Xiao-Fan

    2016-03-15

    Insulin inhibits transcription factor Forkhead box O (FoxO) activity, and the steroid hormone 20-hydroxyecdysone (20E) activates FoxO; however, the mechanism is unclear. We hypothesized that 20E upregulates phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase (PTEN) expression to activate FoxO, thereby promoting proteolysis during molting in the lepidopteran insect Helicoverpa armigera. FoxO expression is increased during molting and metamorphosis. The knockdown of FoxO in fifth instar larvae results in larval molting failure. 20E inhibits FoxO phosphorylation, resulting in FoxO nuclear translocation. Insulin, via Akt, induces FoxO phosphorylation and cytoplasmic localization. 20E represses insulin-induced Akt phosphorylation and FoxO phosphorylation. 20E, via ecdysone receptor B1 (EcRB1) and the ultraspiracle protein (USP1), upregulates PTEN expression, which represses Akt phosphorylation, thereby repressing FoxO phosphorylation. The non-phosphorylated FoxO enters the nucleus and attaches to a FoxO-binding element in the upstream region of the Broad isoform 7 (BrZ7) gene to regulate BrZ7 transcription under 20E induction. 20E upregulates FoxO expression via EcRB1 and USP1. FoxO regulation of BrZ7 expression regulates Carboxypeptidase A expression for final proteolysis during insect molting. Hence, 20E activates FoxO via upregulating PTEN expression to counteract insulin activity and promote proteolysis. PMID:26893349

  6. A TRPA1 channel that senses thermal stimulus and irritating chemicals in Helicoverpa armigera.

    PubMed

    Wei, J J; Fu, T; Yang, T; Liu, Y; Wang, G R

    2015-08-01

    Sensing and responding to changes in the external environment is important for insect survival. Transient receptor potential (TRP) channels are crucial for various sensory modalities including olfaction, vision, hearing, thermosensation and mechanosensation. Here, we identified and characterized a transient receptor potential gene named as HarmTRPA1 in Helicoverpa armigera antennae. HarmTRPA1 was abundantly expressed in the antennae and labial palps. Transcripts of HarmTRPA1 could also be detected in the head and proboscis. Furthermore, functional analyses of HarmTRPA1 were conducted in the Xenopus Oocyte system. The results showed that the HarmTRPA1 channel could be activated by increasing the temperature from 20 to 45 °C. No significant adaptation was observed when the stimulus was repeated. In addition to thermal stimuli, pungent natural compounds including allyl isothiocyanate, cinnamaldehyde and citronellal also activated HarmTRPA1. Taken together, we infer that HarmTRPA1 may function as both a thermal sensor involved in peripheral temperature detection and as a chemical sensor detecting irritating chemicals in vivo. Our data provide valuable insight into the TRPA1 channel in this moth and lay the foundation for developing novel strategies for pest control. PMID:25827167

  7. High nucleotide diversity and limited linkage disequilibrium in Helicoverpa armigera facilitates the detection of a selective sweep.

    PubMed

    Song, S V; Downes, S; Parker, T; Oakeshott, J G; Robin, C

    2015-11-01

    Insecticides impose extreme selective pressures on populations of target pests and so insecticide resistance loci of these species may provide the footprints of 'selective sweeps'. To lay the foundation for future genome-wide scans for selective sweeps and inform genome-wide association study designs, we set out to characterize some of the baseline population genomic parameters of one of the most damaging insect pests in agriculture worldwide, Helicoverpa armigera. To this end, we surveyed nine Z-linked loci in three Australian H. armigera populations. We find that estimates of π are in the higher range among other insects and linkage disequilibrium decays over short distances. One of the surveyed loci, a cytochrome P450, shows an unusual haplotype configuration with a divergent allele at high frequency that led us to investigate the possibility of an adaptive introgression around this locus. PMID:26174024

  8. Adaptation of Habrobracon hebetor (Hymenoptera: Braconidae) to Rearing on Ephestia kuehniella (Lepidoptera: Pyralidae) and Helicoverpa armigera (Lepidoptera: Noctuidae)

    PubMed Central

    Naseri, Bahram; Mohammadzadeh-Bidarani, Mozhgan

    2016-01-01

    Food characteristics strongly regulate digestive enzymatic activity of insects through direct influences on their midgut mechanisms. Insect performance is better on diets that contain nutrients in proportions that fit its digestive enzymes. Little is known about the influences of rearing history on parasitism success of Habrobracon hebetor Say. This research focused on the effect of nutrient regulation on survival, development, and parasitism of H. hebetor. Life history and digestive enzyme activity of fourth-stage larvae of H. hebetor were studied when reared on Ephestia kuehniella Zeller. This parasitoid was then introduced to Helicoverpa armigera (Hübner), and above-mentioned parameters were also studied in the first and fourth generations after transfer. In term of parasitism success, H. hebetor preferred E. kuehniella over He. armigera. When the first and fourth generations of He. armigera-reared H. hebetor were compared, the rearing history affected the life history and enzymatic activity of the parasitoid. A better performance of H. hebetor was achieved after it was reared on He. armigera for the four generations. Because, digestive α-amylase and general protease of the parasitoid were matched with the new host, it used reserve energy for a better performance. Thus, a better performance of H. hebetor could be obtained when the parasitoid was reared on its original host for at least four generations. PMID:26839317

  9. Mutation of an aminopeptidase N gene is associated with Helicoverpa armigera resistance to Bacillus thuringiensis Cry1Ac toxin.

    PubMed

    Zhang, Shaoping; Cheng, Hongmei; Gao, Yulin; Wang, Guirong; Liang, Gemei; Wu, Kongming

    2009-07-01

    A Cry1Ac-resistant strain (Bt-R) of Helicoverpa armigera, with 2971-fold resistance, was derived by selection with Cry1Ac toxin for 75 generations. We used cDNA-amplified fragment length polymorphism analysis to identify those genes differentially expressed in the Cry1Ac-resistant and -susceptible strains, which revealed 212 differentially expressed transcripts among 2000 screened cDNAs. Among these transcript-derived fragments (TDFs), 37 showed some homology to known sequences, including Aminopeptidase N (APN), which is expressed in the midgut epithelium and has been implicated as a Cry1A subfamily receptor in several moths, including H. armigera. We confirmed the TDF by RT-PCR and identified a deletion mutation of apn1 in the Bt-R strain. We expressed the TDF in bacteria. The partial HaAPN1-96S wild-type protein, bound to Cry1Ac on ligand blots, whereas HaAPN1-BtR did not. This suggested that HaAPN1 is a receptor for Bt Cry1Ac and that its deletion mutation is associated with Cry1Ac resistance in H. armigera. The absence of one binding site is responsible for its resistance to Cry1Ac. We developed an allele-specific PCR to monitor whether the apn1 gene in an H. armigera field population produced a similar mutation. No deleted mutants were found in 2250 individuals collected from the field in 2006-2007. PMID:19376227

  10. Relative Fitness of Helicoverpa armigera (Lepidoptera: Noctuidae) on Seven Host Plants: A Perspective for IPM in Brazil.

    PubMed

    Reigada, C; Guimarães, K F; Parra, J R P

    2016-01-01

    The cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a widespread pest of many cultivated and wild plants in Europe, Africa, Asia, and Australia. In 2013, this species was reported in Brazil, attacking various host crops in the midwestern and northeastern regions of the country and is now found countrywide. Aiming to understand the effects of different host plants on the life cycle of H. armigera, we selected seven species of host plants that mature in different seasons and are commonly grown in these regions: cotton (Gossypium hirsutum, "FM993"), corn (Zea mays, "2B587"), soybean (Glycine max, "99R01"), rattlepods (Crotalaria spectabilis), millet (Pennisetum glaucum, "ADR300"), sorghum (Sorghum bicolor, "AGROMEN70G35"), and cowpea (Vigna unguiculata, "SEMPRE VERDE"). The development time of immatures, body weight, survivorship, and fecundity of H. armigera were evaluated on each host plant under laboratory conditions. The bollworms did not survive on corn, millet, or sorghum and showed very low survival rates on rattlepods. Survival rates were highest on soybean, followed by cotton and cowpea. The values for relative fitness found on soybean, cotton, cowpea, and rattlepods were 1, 0.5, 0.43, and 0.03, respectively. Survivorship, faster development time, and fecundity on soybean, cotton, and cowpea were positively correlated. Larger pupae and greater fecundity were found on soybean and cotton. The results indicated that soybean, cotton, and cowpea are the most suitable plants to support the reproduction of H. armigera in the field. PMID:26798139

  11. Adaptation of Habrobracon hebetor (Hymenoptera: Braconidae) to Rearing on Ephestia kuehniella (Lepidoptera: Pyralidae) and Helicoverpa armigera (Lepidoptera: Noctuidae).

    PubMed

    Borzoui, Ehsan; Naseri, Bahram; Mohammadzadeh-Bidarani, Mozhgan

    2016-01-01

    Food characteristics strongly regulate digestive enzymatic activity of insects through direct influences on their midgut mechanisms. Insect performance is better on diets that contain nutrients in proportions that fit its digestive enzymes. Little is known about the influences of rearing history on parasitism success of Habrobracon hebetor Say. This research focused on the effect of nutrient regulation on survival, development, and parasitism of H. hebetor. Life history and digestive enzyme activity of fourth-stage larvae of H. hebetor were studied when reared on Ephestia kuehniella Zeller. This parasitoid was then introduced to Helicoverpa armigera (Hübner), and above-mentioned parameters were also studied in the first and fourth generations after transfer. In term of parasitism success, H. hebetor preferred E. kuehniella over He. armigera. When the first and fourth generations of He. armigera-reared H. hebetor were compared, the rearing history affected the life history and enzymatic activity of the parasitoid. A better performance of H. hebetor was achieved after it was reared on He. armigera for the four generations. Because, digestive α-amylase and general protease of the parasitoid were matched with the new host, it used reserve energy for a better performance. Thus, a better performance of H. hebetor could be obtained when the parasitoid was reared on its original host for at least four generations. PMID:26839317

  12. Expression Analysis and Binding Assays in the Chemosensory Protein Gene Family Indicate Multiple Roles in Helicoverpa armigera.

    PubMed

    Li, Zhao-Qun; Zhang, Shuai; Luo, Jun-Yu; Zhu, Jing; Cui, Jin-Jie; Dong, Shuang-Lin

    2015-05-01

    Chemosensory proteins (CSPs) have been proposed to capture and transport hydrophobic chemicals to receptors on sensory neurons. We identified and cloned 24 CSP genes to better understand the physiological function of CSPs in Helicoverpa armigera. Quantitative real-time polymerase chain reaction assays indicate that CSP genes are ubiquitously expressed in adult H. armigera tissues. Broad expression patterns in adult tissues suggest that CSPs are involved in a diverse range of cellular processes, including chemosensation as well as other functions not related to chemosensation. The H. armigera CSPs that were highly transcribed in sensory organs or pheromone glands (HarmCSPs 6, 9, 18, 19), were recombinantly expressed in bacteria to explore their function. Fluorescent competitive binding assays were used to measure the binding affinities of these CSPs against 85 plant volatiles and 4 pheromone components. HarmCSP6 displays high binding affinity for pheromone components, whereas the other three proteins do not show affinities for any of the compounds tested. HarmCSP6 is expressed in numerous cells located in or close to long sensilla trichodea on the antennae of both males and females. These results suggest that HarmCSP6 may be involved in transporting female sex pheromones in H. armigera. PMID:25893790

  13. Biological activities of Solanum pseudocapsicum (Solanaceae) against cotton bollworm, Helicoverpa armigera Hübner and armyworm, Spodoptera litura Fabricius (Lepidotera: Noctuidae)

    PubMed Central

    Jeyasankar, Alagarmalai; Premalatha, Selvaraj; Elumalai, Kuppusamy

    2012-01-01

    Objective To evaluate the antifeedant, insecticidal and growth inhibition activities of Solanum pseudocapsicum (S. pseudocapsicum) seed extracts against Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera). Methods Hexane, diethyl ether, dichloromethane and ethyl acetate seed extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera. Results Ethyl acetate extract showed promising antifeedant and insecticidal activities against S. litura and H. armigera. Percentage of deformed larvae, pupae and adults were maximum in treatment of ethyl acetate extract. Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae. Conclusions Ethyl acetate extracts of S. pseudocapsicum, showed higher efficiency of antifeedant, insecticidal and growth inhibition activities. Hence, it can be used to controll agricultural insect pests, S. litura and H. armigera. PMID:23593579

  14. Antibiotics influence the toxicity of the delta endotoxins of Bacillus thuringiensis towards the cotton bollworm, Helicoverpa armigera

    PubMed Central

    2014-01-01

    Background The cotton bollworm, Helicoverpa armigera is one of the most important crop pests worldwide. It has developed high levels of resistance to synthetic insecticides, and hence, Bacillus thuringiensis (Bt) formulations are used as a safer pesticide and the Bt genes have been deployed in transgenic crops for controlling this pest. There is an apprehension that H. armigera might develop resistance to transgenic crops in future. Therefore, we studied the role of gut microbes by eliminating them with antibiotics in H. armigera larvae on the toxicity of Bt toxins against this pest. Results Commercial formulation of Bt (Biolep®) and the pure Cry1Ab and Cry1Ac toxin proteins were evaluated at ED50, LC50, and LC90 dosages against the H. armigera larvae with and without antibiotics (which removed the gut microbes). Lowest H. armigera larval mortality due to Bt formulation and the Bt toxins Cry1Ab and Cry1Ac was recorded in insects reared on diets with 250 and 500 μg ml−1 diet of each of the four antibiotics (gentamicin, penicillin, rifampicin, and streptomycin), while the highest larval mortality was recorded in insects reared on diets without the antibiotics. Mortality of H. armigera larvae fed on diets with Bt formulation and the δ-endotoxins Cry1Ab and Cry1Ac was inversely proportional to the concentration of antibiotics in the artificial diet. Nearly 30% reduction in larval mortality was observed in H. armigera larvae from F1 to F3 generation when the larvae were reared on diets without antibiotics (with gut microbes) and fed on 0.15% Bt or 12 μg Cry1Ab or Cry1Ac ml−1 diet, indicating development of resistance to Bt in the presence of gut microflora. However, there were no differences in larval mortality due to Bt, Cry1Ab or Cry1Ac across generations in insects when they were reared on diets with 250 μg of each antibiotic ml−1 diet (without gut microflora). Conclusions The results suggested that antibiotics which eliminated gut microflora

  15. Diapause, cold-hardiness and flight ability of Cry1Ac-resistant and -susceptible strains of Helicoverpa armigera (Lepidoptera: Noctuidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diapause inducement condition, cold hardiness, and flight ability in Cry1Ac-resistant (BtR) and Cry1Ac-susceptible (96S) strains of Helicoverpa armigera (Hübner) were compared in the laboratory. The BtR strain was derived from the 96S strain and shows 1375-fold resistance to the Cry1Ac toxin aft...

  16. Elevated CO2 Reduces the Resistance and Tolerance of Tomato Plants to Helicoverpa armigera by Suppressing the JA Signaling Pathway

    PubMed Central

    Ren, Qin; Zhu-Salzman, Keyan; Kang, Le; Wang, Chenzhu; Li, Chuanyou; Ge, Feng

    2012-01-01

    Both resistance and tolerance, which are two strategies that plants use to limit biotic stress, are affected by the abiotic environment including atmospheric CO2 levels. We tested the hypothesis that elevated CO2 would reduce resistance (i.e., the ability to prevent damage) but enhance tolerance (i.e., the ability to regrow and compensate for damage after the damage has occurred) of tomato plants to the cotton bollworm, Helicoverpa armigera. The results showed that elevated CO2 reduced resistance by decreasing the jasmonic acid (JA) level and activities of lipoxygenase, proteinase inhibitors, and polyphenol oxidase in wild-type (WT) plants infested with H. armigera. Consequently, the activities of total protease, trypsin-like enzymes, and weak and active alkaline trypsin-like enzymes increased in the midgut of H. armigera when fed on WT plants grown under elevated CO2. Unexpectedly, the tolerance of the WT to H. armigera (in terms of photosynthetic rate, activity of sucrose phosphate synthases, flower number, and plant biomass and height) was also reduced by elevated CO2. Under ambient CO2, the expression of resistance and tolerance to H. armigera was much greater in wild type than in spr2 (a JA-deficient genotype) plants, but elevated CO2 reduced these differences of the resistance and tolerance between WT and spr2 plants. The results suggest that the JA signaling pathway contributes to both plant resistance and tolerance to herbivorous insects and that by suppressing the JA signaling pathway, elevated CO2 will simultaneously reduce the resistance and tolerance of tomato plants. PMID:22829948

  17. Frequency of Bt resistance alleles in Helicoverpa armigera in the Xinjiang cotton-planting region of China.

    PubMed

    Li, Guoping; Feng, Hongqiang; Gao, Yulin; Wyckhuys, Kris A G; Wu, Kongming

    2010-10-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a key insect pest of cotton in Xinjiang cotton-planting region of northwest China. In this region, cotton is grown on average ≈ 1.65 million ha (1.53 ≈ 1.80 million ha) annually in largely monoculture agricultural landscapes, similarly to cropping systems in the United States or Australia. Under such cropping regimes, naturally occurring refuges (with non-Bt crops) may be insufficient to prevent H. armigera resistance development to Bt toxins. Therefore, we assessed frequency of alleles conferring resistance to Cry1Ac toxin of F(1) and F(2) offspring of H. armigera isofemale lines from two distinct localities in the region during 2005-2009. More specifically, a total of 224 isofemale lines was collected from Korla County (≈ 70% Bt cotton adoption) and 402 lines from Shache County (≈ 5% Bt cotton planting). Subsequent offspring was screened on Cry1Ac artificial diet. From 2005 to 2009, resistance gene frequency in Korla fluctuated between 0.0000 and 0.0040, while being 0.0000-0.0008 in individuals collected from Shache, and there were no significant increases in both counties from 2005 to 2009. Relative average development rates (RADRs) of larvae in F(1) tests showed significant increases from Korla, but not in Shache. RADR of F(1) larvae is significantly correlated with RADR of F(2) offspring, indicating genetic variation in response to toxin in field H. armigera population. Although the occurrence of Cry1Ac resistance alleles was low in Xinjiang cotton-planting region of China, particular attention should be given to H. armigera resistance development in Korla County. PMID:22546469

  18. Diversity in gut microflora of Helicoverpa armigera populations from different regions in relation to biological activity of Bacillus thuringiensis δ-endotoxin Cry1Ac.

    PubMed

    Paramasiva, Inakarla; Shouche, Yogesh; Kulkarni, Girish Jayant; Krishnayya, Pulipaka Venkata; Akbar, Shaik Mohammed; Sharma, Hari Chand

    2014-12-01

    Transgenic crops expressing toxin proteins from Bacillus thuringiensis (Bt) have been deployed on a large scale for management of Helicoverpa armigera. Resistance to Bt toxins has been documented in several papers, and therefore, we examined the role of midgut microflora of H. armigera in its susceptibility to Bt toxins. The susceptibility of H. armigera to Bt toxin Cry1Ac was assessed using Log-dose-Probit analysis, and the microbial communities were identified by 16S rRNA sequencing. The H. armigera populations from nine locations harbored diverse microbial communities, and had some unique bacteria, suggesting a wide geographical variation in microbial community in the midgut of the pod borer larvae. Phylotypes belonging to 32 genera were identified in the H. armigera midgut in field populations from nine locations. Bacteria belonging to Enterobacteriaceae (Order Bacillales) were present in all the populations, and these may be the common members of the H. armigera larval midgut microflora. Presence and/or absence of certain species were linked to H. armigera susceptibility to Bt toxins, but there were no clear trends across locations. Variation in susceptibility of F1 neonates of H. armigera from different locations to the Bt toxin Cry1Ac was found to be 3.4-fold. These findings support the idea that insect migut microflora may influence the biological activity of Bt toxins. PMID:25195523

  19. Silencing the HaHR3 Gene by Transgenic Plant-mediated RNAi to Disrupt Helicoverpa armigera Development

    PubMed Central

    Xiong, Yehui; Zeng, Hongmei; Zhang, Yuliang; Xu, Dawei; Qiu, Dewen

    2013-01-01

    RNA interference (RNAi) caused by exogenous double-stranded RNA (dsRNA) has developed into a powerful technique in functional genomics, and to date it is widely used to down-regulate crucial physiology-related genes to control pest insects. A molt-regulating transcription factor gene, HaHR3, of cotton bollworm (Helicoverpa armigera) was selected as the target gene. Four different fragments covering the coding sequence (CDS) of HaHR3 were cloned into vector L4440 to express dsRNAs in Escherichia coli. The most effective silencing fragment was then cloned into a plant over-expression vector to express a hairpin RNA (hpRNA) in transgenic tobacco (Nicotiana tabacum). When H. armigera larvae were fed the E. coli or transgenic plants, the HaHR3 mRNA and protein levels dramatically decreased, resulting developmental deformity and larval lethality. The results demonstrate that both recombinant bacteria and transgenic plants could induce HaHR3 silence to disrupt H. armigera development, transgenic plant-mediated RNAi is emerging as a powerful approach for controlling insect pests. PMID:23630449

  20. Assessing the role of non-cotton refuges in delaying Helicoverpa armigera resistance to Bt cotton in West Africa

    PubMed Central

    Brévault, Thierry; Nibouche, Samuel; Achaleke, Joseph; Carrière, Yves

    2012-01-01

    Non-cotton host plants without Bacillus thuringiensis (Bt) toxins can provide refuges that delay resistance to Bt cotton in polyphagous insect pests. It has proven difficult, however, to determine the effective contribution of such refuges and their role in delaying resistance evolution. Here, we used biogeochemical markers to quantify movement of Helicoverpa armigera moths from non-cotton hosts to cotton fields in three agricultural landscapes of the West African cotton belt (Cameroon) where Bt cotton was absent. We show that the contribution of non-cotton hosts as a source of moths was spatially and temporally variable, but at least equivalent to a 7.5% sprayed refuge of non-Bt cotton. Simulation models incorporating H. armigera biological parameters, however, indicate that planting non-Bt cotton refuges may be needed to significantly delay resistance to cotton producing the toxins Cry1Ac and Cry2Ab. Specifically, when the concentration of one toxin (here Cry1Ac) declined seasonally, resistance to Bt cotton often occurred rapidly in simulations where refuges of non-Bt cotton were rare and resistance to Cry2Ab was non-recessive, because resistance was essentially driven by one toxin (here Cry2Ab). The use of biogeochemical markers to quantify insect movement can provide a valuable tool to evaluate the role of non-cotton refuges in delaying the evolution of H. armigera resistance to Bt cotton. PMID:25568029

  1. Silencing the HaAK Gene by Transgenic Plant-Mediated RNAi Impairs Larval Growth of Helicoverpa armigera

    PubMed Central

    Liu, Feng; Wang, Xiao-Dong; Zhao, Yi-Ying; Li, Yan-Jun; Liu, Yong-Chang; Sun, Jie

    2015-01-01

    Insect pests have caused noticeable economic losses in agriculture, and the heavy use of insecticide to control pests not only brings the threats of insecticide resistance but also causes the great pollution to foods and the environment. Transgenic plants producing double-stranded RNA (dsRNA) directed against insect genes have been is currently developed for protection against insect pests. In this study, we used this technology to silence the arginine kinase (AK) gene of Helicoverpa armigera (HaAK), encoding a phosphotransferase that plays a critical role in cellular energy metabolism in invertebrate. Transgenic Arabidopsis plants producing HaAK dsRNA were generated by Agrobacterium-mediated transformation. The maximal mortality rate of 55% was reached when H. armigera first-instar larvae were fed with transgenic plant leaves for 3 days, which was dramatically higher than the 18% mortality recorded in the control group. Moreover, the ingestion of transgenic plants significantly retarded larval growth, and the transcript levels of HaAK were also knocked down by up to 52%. The feeding bioassays further indicated that the inhibition efficiency was correlated with the integrity and concentration of the produced HaAK dsRNA in transgenic plants. These results strongly show that the resistance to H. armigera was improved in transgenic Arabidopsis plants, suggesting that the RNAi targeting of AK has the potential for the control of insect pests. PMID:25552931

  2. Antennal Transcriptome Analysis and Comparison of Chemosensory Gene Families in Two Closely Related Noctuidae Moths, Helicoverpa armigera and H. assulta

    PubMed Central

    Zhang, Jin; Wang, Bing; Dong, Shuanglin; Cao, Depan; Dong, Junfeng; Walker, William B.; Liu, Yang; Wang, Guirong

    2015-01-01

    To better understand the olfactory mechanisms in the two lepidopteran pest model species, the Helicoverpa armigera and H. assulta, we conducted transcriptome analysis of the adult antennae using Illumina sequencing technology and compared the chemosensory genes between these two related species. Combined with the chemosensory genes we had identified previously in H. armigera by 454 sequencing, we identified 133 putative chemosensory unigenes in H. armigera including 60 odorant receptors (ORs), 19 ionotropic receptors (IRs), 34 odorant binding proteins (OBPs), 18 chemosensory proteins (CSPs), and 2 sensory neuron membrane proteins (SNMPs). Consistent with these results, 131 putative chemosensory genes including 64 ORs, 19 IRs, 29 OBPs, 17 CSPs, and 2 SNMPs were identified through male and female antennal transcriptome analysis in H. assulta. Reverse Transcription-PCR (RT-PCR) was conducted in H. assulta to examine the accuracy of the assembly and annotation of the transcriptome and the expression profile of these unigenes in different tissues. Most of the ORs, IRs and OBPs were enriched in adult antennae, while almost all the CSPs were expressed in antennae as well as legs. We compared the differences of the chemosensory genes between these two species in detail. Our work will surely provide valuable information for further functional studies of pheromones and host volatile recognition genes in these two related species. PMID:25659090

  3. Sequencing and characterization of six cDNAs putatively encoding three pairs of pheromone receptors in two sibling species, Helicoverpa armigera and Helicoverpa assulta.

    PubMed

    Zhang, Dan-Dan; Zhu, Kun Yan; Wang, Chen-Zhu

    2010-06-01

    Pheromone receptors (PRs) on male antennae mediate specific and sensitive detection of sex pheromone components in lepidopterans. In this study, we identified and sequenced six putative cDNAs encoding PRs from sibling species, namely HarmOR1, HarmOR2 and HarmOR3 in Helicoverpa armigera and HassOR1, HassOR2 and HassOR3 in Helicoverpa assulta, which appeared to be orthologs of Heliothis virescens putative PR genes HvOR13, HvOR11 and HvOR16, respectively. Expression patterns of the six PR genes were evaluated by quantitative real-time PCR (qRT-PCR). All the putative PR genes exhibited male-biased expression patterns in adult antennae except for HarmOR2 and HassOR2 that showed similar expression levels in male and female antennae. Expression level of HarmOR1 was significantly higher than those of HarmOR2 and HarmOR3 in male antennae of H. armigera, but the three corresponding PR genes in male antennae of H. assulta showed similar expression levels. This implies the role of the PR encoded by HarmOR1 for interacting with Z11-16:Ald. The level of HarmOR1 transcript was significantly higher than that of HassOR1. These results were consistent with the ratio of Z11-16:Ald in their sex pheromone blends and the abundance of sensilla tuned to Z11-16:Ald on antennae of male adults of the two species. PMID:19962987

  4. Field Evolved Resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) to Bacillus thuringiensis Toxin Cry1Ac in Pakistan

    PubMed Central

    Alvi, Anwaar H. K.; Sayyed, Ali H.; Naeem, Muhammad; Ali, Muhammad

    2012-01-01

    Helicoverpa armigera (Hübner) is one of the most destructive pests of several field and vegetable crops, with indiscriminate use of insecticides contributing to multiple instances of resistance. In the present study we assessed whether H. armigera had developed resistance to Bt cotton and compared the results with several conventional insecticides. Furthermore, the genetics of resistance was also investigated to determine the inheritance to Cry1Ac resistance. To investigate the development of resistance to Bt cotton, and selected foliar insecticides, H. armigera populations were sampled in 2010 and 2011 in several cotton production regions in Pakistan. The resistance ratios (RR) for Cry1Ac, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin and deltamethrin were 580-fold, 320-, 1110-, 1950-, 200-, 380, 690, and 40-fold, respectively, compared with the laboratory susceptible (Lab-PK) population. Selection of the field collected population with Cry1Ac in 2010 for five generations increased RR to 5440-fold. The selection also increased RR for deltamethrin, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin to 125-folds, 650-, 2840-, 9830-, 370-, 3090-, 1330-fold. The estimated LC50s for reciprocal crosses were 105 µg/ml (Cry1Ac-SEL female × Lab-PK male) and 81 g µg/ml (Lab-PK female × Cry1Ac-SEL male) suggesting that the resistance to Cry1Ac was autosomal; the degree of dominance (DLC) was 0.60 and 0.57 respectively. Mixing of enzyme inhibitors significantly decreased resistance to Cry1Ac suggesting that the resistance to Cry1Ac and other insecticides tested in the present study was primarily metabolic. Resistance to Cry1Ac was probably due to a single but unstable factor suggesting that crop rotation with non-Bt cotton or other crops could reduce the selection pressure for H. armigera and improve the sustainability of Bt cotton. PMID:23077589

  5. Relative Fitness of Helicoverpa armigera (Lepidoptera: Noctuidae) on Seven Host Plants: A Perspective for IPM in Brazil

    PubMed Central

    Reigada, C.; Guimarães, K. F.; Parra, J. R. P.

    2016-01-01

    The cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a widespread pest of many cultivated and wild plants in Europe, Africa, Asia, and Australia. In 2013, this species was reported in Brazil, attacking various host crops in the midwestern and northeastern regions of the country and is now found countrywide. Aiming to understand the effects of different host plants on the life cycle of H. armigera, we selected seven species of host plants that mature in different seasons and are commonly grown in these regions: cotton (Gossypium hirsutum, “FM993”), corn (Zea mays, “2B587”), soybean (Glycine max, “99R01”), rattlepods (Crotalaria spectabilis), millet (Pennisetum glaucum, “ADR300”), sorghum (Sorghum bicolor, “AGROMEN70G35”), and cowpea (Vigna unguiculata, “SEMPRE VERDE”). The development time of immatures, body weight, survivorship, and fecundity of H. armigera were evaluated on each host plant under laboratory conditions. The bollworms did not survive on corn, millet, or sorghum and showed very low survival rates on rattlepods. Survival rates were highest on soybean, followed by cotton and cowpea. The values for relative fitness found on soybean, cotton, cowpea, and rattlepods were 1, 0.5, 0.43, and 0.03, respectively. Survivorship, faster development time, and fecundity on soybean, cotton, and cowpea were positively correlated. Larger pupae and greater fecundity were found on soybean and cotton. The results indicated that soybean, cotton, and cowpea are the most suitable plants to support the reproduction of H. armigera in the field. PMID:26798139

  6. Field evolved resistance in Helicoverpa armigera (Lepidoptera: Noctuidae) to Bacillus thuringiensis toxin Cry1Ac in Pakistan.

    PubMed

    Alvi, Anwaar H K; Sayyed, Ali H; Naeem, Muhammad; Ali, Muhammad

    2012-01-01

    Helicoverpa armigera (Hübner) is one of the most destructive pests of several field and vegetable crops, with indiscriminate use of insecticides contributing to multiple instances of resistance. In the present study we assessed whether H. armigera had developed resistance to Bt cotton and compared the results with several conventional insecticides. Furthermore, the genetics of resistance was also investigated to determine the inheritance to Cry1Ac resistance. To investigate the development of resistance to Bt cotton, and selected foliar insecticides, H. armigera populations were sampled in 2010 and 2011 in several cotton production regions in Pakistan. The resistance ratios (RR) for Cry1Ac, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin and deltamethrin were 580-fold, 320-, 1110-, 1950-, 200-, 380, 690, and 40-fold, respectively, compared with the laboratory susceptible (Lab-PK) population. Selection of the field collected population with Cry1Ac in 2010 for five generations increased RR to 5440-fold. The selection also increased RR for deltamethrin, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin to 125-folds, 650-, 2840-, 9830-, 370-, 3090-, 1330-fold. The estimated LC(50s) for reciprocal crosses were 105 µg/ml (Cry1Ac-SEL female × Lab-PK male) and 81 g µg/ml (Lab-PK female × Cry1Ac-SEL male) suggesting that the resistance to Cry1Ac was autosomal; the degree of dominance (D(LC)) was 0.60 and 0.57 respectively. Mixing of enzyme inhibitors significantly decreased resistance to Cry1Ac suggesting that the resistance to Cry1Ac and other insecticides tested in the present study was primarily metabolic. Resistance to Cry1Ac was probably due to a single but unstable factor suggesting that crop rotation with non-Bt cotton or other crops could reduce the selection pressure for H. armigera and improve the sustainability of Bt cotton. PMID:23077589

  7. Cry2Ab tolerance response of Helicoverpa armigera (Lepidoptera: Noctuidae) populations from CrylAc cotton planting region.

    PubMed

    Gao, Yulin; Wu, Kongming; Gould, Fred; Shen, Zhicheng

    2009-06-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is an important lepidopteran pest of cotton, Gossypium hirsutum L., in Asia. Transgenic cotton expressing the cry1Ac gene from Bacillus thuringiensis (Bt) has been widely planted for control of this pest. For managing the potential risk from resistance evolution in this pest, a new transgenic Bt cotton containing cry1Ac and cry2Ab genes (gene pyramided strategy) was designed as a successor of cry1Ac cotton. This article reports on levels of Cry2Ab tolerance in H. armigera populations from CrylAc cotton planting region in China based on bioassays of F1 and F2 offspring of isofemale lines. In total, 572 isofemale families of H. armigera from Xiajin County of Shandong Province (an intensive Bt cotton-planting area) and 124 families from Anci County of Hebei Province [a multiple-crop system, including corn (Zea mays L.), soybean (Gycine max (L.) Merr., peanut (Arachis spp.), and Bt cotton] were screened with both Cry1Ac- and Cry2Ab-containing diets in 2008. The bioassays results indicated that relative average development rates (RADR) of F1 full-sib families from field-collected female moths on Cry1Ac- and Cry2Ab-containing diet were positively correlated. The same correlation was found in the F2 generation, indicating cross-tolerance between Cry1Ac and Cry2Ab in field populations of H. armigera in Yellow River cotton-farming region of China. This cross-tolerance must be considered in evaluating the utility of pyramiding Bt genes in cotton for delaying evolution of resistance. PMID:19610441

  8. Gene cloning and expression of cadherin in midgut of Helicoverpa armigera and its Cry1A binding region.

    PubMed

    Wang, Guirong; Wu, Kongming; Liang, Gemei; Guo, Yuyuan

    2005-08-01

    Cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. Recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of Bt toxin Cry1A and the variation of cadherin-like is related to insect's resistance to Cry1A. The full-length cDNA encoding cadherin-like of Helicoverpa armigera is cloned by degenerate PCR and RACE techniques and the gene was designated as BtR-harm, which is 5581 bp in full-length, encoding 1730 amino acid residues (BtR-harm was deposited in GenBank and the accession number is AF519180). Its predicted molecular weight and isoelectric point were 195.39 kDa and 4.23, respectively. The inferred amino acid sequence includes a signal sequence, 11 cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. Sequence analysis indicated that the deduced protein sequence was most similar to the cadherin-like from Heliothis virescens with 84.2% identity and highly similar to three other lepidopteran cadherin from Bombyx mori, Manduca sexta and Pectinophora gossypiella, with the sequence identities of 60.3.6%, 57.5% and 51.0%, respectively. The cDNA encoding cadherin gene was expressed successfully in E. coli and the recombinant proteins can bind with Cry1Ac. Truncation analysis and binding experiment of BtR-harm revealed that the Cry1A binding region was a contiguous 244-amino acid sequence, which located between amino acid 1217 and 1461. Semi-quantitative RT-PCR analysis showed that BtR-harm was highly expressed in midgut of H. armigera, very low expressed in foregut and hindgut and was not expressed in other tissues. After H. armigera producing resistance to Cry1Ac, the expression quantity of BtR-harm significantly decreased in midgut of H. armigera. It is the first confirmation that BtR-harm can function as receptor of Cry1Ac in H. armigera and the binding region was located on a contiguous 244 amino acid sequence

  9. Species From the Heliothinae Complex (Lepidoptera: Noctuidae) in Tucumán, Argentina, an Update of Geographical Distribution of Helicoverpa armigera.

    PubMed

    Murúa, M Gabriela; Cazado, Lucas E; Casmuz, Augusto; Herrero, M Inés; Villagrán, M Elvira; Vera, Alejandro; Sosa-Gómez, Daniel R; Gastaminza, Gerardo

    2016-01-01

    The Heliothinae complex in Argentina encompasses Helicoverpa gelotopoeon (Dyar), Helicoverpa zea (Boddie), Helicoverpa armigera (Hübner), and Chloridea virescens (Fabricius). In Tucumán, the native species H. gelotopoeon is one of the most voracious soybean pests and also affects cotton and chickpea, even more in soybean-chickpea succession cropping systems. Differentiation of the Heliothinae complex in the egg, larva, and pupa stages is difficult. Therefore, the observation of the adult wing pattern design and male genitalia is useful to differentiate species. The objective of this study was to identify the species of the Heliothinae complex, determine population fluctuations of the Heliothinae complex in soybean and chickpea crops using male moths collected in pheromone traps in Tucuman province, and update the geographical distribution of H. armigera in Argentina. The species found were H. gelotopoeon, H. armigera, H. zea, and C. virescens. Regardless of province, county, crop, and year, the predominant species was H. gelotopoeon Considering the population dynamics of H. gelotopoeon and H. armigera in chickpea and soybean crops, H. gelotopoeon was the most abundant species in both crops, in all years sampled, and the differences registered were significant. On the other hand, according to the Sistema Nacional Argentino de Vigilancia y Monitoreo de Plagas (SINAVIMO) database and our collections, H. armigera was recorded in eight provinces and 20 counties of Argentina, and its larvae were found on soybean, chickpea, sunflower crops and spiny plumeless thistle (Carduus acanthoides). This is the first report of H. armigera in sunflower and spiny plumeless thistle in Argentina. PMID:27324588

  10. Species From the Heliothinae Complex (Lepidoptera: Noctuidae) in Tucumán, Argentina, an Update of Geographical Distribution of Helicoverpa armigera

    PubMed Central

    Murúa, M. Gabriela; Cazado, Lucas E.; Casmuz, Augusto; Herrero, M. Inés; Villagrán, M. Elvira; Vera, Alejandro; Sosa-Gómez, Daniel R.; Gastaminza, Gerardo

    2016-01-01

    The Heliothinae complex in Argentina encompasses Helicoverpa gelotopoeon (Dyar), Helicoverpa zea (Boddie), Helicoverpa armigera (Hübner), and Chloridea virescens (Fabricius). In Tucumán, the native species H. gelotopoeon is one of the most voracious soybean pests and also affects cotton and chickpea, even more in soybean-chickpea succession cropping systems. Differentiation of the Heliothinae complex in the egg, larva, and pupa stages is difficult. Therefore, the observation of the adult wing pattern design and male genitalia is useful to differentiate species. The objective of this study was to identify the species of the Heliothinae complex, determine population fluctuations of the Heliothinae complex in soybean and chickpea crops using male moths collected in pheromone traps in Tucuman province, and update the geographical distribution of H. armigera in Argentina. The species found were H. gelotopoeon, H. armigera, H. zea, and C. virescens. Regardless of province, county, crop, and year, the predominant species was H. gelotopoeon. Considering the population dynamics of H. gelotopoeon and H. armigera in chickpea and soybean crops, H. gelotopoeon was the most abundant species in both crops, in all years sampled, and the differences registered were significant. On the other hand, according to the Sistema Nacional Argentino de Vigilancia y Monitoreo de Plagas (SINAVIMO) database and our collections, H. armigera was recorded in eight provinces and 20 counties of Argentina, and its larvae were found on soybean, chickpea, sunflower crops and spiny plumeless thistle (Carduus acanthoides). This is the first report of H. armigera in sunflower and spiny plumeless thistle in Argentina. PMID:27324588

  11. Effects of climate change on overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Huang, Jian; Li, Jing

    2015-07-01

    Climate change significantly affects insects' behaviors. Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most serious insect pests in the world. Much is known about the survival of the overwintering population and spring emergence of H. armigera. However, little is known about the effects of climate change on overwintering and spring emergence of H. armigera. This study investigated the effects of changes of air and soil temperatures and precipitation on overwintering pupae of H. armigera by analyzing historical data from Magaiti County in northwest China using statistical methods. The results showed that during the period of 1989-2006, the climate warming advanced the first-appearance date of overwintering pupae eclosion (FD) and end date of overwintering pupae eclosion (ED) by 1.276 and 0.193 days per year, respectively; the duration between the FD and ED (DFEPE) was prolonged by 1.09 days per year, which resulted in more eclosion of overwintering pupae. For a 1 °C increase in the maximum air temperature ( T max) in winter, the FD became earlier by 3.234 days. Precipitation in winter delayed the FD and ED and produced little relative influence on DFEPE. A 1-mm increase of precipitation in winter delayed the FD and ED by 0.850 and 0.494 days, respectively. Mean air temperature ( T mean) in March, with a 41.3 % relative influence, precipitation in winter, with a 49.0 % relative influence, and T mean in March, with a 37.5 % relative influence, were the major affecting factors on FD, ED, and DFEPE, respectively. T max in February with a 53.0 % relative influence was the major affecting factor on the mortality of overwintering pupae (MOP). Increased soil temperatures in October and November and autumn and air temperatures in winter could decrease the MOP, though the relative influences were lower than T max in February. Increased precipitation in winter increased the MOP, but the relative influence was only 4.2 % because of little precipitation

  12. Effect of Larvae Treated with Mixed Biopesticide Bacillus thuringiensis - Abamectin on Sex Pheromone Communication System in Cotton Bollworm, Helicoverpa armigera

    PubMed Central

    Shen, Li-Ze; Chen, Peng-Zhou; Xu, Zhi-Hong; Deng, Jian-Yu; Harris, Marvin-K; Wanna, Ruchuon; Wang, Fu-Min; Zhou, Guo-Xin; Yao, Zhang-Liang

    2013-01-01

    Third instar larvae of the cotton bollworm (Helicoverpa armigera) were reared with artificial diet containing a Bacillus thuringiensis - abamectin (BtA) biopesticide mixture that resulted in 20% mortality (LD20). The adult male survivors from larvae treated with BtA exhibited a higher percentage of “orientation” than control males but lower percentages of “approaching” and “landing” in wind tunnel bioassays. Adult female survivors from larvae treated with BtA produced higher sex pheromone titers and displayed a lower calling percentage than control females. The ratio of Z-11-hexadecenal (Z11–16:Ald) and Z-9-hexadecenal (Z9–16:Ald) in BtA-treated females changed and coefficients of variation (CV) of Z11–16:Ald and Z9–16:Ald were expanded compared to control females. The peak circadian calling time of BtA-treated females occurred later than that of control females. In mating choice experiment, both control males and BtA-treated males preferred to mate with control females and a portion of the Bt-A treated males did not mate whereas all control males did. Our Data support that treatment of larvae with BtA had an effect on the sex pheromone communication system in surviving H.armigera moths that may contribute to assortative mating. PMID:23874751

  13. Electrophysiological and behavioral responses of female Helicoverpa armigera to compounds identified in flowers of African marigold, Tagetes erecta.

    PubMed

    Bruce, T J; Cork, A

    2001-06-01

    Seven electrophysiologically active compounds were detected in air-entrained headspace samples of live flowers of Tagetes erecta analyzed by gas chromatography (GC) linked to a female Helicoverpa armigera electroantennograph (EAG) using polar and nonpolar capillary columns. These compounds were subsequently identified using GC linked to mass spectrometry as benzaldehyde, (S)-(-)-limonene, (R,S)-(+/-)-linalool, (E)-myroxide, (Z)-beta-ocimene, phenylacetaldehyde, and (R)-(-)-piperitone. Electrophysiological activity was confirmed by EAG with a 1-microg dose of each compound on filter paper eliciting EAG responses that were significantly greater than the solvent control response from female moths. Wind-tunnel bioassays with T. erecta headspace samples, equivalent to 0.4 flower/hr emission from a live flower, elicited a significant increase in the number of upwind approaches from female H. armigera relative to a solvent control. Similarly, a seven-component synthetic blend of EAG-active compounds identified from T. erecta presented in the same ratio (1.0:1.6:0.7:1.4:0.4:5.0:2.7, respectively) and concentration (7.2 microg) as found in the natural sample elicited a significant increase in the number of upwind approaches relative to a solvent control during a 12-min bioassay that was equivalent to that elicited by the natural T. erecta floral volatiles. PMID:11504018

  14. A Toxin-Binding Alkaline Phosphatase Fragment Synergizes Bt Toxin Cry1Ac against Susceptible and Resistant Helicoverpa armigera

    PubMed Central

    Xiao, Yutao; Zhang, Dandan; Zhang, Yongdong; Li, Xianchun; Tabashnik, Bruce E.; Wu, Kongming

    2015-01-01

    Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f) was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects. PMID:25885820

  15. Know your ABCs: Characterization and gene expression dynamics of ABC transporters in the polyphagous herbivore Helicoverpa armigera.

    PubMed

    Bretschneider, Anne; Heckel, David G; Vogel, Heiko

    2016-05-01

    Polyphagous insect herbivores are adapted to many different secondary metabolites of their host plants. However, little is known about the role of ATP-binding cassette (ABC) transporters, a multigene family involved in detoxification processes. To study the larval response of the generalist Helicoverpa armigera (Lepidoptera) and the putative role of ABC transporters, we performed developmental assays on artificial diet supplemented with secondary metabolites from host plants (atropine-scopolamine, nicotine and tomatine) and non-host plants (taxol) in combination with a replicated RNAseq experiment. A maximum likelihood phylogeny identified the subfamily affiliations of the ABC transporter sequences. Larval performance was equal on the atropine-scopolamine diet and the tomatine diet. For the latter we could identify a treatment-specific upregulation of five ABC transporters in the gut. No significant developmental difference was detected between larvae fed on nicotine or taxol. This was also mirrored in the upregulation of five ABC transporters when fed on either of the two diets. The highest number of differentially expressed genes was recorded in the gut samples in response to feeding on secondary metabolites. Our results are consistent with the expectation of a general detoxification response in a polyphagous herbivore. This is the first study to characterize the multigene family of ABC transporters and identify gene expression changes across different developmental stages and tissues, as well as the impact of secondary metabolites in the agricultural pest H. armigera. PMID:26951878

  16. Oral Administration of TAT-PTD-Diapause Hormone Fusion Protein Interferes With Helicoverpa armigera (Lepidoptera: Noctuidae) Development.

    PubMed

    Zhou, Zhou; Li, Yongli; Yuan, Chunyan; Zhang, Yongan; Qu, Liangjian

    2015-01-01

    Diapause hormone (DH), which can terminate diapause in Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), has shown promise as a pest control method. However, the main challenge in using DH as an insecticide lies in achieving effective oral delivery, since the peptide may be degraded by digestive enzymes in the gut. To improve the efficacy of oral DH application, the Clostera anastomosis (L.) (Lepidoptera: Notodontidae) diapause hormone (caDH) was fused to the Protein Transduction Domain (PTD) of the human immunodeficiency virus-1 transactivator of transcription (TAT). Cellular transduction of TAT-caDH was verified with the use of a green fluorescent protein fusion, and its ability to terminate diapause was verified by injection into diapausing H. armigera pupae. Orally administered TAT-caDH resulted in larval growth inhibition. In TAT-caDH-treated insects, larval duration was delayed and the pupation rates were decreased at both development promoting conditions [27 °C, a photoperiod of 14:10(L:D) h] and diapause inducing conditions [20 °C, a photoperiod of 10:14(L:D) h]. No significant difference in diapause rate was observed between the TAT-caDH-treated and caDH-treated or control pupae maintained at diapause inducing conditions. Our results show that treatment with a recombinant TAT-caDH protein can affect larval development in H. armigera, and it suggest that TAT-DH treatment may be useful for controlling pests. This study is the first record of oral DH application in insect. PMID:26320262

  17. A Nonhost Peptidase Inhibitor of ~14 kDa from Butea monosperma (Lam.) Taub. Seeds Affects Negatively the Growth and Developmental Physiology of Helicoverpa armigera

    PubMed Central

    Pandey, Prabhash K.; Singh, Dushyant; Singh, Sangram; Khan, M. Y.; Jamal, Farrukh

    2014-01-01

    Helicoverpa armigera is one of the major devastating pests of crop plants. In this context a serine peptidase inhibitor purified from the seeds of Butea monosperma was evaluated for its effect on developmental physiology of H. armigera larvae. B. monosperma peptidase inhibitor on 12% denaturing polyacrylamide gel electrophoresis exhibited a single protein band of ~14 kDa with or without reduction. In vitro studies towards total gut proteolytic enzymes of H. armigera and bovine trypsin indicated measurable inhibitory activity. B. monosperma peptidase inhibitor dose for 50% mortality and weight reduction by 50% were 0.5% w/w and 0.10% w/w, respectively. The IC50 of B. monosperma peptidase inhibitor against total H. armigera gut proteinases activity was 2.0 µg/mL. The larval feeding assays suggested B. monosperma peptidase inhibitor to be toxic as reflected by its retarded growth and development, consequently affecting fertility and fecundity of pest and prolonging the larval-pupal duration of the insect life cycle of H. armigera. Supplementing B. monosperma peptidase inhibitor in artificial diet at 0.1% w/w, both the efficiencies of conversion of ingested as well as digested food were downregulated, whereas approximate digestibility and metabolic cost were enhanced. The efficacy of Butea monosperma peptidase inhibitor against progressive growth and development of H. armigera suggest its usefulness in insect pest management of food crops. PMID:24860667

  18. Molecular identification of three novel glutaredoxin genes that play important roles in antioxidant defense in Helicoverpa armigera.

    PubMed

    Zhang, Song-Dou; Shen, Zhong-Jian; Liu, Xiao-Ming; Li, Zhen; Zhang, Qing-Wen; Liu, Xiao-Xia

    2016-08-01

    Glutaredoxins (Grxs), also known as thioltransferases, play key roles in maintaining intracellular redox balance and protecting cells from oxidative damage in plants and mammals. We tested whether Grxs play important roles in antioxidant defense in insects using the moth, Helicoverpa armigera. We obtained the full-length cDNA sequences of three novel Grx genes, named HaGrx, HaGrx3, and HaGrx5. Sequence analysis indicated that HaGrx shared a high amino acid identity (58%-78%) and a CPYC motif of conserved redox activity with homologues from other selected insect species. In contrast, HaGrx3 and HaGrx5 both shared a CGF(S/G) motif, a conserved catalytic domain, with other orthologous genes. Quantitative real-time PCR results revealed that HaGrx, HaGrx3, and HaGrx5 exhibited temporally- and spatially-dependent patterns of expression. The mRNA expression of HaGrx, HaGrx3, and HaGrx5 was induced by various temperature stresses and H2O2 treatments. We further investigated the knockdown of HaGrx, HaGrx3, and HaGrx5 in H. armigera larvae and found that most of the selected antioxidant genes were up regulated. However, Tpx was down regulated, and further interpretation of the complementary functions of these antioxidant genes is still required. We also determined the effect of HaGrx, HaGrx3, and HaGrx5 knockdown on antioxidant enzymatic activity and metabolite content. The enzymatic activities of SOD, CAT, and POD, and the metabolite contents of hydrogen peroxide, ascorbate, protein carbonyl, and total GSH increased after RNAi mediated knockdown of HaGrx, HaGrx3, and HaGrx5. These results supported our hypothesis that HaGrx, HaGrx3, and HaGrx5 play important roles in antioxidant defense of Helicoverpa armigera and provided a theoretical basis for further in-depth study of physiological function in the insect glutaredoxin family genes. PMID:27339760

  19. Resistance to Bacillus thuringiensis toxin Cry2Ab in a strain of Helicoverpa armigera (Lepidoptera: Noctuidae) in Australia.

    PubMed

    Mahon, R J; Olsen, K M; Garsia, K A; Young, S R

    2007-06-01

    Transgenic cotton, Gossypium hirsutum L., expressing the crylAc and cry2Ab genes from Bacillus thuringiensis (Bt) Berliner variety kurstaki in a pyramid (Bollgard II) was widely planted for the first time in Australia during the 2004-2005 growing season. Before the first commercial Bollgard II crops, limited amounts of cotton expressing only the crylAc gene (Ingard) was grown for seven seasons. No field failures due to resistance to CrylAc toxin were observed during that period and a monitoring program indicated that the frequency of genes conferring high level resistance to the CrylAc toxin were rare in the major pest of cotton, Helicoverpa armigera (Htibner) (Lepidoptera: Noctuidae). Before the deployment of Bollgard II, an allele conferring resistance to Cry2Ab toxin was detected in field-collected H. armigera. We established a colony (designated SP15) consisting of homozygous resistant individuals and examined their characteristics through comparison with individuals from a Bt-susceptible laboratory colony (GR). Through specific crosses and bioassays, we established that the resistance present in SP15 was due to a single autosomal gene. The resistance was recessive. Homozygotes were highly resistant to Cry2Ab toxin, so much so, that we were unable to induce significant mortality at the maximum concentration of toxin available. Homozygotes also were unaffected when fed leaves of a cotton variety expressing the cry2Ab gene. Although cross-resistant to Cry2Aa toxin, SP15 was susceptible to CrylAc and to the Bt product DiPel. PMID:17598553

  20. Isotopes and Trace Elements as Natal Origin Markers of Helicoverpa armigera – An Experimental Model for Biosecurity Pests

    PubMed Central

    Holder, Peter W.; Armstrong, Karen; Van Hale, Robert; Millet, Marc-Alban; Frew, Russell; Clough, Timothy J.; Baker, Joel A.

    2014-01-01

    Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150–3000 km apart). Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The geographic resolution

  1. Next-Generation Sequencing-Based Transcriptome Analysis of Helicoverpa armigera Larvae Immune-Primed with Photorhabdus luminescens TT01

    PubMed Central

    Zhao, Zengyang; Wu, Gongqing; Wang, Jia; Liu, Chunlin; Qiu, Lihong

    2013-01-01

    Although invertebrates are incapable of adaptive immunity, immunal reactions which are functionally similar to the adaptive immunity of vertebrates have been described in many studies of invertebrates including insects. The phenomenon was termed immune priming. In order to understand the molecular mechanism of immune priming, we employed Illumina/Solexa platform to investigate the transcriptional changes of the hemocytes and fat body of Helicoverpa armigera larvae immune-primed with the pathogenic bacteria Photorhabdus luminescens TT01. A total of 43.6 and 65.1 million clean reads with 4.4 and 6.5 gigabase sequence data were obtained from the TT01 (the immune-primed) and PBS (non-primed) cDNA libraries and assembled into 35,707 all-unigenes (non-redundant transcripts), which has a length varied from 201 to 16,947 bp and a N50 length of 1,997 bp. For 35,707 all-unigenes, 20,438 were functionally annotated and 2,494 were differentially expressed after immune priming. The differentially expressed genes (DEGs) are mainly related to immunity, detoxification, development and metabolism of the host insect. Analysis on the annotated immune related DEGs supported a hypothesis that we proposed previously: the immune priming phenomenon observed in H. armigera larvae was achieved by regulation of key innate immune elements. The transcriptome profiling data sets (especially the sequences of 1,022 unannotated DEGs) and the clues (such as those on immune-related signal and regulatory pathways) obtained from this study will facilitate immune-related novel gene discovery and provide valuable information for further exploring the molecular mechanism of immune priming of invertebrates. All these will increase our understanding of invertebrate immunity which may provide new approaches to control insect pests or prevent epidemic of infectious diseases in economic invertebrates in the future. PMID:24302999

  2. EAG and behavioral responses of Helicoverpa armigera males to volatiles from poplar leaves and their combinations with sex pheromone.

    PubMed

    Deng, Jian-Yu; Huang, Yong-Ping; Wei, Hong-Yi; Du, Jia-Wei

    2004-12-01

    Electroantennogram (EAG) evaluation of selected compounds from wilted leaves of black poplar, Populus nigra, showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol, phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%, 50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles should modify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field. PMID:15547967

  3. Dynamic transcriptome analysis and volatile profiling of Gossypium hirsutum in response to the cotton bollworm Helicoverpa armigera

    PubMed Central

    Huang, Xin-Zheng; Chen, Jie-Yin; Xiao, Hai-Jun; Xiao, Yu-Tao; Wu, Juan; Wu, Jun-Xiang; Zhou, Jing-Jiang; Zhang, Yong-Jun; Guo, Yu-Yuan

    2015-01-01

    In response to insect herbivory, plants emit elevated levels of volatile organic compounds for direct and indirect resistance. However, little is known about the molecular and genomic basis of defense response that insect herbivory trigger in cotton plants and how defense mechanisms are orchestrated in the context of other biological processes. Here we monitored the transcriptome changes and volatile characteristics of cotton plants in response to cotton bollworm (CBW; Helicoverpa armigera) larvae infestation. Analysis of samples revealed that 1,969 transcripts were differentially expressed (log2|Ratio| ≥ 2; q ≤ 0.05) after CBW infestation. Cluster analysis identified several distinct temporal patterns of transcriptome changes. Among CBW-induced genes, those associated with indirect defense and jasmonic acid pathway were clearly over-represented, indicating that these genes play important roles in CBW-induced defenses. The gas chromatography-mass spectrometry (GC-MS) analyses revealed that CBW infestation could induce cotton plants to release volatile compounds comprised lipoxygenase-derived green leaf volatiles and a number of terpenoid volatiles. Responding to CBW larvae infestation, cotton plants undergo drastic reprogramming of the transcriptome and the volatile profile. The present results increase our knowledge about insect herbivory-induced metabolic and biochemical processes in plants, which may help improve future studies on genes governing processes. PMID:26148847

  4. Limited survival of a Cry2Ab-resistant strain of Helicoverpa armigera (Lepidoptera: Noctuidae) on Bollgard II.

    PubMed

    Mahon, R J; Olsen, K M

    2009-04-01

    Bollgard II cotton (which expresses two Bt insecticidal genes cry1Ac/cry2Ab) and conventional cotton, grown in the laboratory or field and sampled at different stages, was exposed to Helicoverpa armigera (Hübner) larvae of three genotypes: homozygous for resistance to Cry2Ab; homozygous for susceptibility to Cry2Ab, and heterozygous for resistance. Survival of all genotypes was limited on Bollgard II but increased as plants aged. This was particularly the case for homozygous resistant individuals, with 8.5% of this genotype surviving to pupation on mature cotton. The increasing survival is assumed to be caused by the decline in the titer of Cry1Ac toxin after flowering in Bollgard II because Cry2Ab homozygous resistant larvae can tolerate high levels of Cry2Ab toxin. Larvae heterozygous for resistance performed no better on Bollgard II than homozygous susceptible larvae. Survivors on Bollgard II grew more slowly and produced smaller pupae that yielded adults with reduced longevity and fecundity. When reared on conventional cotton, all genotypes generally performed equally, indicating an absence of fitness costs associated with Cry2Ab resistance under the conditions examined. PMID:19449653

  5. Central Projections of Gustatory Receptor Neurons in the Medial and the Lateral Sensilla Styloconica of Helicoverpa armigera Larvae

    PubMed Central

    Tang, Qing-Bo; Zhan, Huan; Cao, Huan; Berg, Bente G.; Yan, Feng-Ming; Zhao, Xin-Cheng

    2014-01-01

    Food selection behavior of lepidopteran larvae is predominantly governed by the activation of taste neurons present in two sensilla styloconica located on the galea of the maxilla. In this study, we present the ultrastructure of the sensilla styloconica and the central projection pattern of their associated receptor neurons in larvae of the heliothine moth, Helicoverpa armigera. By means of light microscopy and scanning electron microscopy, the previous findings of two morphologically fairly similar sensilla comprising a socketed conic tip inserted into a large peg were confirmed. However, the peg size of the medial sensillum was found to be significantly bigger than that of the lateral sensillum. The sensory neurons derived from each sensillum styloconicum were mapped separately using anterograde staining experiments combined with confocal laser-scanning microscopy. For determining the afferents’ target regions relative to each other, we reconstructed the labeled axons and placed them into a common reference framework. The sensory axons from both sensilla projected via the ipsilateral maxillary nerve to the suboesophageal ganglion and further through the ipsilateral circumoesophageal connective to the brain. In the suboesophageal ganglion, the sensory projections targeted two areas of the ipsilateral maxillary neuropil, one located in the ventrolateral neuromere and the other adjacent to the neuromere midline. In the brain, the axon terminals targeted the dorso-anterior area of the ipsilateral tritocerebrum. As confirmed by the three-dimensional reconstructions, the target regions of the neural projections originating from each of the two sensilla styloconica were identical. PMID:24740428

  6. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera

    PubMed Central

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem. PMID:27399776

  7. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera.

    PubMed

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem. PMID:27399776

  8. Molecular and biochemical characterization of the effects of insecticidal toxin from Meloidae beetles on Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae).

    PubMed

    Khan, R A; Rashid, M; Wang, D; Zhang, Y L

    2013-01-01

    The molecular and biochemical effects of an insecticidal toxin extracted from Meloidae beetles were investigated on Helicoverpa armigera. The toxin was identified as cantharidin, a well-known natural compound produced by beetles of family Meloidae and Oedemeridae. Furthermore, the effect of the toxin on the metabolic enzymes alkaline phosphatase (ALP) and glutathione S-transferase (GST), responsible for the metabolism of insecticides, was also investigated. Results of a diet incorporation bioassay performed under laboratory conditions showed that the LC50 value of cantharidin was 0.068 mg/g. The body weight of the insect was also significantly reduced by cantharidin treatment. The LC10 concentration of cantharidin, 0.01 mg/g, was also tested to determine its effect on ALP and GST. Our results showed that cantharidin significantly inhibited ALP activity after 48 h, whereas GST activity was significantly inhibited after 24 h. The decline of ALP and GST transcript levels was also validated by semiquantitative RT-PCR analysis. It may be concluded from the results that ALPs and GSTs may be targets of the cantharidin intoxication mechanism. Moreover, the inability of ALP and GST to metabolize cantharidin shows that the mechanism of detoxification for cantharidin is different from that for conventional insecticides. On the basis of our investigations, the chemical structure of insecticides may be modified using a model structure of cantharidin, to avoid metabolism by metabolic enzymes. PMID:24222219

  9. Effects of dietary quercetin on performance and cytochrome P450 expression of the cotton bollworm, Helicoverpa armigera.

    PubMed

    Liu, D; Yuan, Y; Li, M; Qiu, X

    2015-12-01

    Quercetin is ubiquitous in terrestrial plants. The cotton bollworm Helicoverpa armigera as a highly polyphagous insect has caused severe crop losses. Until now, interactions between this pest and quercetin are poorly understood at the biochemical and molecular levels. In this study, we investigated the in vivo effects of quercetin on performance of cotton bollworm and on cytochrome P450 (P450) expression. Deleterious effects of quercetin on the performance of the cotton bollworm, including growth, survival, pupation and adult emergence were observed after oral administration of 3 and 10 mg g(-1) quercetin to larvae since the third instar, whereas no significant toxic effect was found at 0.1 mg g(-1) quercetin treatment. Piperonyl butoxide treatment enhanced the toxicity of quercetin. In vitro metabolism studies showed that quercetin was rapidly transformed by gut enzymes of fifth instar larvae of the cotton bollworm. qRT-PCR results revealed that the effect of quercetin on P450 expression was tissue- and dose-specific. Quercetin regulated P450 expression in a mild manner, and it could serve as P450 inducer (CYP337B1, CYP6B6) or repressor (CYP337B1, CYP6B7, CYP6B27, CYP9A14, CYP6AE11, and CYP4M7). These findings are important for advancing our understanding of the biochemical and molecular response of insects to plant toxins and have implications for a smart pest control. PMID:26440448

  10. Over-expression of multiple cytochrome P450 genes in fenvalerate-resistant field strains of Helicoverpa armigera from north of China.

    PubMed

    Xu, Li; Li, Dongzhi; Qin, Jianying; Zhao, Weisong; Qiu, Lihong

    2016-09-01

    Pyrethroid resistance was one of the main reasons for control failure of cotton bollworm Helicoverpa armigera (Hübner) in China. The promotion of Bt crops decreased the application of chemical insecticides in controlling H.armigera. However, the cotton bollworm still kept high levels of resistance to fenvalerate. In this study, the resistance levels of 8 field-collected strains of H. armigera from north of China to 4 insecticides, as well as the expression levels of related P450 genes were investigated. The results of bioassay indicated that the resistance levels to fenvalerate in the field strains varied from 5.4- to 114.7-fold, while the resistance levels to lambda-cyhalothrin, phoxim and methomyl were low, which were ranged from 1.5- to 5.2-, 0.2- to 1.6-, and 2.9- to 8.3- fold, respectively, compared to a susceptible strain. Synergistic experiment showed that PBO was the most effective synergist in increasing the sensitivity of H. armigera to fenvalerate, suggesting that P450 enzymes were involved in the pyrethroid resistance in the field strains. The results of quantitative RT-PCR indicated that eight P450 genes (CYP332A1, CYP4L11, CYP4L5, CYP4M6, CYP4M7, CYP6B7, CYP9A12, CYP9A14) were all significantly overexpressed in Hejian1 and Xiajin1 strains of H. armigera collected in 2013, and CYP4L5 was significantly overexpressed in all the 6 field strains collected in 2014. CYP332A1, CYP6B7 and CYP9A12 had very high overexpression levels in all the field strains, indicating their important roles in fenvalerate resistance. The results suggested that multiple P450 genes were involved in the high-level fenvalerate-resistance in different field strains of H. armigera collected from north of China. PMID:27521913

  11. Induced resistance in groundnut by jasmonic acid and salicylic acid through alteration of trichome density and oviposition by Helicoverpa armigera (Lepidoptera: Noctuidae)

    PubMed Central

    War, Abdul Rashid; Hussain, Barkat; Sharma, Hari C.

    2013-01-01

    Jasmonic acid (JA) and salicylic acid (SA) are important phytohormones involved in plant resistance against insect herbivory and pathogen infection. Application of JA and SA induces several defensive traits in plants. Here we investigated the effect of JA and SA on trichome density in five groundnut genotypes [ICGV 86699, ICGV 86031, ICG 2271, ICG 1697 (resistant) and JL 24 (susceptible)]. The effect of JA- and SA-induced resistance on the oviposition behaviour of Helicoverpa armigera on different groundnut genotypes was also studied. Pre-treatment with JA increased numbers of trichomes in the insect-resistant genotypes, ICGV 86699, ICGV 86031, ICG 2271, and ICG 1697. The induction was greater at 10 days after treatment. Jasmonic acid- and SA-treated plants showed a substantial effect on the oviposition behaviour of H. armigera. Jasmonic acid application and herbivory reduced the number of eggs laid by H. armigera in all the groundnut genotypes tested. However, a greater reduction was recorded on plants pre-treated with JA. More egg laying was recorded in JL 24 in all the treatments as compared to the insect-resistant genotypes. These results suggested that pre-treatment with JA increased trichome density in groundnut plants, which conferred antixenosis for oviposition by H. armigera.

  12. A comparison of artificial diet and hybrid sweet corn for the rearing of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) based on life table characteristics.

    PubMed

    Jha, Ratna K; Chi, Hsin; Tang, Li- Cheng

    2012-02-01

    The demographic characteristics of Helicoverpa armigera (Hübner) reared on hybrid sweet corn (Zea mays L. variety saccharata) (hybrid super sweet corn KY bright jean) and on an artificial diet were compared by using the age-stage, two-sex life table. Because the hatch rate of eggs varies with maternal age, age-specific fecundity was calculated based on the numbers of hatched eggs to reveal the biological characteristics of H. armigera accurately. The intrinsic rate of increase (r), finite rate (λ) and mean generation time (T) of H. armigera were 0.0853 d(-1), 1.0890 d(-1), and 46.6 d, respectively, on Z. mays and 0.1015 d(-1), 1.1068 d(-1), and 46.3 d, respectively, on the artificial diet. There were significant differences in the intrinsic rate of increase and finite rate between two treatments. The age-stage life expectancy and reproductive value also were calculated. The relationships among the net reproductive rate, the mean female fecundity, the number of emerged females, and the total number of individuals used in the life table study are consistent with theoretical expectations. We recommend the age-stage, two-sex life table for use in insect demographic studies to incorporate both sexes and the variation in developmental rate among individuals and to obtain accurate population parameters. The artificial diet is more suitable for the mass rearing of H. armigera. PMID:22525057

  13. Fitness costs to Helicoverpa armigera after exposure to sub-lethal concentrations of Metarhizium anisopliae sensu lato: Study on F1 generation.

    PubMed

    Jarrahi, Azadeh; Safavi, Seyed Ali

    2016-07-01

    The entomopathogenic fungus, Metarhizium anisopliae (Metsch.) Sorokin is a valuable biocontrol agent attacking larval stages of many lepidopteran pests including Helicoverpa armigera (Hübner). Sub-lethal effects of M. anisopliae sensu lato (s.l.) (isolate M14) were investigated on life table parameters of offspring from treated larvae of H. armigera. Duration of different life stages was significantly affected by fungal treatments. Fecundity was decreased in females derived from H. armigera larvae treated with M. anisopliae s.l. Sub-lethal concentrations of the entomopathogen reduced the net reproduction rate (R0) of F1 insects for all treatments compared with the control. Similar reductions were observed for the intrinsic and the finite rates of increase (rm and λ, respectively). The mean generation time (T) and the doubling time (DT) were statistically higher in offspring of individuals exposed to some fungal concentrations than control insects. Our results indicated that there was a significant decrease in the F1 population of H. armigera derived from larvae that were exposed to sub-lethal concentrations of M. anisopliae s.l. PMID:27247225

  14. Successive Use of Non-Host Plant Proteinase Inhibitors Required for Effective Inhibition of Helicoverpa armigera Gut Proteinases and Larval Growth1

    PubMed Central

    Harsulkar, Abhay M.; Giri, Ashok P.; Patankar, Aparna G.; Gupta, Vidya S.; Sainani, Mohini N.; Ranjekar, Prabhakar K.; Deshpande, Vasanti V.

    1999-01-01

    We report on the efficacy of proteinase inhibitors (PIs) from three host plants (chickpea [Cicer arietinum], pigeonpea [Cajanus cajan], and cotton [Gossypium arboreum]) and three non-host (groundnut [Arachis hypogea], winged bean [Psophocarpus tetragonolobus], and potato [Solanum tuberosum]) in retarding the growth of Helicoverpa armigera larvae, a devastating pest of important crop plants. Enzyme assays and electrophoretic analysis of interaction of H. armigera gut proteinases (HGPs) with PIs revealed that non-host PIs inhibited HGP activity efficiently whereas host PIs were ineffective. In the electrophoretic assay, trypsin inhibitor activity bands were detected in all of the host and non-host plants, but HGP inhibitor activity bands were present only in non-host plants (except cotton in the host plant group). H. armigera larvae reared on a diet containing non-host PIs showed growth retardation, a reduction in total and trypsin-like proteinase activity, and the production of inhibitor-insensitive proteinases. Electrophoretic analysis of PI-induced HGP showed differential regulation of proteinase isoforms. Interestingly, HGP activity induced in response to dietary potato PI-II was inhibited by winged bean PIs. The optimized combination of potato PI-II and winged bean PIs identified in the present study and their proposed successive use has potential in developing H. armigera-resistant transgenic plants. PMID:10517841

  15. Antifeedant, larvicidal and growth inhibitory bioactivities of novel polyketide metabolite isolated from Streptomyces sp. AP-123 against Helicoverpa armigera and Spodoptera litura

    PubMed Central

    2013-01-01

    Background Considerable attention has been paid to actinomycetes, especially the secondary metabolites obtained from Streptomyces species, as the best alternatives to chemicals as biological control agents for polyphagous pests such as Helicoverpa armigera and Spodoptera litura. On the basis of their novel biocontrol attributes, novel polyketide metabolite isolated from marine Streptomyces sp. AP-123 exhibited significant antifeedant, larvicidal and growth inhibitory activities against polyphagous pests. Results Leaf disc no-choice method was used for the insect bioassay. The polyketide metabolite presented significant antifeedant activities against H. armigera (78.51%) and S. litura (70.75%) at 1000 ppm concentration. The metabolite also exhibited high larvicidal activities against H. armigera (63.11%) and S. litura (58.22%) and the LC50 values were 645.25 ppm for H. armigera and 806.54 ppm for S. litura. The metabolite also prolonged the larval–pupal duration of the insects at all the tested concentrations. Conclusions The activities of the polyketide metabolite were concentration dependent for both the insects therefore it could be used as an agent to prepare new pesticidal formulations. PMID:23668716

  16. Functional validation of cadherin as a receptor of Bt toxin Cry1Ac in Helicoverpa armigera utilizing the CRISPR/Cas9 system.

    PubMed

    Wang, Jing; Zhang, Haonan; Wang, Huidong; Zhao, Shan; Zuo, Yayun; Yang, Yihua; Wu, Yidong

    2016-09-01

    Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out. A single positive CRISPR event with a frame shift deletion of 4 nucleotides was identified and made homozygous to create a knockout line named SCD-Cad. Western blotting confirmed that HaCad was no longer expressed in the SCD-Cad line while an intact HaCad of 210 kDa was present in the parental SCD strain. Insecticide bioassays were used to show that SCD-Cad exhibited 549-fold resistance to Cry1Ac compared with SCD, but no significant change in susceptibility to Cry2Ab. Our results not only provide strong reverse genetics evidence for HaCad as a functional receptor of Cry1Ac, but also demonstrate that the CRISPR/Cas9 technique can act as a powerful and efficient genome editing tool to study gene function in a global agricultural pest, H. armigera. PMID:27343383

  17. Nutritional performance and activity of some digestive enzymes of the cotton bollworm, Helicoverpa armigera, in response to seven tested bean cultivars.

    PubMed

    Namin, Foroogh Rahimi; Naseri, Bahram; Razmjou, Jabraeil

    2014-01-01

    Nutritional performance and activity of some digestive enzymes (protease and α-amylase) of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) in response to feeding on bean (Phaseolus vulgaris L. (Fabales: Fabaceae)) cultivars (Shokufa, Akhtar, Sayyad, Naz, Pak, Daneshkadeh, and Talash) were evaluated under laboratory conditions (25 ± 1°C, 65 ± 5% RH, and a 16:8 L:D photoperiod). The highest and lowest respective values of approximate digestibility were observed when fourth, fifth, and sixth larval instar H. armigera were fed red kidney bean Akhtar and white kidney bean Daneshkadeh. The efficiency of conversion of ingested and digested food was highest when H. armigera was fed red kidney beans Akhtar and Naz and lowest when they were fed white kidney bean Pak. The highest protease activity of fifth instars was observed when they were fed red kidney bean Naz, and the highest amylase activity of fifth instars was observed when they were fed red kidney bean Sayyad. Sixth instar larvae that fed on red kidney bean Sayyad showed the highest protease activity. Larvae reared on common bean Talash and white kidney bean Pak showed the highest amylase activity. Among bean cultivars tested, red kidney bean Sayyad was the most unsuitable host for feeding H. armigera. PMID:25368049

  18. A Multiplex Real-Time PCR Assay to Diagnose and Separate Helicoverpa armigera and H. zea (Lepidoptera: Noctuidae) in the New World

    PubMed Central

    Gilligan, Todd M.; Tembrock, Luke R.; Farris, Roxanne E.; Barr, Norman B.; van der Straten, Marja J.; van de Vossenberg, Bart T. L. H.; Metz-Verschure, Eveline

    2015-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), and the corn earworm, H. zea (Boddie), are two of the most important agricultural pests in the world. Diagnosing these two species is difficult—adults can only be separated with a complex dissection, and larvae cannot be identified to species using morphology, necessitating the use of geographic origin for identification in most instances. With the discovery of H. armigera in the New World, identification of immature Helicoverpa based on origin is no longer possible because H. zea also occurs in all of the geographic regions where H. armigera has been discovered. DNA barcoding and restriction fragment length polymorphism (RFLP) analyses have been reported in publications to distinguish these species, but these methods both require post-PCR processing (i.e., DNA sequencing or restriction digestion) to complete. We report the first real-time PCR assay to distinguish these pests based on two hydrolysis probes that bind to a segment of the internal transcribed spacer region 2 (ITS2) amplified using a single primer pair. One probe targets H. armigera, the second probe targets H. zea, and a third probe that targets a conserved segment of 18S rDNA is used as a control of DNA quality. The assay can be completed in 50 minutes when using isolated DNA and is successfully tested on larvae intercepted at ports of entry and adults captured during domestic surveys. We demonstrate that the assay can be run in triplex with no negative effects on sensitivity, can be run using alternative real-time PCR reagents and instruments, and does not cross react with other New World Heliothinae. PMID:26558366

  19. Transcriptional responses underlying the hormetic and detrimental effects of the plant secondary metabolite gossypol on the generalist herbivore Helicoverpa armigera

    PubMed Central

    2011-01-01

    Background Hormesis is a biphasic biological response characterized by the stimulatory effect at relatively low amounts of chemical compounds which are otherwise detrimental at higher concentrations. A hormetic response in larval growth rates has been observed in cotton-feeding insects in response to increasing concentrations of gossypol, a toxic metabolite found in the pigment glands of some plants in the family Malvaceae. We investigated the developmental effect of gossypol in the cotton bollworm, Helicoverpa armigera, an important heliothine pest species, by exposing larvae to different doses of this metabolite in their diet. In addition, we sought to determine the underlying transcriptional responses to different gossypol doses. Results Larval weight gain, pupal weight and larval development time were measured in feeding experiments and a hormetic response was seen for the first two characters. On the basis of net larval weight gain responses to gossypol, three concentrations (0%, 0.016% and 0.16%) were selected for transcript profiling in the gut and the rest of the body in a two-color double reference design microarray experiment. Hormesis could be observed at the transcript level, since at the low gossypol dose, genes involved in energy acquisition such as β-fructofuranosidases were up-regulated in the gut, and genes involved in cell adhesion were down-regulated in the body. Genes with products predicted to be integral to the membrane or associated with the proteasome core complex were significantly affected by the detrimental dose treatment in the body. Oxidoreductase activity-related genes were observed to be significantly altered in both tissues at the highest gossypol dose. Conclusions This study represents the first transcriptional profiling approach investigating the effects of different concentrations of gossypol in a lepidopteran species. H. armigera's transcriptional response to gossypol feeding is tissue- and dose-dependent and involves diverse

  20. The seesaw effect of winter temperature change on the recruitment of cotton bollworms Helicoverpa armigera through mismatched phenology.

    PubMed

    Reddy, Gadi V P; Shi, Peijian; Hui, Cang; Cheng, Xiaofei; Ouyang, Fang; Ge, Feng

    2015-12-01

    Knowing how climate change affects the population dynamics of insect pests is critical for the future of integrated pest management. Rising winter temperatures from global warming can drive increases in outbreaks of some agricultural pests. In contrast, here we propose an alternative hypothesis that both extremely cold and warm winters can mismatch the timing between the eclosion of overwintering pests and the flowering of key host plants. As host plants normally need higher effective cumulative temperatures for flowering than insects need for eclosion, changes in flowering time will be less dramatic than changes in eclosion time, leading to a mismatch of phenology on either side of the optimal winter temperature. We term this the "seesaw effect." Using a long-term dataset of the Old World cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in northern China, we tested this seesaw hypothesis by running a generalized additive model for the effects of the third generation moth in the preceding year, the winter air temperature, the number of winter days below a critical temperature and cumulative precipitation during winter on the demography of the overwintering moth. Results confirmed the existence of the seesaw effect of winter temperature change on overwintering populations. Pest management should therefore consider the indirect effect of changing crop phenology (whether due to greenhouse cultivation or to climate change) on pest outbreaks. As arthropods from mid- and high latitudes are actually living in a cooler thermal environment than their physiological optimum in contrast to species from lower latitudes, the effects of rising winter temperatures on the population dynamics of arthropods in the different latitudinal zones should be considered separately. The seesaw effect makes it more difficult to predict the average long-term population dynamics of insect pests at high latitudes due to the potential sharp changes in annual growth rates

  1. Molecular Characterization and Function Analysis of the Vitellogenin Receptor from the Cotton Bollworm, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae)

    PubMed Central

    Xiao, Haijun; Xie, Bingtang; Smagghe, Guy; Guo, Yuyuan; Liang, Gemei

    2016-01-01

    Developing oocytes accumulate plentiful yolk protein during oogenesis through receptor-mediated endocytosis. The vitellogenin receptor (VgR), belonging to the low-density lipoprotein receptor (LDLR) family, regulates the absorption of yolk protein. In this work, the full-length vitellogenin receptor (HaVgR) in the cotton bollworm Helicoverpa armigera was identified, encoding a 1817 residue protein. Sequence alignment revealed that the sequence of HaVgR contained all of the conservative structural motifs of LDLR family members, and phylogenetic analysis indicated that HaVgR had a high identity among Lepidoptera and was distinct from that of other insects. Consistent with other insects, HaVgR was specifically expressed in ovarian tissue. The developmental expression pattern showed that HaVgR was first transcribed in the newly metamorphosed female adults, reached a peak in 2-day-old adults and then declined. Western blot analysis also revealed an ovarian-specific and developing expression pattern, which was consistent with the HaVgR mRNA transcription. Moreover, RNAi-mediated HaVgR knockdown strongly reduced the VgR expression in both the mRNA and protein levels, which inhibited the yolk protein deposition in the ovaries, led to the dramatic accumulation of vitellogenin and the up-regulation of HaVg expression in hemolymph, and eventually resulted in a declined fecundity. Together, all of these findings demonstrate that HaVgR is a specific receptor in uptake and transportation of yolk protein for the maturation of oocytes and that it plays a critical role in female reproduction. PMID:27192057

  2. New Insight to Structure-Function Relationship of GalNAc Mediated Primary Interaction between Insecticidal Cry1Ac Toxin and HaALP Receptor of Helicoverpa armigera

    PubMed Central

    Sengupta, Anindita; Sarkar, Anindya; Priya, Prerna; Ghosh Dastidar, Shubhra; Das, Sampa

    2013-01-01

    Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns. PMID:24205171

  3. PROTECTION OF SWEET CORN FROM OSTRINIA NUBILALIS HBN. AND HELICOVERPA ARMIGERA HBN.

    PubMed

    Vuković, S; Indić, D; Grahovac, M; Franeta, F

    2015-01-01

    O. nubilalis and H. armigera regularly occur and cause significant damages in corn crops in Serbia, particularly under global warming conditions. Several measures are applied against these pests (crop rotation, tolerant and resistant hybrids, monitoring, forecast, chemical measures). Larvae damage stem, panicle and ear, which favour development of saprophytes and secondary infections by mycotoxin producing, pathogenic fungi. The aim of the paper was to test the efficacy of the insecticides azadirachtin and indoxacarb in sweet corn protection against the mentioned pests. The trials were conducted in 2014 at two localities (Becej B. and PoIjanice P.) on sweet corn, hybrid Enterprise according to standard OEPP methods (PP1/13; 1/152; 1/135). Products on the basis of azadirachtin (10 g a.i./I of product) at a rate of 0.4 and 0.5% and indoxacarb (150 g a.i./I of product) at a rate of 0.25 I/ha, were applied. Treatments were conducted on the 5th of August with tractor sprayers (high clearance). The plot size was 5000 m². Three assessments were made. The first one prior to treatment, on 25 randomly selected plants per replicate, and the number of O. nubilalis and H. armigera egg masses and larvae on silk was registered. In the second assessment (18th of August), on 20 randomly selected plants per replicate, the number of damaged plants and the number of vital larvae was registered. In the third assessment, immediately before harvest (28th of August, i.e. 12th of September) on 20 randomly selected plants per replicate, the number of plants broken below ear (fallen on the ground), damaged ears and vital larvae, was determined. Results are presented as means, efficacy (E%) according to Abbott and significance of differences by LSD test (5%). At B locality egg masses of O. nubilalis were registered on ear silk on 13-19% of plants and larvae on 3-7%, and larvae of H. armigera on 2-4%. At P locality egg masses of O. nubilalis were present on 34-40.8% of plants. After 13 days

  4. Bacillus subtillis RTSBA6 6.00, a new strain isolated from gut of Helicoverpa armigera (Lepidoptera: Noctuidae) produces chymotrypsin-like proteases

    PubMed Central

    Shinde, Ashok A.; Shaikh, Faiyaz K.; Padul, Manohar V.; Kachole, Manvendra S.

    2012-01-01

    Exploring bacterial communities with proteolytic activity from the gut of the Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) insect pests was the purpose of this study. As initial efforts to achieve this goal here we report the isolation of new Bacillus subtillis RTSBA6 6.00 strain from the gut of H. armigera and demonstrated as proteases producer. Zymographic analysis revealed 12 proteolytic bands with apparent molecular weights ranging from 20 to 185 kDa. Although some activity was detected at acidic pH, the major activity was observed at slight alkaline pH (7.8). The optimum temperature was found to be 35 °C with complete loss of activity at 70 °C. All proteases were completely inactivated by PMSF (phenylmethylsulfonyl fluoride) and TPCK (N-tosyl-l-phenylalanine chloromethyl ketone), suggesting that proteases secreted by B. subtillis RTSBA6 6.00 belong to serine proteases class with chymotrypsin-like activity. The occurrence of protease producing bacterial community in the gut of the H. armigera advocates its probable assistance to insect in proteinaceous food digestion and adaptation to protease inhibitors of host plants. PMID:23961192

  5. A bifunctional α-amylase/trypsin inhibitor from pigeonpea seeds: Purification, biochemical characterization and its bio-efficacy against Helicoverpa armigera.

    PubMed

    Gadge, Prafull P; Wagh, Sandip K; Shaikh, Faiyaz K; Tak, Rajesh D; Padul, Manohar V; Kachole, Manvendra S

    2015-11-01

    This paper evaluates α-amylase inhibitor (α-AI) mediated defense of pigeonpea against Helicoverpa armigera. A bifunctional α-amylase/trypsin inhibitor was purified from the seeds of pigeonpea by native liquid phase isoelectric focusing (N-LP-IEF), affinity chromatography and preparative electrophoresis. Its in-vivo and in-vitro interaction with midgut amylases of H. armigera was studied along with growth inhibitory activity. One and two dimensional (2D) zymographic analyses revealed that the purified inhibitor is dimeric glycoprotein (60.2kDa and 56kDa) exist in a multi-isomeric form with five pI variants (pI 5.5 to 6.3). It was found to be heat labile with complete inactivation up to 80°C and stable over a wide range of pH (4-11). The slow binding and competitive type of α-amylase inhibition was observed with 0.08μM of dissociation constant (Ki) for the enzyme-inhibitor complex (EI). The internal protein sequence of two subunits obtained by mass spectrometry matched with cereal-type α-AI, a conserved domain from AAI_LTSS superfamily and sialyltransferase-like protein respectively. In-vivo studies indicated up-regulation of total midgut α-amylase activity with negative effect on growth rate of H. armigera suggesting its suitability for pest control. PMID:26615146

  6. Spatio-Temporal Distribution of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) in a Cotton Production Area.

    PubMed

    Milonas, P; Gogou, C; Papadopoulou, A; Fountas, S; Liakos, V; Papadopoulos, N T

    2016-06-01

    Helicoverpa armigera (Hübner) and Pectinophora gossypiella (Saunders) are major pests of cotton in Greece and elsewhere. Analysing male captures in pheromone traps over two seasons, in two cotton producing sites in central Greece, the spatial and temporal variation in population dynamics were examined. In 2007, captures of male H. armigera increased in late July and maintained at high levels for 1 month and declined at the end of August. For P. gossypiella, male captures remained at low levels during summer, increased late in August, peaked at mid of September and declined toward the end of the season. In 2008, trap captures of both species increased sharply by the end of June and remained at relatively high levels until August and September for P. gossypiella and H. armigera, respectively. Spatial analysis produced a spatial trend map over space, a temporal stability map over time and a spatial and temporal trend map for both species, which could lead in separating the field into management zones, and direct control to areas that exhibit high densities of the pest population and are stable over time. PMID:27008478

  7. Recombinantly expressed isoenzymic aminopeptidases from Helicoverpa armigera (American cotton bollworm) midgut display differential interaction with closely related Bacillus thuringiensis insecticidal proteins.

    PubMed Central

    Rajagopal, R; Agrawal, Neema; Selvapandiyan, Angamuthu; Sivakumar, S; Ahmad, Suhail; Bhatnagar, Raj K

    2003-01-01

    Several investigators have independently identified membrane-associated aminopeptidases in the midgut of insect larvae as the initial interacting ligand to the insecticidal crystal proteins of Bacillus thuringiensis. Though several isoenzymes of aminopeptidases have been identified from the midgut of an insect and their corresponding cDNA cloned, only one of the isoform has been expressed heterologously and studied for its binding to Cry toxins. Here we report the cloning and expression of two aminopeptidases N from Helicoverpa armigera (American cotton bollworm) (HaAPNs). The full-length cDNA of H. armigera APN1 (haapn1) is 3205 bp in size and encodes a 1000-amino-acid protein, while H. armigera APN2 (haapn2) is 3116 bp in size and corresponds to a 1012-amino-acid protein. Structurally these proteins show sequence similarity to other insect aminopeptidases and possess characteristic aminopeptidase motifs. Both the genes have been expressed in Trichoplusia ni (cabbage looper) cells using a baculovirus expression vector. The expressed aminopeptidases are membrane-associated, catalytically active and glycosylated. Ligand-blot analysis of both these aminopeptidases with bioactive Cry1Aa, Cry1Ab and Cry1Ac proteins displayed differential interaction. All the three toxins bound to HaAPN1, whereas only Cry1Ac interacted with HaAPN2. This is the first report demonstrating differential Cry-toxin-binding abilities of two different aminopeptidases from a susceptible insect. PMID:12441000

  8. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

    PubMed

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover. PMID:26514355

  9. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  10. Population Genetic Structure of the Cotton Bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in India as Inferred from EPIC-PCR DNA Markers

    PubMed Central

    Behere, Gajanan Tryambak; Tay, Wee Tek; Russell, Derek Alan; Kranthi, Keshav Raj; Batterham, Philip

    2013-01-01

    Helicoverpa armigera is an important pest of cotton and other agricultural crops in the Old World. Its wide host range, high mobility and fecundity, and the ability to adapt and develop resistance against all common groups of insecticides used for its management have exacerbated its pest status. An understanding of the population genetic structure in H. armigera under Indian agricultural conditions will help ascertain gene flow patterns across different agricultural zones. This study inferred the population genetic structure of Indian H. armigera using five Exon-Primed Intron-Crossing (EPIC)-PCR markers. Nested alternative EPIC markers detected moderate null allele frequencies (4.3% to 9.4%) in loci used to infer population genetic structure but the apparently genome-wide heterozygote deficit suggests in-breeding or a Wahlund effect rather than a null allele effect. Population genetic analysis of the 26 populations suggested significant genetic differentiation within India but especially in cotton-feeding populations in the 2006–07 cropping season. In contrast, overall pair-wise FST estimates from populations feeding on food crops indicated no significant population substructure irrespective of cropping seasons. A Baysian cluster analysis was used to assign the genetic make-up of individuals to likely membership of population clusters. Some evidence was found for four major clusters with individuals in two populations from cotton in one year (from two populations in northern India) showing especially high homogeneity. Taken as a whole, this study found evidence of population substructure at host crop, temporal and spatial levels in Indian H. armigera, without, however, a clear biological rationale for these structures being evident. PMID:23326431

  11. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Huang, Jian

    2015-10-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  12. Negative effects of a nonhost proteinase inhibitor of ~19.8 kDa from Madhuca indica seeds on developmental physiology of Helicoverpa armigera (Hübner).

    PubMed

    Jamal, Farrukh; Singh, Dushyant; Pandey, Prabhash K

    2014-01-01

    An affinity purified trypsin inhibitor from the seed flour extracts of Madhuca indica (MiTI) on denaturing polyacrylamide gel electrophoresis showed that MiTI consisted of a single polypeptide chain with molecular mass of ~19.8 kDa. MiTI inhibited the total proteolytic and trypsin-like activities of the midgut proteinases of Helicoverpa armigera larvae by 87.51% and 76.12%, respectively, at concentration of 5 µg/mL with an IC50 of 1.75 µg/mL against trypsin like midgut proteinases. The enzyme kinetic studies demonstrated that MiTI is a competitive inhibitor with a K i value of 4.1 × 10(-10) M for Helicoverpa trypsin like midgut proteinases. In vivo experiments with different concentrations of MiTI in artificial diet (0.5, 1.0, and 1.5% w/w) showed an effective downfall in the larval body weight and an increase in larval mortality. The concentration of MiTI in the artificial diet to cause 50% mortality (LD50) of larvae was 1.5% w/w and that to cause reduction in mass of larvae by 50% (ED50) was 1.0% w/w. Nutritional indices observations suggest the toxic and adverse effects of MiTI on the growth and development of H. armigera larvae. The results suggest a strong bioinsecticidal potential of affinity purified MiTI which can be exploited in insect pest management of crop plants. PMID:25298962

  13. Negative Effects of a Nonhost Proteinase Inhibitor of ~19.8 kDa from Madhuca indica Seeds on Developmental Physiology of Helicoverpa armigera (Hübner)

    PubMed Central

    Jamal, Farrukh; Singh, Dushyant; Pandey, Prabhash K.

    2014-01-01

    An affinity purified trypsin inhibitor from the seed flour extracts of Madhuca indica (MiTI) on denaturing polyacrylamide gel electrophoresis showed that MiTI consisted of a single polypeptide chain with molecular mass of ~19.8 kDa. MiTI inhibited the total proteolytic and trypsin-like activities of the midgut proteinases of Helicoverpa armigera larvae by 87.51% and 76.12%, respectively, at concentration of 5 µg/mL with an IC50 of 1.75 µg/mL against trypsin like midgut proteinases. The enzyme kinetic studies demonstrated that MiTI is a competitive inhibitor with a Ki value of 4.1 × 10−10 M for Helicoverpa trypsin like midgut proteinases. In vivo experiments with different concentrations of MiTI in artificial diet (0.5, 1.0, and 1.5% w/w) showed an effective downfall in the larval body weight and an increase in larval mortality. The concentration of MiTI in the artificial diet to cause 50% mortality (LD50) of larvae was 1.5% w/w and that to cause reduction in mass of larvae by 50% (ED50) was 1.0% w/w. Nutritional indices observations suggest the toxic and adverse effects of MiTI on the growth and development of H. armigera larvae. The results suggest a strong bioinsecticidal potential of affinity purified MiTI which can be exploited in insect pest management of crop plants. PMID:25298962

  14. Effects of dietary sodium on performance, flight and compensation strategies in the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    PubMed Central

    2010-01-01

    Background Sodium is critical for many physiological functions in insects. Herbivorous insects should expend considerable energy to compensate for sodium deficiency due to low sodium concentration in most inland plants upon which they feed. However, sodium compensation behaviors such as mud-puddling have been observed in some species but not in others. We expect that there may be other sodium compensation strategies in insects. Here, we select a rarely mud-puddling insect species, the cotton boll worm, Helicoverpa armigera, and determine the effects of dietary sodium on performance and flight, and examine their means of sodium compensation. Results When freshly hatched H. armigera neonates were cultured on one of three diets differing in sodium contents (diet A, B and C with a high, middle and low sodium concentrations, respectively), the larvae on diet C grew larger, had a higher mortality rate and a shorter development period than those on diet A and B. The larvae previously fed from 1st to 3rd instar on diet C consumed more subsequent diet when they were transferred to diet A or C at 4th instar, comparing to those previously fed on diet A. Moreover, any 4th-instar larvae on diet C consumed a greater amount of food than those on diet A, no matter which diet the larvae had previously ingested from 1st to 3rd instar. Moths from diet A and B flew more rapidly than those from diet C, with similar sugar and lipid utilization rates among the three test groups. When a 5th-instar cannibal from diet A, B or C and a 5th-instar victim from diet A were housed together, many more cannibals from diet C ate their victims. When a victim from diet A, B or C was provided, a cannibal from diet C was more likely to eat the victim from diet A. When newly emerged moths had been exposed to 3% sodium chloride solution for all scotophase period, the average weight increase (proxy for sodium solution intake) for moths from diet A was lower than those from diet B or C. Conclusion Sodium

  15. Kinetic assessment and effect on developmental physiology of a trypsin inhibitor from Eugenia jambolana (Jambul) seeds on Helicoverpa armigera (Hübner).

    PubMed

    Singh, Dushyant; Jamal, Farrukh; Pandey, Prabhash K

    2014-02-01

    A trypsin inhibitor was purified from the seeds of Eugenia jambolana (Jambul) with a fold purification of 14.28 and a yield recovery of 2.8%. Electrophoretic analysis of E. jambolana trypsin inhibitor (EjTI) revealed a molecular weight of approximately 17.4 kDa on 12% denaturing polyacrylamide gel electrophoresis with or without reduction. EjTI exhibited high stability over a wide range of temperatures (4-80 °C for 30 min) and pH (3.0-10.0) and inhibited trypsin-like activities of the midgut proteinases of fourth instar Helicoverpa armigera larvae by approximately 86%. Feeding assays containing 0.05, 0.15, and 0.45 (% w/w) EjTI on functionally important fourth-instar larvae indicated a dose-dependent downfall in the larval body weight as well as on extent of survival. The nutritional analysis suggests that EjTI exerts toxic effects on H. armigera. Dixon plot analysis revealed competitive inhibition of larval midgut proteinases by EjTI, with an inhibition constant (Ki ) of approximately 3.1 × 10(-9) M. However, inhibitor kinetics using double reciprocal plots for trypsin inhibition demonstrated a mixed inhibition pattern. These observations suggest the potential of E. jambolana trypsin inhibitor protein in insect pest management. PMID:24436204

  16. Frequency of alleles conferring resistance to the Bt toxins Cry1Ac and Cry2Ab in Australian populations of Helicoverpa armigera (Lepidoptera: Noctuidae).

    PubMed

    Mahon, R J; Olsen, K M; Downes, S; Addison, S

    2007-12-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is an important lepidopteran pest of cotton (Gossypium spp.) in Australia and the Old World. From 2002, F2 screens were used to examine the frequency of resistance alleles in Australian populations of H. armigera to Bacillus thuringiensis (Bt) CrylAc and Cry2Ab, the two insecticidal proteins present in the transgenic cotton Bollgard II. At that time, Ingard (expressing Cry1Ac) cotton had been grown in Australia for seven seasons, and Bollgard II was about to be commercially released. The principal objective of our study was to determine whether sustained exposure caused an elevated frequency of alleles conferring resistance to Cry1Ac in a species with a track record of evolving resistance to conventional insecticides. No major alleles conferring resistance to Cry1Ac were found. The frequency of resistance alleles for Cry1Ac was <0.0003, with a 95% credibility interval between 0 and 0.0009. In contrast, alleles conferring resistance to Cry2Ab were found at a frequency of 0.0033 (0.0017, 0.0055). The first isolation of this allele was found before the widespread deployment of Bollgard II. For both toxins the experiment-wise detection probability was 94.4%. Our results suggest that alleles conferring resistance to Cry1Ac are rare and that a relatively high baseline frequency of alleles conferring resistance to Cry2Ab existed before the introduction of Bt cotton containing this toxin. PMID:18232402

  17. Isomer-specific comparisons of the hydrolysis of synthetic pyrethroids and their fluorogenic analogues by esterases from the cotton bollworm Helicoverpa armigera.

    PubMed

    Yuan, G; Li, Y; Farnsworth, C A; Coppin, C W; Devonshire, A L; Scott, C; Russell, R J; Wu, Y; Oakeshott, J G

    2015-06-01

    The low aqueous solubility and chiral complexity of synthetic pyrethroids, together with large differences between isomers in their insecticidal potency, have hindered the development of meaningful assays of their metabolism and metabolic resistance to them. To overcome these problems, Shan and Hammock (2001) [7] therefore developed fluorogenic and more water-soluble analogues of all the individual isomers of the commonly used Type 2 pyrethroids, cypermethrin and fenvalerate. The analogues have now been used in several studies of esterase-based metabolism and metabolic resistance. Here we test the validity of these analogues by quantitatively comparing their hydrolysis by a battery of 22 heterologously expressed insect esterases with the hydrolysis of the corresponding pyrethroid isomers by these esterases in an HPLC assay recently developed by Teese et al. (2013) [14]. We find a strong, albeit not complete, correlation (r = 0.7) between rates for the two sets of substrates. The three most potent isomers tested were all relatively slowly degraded in both sets of data but three esterases previously associated with pyrethroid resistance in Helicoverpa armigera did not show higher activities for these isomers than did allelic enzymes derived from susceptible H. armigera. Given their amenability to continuous assays at low substrate concentrations in microplate format, and ready detection of product, we endorse the ongoing utility of the analogues in many metabolic studies of pyrethroids. PMID:26047117

  18. Effect of larvae treated with mixed biopesticide Bacillus thuringiensis-abamectin on sex pheromone communication system in cotton bollworm, Helicoverpa armigera.

    PubMed

    Shen, Li-Ze; Chen, Peng-Zhou; Xu, Zhi-Hong; Deng, Jian-Yu; Harris, Marvin-K; Wanna, Ruchuon; Wang, Fu-Min; Zhou, Guo-Xin; Yao, Zhang-Liang

    2013-01-01

    Third instar larvae of the cotton bollworm (Helicoverpa armigera) were reared with artificial diet containing a Bacillus thuringiensis-abamectin (BtA) biopesticide mixture that resulted in 20% mortality (LD20). The adult male survivors from larvae treated with BtA exhibited a higher percentage of "orientation" than control males but lower percentages of "approaching" and "landing" in wind tunnel bioassays. Adult female survivors from larvae treated with BtA produced higher sex pheromone titers and displayed a lower calling percentage than control females. The ratio of Z-11-hexadecenal (Z11-16:Ald) and Z-9-hexadecenal (Z9-16:Ald) in BtA-treated females changed and coefficients of variation (CV) of Z11-16:Ald and Z9-16:Ald were expanded compared to control females. The peak circadian calling time of BtA-treated females occurred later than that of control females. In mating choice experiment, both control males and BtA-treated males preferred to mate with control females and a portion of the Bt-A treated males did not mate whereas all control males did. Our Data support that treatment of larvae with BtA had an effect on the sex pheromone communication system in surviving H. armigera moths that may contribute to assortative mating. PMID:23874751

  19. Ectopic expression of GroEL from Xenorhabdus nematophila in tomato enhances resistance against Helicoverpa armigera and salt and thermal stress.

    PubMed

    Kumari, Punam; Mahapatro, Gagan Kumar; Banerjee, Nirupama; Sarin, Neera Bhalla

    2015-10-01

    The GroEL homolog XnGroEL protein of Xenorhabdus nematophila belongs to a highly conserved family of molecular chaperones/heat shock proteins (Hsps). XnGroEL was shown to possess oral insecticidal activity against a major crop pest Helicoverpa armigera. Under normal conditions, the Hsps/chaperones facilitate folding, assembly, and translocation of cellular proteins, while in stress conditions they protect proteins from denaturation. In this study, we describe generation of transgenic tomato plants overexpressing insecticidal XnGroEL protein and their tolerance to biotic and abiotic stresses. Presence of XnGroEL in the transgenic tomato lines conferred resistance against H. armigera showing 100% (p ≤ 0.001) mortality of neonates. In addition, XnGroEL provided thermotolerance and protection against high salt concentration to the tomato plants. Expression of XnGroEL minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane system of the plants under heat and salt stress. The enhanced tolerance to abiotic stresses correlated with increase in the anti-oxidative enzyme activity and reduced H2O2 accumulation in transgenic tomato plants. The variety of beneficial properties displayed by XnGroEL protein provides an opportunity for value addition and improvement of crop productivity. PMID:25958082

  20. Transgenic plants over-expressing insect-specific microRNA acquire insecticidal activity against Helicoverpa armigera: an alternative to Bt-toxin technology.

    PubMed

    Agrawal, Aditi; Rajamani, Vijayalakshmi; Reddy, Vanga Siva; Mukherjee, Sunil Kumar; Bhatnagar, Raj K

    2015-10-01

    The success of Bt transgenics in controlling predation of crops has been tempered by sporadic emergence of resistance in targeted insect larvae. Such emerging threats have prompted the search for novel insecticidal molecules that are specific and could be expressed through plants. We have resorted to small RNA-based technology for an investigative search and focused our attention to an insect-specific miRNA that interferes with the insect molting process resulting in the death of the larvae. In this study, we report the designing of a vector that produces artificial microRNA (amiR), namely amiR-24, which targets the chitinase gene of Helicoverpa armigera. This vector was used as transgene in tobacco. Northern blot and real-time analysis revealed the high level expression of amiR-24 in transgenic tobacco plants. Larvae feeding on the transgenic plants ceased to molt further and eventually died. Our results demonstrate that transgenic tobacco plants can express amiR-24 insectice specific to H. armigera. PMID:25947089

  1. Disruption of a Cadherin Gene Associated with Resistance to Cry1Ac δ-Endotoxin of Bacillus thuringiensis in Helicoverpa armigera

    PubMed Central

    Xu, Xinjun; Yu, Liangying; Wu, Yidong

    2005-01-01

    A laboratory strain (GY) of Helicoverpa armigera (Hübner) was established from surviving larvae collected from transgenic cotton expressing a Bacillus thuringiensis var. kurstaki insecticidal protein (Bt cotton) in Gaoyang County, Hebei Province, People's Republic of China, in 2001. The GYBT strain was derived from the GY strain through 28 generations of selection with activated Cry1Ac delivered by diet surface contamination. When resistance to Cry1Ac in the GYBT strain increased to 564-fold after selection, we detected high levels of cross-resistance to Cry1Aa (103-fold) and Cry1Ab (>46-fold) in the GYBT strain with reference to those in the GY strain. The GYBT strain had a low level of cross-resistance to B. thuringiensis var. kurstaki formulation (Btk) (5-fold) and no cross-resistance to Cry2Aa (1.4-fold). Genetic analysis showed that Cry1Ac resistance in the GYBT strain was controlled by one autosomal and incompletely recessive gene. The cross-resistance pattern and inheritance mode suggest that the Cry1Ac resistance in the GYBT strain of H. armigera belongs to “mode 1,” the most common type of lepidopteran resistance to B. thuringiensis toxins. A cadherin gene was cloned and sequenced from both the GY and GYBT strains. Disruption of the cadherin gene by a premature stop codon was associated with a high level of Cry1Ac resistance in H. armigera. Tight linkage between Cry1Ac resistance and the cadherin locus was observed in a backcross analysis. Together with previous evidence found with Heliothis virescens and Pectinophora gossypiella, our results confirmed that the cadherin gene is a preferred target for developing DNA-based monitoring of B. thuringiensis resistance in field populations of lepidopteran pests. PMID:15691952

  2. Disruption of Ha_BtR alters binding of Bacillus thuringiensis delta-endotoxin Cry1Ac to midgut BBMVs of Helicoverpa armigera.

    PubMed

    Xu, Xinjun; Wu, Yidong

    2008-01-01

    Disruption of the Ha_BtR (a cadherin gene) is genetically linked to resistance to Cry1Ac delta-endotoxin of Bacillus thuringiensis in the GYBT strain of Helicoverpa armigera. Brush border membrane vesicles (BBMVs) prepared from midguts of both the Cry1Ac-resistant GYBT strain (homozygous for a deletion knockout of Ha_BtR) and the susceptible GY strain (homozygous for the wild type of Ha_BtR) possessed saturable and specific binding ability to (125)I-Cry1Ac. The binding constant (K(d)) of the GY strain was significantly lower than that of the resistant GYBT strain, whereas their binding site concentrations (B(max)) were similar. When midgut BBMVs were reacted directly with streptavidin conjugated to horseradish peroxidase, the GY strain had very clear 120- and 85-kDa protein bands, which indicated that the 120- and 85-kDa bands are endogenous biotin-containing proteins. However, the GYBT strain almost completely lost these two biotin-containing proteins. Ligand blotting with biotinylated Cry1Ac toxin showed midgut BBMVs of the GY strain contain five protein bands of 210-, 190-, 150-, 120-, and 85-kDa, respectively, while BBMVs of the GYBT strain contain only two protein bands of 150- and 120-kDa. 120-kDa bands may consist of two proteins with coincidentally the same molecular weight (putatively, an APN and a biotin-containing protein). Our results showed that the binding pattern of Cry1Ac to midgut BBMVs of H. armigera was altered quantitatively and qualitatively by knockout of Ha_BtR. There are multiple Cry1Ac-binding proteins in the midgut of susceptible H. armigera, but only the Ha_BtR can be considered as a putative functional receptor of Cry1Ac. Possible involvement of other receptor proteins in the intoxication process in vivo could not be excluded. PMID:17681529

  3. Yeast one-hybrid screening the potential regulator of CYP6B6 overexpression of Helicoverpa armigera under 2-tridecanone stress.

    PubMed

    Zhao, J; Liu, X N; Li, F; Zhuang, S Z; Huang, L N; Ma, J; Gao, X W

    2016-04-01

    In insect, the cytochrome P450 plays a pivotal role in detoxification to toxic allelochemicals. Helicoverpa armigera can tolerate and survive in 2-tridecanone treatment owing to the CYP6B6 responsive expression, which is controlled by some regulatory DNA sequences and transcription regulators. Therefore, the 2-tridecanone responsive region and transcription regulators of the CYP6B6 are responsible for detoxification of cotton bollworm. In this study, we used yeast one-hybrid to screen two potential transcription regulators of the CYP6B6 from H. armigera that respond to the plant secondary toxicant 2-tridecanone, which were named Prey1 and Prey2, respectively. According to the NCBI database blast, Prey1 is the homology with FK506 binding protein (FKBP) of Manduca sexta and Bombyx mori that belongs to the FKBP-C superfamily, while Prey2 may be a homology of an unknown protein of Papilio or the fcaL24 protein homology of B. mori. The electrophoretic mobility shift assays revealed that the FKBP of prokaryotic expression could specifically bind to the active region of the CYP6B6 promoter. After the 6th instar larvae of H. armigera reared on 2-tridecanone artificial diet, we found there were similar patterns of CYP6B6 and FKBP expression of the cotton bollworm treated with 10 mg g-1 2-tridecanone for 48 h, which correlation coefficient was the highest (0.923). Thus, the FKBP is identified as a strong candidate for regulation of the CYP6B6 expression, when the cotton bollworm is treated with 2-tridecanone. This may lead us to a better understanding of transcriptional mechanism of CYP6B6 and provide very useful information for the pest control. PMID:26696496

  4. The impact of ingested potato type II inhibitors on the production of the major serine proteases in the gut of Helicoverpa armigera.

    PubMed

    Stevens, J A; Dunse, K M; Guarino, R F; Barbeta, B L; Evans, S C; West, J A; Anderson, M A

    2013-02-01

    The flowers of the ornamental tobacco produce high levels of a series of 6 kDa serine protease inhibitors (NaPIs) that are effective inhibitors of trypsins and chymotrypsins from lepidopteran species. These inhibitors have a negative impact on the growth and development of lepidopteran larvae and have a potential role in plant protection. Here we investigate the effect of NaPIs on the activity and levels of serine proteases in the gut of Helicoverpa armigera larvae and explore the adaptive mechanisms larvae employ to overcome the negative effects of NaPIs in the diet. Polyclonal antibodies were raised against a Helicoverpa punctigera trypsin that is a target for NaPIs and two H. punctigera chymotrypsins; one that is resistant and one that is susceptible to inhibition by NaPIs. The antibodies were used to optimize procedures for extraction of proteases for immunoblot analysis and to assess the effect of NaPIs on the relative levels of the proteases in the gut and frass. We discovered that consumption of NaPIs did not lead to over-production of trypsins or chymotrypsins but did result in excessive loss of proteases to the frass. PMID:23247047

  5. Cloning and Tissue-Specific Expression of a Chitin Deacetylase Gene from Helicoverpa armigera (Lepidoptera: Noctuidae) and Its Response to Bacillus thuringiensis

    PubMed Central

    Han, Guoying; Li, Xiumin; Zhang, Ting; Zhu, Xiaoting

    2015-01-01

    Chitin deacetylases (CDAs) convert chitin into chitosan, the N-deacetylated form of chitin, which influences the mechanical and permeability properties of structures such as the cuticle and peritrophic matrices. In this article, a new CDA encoding gene, Hacda2, was cloned by reverse transcription-polymerase chain reaction method in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), with an open reading frame of 1,611 bp. The deduced protein composed of 536 amino acid residues with a signal peptide, a chitin-binding domain, a low-density lipoprotein receptor class A domain, and a polysaccharide deacetylase-like catalytic domain. The highest expression level of Hacda2 was detected in fat body among tissues tested in the fifth-instar larvae using real-time quantitative polymerase chain reaction method. Feeding of Bacillus thuringiensis (Bt) (Bacillales: Bacillaceae) diet changed the expression level of Hacda1, Hacda2, Hacda5a, and Hacda5b significantly and differentially in the third-instar larvae. Hacda5a and Hacda5b expression were initially down-regulated and then up-regulated, whereas, the expression level of Hacda1 and Hacda2 was suppressed constantly postfeeding on Bt diet. These results suggested that HaCDAs may be involved in the response of H. armigera larvae to Bt and may be helpful to elucidate the roles of HaCDAs in the action of Bt cry toxin. The potential of HaCDAs to be used as synergists of Bt insecticidal protein needs to be further tested. PMID:26163665

  6. Identification and characterization of the Sudanese Bacillus thuringiensis and related bacterial strains for their efficacy against Helicoverpa armigera and Tribolium castaneum.

    PubMed

    Gorashi, N E; Tripathi, M; Kalia, V; Gujar, G T

    2014-06-01

    Forty-four isolates of Bacillus thuringiensis like bacteria from various sources in different locations from Sudan were tested for their insecticidal activity. The toxicity of these isolates ranged from 6.6 to 70% to the neonates of cotton bollworm, Helicoverpa armigera at 10 ppm concentration. The most effective ones are Kb-29, St-6 and Wh-1 comparable with HD-1. Toxicity of isolates to larvae of the red flour beetle, Tribolium castaneum ranged from 20 to 100%. Isolates St-2 and St-23 gave 100% larval mortality within 15 days of exposure and were at par with Ab-8, Ab-12, Kb-26, Kb-30, Om-4, Po-2, Po-5, Po-7, Sa-8 and Wh-5 and were also comparable with E. coli clone expressing Cry3 toxin. The most effective five isolates viz., Kb-29, St-2, St-6, St-23 and Wh-1 belonged to B. thuringiensis. The St-6 isolate, which also showed high toxicity to T. castaneum larvae, had cry1 genes along with coleopteran active cry28 genes, but not cry3 genes. Of the 25 isolates characterized with 16s DNA sequencing, seven belonged to Paenibacillus spp., one Lysinibacillus sphaericus, one Bacillus pumilus, four Bacillus spp., and rest 12 belonged to B. thuringiensis. Biochemical characterization in each species showed variation. The present study shows potential of some isolates like Kb-29, St-2, St-6, St-23 and Wh-1 as promising bioinsecticides. PMID:24956895

  7. Identification of ABCC2 as a binding protein of Cry1Ac on brush border membrane vesicles from Helicoverpa armigera by an improved pull-down assay.

    PubMed

    Zhou, Zishan; Wang, Zeyu; Liu, Yuxiao; Liang, Gemei; Shu, Changlong; Song, Fuping; Zhou, Xueping; Bravo, Alejandra; Soberón, Mario; Zhang, Jie

    2016-08-01

    Cry1Ac toxin-binding proteins from Helicoverpa armigera brush border membrane vesicles were identified by an improved pull-down method that involves coupling Cry1Ac to CNBr agarose combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). According to the LC-MS/MS results, Cry1Ac toxin could bind to six classes of aminopeptidase-N, alkaline phosphatase, cadherin-like protein, ATP-binding cassette transporter subfamily C protein (ABCC2), actin, ATPase, polycalin, and some other proteins not previously characterized as Cry toxin-binding molecules such as dipeptidyl peptidase or carboxyl/choline esterase and some serine proteases. This is the first report that suggests the direct binding of Cry1Ac toxin to ABCC2 in H. armigera. PMID:27037552

  8. Insecticidal and Antifeedant Activities of Clerodane Diterpenoids Isolated from the Indian Bhant Tree, Clerodendron infortunatum, Against the Cotton Bollworm, Helicoverpa armigera

    PubMed Central

    Abbaszadeh, Gholamreza; Srivastava, Chitra; Walia, Suresh

    2014-01-01

    The Indian bhant tree, Clerodendron infortunatum L. (Lamialus: Lamiaceae), is a well-known medicinal plant, but little information about its bioefficacy against agricultural pests exists. This scarcity was addressed in the present study, in which dried leaves of C. infortunatum were subjected to extraction with hexane and methanol and then partitioned using different solvents of varying polarity. In a preliminary bioassay, the antifeedant effects of the crude extracts and fractions were tested on a highly polyphagous pest, the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), using the no-choice test method with cabbage leaf discs. The methanol fraction resulted in maximum antifeedant activity. This fraction was further subjected to crystallization and column chromatography in order to isolate the compounds responsible for the activity. Three pure compounds were isolated and identified as clerodin (CL), 15-methoxy-14, 15-dihydroclerodin (MD), and 15-hydroxy-14, 15-dihyroclerodin (HD). The antifeedant activity of these compounds was studied using a choice as well as a no-choice test method with 24 and 48 hr observation periods. Insecticidal activity was measured using the topical application method at 0.5, 1, 1.5, 2, 2.5, and 3% concentrations, and data were recorded 24, 48, and 72 hr after treatment. In the no-choice test conditions, compounds CL and MD showed significantly higher antifeedant activity compared to the key ingredient in many commercial pesticides, azadirachtin, at its highest concentration. Compound HD also showed very good antifeedant activity, which did not differ significantly from that of azadirachtin. In the choice test conditions, all three compounds and azadirachtin showed 100% antifeedant activity at the highest concentration. Antifeedant Index (AI50) values of CL, MD, and HD were 6, 6, and 8 ppm in choice tests, and increased to 8, 9, and 11 ppm in the no-choice tests, respectively. Insecticidal activity of the isolated

  9. Insecticidal and antifeedant activities of clerodane diterpenoids isolated from the Indian bhant tree, Clerodendron infortunatum, against the cotton bollworm, Helicoverpa armigera.

    PubMed

    Abbaszadeh, Gholamreza; Srivastava, Chitra; Walia, Suresh

    2014-01-01

    The Indian bhant tree, Clerodendron infortunatum L. (Lamialus: Lamiaceae), is a well-known medicinal plant, but little information about its bioefficacy against agricultural pests exists. This scarcity was addressed in the present study, in which dried leaves of C. infortunatum were subjected to extraction with hexane and methanol and then partitioned using different solvents of varying polarity. In a preliminary bioassay, the antifeedant effects of the crude extracts and fractions were tested on a highly polyphagous pest, the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), using the no-choice test method with cabbage leaf discs. The methanol fraction resulted in maximum antifeedant activity. This fraction was further subjected to crystallization and column chromatography in order to isolate the compounds responsible for the activity. Three pure compounds were isolated and identified as clerodin (CL), 15-methoxy-14, 15-dihydroclerodin (MD), and 15-hydroxy-14, 15-dihyroclerodin (HD). The antifeedant activity of these compounds was studied using a choice as well as a no-choice test method with 24 and 48 hr observation periods. Insecticidal activity was measured using the topical application method at 0.5, 1, 1.5, 2, 2.5, and 3% concentrations, and data were recorded 24, 48, and 72 hr after treatment. In the no-choice test conditions, compounds CL and MD showed significantly higher antifeedant activity compared to the key ingredient in many commercial pesticides, azadirachtin, at its highest concentration. Compound HD also showed very good antifeedant activity, which did not differ significantly from that of azadirachtin. In the choice test conditions, all three compounds and azadirachtin showed 100% antifeedant activity at the highest concentration. Antifeedant Index (AI50) values of CL, MD, and HD were 6, 6, and 8 ppm in choice tests, and increased to 8, 9, and 11 ppm in the no-choice tests, respectively. Insecticidal activity of the isolated

  10. Impact of the Stem Extract of Thevetia neriifolia on the Feeding Potential and Histological Architecture of the Midgut Epithelial Tissue of Early Fourth Instars of Helicoverpa armigera Hübner

    PubMed Central

    Mishra, Monika; Gupta, Kamal Kumar; Kumar, Sarita

    2015-01-01

    Helicoverpa armigera Hübner is one of the most important agricultural crop pests in the world causing heavy crop yield losses. The continued and indiscriminate use of synthetic insecticides in agriculture for their control has received wide public apprehension because of multifarious problems, including insecticide resistance, resurgence of pest species, environmental pollution, and toxic hazards to humans and nontarget organisms. These problems have necessitated the need to explore and develop alternative strategies using eco-friendly and biodegradable plant products. In view of this, the efficacy of Thevetia neriifolia methanol stem extract was evaluated against the early fourth instars of H. armigera as an antifeedant and stomach poison agent. Feeding of larvae with the diet containing 0.005%–5.0% extract resulted in 2.06%–37.35% antifeedant index; the diet with 5.0% extract caused 54.3% reduced consumption. The negative impact of extract on larval feeding resulted in 37.5%–77.7% starvation, causing adverse effects on the larval weight. Choice between control and experimental diet resulted in feeding preference of larvae for the control diet, leading to 7.3%–42.9% reduced consumption of extract-containing diet. The only exception was the diet with 0.005% extract, which could not cause any deterrence. The midgut histological architecture of H. armigera larvae fed with 0.005%–0.05% extract-containing diet with negligible antifeedant potential showed significant damage, shrinkage, and distortion and vacuolization of gut tissues and peritrophic membrane, causing the disintegration of epithelial, goblet, and regenerative cells; the damage increased with the increase in concentration. These changes in the gut caused negative impact on the digestion and absorption of food and thus nutritional deficiency in the larvae, which could probably affect their growth and development. This study reveal the appreciable stomach poison potential of T. neriifolia stem

  11. Diversity of aminopeptidases, derived from four lepidopteran gene duplications, and polycalins expressed in the midgut of Helicoverpa armigera: Identification of proteins binding the δ-endotoxin, Cry1Ac of Bacillus thuringiensis

    PubMed Central

    Angelucci, Constanza; Barrett-Wilt, Gregory A.; Hunt, Donald F.; Akhurst, Raymond J.; East, Peter D.; Gordon, Karl H.J.; Campbell, Peter M.

    2010-01-01

    Helicoverpa armigera midgut proteins that bind the Bacillus thuringiensis (Bt) δ-endotoxin Cry1Ac were purified by affinity chromatography. SDS-PAGE showed that several proteins were eluted with N-acetylgalactosamine and no further proteins were detected after elution with urea. Tandem mass spectral data for tryptic peptides initially indicated that the proteins resembled aminopeptidases (APNs) from other lepidopterans and cDNA sequences for seven APNs were isolated from H. armigera through a combination of cloning with primers derived from predicted peptide sequences and established EST libraries. Phylogenetic analysis showed lepidopteran APN genes in nine clades of which five were part of a lepidopteran-specific radiation. The Cry1Ac-binding proteins were then identified with four of the seven HaAPN genes. Three of those four APNs are likely orthologs of APNs characterised as Cry1Ac-binding proteins in other lepidopterans. The fourth Cry1Ac-binding APN has orthologs not previously identified as Cry1Ac-binding partners. The HaAPN genes were expressed predominantly in the midgut through larval development. Each showed consistent expression along the length of the midgut but five of the genes were expressed at levels about two orders of magnitude greater than the remaining two. The remaining mass spectral data identified sequences encoding polycalin proteins with multiple lipocalin-like domains. A polycalin has only been previously reported in another lepidopteran, Bombyx mori, but polycalins in both species are now linked with binding of Bt Cry toxins. This is the first report of hybrid, lipocalin-like domains in shorter polycalin sequences that are not present in the longest sequence. We propose that these hybrid domains are generated by alternative splicing of the mRNA. PMID:18549954

  12. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding

    PubMed Central

    Chakroun, Maissa; Banyuls, Núria; Walsh, Tom; Downes, Sharon; James, Bill; Ferré, Juan

    2016-01-01

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past four seasons until 2014/15. Three new isofemale lines were determined to be allelic with previously isolated lines, suggesting that they belong to one common gene and this mechanism is relatively frequent. Vip3Aa-resistance does not confer cross-resistance to Cry1Ac or Cry2Ab. Vip3Aa was labeled with 125I and used to show specific binding to H. armigera brush-border membrane vesicles (BBMV). Binding was of high affinity (Kd = 25 and 19 nM for susceptible and resistant insects, respectively) and the concentration of binding sites was high (Rt = 140 pmol/mg for both). Despite the narrow-spectrum resistance, binding of 125I-labeled Vip3Aa to BBMV of resistant and susceptible insects was not significantly different. Proteolytic conversion of Vip3Aa protoxin into the activated toxin rendered the same products, though it was significantly slower in resistant insects. PMID:27095284

  13. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding.

    PubMed

    Chakroun, Maissa; Banyuls, Núria; Walsh, Tom; Downes, Sharon; James, Bill; Ferré, Juan

    2016-01-01

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past four seasons until 2014/15. Three new isofemale lines were determined to be allelic with previously isolated lines, suggesting that they belong to one common gene and this mechanism is relatively frequent. Vip3Aa-resistance does not confer cross-resistance to Cry1Ac or Cry2Ab. Vip3Aa was labeled with (125)I and used to show specific binding to H. armigera brush-border membrane vesicles (BBMV). Binding was of high affinity (Kd = 25 and 19 nM for susceptible and resistant insects, respectively) and the concentration of binding sites was high (Rt = 140 pmol/mg for both). Despite the narrow-spectrum resistance, binding of (125)I-labeled Vip3Aa to BBMV of resistant and susceptible insects was not significantly different. Proteolytic conversion of Vip3Aa protoxin into the activated toxin rendered the same products, though it was significantly slower in resistant insects. PMID:27095284

  14. Expression of recombinant and mosaic Cry1Ac receptors from Helicoverpa armigera and their influences on the cytotoxicity of activated Cry1Ac to Spodoptera litura Sl-HP cells.

    PubMed

    Xu, Peng; Islam, Mayira; Xiao, Yutao; He, Fei; Li, Yi; Peng, Jianxin; Hong, Huazhu; Liu, Chenxi; Liu, Kaiyu

    2016-05-01

    Bacillus thuringiensis (Bt) toxin receptors play important roles in the killing of pests, and investigation on characterization of the receptors is essential for utilization of Bt and management of insect resistance. Here, recombinant and mosaic receptors of Bt Cry1Ac toxin from Helicoverpa armigera were expressed in Spodoptera litura Sl-HP cells and their influences on cytotoxicity of activated Cry1Ac toxin were investigated. When H. armigera aminopeptidase N1 (APN1), alkaline phosphatase 2 (ALP2) and cadherin fused with or without GFP tag were, respectively, expressed in Sl-HP cells, live cell-immunofluorescence staining detection revealed that the quantity of the toxin binding to cadherin or cadherin-GFP was much more than that binding to ALP2 and APN1 or their fusion proteins with GFP, and only the cadherin- or cadherin-GFP-expressing cells showed aberrant cell morphology after the treatment of the toxin at low concentrations. ALP2 and APN1 fused with or without GFP tag did not significantly enhance the cadherin-mediated cytotoxicity of the toxin. The mosaic ALP-TBR-GFP-GPI was located on cell membrane, but did not bind to the toxin. The mosaic truncated cadherin-GFP-GPI was not located on cell membrane even if the signal peptide was sustained. The concentrations of the toxin resulting in swelling of 50 % cells for noncadherin-expressing Sl-HP cells and cadherin-expressing Hi5 cells were 5.08 and 9.50 µg/ml within 1 h, respectively. Taken together, our data have indicated that the binding affinity of ALP2 and APN1 to activated Cry1Ac toxin is much weaker than that of cadherin and both ALP2 and APN1 do not enhance the cytotoxicity of the toxin even though cadherin is co-expressed, and the mosaic receptor of ALP2 inserted with cadherin toxin binding domain does not mediate cytotoxicity of the toxin. In addition, the noncadherin-expressing Sl-HP cells are more susceptible to activated Cry1Ac than the cadherin-expressing Hi5 cells. PMID:25412589

  15. Proteomic Analysis of Mamestra Brassicae Nucleopolyhedrovirus Progeny Virions from Two Different Hosts

    PubMed Central

    Hou, Dianhai; Chen, Xi

    2016-01-01

    Mamestra brassicae nucleopolyhedrovirus (MabrNPV) has a wide host range replication in more than one insect species. In this study, a sequenced MabrNPV strain, MabrNPV-CTa, was used to perform proteomic analysis of both BVs and ODVs derived from two infected hosts: Helicoverpa armigera and Spodoptera exigua. A total of 82 and 39 viral proteins were identified in ODVs and BVs, respectively. And totally, 23 and 76 host proteins were identified as virion-associated with ODVs and BVs, respectively. The host proteins incorporated into the virus particles were mainly involved in cytoskeleton, signaling, vesicle trafficking, chaperone and metabolic systems. Some host proteins, such as actin, cyclophilin A and heat shock protein 70 would be important for viral replication. Several host proteins involved in immune response were also identified in BV, and a C-type lectin protein was firstly found to be associated with BV and its family members have been demonstrated to be involved in entry process of other viruses. This study facilitated the annotation of baculovirus genome, and would help us to understand baculovirus virion structure. Furthermore, the identification of host proteins associated with virions produced in vivo would facilitate investigations on the involvement of intriguing host proteins in virus replication. PMID:27058368

  16. The Lymantria dispar nucleopolyhedrovirus contains the capsid-associated p24 protein gene.

    PubMed

    Slavicek, James M; Hayes-Plazolles, Nancy

    2003-01-01

    During the course of investigations on a wild-type strain of Lymantria dispar multinucleocapsid nucleopolyhedrovirus (LdMNPV), a region of the viral genome was analyzed and found to contain 697 bp that is lacking in the sequenced strain (5-6) of LdMNPV (Kuzio et al., Virology 253, 17-34, 1999). The sequenced strain of LdMNPV contains a mutation in the 25 K few polyhedra (FP) gene, and exhibits the phenotype of a FP mutant. The additional sequence was located at approximately 81.4 map units within the viral genome, and was found in 10 different wild-type LdMNPV genotypic variants analyzed. Since the additional sequence wasfound in all wild-type virus strains analyzed, this sequence should be included in the representative LdMNPV genome. Sequence analysis of the genomic region containing the additional sequences revealed the presence of a homologue of the Autographa californica MNPV capsid-associated p24 gene (ORF 129). This gene, absent in LdMNPV isolate 5-6, is also present in the Orgyia pseudotsugata MNPV, Bombyx mori NPV, Spodoptera exigua MNPV, S. litura MNPV, Mamestra configurata MNPV, Helicoverpa armigera SNPV, H. zea SNPV, Buzura suppressaria SNPV, Xestia c-nigrum granulovirus, Plutella xylostella GV, and Cydia pomonella GV. PMID:12680688

  17. Proteomic Analysis of Mamestra Brassicae Nucleopolyhedrovirus Progeny Virions from Two Different Hosts.

    PubMed

    Hou, Dianhai; Chen, Xi; Zhang, Lei-Ke

    2016-01-01

    Mamestra brassicae nucleopolyhedrovirus (MabrNPV) has a wide host range replication in more than one insect species. In this study, a sequenced MabrNPV strain, MabrNPV-CTa, was used to perform proteomic analysis of both BVs and ODVs derived from two infected hosts: Helicoverpa armigera and Spodoptera exigua. A total of 82 and 39 viral proteins were identified in ODVs and BVs, respectively. And totally, 23 and 76 host proteins were identified as virion-associated with ODVs and BVs, respectively. The host proteins incorporated into the virus particles were mainly involved in cytoskeleton, signaling, vesicle trafficking, chaperone and metabolic systems. Some host proteins, such as actin, cyclophilin A and heat shock protein 70 would be important for viral replication. Several host proteins involved in immune response were also identified in BV, and a C-type lectin protein was firstly found to be associated with BV and its family members have been demonstrated to be involved in entry process of other viruses. This study facilitated the annotation of baculovirus genome, and would help us to understand baculovirus virion structure. Furthermore, the identification of host proteins associated with virions produced in vivo would facilitate investigations on the involvement of intriguing host proteins in virus replication. PMID:27058368

  18. Gut transcription in Helicoverpa zea is dynamically altered in response to baculovirus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Helicoverpa zea transcriptome was analyzed 24 hours after H. zea larvae fed on artificial diet laced with Helicoverpa zea single nucleopolyhedrovirus (HzSNPV). Significant differential regulation of 1,139 putative genes (P<0.05 T-test with Benjamini and Hochberg False Discovery Rate) was detect...

  19. Natural history and intragenomic dynamics of the Transib transposon Hztransib in the cotton bollworm Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hztransib recently identified from Helicoverpa zea represents the first intact and transcriptionally active Transib element. Its open reading frame was detected in H. armigera, from which H. zea evolved, and H. assulta, the common ancestor of H. zea and H. armigera. But its remaining parts were foun...

  20. Transcriptome sequencing of and microarray development for a Helicoverpa zea cell line to investigate in vitro insect cell-baculovirus interactions.

    PubMed

    Nguyen, Quan; Palfreyman, Robin W; Chan, Leslie C L; Reid, Steven; Nielsen, Lars K

    2012-01-01

    The Heliothine insect complex contains some of the most destructive pests of agricultural crops worldwide, including the closely related Helicoverpa zea and H. armigera. Biological control using baculoviruses is practiced at a moderate level worldwide. In order to enable more wide spread use, a better understanding of cell-virus interactions is required. While many baculoviruses have been sequenced, none of the Heliothine insect genomes have been available. In this study, we sequenced, assembled and functionally annotated 29,586 transcripts from cultured H. zea cells using Illumina 100 bps and paired-end transcriptome sequencing (RNA-seq). The transcript sequences had high assembly coverage (64.5 times). 23,401 sequences had putative protein functions, and over 13,000 sequences had high similarities to available sequences in other insect species. The sequence database was estimated to cover at least 85% of all H. zea genes. The sequences were used to construct a microarray, which was evaluated on the infection of H. zea cells with H. Armigera single-capsid nucleopolyhedrovirus (HearNPV). The analysis revealed that up-regulation of apoptosis genes is the main cellular response in the early infection phase (18 hours post infection), while genes linked to four major immunological signalling pathways (Toll, IMD, Jak-STAT and JNK) were down-regulated. Only small changes (generally downwards) were observed for central carbon metabolism. The transcriptome and microarray platform developed in this study represent a greatly expanded resource base for H. zea insect-HearNPV interaction studies, in which key cellular pathways such as those for metabolism, immune response, transcription and replication have been identified. This resource will be used to develop better cell culture-based virus production processes, and more generally to investigate the molecular basis of host range and susceptibility, virus infectivity and virulence, and the ecology and evolution of

  1. Efficacy of four traps in capturing male Helicoverpa moths in north Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species in the genus Helicoverpa include agricultural pests that attack a variety of crops worldwide. In North America, the most important species is H. zea but in the Eastern Hemisphere H. armigera is the most important species and is a threat to invade the U.S. USDA-APHIS-PPQ has an active trapp...

  2. Two year field study to evaluate the efficacy of Mamestra brassicae nucleopolyhedrovirus combined with proteins derived from Xestia c-nigrum granulovirus.

    PubMed

    Goto, Chie; Mukawa, Shigeyuki; Mitsunaga, Takayuki

    2015-03-01

    Japan has only three registered baculovirus biopesticides despite its long history of studies on insect viruses. High production cost is one of the main hindrances for practical use of baculoviruses. Enhancement of insecticidal effect is one possible way to overcome this problem, so there have been many attempts to develop additives for baculoviruses. We found that alkaline soluble proteins of capsules (GVPs) of Xestia c-nigrum granulovirus can increase infectivity of some viruses including Mamestra brassicae nucleopolyhedrovirus (MabrNPV), and previously reported that MabrNPV mixed with GVPs was highly infectious to three important noctuid pests of vegetables in the following order, Helicoverpa armigera, M. brassicae, and Autographa nigrisigna. In this study, small-plot experiments were performed to assess concentrations of MabrNPV and GVPs at three cabbage fields and a broccoli field for the control of M. brassicae. In the first experiment, addition of GVPs (10 µg/mL) to MabrNPV at 106 OBs/mL resulted in a significant increase in NPV infection (from 53% to 66%). In the second experiment, the enhancing effect of GVP on NPV infection was confirmed at 10-times lower concentrations of MabrNPV. In the third and fourth experiments, a 50% reduction in GVPs (from 10 µg/mL to 5 µg/mL) did not result in a lowering of infectivity of the formulations containing MabrNPV at 105 OBs/mL. These results indicate that GVPs are promising additives for virus insecticides. PMID:25760139

  3. Two Year Field Study to Evaluate the Efficacy of Mamestra brassicae Nucleopolyhedrovirus Combined with Proteins Derived from Xestia c-nigrum Granulovirus

    PubMed Central

    Goto, Chie; Mukawa, Shigeyuki; Mitsunaga, Takayuki

    2015-01-01

    Japan has only three registered baculovirus biopesticides despite its long history of studies on insect viruses. High production cost is one of the main hindrances for practical use of baculoviruses. Enhancement of insecticidal effect is one possible way to overcome this problem, so there have been many attempts to develop additives for baculoviruses. We found that alkaline soluble proteins of capsules (GVPs) of Xestia c-nigrum granulovirus can increase infectivity of some viruses including Mamestra brassicae nucleopolyhedrovirus (MabrNPV), and previously reported that MabrNPV mixed with GVPs was highly infectious to three important noctuid pests of vegetables in the following order, Helicoverpa armigera, M. brassicae, and Autographa nigrisigna. In this study, small-plot experiments were performed to assess concentrations of MabrNPV and GVPs at three cabbage fields and a broccoli field for the control of M. brassicae. In the first experiment, addition of GVPs (10 µg/mL) to MabrNPV at 106 OBs/mL resulted in a significant increase in NPV infection (from 53% to 66%). In the second experiment, the enhancing effect of GVP on NPV infection was confirmed at 10-times lower concentrations of MabrNPV. In the third and fourth experiments, a 50% reduction in GVPs (from 10 µg/mL to 5 µg/mL) did not result in a lowering of infectivity of the formulations containing MabrNPV at 105 OBs/mL. These results indicate that GVPs are promising additives for virus insecticides. PMID:25760139

  4. Efficacies of four pheromone-baited traps in capturing male Helicoverpa (Lepidoptera: Noctuidae) moths in northern Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Helicoverpa armigera (Hübner) is a serious pest of grain, row, and vegetable crops throughout much of the world, although it is currently not established in the United States. USDA-APHIS and the Cooperative Agricultural Pest Survey program are charged with the responsibility to monitor for this ins...

  5. Bio-potency of a 21 kDa Kunitz-type trypsin inhibitor from Tamarindus indica seeds on the developmental physiology of H. armigera.

    PubMed

    Pandey, Prabhash K; Jamal, Farrukh

    2014-11-01

    A trypsin inhibitor purified from the seeds of Tamarindus indica by Sephadex G-75, DEAE-Sepharose and Trypsin-Sepharose CL-4B columns was studied for its antifeedant, larvicidal, pupicidal and growth inhibitory activities against Helicoverpa armigera larvae. Tamarindus trypsin inhibitor (TTI) exhibited inhibitory activity towards total gut proteolytic enzymes of H. armigera (~87%) and bovine trypsin (~84%). Lethal doses which caused mortality and weight reduction by 50% were 1% w/w and 0.50% w/w, respectively. IC50 of TTI against Helicoverpa midgut proteases and bovine trypsin were ~2.10 µg/ml and 1.68 µg/ml respectively. In larval feeding studies the 21 kDa Kunitz-type protein was found to retard growth and development, prolonged the larval-pupal development durations along with adversely affecting the fertility and fecundity of H. armigera. In artificial diet at 0.5% w/w TTI, the efficiency of conversion of ingested food as well as of digested food, relative growth rate, growth index declined whereas approximate digestibility, metabolic cost, relative consumption rate, consumption index and total developmental period enhanced for H. armigera larvae. These results suggest that TTI has toxic and adverse effect on the developmental physiology of H. armigera and could be useful in controlling the pest H. armigera. PMID:25454525

  6. Evolution, ecology and management of resistance in Helicoverpa spp. to Bt cotton in Australia.

    PubMed

    Downes, Sharon; Mahon, Rod

    2012-07-01

    Prior to the widespread adoption of two-gene Bt cotton (Bollgard II®) in Australia, the frequency of resistance alleles to one of the deployed proteins (Cry2Ab) was at least 0.001 in the pests targeted namely, Helicoverpa armigera and Helicoverpa punctigera. In the 7 years hence, there has been a statistically significant increase in the frequency of alleles conferring Cry2Ab resistance in field populations of H. punctigera. This paper reviews the history of deploying Bt cotton in Australia, the characteristics of the isolated Cry2Ab resistance that likely impact on resistance evolution, aspects of the efficacy of Bollgard IIχ, and the behavioural ecology of Helicoverpa spp. larvae as it pertains to resistance management. It also presents up-to-date frequencies of resistant alleles for H. punctigera and reviews the same information for H. armigera. This is followed by a discussion of current resistance management strategies. The consequences of the imminent release of a third generation product that utilizes the novel vegetative insecticidal protein Vip3A are then considered. The area planted to Bt-crops is anticipated to continue to rise worldwide and many biotechnical companies intend to add Vip3A to existing products; therefore the information reviewed herein for Australia is likely to be pertinent to other situations. PMID:22537836

  7. Peripheral Coding of Sex Pheromone Blends with Reverse Ratios in Two Helicoverpa Species

    PubMed Central

    Huang, Ling-Qiao; Yan, Fu-Shun; Wang, Chen-Zhu

    2013-01-01

    The relative proportions of components in a pheromone blend play a major role in sexual recognition in moths. Two sympatric species, Helicoverpa armigera and Helicoverpa assulta, use (Z)-11-hexadecenal (Z11–16: Ald) and (Z)-9-hexadecenal (Z9–16: Ald) as essential sex pheromone components but in very different ratios, 97∶3 and 7∶93 respectively. Using wind tunnel tests, single sensillum recording and in vivo calcium imaging, we comparatively studied behavioral responses and physiological activities at the level of antennal sensilla and antennal lobe (AL) in males of the two species to blends of the two pheromone components in different ratios (100∶0, 97∶3, 50∶50, 7∶93, 0∶100). Z11–16: Ald and Z9–16: Ald were recognized by two populations of olfactory sensory neurons (OSNs) in different trichoid sensilla on antennae of both species. The ratios of OSNs responding to Z11–16:Ald and Z9–16:Ald OSNs were 100∶28.9 and 21.9∶100 in H. armigera and H. assulta, respectively. The Z11–16:Ald OSNs in H. armigera exhibited higher sensitivity and efficacy than those in H. assulta, while the Z9–16:Ald OSNs in H. armigera had the same sensitivity but lower efficacy than those in H. assulta. At the dosage of 10 µg, Z11–16: Ald and Z9–16: Ald evoked calcium activity in 8.5% and 3.0% of the AL surface in H. armigera, while 5.4% and 8.6% of AL in H. assulta, respectively. The calcium activities in the AL reflected the peripheral input signals of the binary pheromone mixtures and correlated with the behavioral output. These results demonstrate that the binary pheromone blends were precisely coded by the firing frequency of individual OSNs tuned to Z11–16: Ald or Z9–16: Ald, as well as their population sizes. Such information was then accurately reported to ALs of H. armigera and H. assulta, eventually producing different behaviors. PMID:23894593

  8. Peripheral coding of sex pheromone blends with reverse ratios in two helicoverpa species.

    PubMed

    Wu, Han; Hou, Chao; Huang, Ling-Qiao; Yan, Fu-Shun; Wang, Chen-Zhu

    2013-01-01

    The relative proportions of components in a pheromone blend play a major role in sexual recognition in moths. Two sympatric species, Helicoverpa armigera and Helicoverpa assulta, use (Z)-11-hexadecenal (Z11-16: Ald) and (Z)-9-hexadecenal (Z9-16: Ald) as essential sex pheromone components but in very different ratios, 97∶3 and 7∶93 respectively. Using wind tunnel tests, single sensillum recording and in vivo calcium imaging, we comparatively studied behavioral responses and physiological activities at the level of antennal sensilla and antennal lobe (AL) in males of the two species to blends of the two pheromone components in different ratios (100∶0, 97∶3, 50∶50, 7∶93, 0∶100). Z11-16: Ald and Z9-16: Ald were recognized by two populations of olfactory sensory neurons (OSNs) in different trichoid sensilla on antennae of both species. The ratios of OSNs responding to Z11-16:Ald and Z9-16:Ald OSNs were 100∶28.9 and 21.9∶100 in H. armigera and H. assulta, respectively. The Z11-16:Ald OSNs in H. armigera exhibited higher sensitivity and efficacy than those in H. assulta, while the Z9-16:Ald OSNs in H. armigera had the same sensitivity but lower efficacy than those in H. assulta. At the dosage of 10 µg, Z11-16: Ald and Z9-16: Ald evoked calcium activity in 8.5% and 3.0% of the AL surface in H. armigera, while 5.4% and 8.6% of AL in H. assulta, respectively. The calcium activities in the AL reflected the peripheral input signals of the binary pheromone mixtures and correlated with the behavioral output. These results demonstrate that the binary pheromone blends were precisely coded by the firing frequency of individual OSNs tuned to Z11-16: Ald or Z9-16: Ald, as well as their population sizes. Such information was then accurately reported to ALs of H. armigera and H. assulta, eventually producing different behaviors. PMID:23894593

  9. Transcriptome comparison of the sex pheromone glands from two sibling Helicoverpa species with opposite sex pheromone components

    PubMed Central

    Li, Zhao-Qun; Zhang, Shuai; Luo, Jun-Yu; Wang, Chun-Yi; Lv, Li-Min; Dong, Shuang-Lin; Cui, Jin-Jie

    2015-01-01

    Differences in sex pheromone component can lead to reproductive isolation. The sibling noctuid species, Helicoverpa armigera and Helicoverpa assulta, share the same two sex pheromone components, Z9-16:Ald and Z11-16:Ald, but in opposite ratios, providing an typical example of such reproductive isolation. To investigate how the ratios of the pheromone components are differently regulated in the two species, we sequenced cDNA libraries from the pheromone glands of H. armigera and H. assulta. After assembly and annotation, we identified 108 and 93 transcripts putatively involved in pheromone biosynthesis, transport, and degradation in H. armigera and H. assulta, respectively. Semi-quantitative RT-PCR, qRT-PCR, phylogenetic, and mRNA abundance analyses suggested that some of these transcripts involved in the sex pheromone biosynthesis pathways perform. Based on these results, we postulate that the regulation of desaturases, KPSE and LPAQ, might be key factor regulating the opposite component ratios in the two sibling moths. In addition, our study has yielded large-scale sequence information for further studies and can be used to identify potential targets for the bio-control of these species by disrupting their sexual communication. PMID:25792497

  10. Sensillar expression and responses of olfactory receptors reveal different peripheral coding in two Helicoverpa species using the same pheromone components

    PubMed Central

    Chang, Hetan; Guo, Mengbo; Wang, Bing; Liu, Yang; Dong, Shuanglin; Wang, Guirong

    2016-01-01

    Male moths efficiently recognize conspecific sex pheromones thanks to their highly accurate and specific olfactory system. The Heliothis/Helicoverpa species are regarded as good models for studying the perception of sex pheromones. In this study, we performed a series of experiments to investigate the peripheral mechanisms of pheromone coding in two-closely related species, Helicoverpa armigera and H. assulta. The morphology and distribution patterns of sensilla trichoidea are similar between the two species when observed at the scanning electron microscope, but their performances are different. In H. armigera, three functional types of sensilla trichoidea (A, B and C) were found to respond to different pheromone components, while in H. assulta only two types of such sensilla (A and C) could be detected. The response profiles of all types of sensilla trichoidea in the two species well matched the specificities of the pheromone receptors (PRs) expressed in the same sensilla, as measured in voltage-clamp experiments. The expressions of PRs in neighboring olfactory sensory neurons (OSNs) within the same trichoid sensillum were further confirmed by in situ hybridization. Our results show how the same pheromone components can code for different messages at the periphery of two Helicoverpa species. PMID:26744070

  11. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigers to Bt Soybean in Brazil

    PubMed Central

    Bacalhau, Fabiana B.; Amado, Douglas; Carvalho, Renato A.; Martinelli, Samuel; Head, Graham P.; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL−1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  12. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigers to Bt Soybean in Brazil.

    PubMed

    Dourado, Patrick M; Bacalhau, Fabiana B; Amado, Douglas; Carvalho, Renato A; Martinelli, Samuel; Head, Graham P; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL-1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  13. Frequency of Bt resistance alleles in H. armigera during 2006-2008 in Northern China.

    PubMed

    Gao, Yulin; Wu, Kongming; Gould, Fred

    2009-08-01

    Helicoverpa armigera is an important lepidopteran pest of cotton in China. From 2002, the frequency of Bt resistance alleles and quantitative shifts in larval Cry1Ac tolerance of field H. armigera population were monitored using bioassays of F(1) and F(2) offspring of isofemale lines from Xiajin County of Shandong Province (an intensive Bt cotton planting area) and Anci County of Hebei Province (a multiple-crop system including corn, soybean, peanut, and Bt cotton) in northern China. During 2006-2008, a total of 2,306 isofemale lines from the Xiajin population and a total of 1,270 isofemale lines from the Anci population were successfully screened on Cry1Ac diets. For each year, it was estimated that the major resistance gene frequency in Xiajin population in 2006, 2007, and 2008 was 0, 0.00022, and 0.00033, respectively. No major alleles conferring resistance to Cry1Ac were found in the Anci population; the frequency of resistance alleles for Cry1Ac was 0. Based on the relative average development rates (RADRs) of H. armigera larvae in F(1) tests, no substantial increase in Cry1Ac tolerance was found in either location over the 3-yr period. There were also significantly positive correlations between RADR of lines in the F(1) generation and the RADR of their F(2) offspring, indicating genetic variation in response to toxin. The low frequency of resistance alleles found in this study and in our previous results from 2002 to 2005 suggest the frequency of resistance alleles has remained low and that natural refugia resistance management strategy maybe effective for delaying resistance evolution in H. armigera to Bt cotton in northern China. PMID:19689916

  14. Sequence similarity and functional comparisons of pheromone receptor orthologs in two closely related Helicoverpa species.

    PubMed

    Jiang, Xiao-Jing; Guo, Hao; Di, Chang; Yu, Shanlin; Zhu, Ligui; Huang, Ling-Qiao; Wang, Chen-Zhu

    2014-05-01

    The olfactory system of moth species in subfamily Heliothinae is an attractive model to study the evolution of the pheromone reception because they show distinct differentiation in sex pheromone components or ratios that activate pheromone receptors (PRs). However, functional assessment of PRs in closely related species remains largely untried. Here we present a special cloning strategy to isolate full-length cDNAs encoding candidate odorant receptors (ORs) from Helicoverpa armigera (Harm) and Helicoverpa assulta (Hass) on the basis of Heliothis virescens ORs, and investigate the functional properties of PRs to determine how the evolution of moth PRs contribute to intraspecific mating choice and speciation extension. We cloned 11 OR orthologs from H. armigera and 10 from H. assulta. We functionally characterized the responses of PRs of both species to seven pheromone compounds using the heterologous expression system of Xenopus ooctyes. HassOR13 was found to be highly tuned to the sex pheromone component Z11-16:Ald, and unexpectedly, both HarmOR14b and HassOR16 were specific for Z9-14:Ald. However, HarmOR6 and HassOR6 showed much higher specificity to Z9-16:OH than to Z9-16:Ald or Z9-14:Ald. HarmOR11, HarmOR14a, HassOR11 and HassOR14b failed to respond to the tested chemicals. Based on our results and previous research, we can show that some PR orthologs from H. armigera, H. assulta and H. virescens such as OR13s have similar ligand selectivity, but others have different ligand specificity. The combined PR function and sex pheromone component analysis suggests that the evolution of PRs can meet species-specific demands. PMID:24632377

  15. A host-plant specialist, Helicoverpa assulta, is more tolerant to capsaicin from Capsicum annuum than other noctuid species.

    PubMed

    Ahn, Seung-Joon; Badenes-Pérez, Francisco R; Heckel, David G

    2011-09-01

    Plant secondary compounds not only play an important role in plant defense, but have been a driving force for host adaptation by herbivores. Capsaicin (8-methyl-N-vanillyl-6-nonenamide), an alkaloid found in the fruit of Capsicum spp. (Solanaceae), is responsible for the pungency of hot pepper fruits and is unique to the genus. The oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae), is a specialist herbivore feeding on solanaceous plants including Capsicum annuum, and is one of a very few insect herbivores worldwide capable of feeding on hot pepper fruits. To determine whether this is due in part to an increased physiological tolerance of capsaicin, we compared H. assulta with another specialist on Solanaceae, Heliothis subflexa, and four generalist species, Spodoptera frugiperda, Heliothis virescens, Helicoverpa armigera, and Helicoverpa zea, all belonging to the family Noctuidae. When larvae were fed capsaicin-spiked artificial diet for the entire larval period, larval mortality increased in H. subflexa and H. zea but decreased in H. assulta. Larval growth decreased on the capsaicin-spiked diet in four of the species, was unaffected in H. armigera and increased in H. assulta. Food consumption and utilization experiments showed that capsaicin decreased relative consumption rate (RCR), relative growth rate (RGR) and approximate digestibility (AD) in H. zea, and increased AD and the efficiency of conversion of ingested food (ECI) in H. armigera; whereas it did not significantly change any of these nutritional indices in H. assulta. The acute toxicity of capsaicin measured by injection into early fifth instar larvae was less in H. assulta than in H. armigera and H. zea. Injection of high concentrations produced abdominal paralysis and self-cannibalism. Injection of sub-lethal doses of capsaicin resulted in reduced pupal weights in H. armigera and H. zea, but not in H. assulta. The results indicate that H. assulta is more tolerant to capsaicin than

  16. History and Current Status of Development and Use of Viral Insecticides in China

    PubMed Central

    Sun, Xiulian

    2015-01-01

    The use of insect viruses as biological control agents started in the early 1960s in China. To date, more than 32 viruses have been used to control insect pests in agriculture, forestry, pastures, and domestic gardens in China. In 2014, 57 products from 11 viruses were authorized as commercial viral insecticides by the Ministry of Agriculture of China. Approximately 1600 tons of viral insecticidal formulations have been produced annually in recent years, accounting for about 0.2% of the total insecticide output of China. The development and use of Helicoverpa armigera nucleopolyhedrovirus, Mamestra brassicae nucleopolyhedrovirus, Spodoptera litura nucleopolyhedrovirus, and Periplaneta fuliginosa densovirus are discussed as case studies. Additionally, some baculoviruses have been genetically modified to improve their killing rate, infectivity, and ultraviolet resistance. In this context, the biosafety assessment of a genetically modified Helicoverpa armigera nucleopolyhedrovirus is discussed. PMID:25609304

  17. Biology, Ecology, and Evolving Management of Helicoverpa zea (Lepidoptera: Noctuidae) in Sweet Corn in the United States.

    PubMed

    Olmstead, Daniel L; Nault, Brian A; Shelton, Anthony M

    2016-08-01

    The corn earworm, Helicoverpa zea (Boddie), is a polyphagous pest found throughout the United States, where it attacks many field and vegetable crops. Although H. zea has long been a traditional pest of sweet corn, its importance to this crop has increased dramatically over the past two decades. In this review, we summarize information critical for current and future management of H. zea in sweet corn production in the United States. First, we discuss the pest status of H. zea and its life history, including migration, infestation and larval development, diapause, overwintering, and abiotic factors that affect its biology. Next we describe monitoring methods, crop protection decision-making processes, chemical control options, and the use of genetic technologies for control of H. zea Alternative H. zea management options including biological control, cultural controls, host plant resistance, and pheromone disruption are also reviewed. The role of climate change and its effects on H. zea and its ecology are discussed, as well as the recent invasion of its relative, Helicoverpa armigera (Hübner), which is a major pest of corn in other parts of the world. To conclude, we suggest future research opportunities for H. zea and H. armigera management in sweet corn. PMID:27329622

  18. Specific olfactory neurons and glomeruli are associated to differences in behavioral responses to pheromone components between two Helicoverpa species.

    PubMed

    Wu, Han; Xu, Meng; Hou, Chao; Huang, Ling-Qiao; Dong, Jun-Feng; Wang, Chen-Zhu

    2015-01-01

    Sex pheromone communication of moths helps to understand the mechanisms underlying reproductive isolation and speciation. Helicoverpa armigera and Helicoverpa assulta use (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as pheromone components in reversed ratios, 97:3 and 5:95, respectively. H. armigera also produces trace amount of (Z)-9-tetradecenal (Z9-14:Ald) in the sex pheromone gland, but H. assulta does not. Wind tunnel studies revealed that the addition of small amounts (0.3%) of Z9-14:Ald to the main pheromone blend of H. armigera increased the males' attraction, but at higher doses (1%, 10%) the same compound acted as an inhibitor. In H. assulta, Z9-14:Ald reduced male attraction when presented as 1% to the pheromone blend, but was ineffective at lower concentrations (0.3%). Three types (A-C) of sensilla trichodea in antennae were identified by single sensillum recording, responding to Z11-16:Ald, Z9-14:Ald, and both Z9-16:Ald and Z9-14:Ald, respectively. Calcium imaging in the antennal lobes (ALs) revealed that the input information of the three chemicals was transmitted to three units of the macroglomerular complex (MGC) in ALs in both species: a large glomerulus for the major pheromone components, a small one for the minor pheromone components, and a third one for the behavioral antagonists. The type A and C neurons tuned to Z11-16:Ald and Z9-16:Ald had a reversed target in the MGC between the two species. In H. armigera, low doses (1, 10 μg) of Z9-14:Ald dominantly activated the glomerulus which processes the minor pheromone component, while a higher dose (100 μg) also evoked an equal activity in the antagonistic glomerulus. In H. assulta, instead, Z9-14:Ald always strongly activated the antagonistic glomerulus. These results suggest that Z9-14:Ald plays different roles in the sexual communication of two Helicoverpa species through activation of functionally different olfactory pathways. PMID:26300751

  19. Specific olfactory neurons and glomeruli are associated to differences in behavioral responses to pheromone components between two Helicoverpa species

    PubMed Central

    Wu, Han; Xu, Meng; Hou, Chao; Huang, Ling-Qiao; Dong, Jun-Feng; Wang, Chen-Zhu

    2015-01-01

    Sex pheromone communication of moths helps to understand the mechanisms underlying reproductive isolation and speciation. Helicoverpa armigera and Helicoverpa assulta use (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as pheromone components in reversed ratios, 97:3 and 5:95, respectively. H. armigera also produces trace amount of (Z)-9-tetradecenal (Z9-14:Ald) in the sex pheromone gland, but H. assulta does not. Wind tunnel studies revealed that the addition of small amounts (0.3%) of Z9-14:Ald to the main pheromone blend of H. armigera increased the males' attraction, but at higher doses (1%, 10%) the same compound acted as an inhibitor. In H. assulta, Z9-14:Ald reduced male attraction when presented as 1% to the pheromone blend, but was ineffective at lower concentrations (0.3%). Three types (A–C) of sensilla trichodea in antennae were identified by single sensillum recording, responding to Z11-16:Ald, Z9-14:Ald, and both Z9-16:Ald and Z9-14:Ald, respectively. Calcium imaging in the antennal lobes (ALs) revealed that the input information of the three chemicals was transmitted to three units of the macroglomerular complex (MGC) in ALs in both species: a large glomerulus for the major pheromone components, a small one for the minor pheromone components, and a third one for the behavioral antagonists. The type A and C neurons tuned to Z11-16:Ald and Z9-16:Ald had a reversed target in the MGC between the two species. In H. armigera, low doses (1, 10 μg) of Z9-14:Ald dominantly activated the glomerulus which processes the minor pheromone component, while a higher dose (100 μg) also evoked an equal activity in the antagonistic glomerulus. In H. assulta, instead, Z9-14:Ald always strongly activated the antagonistic glomerulus. These results suggest that Z9-14:Ald plays different roles in the sexual communication of two Helicoverpa species through activation of functionally different olfactory pathways. PMID:26300751

  20. Gut Transcription in Helicoverpa zea is Dynamically Altered in Response to Baculovirus Infection

    PubMed Central

    Noland, Jeffrey E.; Breitenbach, Jonathan E.; Popham, Holly J. R.; Hum-Musser, Sue M.; Vogel, Heiko; Musser, Richard O.

    2013-01-01

    The Helicoverpa zea transcriptome was analyzed 24 h after H. zea larvae fed on artificial diet laced with Helicoverpa zea single nucleopolyhedrovirus (HzSNPV). Significant differential regulation of 1,139 putative genes (p < 0.05 T-test with Benjamini and Hochberg False Discovery Rate) was detected in the gut epithelial tissue; where 63% of these genes were down-regulated and 37% of genes were up-regulated compared to the mock-infected control. Genes that play important roles in digestive physiology were noted as being generally down-regulated. Among these were aminopeptidases, trypsin-like serine proteases, lipases, esterases and serine proteases. Genes related to the immune response reacted in a complex nature having peptidoglycan binding and viral antigen recognition proteins and antiviral pathway systems down-regulated, whereas antimicrobial peptides and prophenoloxidase were up-regulated. In general, detoxification genes, specifically cytochrome P450 and glutathione S-transferase were down-regulated as a result of infection. This report offers the first comparative transcriptomic study of H. zea compared to HzSNPV infected H. zea and provides further groundwork that will lead to a larger understanding of transcriptional perturbations associated with viral infection and the host response to the viral insult in what is likely the most heavily infected tissue in the insect. PMID:26462433

  1. Three pheromone-binding proteins help segregation between two Helicoverpa species utilizing the same pheromone components.

    PubMed

    Guo, Hao; Huang, Ling-Qiao; Pelosi, Paolo; Wang, Chen-Zhu

    2012-09-01

    The two sibling species Helicoverpa armigera and Helicoverpa assulta utilise the same two aldehydes as their sex pheromones, but in opposite ratios. In both species three odorant-binding proteins (OBPs) can be classified as pheromone-binding proteins (PBPs). To investigate the role of these three PBPs in chemical communication between sexes and their mode of action, we have expressed the proteins in bacteria and prepared mutants lacking their C-terminal regions. Using polyclonal antibodies we found that the expression of the three PBPs is basically confined to the antennae of both sexes and both species. Binding experiments with the fluorescent probe N-phenyl-1-naphthylamine across a pH range indicated that, the affinity of wild-type proteins decreases at low pH, while that of the mutants is not or less affected, suggesting that a conformational change of the C-terminus occurs in these proteins, as reported for other lepidopteran OBPs. All three proteins bind with similar strength both pheromone components, as well as their corresponding alcohols and acetates. However, they exhibit significant selectivity to linear alcohols and aldehydes of different length, with optimal affinities to the ligand of 13-15 carbon atoms for PBP1 and 12-14 carbon atoms for PBP2. We suggest that all three PBPs might cooperate to build a unique olfactory image, that could help avoiding cross-mating between the two species and with other noctuids. PMID:22750167

  2. A tale of two trapping methods: Helicoverpa spp. (Lepidoptera, Noctuidae) in pheromone and light traps in Australian cotton production systems.

    PubMed

    Baker, G H; Tann, C R; Fitt, G P

    2011-02-01

    Pheromone and light traps have often been used in ecological studies of two major noctuid pests of agriculture in Australia, Helicoverpa armigera and H. punctigera. However, results from these two methods have rarely been compared directly. We set pheromone and light traps adjacent to or amongst cotton and various other crops for 10-11 years in the Namoi Valley, in northern New South Wales, Australia. Catches in pheromone traps suggested a major peak in (male) numbers of H. punctigera in early spring, with relatively few moths caught later in the summer cropping season. In contrast, (male) H. armigera were most abundant in late summer. Similar trends were apparent for catches of both male and female H. armigera in light traps, but both sexes of H. punctigera were mostly caught in mid-summer. For both species, males were more commonly caught than females. These catch patterns differed from some previous reports. At least three generations of both species were apparent in the catches. There was some evidence that the abundance of later generations could be predicted from the size of earlier generations; but, unlike previous authors, we found no positive relationships between local winter rainfall and subsequent catches of moths, nor did we find persuasive evidence of correlations between autumn and winter rainfall in central Australia and the abundance of subsequent 1st generation H. punctigera moths. Female H. punctigera were consistently more mature (gravid) and more frequently mated than those of H. armigera. Overall, our results highlight the variability in trap catches of these two species and question the use of trap catches and weather as predictors of future abundance in cropping regions. PMID:20504387

  3. Binding Site Alteration Is Responsible for Field-Isolated Resistance to Bacillus thuringiensis Cry2A Insecticidal Proteins in Two Helicoverpa Species

    PubMed Central

    Caccia, Silvia; Hernández-Rodríguez, Carmen Sara; Mahon, Rod J.; Downes, Sharon; James, William; Bautsoens, Nadine; Van Rie, Jeroen; Ferré, Juan

    2010-01-01

    Background Evolution of resistance by target pests is the main threat to the long-term efficacy of crops expressing Bacillus thuringiensis (Bt) insecticidal proteins. Cry2 proteins play a pivotal role in current Bt spray formulations and transgenic crops and they complement Cry1A proteins because of their different mode of action. Their presence is critical in the control of those lepidopteran species, such as Helicoverpa spp., which are not highly susceptible to Cry1A proteins. In Australia, a transgenic variety of cotton expressing Cry1Ac and Cry2Ab (Bollgard II) comprises at least 80% of the total cotton area. Prior to the widespread adoption of Bollgard II, the frequency of alleles conferring resistance to Cry2Ab in field populations of Helicoverpa armigera and Helicoverpa punctigera was significantly higher than anticipated. Colonies established from survivors of F2 screens against Cry2Ab are highly resistant to this toxin, but susceptible to Cry1Ac. Methodology/Principal Findings Bioassays performed with surface-treated artificial diet on neonates of H. armigera and H. punctigera showed that Cry2Ab resistant insects were cross-resistant to Cry2Ae while susceptible to Cry1Ab. Binding analyses with 125I-labeled Cry2Ab were performed with brush border membrane vesicles from midguts of Cry2Ab susceptible and resistant insects. The results of the binding analyses correlated with bioassay data and demonstrated that resistant insects exhibited greatly reduced binding of Cry2Ab toxin to midgut receptors, whereas no change in 125I-labeled-Cry1Ac binding was detected. As previously demonstrated for H. armigera, Cry2Ab binding sites in H. punctigera were shown to be shared by Cry2Ae, which explains why an alteration of the shared binding site would lead to cross-resistance between the two Cry2A toxins. Conclusion/Significance This is the first time that a mechanism of resistance to the Cry2 class of insecticidal proteins has been reported. Because we found the same

  4. Genomic diversity of Bombyx mori nucleopolyhedrovirus strains.

    PubMed

    Xu, Yi-Peng; Cheng, Ruo-Lin; Xi, Yu; Zhang, Chuan-Xi

    2013-07-01

    Bombyx mori nucleopolyhedrovirus (BmNPV) is a baculovirus that selectively infects the domestic silkworm. In this study, six BmNPV strains were compared at the whole genome level. We found that the number of bro genes and the composition of the homologous regions (hrs) are the two primary areas of divergence within these genomes. When we compared the ORFs of these BmNPV variants, we noticed a high degree of sequence divergence in the ORFs that are not baculovirus core genes. This result is consistent with the results derived from phylogenetic trees and evolutionary pressure analyses of these ORFs, indicating that ORFs that are not core genes likely play important roles in the evolution of BmNPV strains. The evolutionary relationships of these BmNPV strains might be explained by their geographic origins or those of their hosts. In addition, the total number of hr palindromes seems to affect viral DNA replication in Bm5 cells. PMID:23639478

  5. Complete Mitochondrial Genome of Helicoverpa zea (Lepidoptera: Noctuidae) and Expression Profiles of Mitochondrial-Encoded Genes in Early and Late Embryos.

    PubMed

    Perera, Omaththage P; Walsh, Thomas K; Luttrell, Randall G

    2016-01-01

    The mitochondrial genome (mitogenome) of the bollworm, Helicoverpa zea (Boddie), was assembled using paired-end nucleotide sequence reads generated with a next-generation sequencing platform. Assembly resulted in a mitogenome of 15,348 bp with greater than 17,000-fold average coverage. Organization of the H. zea mitogenome (gene order and orientation) was identical to other known lepidopteran mitogenome sequences. Compared with Helicoverpa armigera (Hübner) mitogenome, there were a few differences in the lengths of gaps between genes, but the lengths of nucleotide overlaps were essentially conserved between the two species. Nucleotide composition of the H. zea mitochondrial genome was very similar to those of the related species H. armigera and Helicoverpa punctigera Wallengren. Mapping of RNA-Seq reads obtained from 2-h eggs and 48-h embryos to protein coding genes (PCG) revealed that all H. zea PCGs were processed as single mature gene transcripts except for the bicistronic atp8 + atp6 transcript. A tRNA-like sequence predicted to form a hammer-head-like secondary structure that may play a role in transcription start and mitogenome replication was identified within the control region of the H. zea mitogenome. Similar structures were also found within the control regions of several other lepidopteran species. Expression analysis revealed significant differences in levels of expression of PCGs within each developmental stage, but the pattern of variation was similar in both developmental stages analyzed in this study. Mapping of RNA-Seq reads to PCG transcripts also identified transcription termination and polyadenylation sites that differed from the sites described in other lepidopteran species. PMID:27126963

  6. Complete Mitochondrial Genome of Helicoverpa zea (Lepidoptera: Noctuidae) and Expression Profiles of Mitochondrial-Encoded Genes in Early and Late Embryos

    PubMed Central

    Perera, Omaththage P.; Walsh, Thomas K.; Luttrell, Randall G.

    2016-01-01

    The mitochondrial genome (mitogenome) of the bollworm, Helicoverpa zea (Boddie), was assembled using paired-end nucleotide sequence reads generated with a next-generation sequencing platform. Assembly resulted in a mitogenome of 15,348 bp with greater than 17,000-fold average coverage. Organization of the H. zea mitogenome (gene order and orientation) was identical to other known lepidopteran mitogenome sequences. Compared with Helicoverpa armigera (Hübner) mitogenome, there were a few differences in the lengths of gaps between genes, but the lengths of nucleotide overlaps were essentially conserved between the two species. Nucleotide composition of the H. zea mitochondrial genome was very similar to those of the related species H. armigera and Helicoverpa punctigera Wallengren. Mapping of RNA-Seq reads obtained from 2-h eggs and 48-h embryos to protein coding genes (PCG) revealed that all H. zea PCGs were processed as single mature gene transcripts except for the bicistronic atp8 + atp6 transcript. A tRNA-like sequence predicted to form a hammer-head-like secondary structure that may play a role in transcription start and mitogenome replication was identified within the control region of the H. zea mitogenome. Similar structures were also found within the control regions of several other lepidopteran species. Expression analysis revealed significant differences in levels of expression of PCGs within each developmental stage, but the pattern of variation was similar in both developmental stages analyzed in this study. Mapping of RNA-Seq reads to PCG transcripts also identified transcription termination and polyadenylation sites that differed from the sites described in other lepidopteran species. PMID:27126963

  7. Comparative insecticidal properties of two nucleopolyhedrovirus vectors encoding a similar toxin gene chimer.

    PubMed

    Treacy, M F; Rensner, P E; All, J N

    2000-08-01

    Laboratory, greenhouse and field studies were conducted to characterize the insecticidal properties of genetically altered forms of Autographa californica (Speyer) nucleopolyhedrovirus (AcNPV) and Helicoverpa zea (Boddie) NPV (HzNPV) against selected heliothine species. The altered viruses each contained a chimeric 0.8-kb fragment encoding the insect-specific, sodium channel neurotoxin from the Algerian scorpion Androctonus australis Hector (AaIT, hence recombinant viruses designated Ac-AaIT and Hz-AaIT). Based on LD50 values, results from diet-overlay bioassays showed Ac-AaIT and Hz-AaIT to be equally virulent against larval tobacco budworm, Heliothis virescens (F.), but Hz-AaIT averaged 1,335-fold greater bioactivity than Ac-AaIT against larval cotton bollworm, Helicoverpa zea (Boddie). Hz-AaIT killed larvae of both heliothine species at rates significantly faster than those imparted by HzNPV (viral LT50 values averaged 2.5 and 5.6 d, respectively). In greenhouse studies, foliar sprays of Ac-AaIT and Hz-AaIT were equally effective in controlling H. virescens on cotton; however, Hz-AaIT provided control of H. zea on cotton at a level superior to that of Ac-AaIT. For example, after three weekly sessions of foliar application and H. zea artificial infestation, cotton treated with Ac-AaIT or Hz-AaIT at 10 x 10(11) occulsion bodies (OB)/ha averaged 2.5 and 16.2 nondamaged flower buds per plant, respectively. Another greenhouse study conducted against heliothine species on cotton showed that the quicker killing speed exhibited by Hz-AaIT led to improved plant protection versus HzNPV. Finally, results from three field trials demonstrated that Hz-AaIT at 5-12 x 10(11) OB/ha provided control of the heliothine complex in cotton at levels slightly better than Bacillus thuringiensis, equal to the macrolide, spinosad, and only slightly less than that of selected pyrethroid and carbamate insecticides. Overall, results from these studies indicate that, because of host range

  8. Characterization of a single-nucleocapsid nucleopolyhedrovirus of Thysanoplusia orichalcea L. (Lepidoptera: Noctuidae) from Indonesia.

    PubMed

    Cheng, X W; Carner, G R

    2000-05-01

    A single-nucleocapsid nucleopolyhedrovirus (NPV) isolated from Thysanoplusia orichalcea L. (Lepidoptera:Noctuidae) (ThorNPV) in Indonesia has tetrahedral occlusion bodies (OBs) with a width of 1. 22 microm (range = 0.803-1.931 microm). The length of the virion with an envelope averaged 0.29 and 0.23 microm without an envelope. ThorNPV was propagated in Pseudoplusia includens (Walker) and its authenticity was confirmed by sequence analysis of the polyhedrin gene of the ThorNPV produced in T. orichalcea and P. includens. Polyhedrin amino acid sequence analysis revealed that ThorNPV belongs to Group II of baculoviruses and is closely related to Trichoplusia ni single nucleocapsid NPV, sharing 97.6% sequence identity. Infectivity of ThorNPV against third instar P. includens was low, with a LD(50) value of 65,636 OBs/larva. Electron microscopy of infected tissues showed many polyhedra without virions embedded, which might explain the low virulence against P. includens. Differences in virion occlusion rates between individual cells in the same tissue suggested that the inoculum consisted of at least two variants that differed in the gene(s) controlling virion occlusion. In a host range test using the LD(50) value to P. includens against Spodoptera exigua, S. frugiperda, S. eridania, Anticarsia gemmatalis, Helicoverpa zea, Trichoplusia ni, and P. includens, P. includens was the only species infected. The virus infected primarily the fat body, tracheal epithelium, and hypodermis. The genomic size of the ThorNPV is 135 kb. PMID:10843835

  9. Biological and molecular characterization of a multicapsid nucleopolyhedrovirus from Thysanoplusia orichalcea (L.) (Lepidoptera: Noctuidae).

    PubMed

    Cheng, Xiao-Wen; Carner, Gerald R; Lange, Martin; Jehle, Johannes A; Arif, Basil M

    2005-02-01

    A multicapsid nucleopolyhedrovirus (ThorMNPV) that was co-isolated with a single nucleocapid ThorSNPV from mixed infected larvae of Thysanoplusia orichalcea L. (Lepidoptea: Noctuidae) is characterized. Scanning electron microscopy of ThorMNPV showed a dodecahedral-shaped occlusion body (OB). The occluded virions contained one to as many as eight nucleocapsids/virion. Virion band profiles in gradient centrifugation were consistent in at least 10 rounds of centrifugation from different virion sample preparations. The ThorMNPV had high virulence to third instar Trichoplusia ni and Pseudoplusia includens with LD50 values of 17 and 242OBs per larva, respectively. However, ThorMNPV did not cause mortality in Spodoptera exigua, Spodoptera frugiperda, Spodoptera eridania, Anticarsia gemmatalis, and Helicoverpa zea. ThorMNPV replicates in cells of various tissues such as the fat body and tracheal epithelium cells. T. ni High 5 cells were permissive to ThorMNPV in terms of infection and viral DNA transfection, but SF-21 was less permissive and the infection process was slower. Production of OBs by ThorMNPV in the nuclei of SF-21 was not well pronounced. The genome size of ThorMNPV was estimated to be 136 kb. The polyhedrin gene open reading frame (ORF) was cloned and completely sequenced. The promoter sequence is identical to that of Autographa californica MNPV. Phylogenetic analyses using partial sequences of the polh, lef-8, and lef-9 revealed that ThorMNPV is a member of the Group I NPVs and is related but distinct from the AcMNPV/Rachiplusia ou NPV/Bombyx mori NPV cluster. PMID:15766929

  10. The influence of a 21 kDa Kunitz-type trypsin inhibitor from nonhost madras thorn, Pithecellobium dulce, seeds on H. armigera (Hübner) (Lepidoptera: Noctuidae).

    PubMed

    Pandey, Prabhash K; Singh, Dushyant; Jamal, Farrukh

    2015-05-01

    A trypsin inhibitor purified from the seeds of the Manila tamarind, Pithecellobium dulce (PDTI), was studied for its effects on growth parameters and developmental stages of Helicoverpa armigera. PDTI exhibited inhibitory activity against bovine trypsin (∼86%; ∼1.33 ug/ml IC50). The inhibitory activity of PDTI was unaltered over a wide range of temperature, pH, and in the presence of dithiothreitol. Larval midgut proteases were unable to digest PDTI for up to 12 h of incubation. Dixon and Lineweaver-Burk double reciprocal plots analysis revealed a competitive inhibition mechanism and a Ki of ∼3.9 × 10(-8) M. Lethal dose (0.50% w/w) and dosage for weight reduction by 50% (0.25% w/w) were determined. PDTI showed a dose-dependent effect on mean larval weight and a series of nutritional disturbances. In artificial diet at 0.25% w/w PDTI, the efficiency of conversion of ingested food, of digested food, relative growth rate, and growth index declined, whereas approximate digestibility, relative consumption rate, metabolic cost, consumption index, and total developmental period were increased in larvae. This is the first report of antifeedant and antimetabolic activities of PDTI on midgut proteases of H. armigera. PMID:25580830

  11. Frequency of alleles conferring resistance to the Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in Australian populations of Helicoverpa punctigera (Lepidoptera: Noctuidae) from 2002 to 2006.

    PubMed

    Downes, S; Parker, T L; Mahon, R J

    2009-04-01

    Helicoverpa punctigera and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are important pests of field and horticultural crops in Australia. The former is endemic to the continent, whereas the latter is also distributed in Africa and Asia. Although H. armigera rapidly developed resistance to virtually every group of insecticide used against it, there is only one report of resistance to an insecticide in H. punctigera. In 1996 the Australian cotton industry adopted Ingard, which expresses the Bacillus thuringiensis (Bt) toxin gene cry1Ac. In 2004/2005, Bollgard II (which expresses Cry1Ac and Cry2Ab) replaced Ingard and has subsequently been grown on 80% of the area planted to cotton, Gossypium hirsutum L. From 2002/2003 to 2006/2007, F2 screens were used to detect resistance to Cry1Ac or Cry2Ab. We detected no alleles conferring resistance to Cry1Ac; the frequency was < 0.0005 (n = 2,180 alleles), with a 95% credibility interval between 0 and 0.0014. However, during the same period, we detected alleles that confer resistance to Cry2Ab at a frequency of 0.0018 (n = 2,192 alleles), with a 95% credibility interval between 0.0005 and 0.0040. For both toxins, the experiment-wise detection probability was 94%, i.e., if there actually was a resistance allele in any tested lines, we would have detected it 94% of the time. The first isolation of Cry2Ab resistance in H. punctigera was before the widespread deployment of Bollgard II. This finding supports our published notion for H. armigera that alleles conferring resistance to Cry2Ab may be present at detectable frequencies in populations before selection by transgenic crops. PMID:19449655

  12. Characteristics of resistance to Bacillus thuringiensis toxin Cry2Ab in a strain of Helicoverpa punctigera (Lepidoptera: Noctuidae) isolated from a field population.

    PubMed

    Downes, S; Parker, T L; Mahon, R J

    2010-12-01

    In 1996, the Australian cotton industry adopted Ingard that expresses the Bacillus thuringiensis (Bt) toxin gene cry1Ac and was planted at a cap of 30%. In 2004-2005, Bollgard II, which expresses cry1Ac and cry2Ab, replaced Ingard in Australia, and subsequently has made up >80% of the area planted to cotton, Gossypium hirsutum L. The Australian target species Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) are innately moderately tolerant to Bt toxins, but the absence of a history of insecticide resistance indicates that the latter species is less likely to develop resistance to Bt cotton. From 2002-2003 to 2006-2007, F2 screens were deployed to detect resistance to CrylAc or Cry2Ab in natural populations of H. punctigera. Alleles that conferred an advantage against CrylAc were not detected, but those that conferred resistance to Cry2Ab were present at a frequency of 0.0018 (n = 2,192 alleles). Importantly, the first isolation of Cry2Ab resistance in H. punctigera occurred before significant opportunities to develop resistance in response to Bollgard II. We established a colony (designated Hp4-13) consisting of homozygous resistant individuals and examined their characteristics through comparison with individuals from a Bt-susceptible laboratory colony. Through specific crosses and bioassays, we established that the resistance present in Hp4-13 is due to a single autosomal gene. The resistance is fully recessive. Homozygotes are able to survive a dose of Cry2Ab toxin that is 15 times the reported concentration in field grown Bollgard II in Australia (500 microg/ml) and are fully susceptible to Cry1Ac and to the Bt product DiPel. These characteristics are the same as those described for the first Cry2Ab resistant strain of H. armigera isolated from a field population in Australia. PMID:21309238

  13. Sequence and Organization of the Neodiprion lecontei Nucleopolyhedrovirus Genome

    PubMed Central

    Lauzon, Hilary A. M.; Lucarotti, Christopher J.; Krell, Peter J.; Feng, Qili; Retnakaran, Arthur; Arif, Basil M.

    2004-01-01

    All fully sequenced baculovirus genomes, with the exception of the dipteran Culex nigripalpus nucleopolyhedrovirus (CuniNPV), have previously been from Lepidoptera. This study reports the sequencing and characterization of a hymenopteran baculovirus, Neodiprion lecontei nucleopolyhedrovirus (NeleNPV), from the redheaded pine sawfly. NeleNPV has the smallest genome so far published (81,755 bp) and has a GC content of only 33.3%. It contains 89 potential open reading frames, 43 with baculovirus homologues, 6 identified by conserved domains, and 1 with homology to a densovirus structural protein. Average amino acid identity of homologues ranged from 19.7% with CuniNPV to 24.9% with Spodoptera exigua nucleopolyhedrovirus. The conserved set of baculovirus genes has dropped to 29, since NeleNPV lacks an F protein homologue (ac23/ld130). NeleNPV contains 12 conserved lepidopteran baculovirus genes, including that for DNA binding protein, late expression factor 11 (lef-11), polyhedrin, occlusion derived virus envelope protein-18 (odv-e18), p40, and p45, but lacks 21 others, including lef-3, me53, immediate early gene-1, lef-6, pp31, odv-e66, few polyhedra 25k, odv-e25, protein kinase-1, fibroblast growth factor, and ubiquitin. The lack of identified baculovirus homologues may be due to difficulties in identification, differences in host-virus interactions, or other genes performing similar functions. Gene parity plots showed limited colinearity of NeleNPV with other baculoviruses, and phylogenetic analysis indicates that NeleNPV may have existed before the lepidopteran nucleopolyhedrovirus and granulovirus divergence. The creation of two new Baculoviridae genera to fit hymenopteran and dipteran baculoviruses may be necessary. PMID:15194779

  14. Expression in Antennae and Reproductive Organs Suggests a Dual Role of an Odorant-Binding Protein in Two Sibling Helicoverpa Species

    PubMed Central

    Sun, Ya-Lan; Huang, Ling-Qiao; Pelosi, Paolo; Wang, Chen-Zhu

    2012-01-01

    Odorant-binding proteins (OBPs) mediate both perception and release of semiochemicals in insects. These proteins are the ideal targets for understanding the olfactory code of insects as well as for interfering with their communication system in order to control pest species. The two sibling Lepidopteran species Helicoverpa armigera and H. assulta are two major agricultural pests. As part of our aim to characterize the OBP repertoire of these two species, here we focus our attention on a member of this family, OBP10, particularly interesting for its expression pattern. The protein is specifically expressed in the antennae of both sexes, being absent from other sensory organs. However, it is highly abundant in seminal fluid, is transferred to females during mating and is eventually found on the surface of fertilised eggs. Among the several different volatile compounds present in reproductive organs, OBP10 binds 1-dodecene, a compound reported as an insect repellent. These results have been verified in both H. armigera and H. assulta with no apparent differences between the two species. The recombinant OBP10 binds, besides 1-dodecene, some linear alcohols and several aromatic compounds. The structural similarity of OBP10 with OBP1 of the mosquito Culex quinquefasciatus, a protein reported to bind an oviposition pheromone, and its affinity with 1-dodecene suggest that OBP10 could be a carrier for oviposition deterrents, favouring spreading of the eggs in these species where cannibalism is active among larvae. PMID:22291900

  15. Genomic sequence analysis of a nucleopolyhedrovirus isolated from the diamondback moth, Plutella xylostella.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The CL3 plaque isolate of Plutella xylostella multiple nucleopolyhedrovirus (PlxyMNPV-CL3) is a variant of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) but exhibits a much higher degree of virulence against the diamondback moth, Plutella xylostella. To identify genetic differences ...

  16. Genomic sequence analysis of the Illinois strain of the Agrotis ipsilon multiple nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Agrotis ipsilon multiple nucleopolyhedrovirus (AgipMNPV) is a group II nucleopolyhedrovirus (NPV) from the black cutworm, A. ipsilon, with potential as a biopesticide to control infestations of cutworm larvae. The genome of the Illinois strain of AgipMNPV was completely sequenced. The AgipMNPV...

  17. Gene transduction in mammalian cells using Bombyx mori nucleopolyhedrovirus assisted by glycoprotein 64 of Autographa californica multiple nucleopolyhedrovirus

    PubMed Central

    Kato, Tatsuya; Sugioka, Saki; Itagaki, Kohei; Park, Enoch Y.

    2016-01-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV), an alphabaculovirus, has been widely utilized for protein expression in not only insect cells but also mammalian cells. AcMNPV is closely related to Bombyx mori nucleopolyhedrovirus (BmNPV), and nucleotide sequences of AcMNPV genes have high similarity with those of BmNPV. However, the transduction of BmNPV into mammalian cells has not been reported. In this study, we constructed a recombinant BmNPV (BmNPVΔbgp/AcGP64/EGFP) whose surface 64 kDa glycoprotein (BmGP64) was substituted with that from AcMNPV (AcGP64). BmNPVΔbgp/AcGP64/EGFP also carried an EGFP gene under the control of the CMV promoter. BmNPVΔbgp/AcGP64/EGFP successfully transduced HEK293T cells. In comparison, a control construct (BmNPVΔbgp/BmGP64/EGFP) which possessed BmGP64 instead of AcGP64 did not express EGFP in HEK293T cells. The transduction efficiency of BmNPVΔbgp/AcGP64/EGFP was lower than that of an AcMNPV based-BacMam GFP transduction control. This result indicates that AcGP64 facilitates BmNPV transduction into HEK293T cells. BmNPV can be prepared easily on a large scale because BmNPV can infect silkworm larvae without any special equipment, even though specific diet is needed for silkworm rearing. BmNPV gene transduction into mammalian cells can potentially be applied easily for gene delivery into mammalian cells. PMID:27562533

  18. Geographic isolates of Lymantria dispar multiple nucleopolyhedrovirus: Genome sequence analysis and pathogenicity against European and Asian gypsy moth strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Geographic isolates of Lymantria dispar multiple nucleopolyhedrovirus: Genome sequence analysis and pathogenicity against European and Asian gypsy moth strains. To evaluate the genetic diversity of Lymantria dispar nucleopolyhedrovirus (LdMNPV) at the genomic level, the genomes of three isolates of...

  19. Helicoverpa zea and Bt Cotton in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Helicoverpa zea (Boddie), the bollworm or corn earworm, is the most important lepidopteran pest of Bt cotton in the United States. Corn is the preferred host, but the insect feeds on most flowering crops and wild host plants. As a cotton pest, bollworm has been closely linked to the insecticide-res...

  20. Genomic Sequencing and Analysis of Sucra jujuba Nucleopolyhedrovirus

    PubMed Central

    Liu, Xiaoping; Yin, Feifei; Zhu, Zheng; Hou, Dianhai; Wang, Jun; Zhang, Lei; Wang, Manli; Wang, Hualin; Hu, Zhihong; Deng, Fei

    2014-01-01

    The complete nucleotide sequence of Sucra jujuba nucleopolyhedrovirus (SujuNPV) was determined by 454 pyrosequencing. The SujuNPV genome was 135,952 bp in length with an A+T content of 61.34%. It contained 131 putative open reading frames (ORFs) covering 87.9% of the genome. Among these ORFs, 37 were conserved in all baculovirus genomes that have been completely sequenced, 24 were conserved in lepidopteran baculoviruses, 65 were found in other baculoviruses, and 5 were unique to the SujuNPV genome. Seven homologous regions (hrs) were identified in the SujuNPV genome. SujuNPV contained several genes that were duplicated or copied multiple times: two copies of helicase, DNA binding protein gene (dbp), p26 and cg30, three copies of the inhibitor of the apoptosis gene (iap), and four copies of the baculovirus repeated ORF (bro). Phylogenetic analysis suggested that SujuNPV belongs to a subclade of group II alphabaculovirus, which differs from other baculoviruses in that all nine members of this subclade contain a second copy of dbp. PMID:25329074

  1. Penaeus monodon nucleopolyhedrovirus detection using an immunochromatographic strip test.

    PubMed

    Wangman, Pradit; Longyant, Siwaporn; Chaivisuthangkura, Parin; Sridulyakul, Pattarin; Rukpratanporn, Sombat; Sithigorngul, Paisarn

    2012-08-01

    An immunochromatographic strip test is described for detection of the polyhedrin protein of Penaeus monodon nucleopolyhedrovirus (PemoNPV). The test employs one monoclonal antibody (MAb MBV5) conjugated to colloidal gold to bind to polyhedrin protein and a 1:1:1 mixture of 3 other MAbs (MBV8, 14 and 21) to capture colloidal-gold MAb-protein complexes at a test (T) line on the nitrocellulose strip. A downstream control (C) line of goat anti-mouse immunoglobulin G (GAM) antibody is used to capture excess free colloidal-gold conjugated MBV5 to validate test performance. Heating of homogenates of PemoNPV-infected P. monodon postlarvae prepared in PBS for 30min was necessary to maximize T line color intensity, and homogenates of infected postlarvae could still be scored as PemoNPV-positive when diluted 1:64. A strip test result was obtained within 15min of sample application, and although about 200-fold lower than a one-step PCR test for PemoNPV, its detection sensitivity was comparable to a dot blot. Due to its simplicity not reliant on sophisticated equipment or specialized skills, the strip test could be adopted to screen easily for PemoNPV infections at shrimp hatcheries and farms. PMID:22580094

  2. A Lysine at the C-Terminus of an Odorant-Binding Protein is Involved in Binding Aldehyde Pheromone Components in Two Helicoverpa Species

    PubMed Central

    Sun, Ya-Lan; Huang, Ling-Qiao; Pelosi, Paolo; Wang, Chen-Zhu

    2013-01-01

    Odorant-binding proteins (OBPs) are soluble proteins, whose role in olfaction of insects is being recognized as more and more important. We have cloned, expressed and purified an OBP (HarmOBP7) from the antennae of the moth Helicoverpa armigera. Western blot experiments indicate specific expression of this protein in the antennae of adults. HarmOBP7 binds both pheromone components Z-11-hexadecenal and Z-9-hexadecenal with good affinity. We have also performed a series of binding experiments with linear aldehydes, alcohols and esters, as well as with other compounds and found a requirement of medium size for best affinity. The affinity of OBP7, as well as that of a mutant lacking the last 6 residues does not substantially decrease in acidic conditions, but increases at basic pH values with no significant differences between wild-type and mutant. Binding to both pheromone components, instead, is negatively affected by the lack of the C-terminus. A second mutant, where one of the three lysine residues in the C-terminus (Lys123) was replaced by methionine showed reduced affinity to both pheromone components, as well as to their analogues, thus indicating that Lys123 is involved in binding these compounds, likely forming hydrogen bonds with the functional groups of the ligands. PMID:23372826

  3. Adaptive management of pest resistance by Helicoverpa species (Noctuidae) in Australia to the Cry2Ab Bt toxin in Bollgard II® cotton

    PubMed Central

    Downes, Sharon; Mahon, Rodney J; Rossiter, Louise; Kauter, Greg; Leven, Tracey; Fitt, Gary; Baker, Geoff

    2010-01-01

    In Australia, monitoring Helicoverpa species for resistance to the Cry2Ab toxin in second generation Bacillus thuringiensis (Bt) cotton has precisely fulfilled its intended function: to warn of increases in resistance frequencies that may lead to field failures of the technology. Prior to the widespread adoption of two-gene Bt cotton, the frequency of Cry2Ab resistance alleles was at least 0.001 in H. armigera and H. punctigera. In the 5 years hence, there has been a significant and apparently exponential increase in the frequency of alleles conferring Cry2Ab resistance in field populations of H. punctigera. Herein we review the history of deploying and managing resistance to Bt cotton in Australia, outline the characteristics of the isolated resistance that likely impact on resistance evolution, and use a simple model to predict likely imminent resistance frequencies. We then discuss potential strategies to mitigate further increases in resistance frequencies, until the release of a third generation product. These include mandating larger structured refuges, applying insecticide to crops late in the season, and restricting the area of Bollgard II® cotton. The area planted to Bt-crops is anticipated to continue to rise worldwide; therefore the strategies being considered in Australia are likely to relate to other situations. PMID:25567948

  4. Adaptive management of pest resistance by Helicoverpa species (Noctuidae) in Australia to the Cry2Ab Bt toxin in Bollgard II® cotton.

    PubMed

    Downes, Sharon; Mahon, Rodney J; Rossiter, Louise; Kauter, Greg; Leven, Tracey; Fitt, Gary; Baker, Geoff

    2010-09-01

    In Australia, monitoring Helicoverpa species for resistance to the Cry2Ab toxin in second generation Bacillus thuringiensis (Bt) cotton has precisely fulfilled its intended function: to warn of increases in resistance frequencies that may lead to field failures of the technology. Prior to the widespread adoption of two-gene Bt cotton, the frequency of Cry2Ab resistance alleles was at least 0.001 in H. armigera and H. punctigera. In the 5 years hence, there has been a significant and apparently exponential increase in the frequency of alleles conferring Cry2Ab resistance in field populations of H. punctigera. Herein we review the history of deploying and managing resistance to Bt cotton in Australia, outline the characteristics of the isolated resistance that likely impact on resistance evolution, and use a simple model to predict likely imminent resistance frequencies. We then discuss potential strategies to mitigate further increases in resistance frequencies, until the release of a third generation product. These include mandating larger structured refuges, applying insecticide to crops late in the season, and restricting the area of Bollgard II® cotton. The area planted to Bt-crops is anticipated to continue to rise worldwide; therefore the strategies being considered in Australia are likely to relate to other situations. PMID:25567948

  5. Effects of spinosad and neem on the efficacy of a nucleopolyhedrovirus on pickleworm larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A neem formulation (Neemix® 4.5) and spinosad (SpinTor® 2SC) were tested for their effects when mixed with the multicapsid nucleopolyhedrovirus virus (AgMNPV) from the velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), for control of pickleworm larvae, Diaphania nitidalis...

  6. Plant Phenolics as Radiation Protectants For The Beet Armyworm (Lepidoptera: Noctuidae) Nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirteen phenolics were tested as ultraviolet (UV) protectants for the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner). After 30 minute exposure to UVB/UVB radiation, eleven SeMNPV/phenolic combinations provided good to excellent UV protection when used at a concentra...

  7. Genomic sequence analysis of a fast-killing isolate of the Spodoptera frugiperda multiple nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Six clones of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) were plaque-purified from field isolates collected in Missouri, USA. In bioassays, four of the plaque-purified isolates killed neonate S. frugiperda larvae more rapidly than the field isolates from which they were derived, w...

  8. Complete Genome Sequence of a Western Siberian Lymantria dispar Multiple Nucleopolyhedrovirus Isolate.

    PubMed

    Kabilov, Marsel R; Martemyanov, Vyacheslav V; Tupikin, Alexey E; Baturina, Olga A; Belousova, Irina A; Bondar, Alexander A; Ilyinykh, Alexandr V

    2015-01-01

    A novel strain of Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV-27) was isolated from dead larvae of a Western Siberian (WS) population of gypsy moths (Lymantria dispar L.). We report the complete genome sequence of this strain, comprising 164,108 bp and double-stranded circular DNA encoding 162 predicted open reading frames. PMID:25908142

  9. Proteins associated with Culex nigripalpus Nucleopolyhedrovirus (CuniNPV) occluded virions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Occlusion derived virions (ODVs) of the nucleopolyhedrovirus of Culex nigripalpus (CuniNPV) were purified by sucrose density gradient ultracentrifugation and the proteins were separated on SDS-PAGE and isolated. Proteins were identified using Edman sequencing, matrix assisted laser desorption/ioniza...

  10. Determination and analysis of the genome sequence of Spodoptera littoralis multiple nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Spodoptera littoralis multiple nucleopolyhedrovirus (SpliMNPV), a pathogen of the Egyptian cotton leaf worm Spodoptera littoralis, was subjected to sequencing of its entire DNA genome and bioassay analysis comparing its virulence to that of other baculoviruses. The annotated SpliMNPV genome of...

  11. Genomic sequence analysis of a nucleopolyhedrovirus isolated from the diamondback moth, Plutella xylostella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The CL3 plaque isolate of Plutella xylostella multiple nucleopolyhedrovirus (PlxyMNPV-CL3) exhibits a high degree of genetic similarity with the Autographa californica MNPV but is significantly more virulent against the diamondback moth, P. xylostella, than AcMNPV. To identify genetic differences b...

  12. Genetic and biological variation among nucleopolyhedrovirus isolates from spodoptera frugiperda (lepidotpera: noctuidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A PCR-based method was used to identify and distinguish among 40 uncharacterized nucleopolyhedrovirus (NPV) isolates from the moth Spodoptera frugiperda that were part of an insect virus collection. Phylogenetic analysis was carried out with sequences amplified from two strongly conserved loci (pol...

  13. Comparative infectivity of homologous and heterologous nucleopolyhedroviruses against beet armyworm larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homologous and heterologous nucleopolyhedroviruses (NPVs) were assayed to determine the most effective NPV against beet armyworm larvae, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)(SeMNPV). Included were three isolates from S. exigua, one isolate each from S. littoralis Boisduval, S. litura...

  14. Genomic sequencing and analyses of Lymantria xylina multiple nucleopolyhedrovirus

    PubMed Central

    2010-01-01

    Background Outbreaks of the casuarina moth, Lymantria xylina Swinehoe (Lepidoptera: Lymantriidae), which is a very important forest pest in Taiwan, have occurred every five to 10 years. This moth has expanded its range of host plants to include more than 65 species of broadleaf trees. LyxyMNPV (L. xylina multiple nucleopolyhedrovirus) is highly virulent to the casuarina moth and has been investigated as a possible biopesticide for controlling this moth. LdMNPV-like virus has also been isolated from Lymantria xylina larvae but LyxyMNPV was more virulent than LdMNPV-like virus both in NTU-LY and IPLB-LD-652Y cell lines. To better understand LyxyMNPV, the nucleotide sequence of the LyxyMNPV DNA genome was determined and analysed. Results The genome of LyxyMNPV consists of 156,344 bases, has a G+C content of 53.4% and contains 157 putative open reading frames (ORFs). The gene content and gene order of LyxyMNPV were similar to those of LdMNPV, with 151 ORFs identified as homologous to those reported in the LdMNPV genome. Two genes (Lyxy49 and Lyxy123) were homologous to other baculoviruses, and four unique LyxyMNPV ORFs (Lyxy11, Lyxy19, Lyxy130 and Lyxy131) were identified in the LyxyMNPV genome, including a gag-like gene that was not reported in baculoviruses. LdMNPV contains 23 ORFs that are absent in LyxyMNPV. Readily identifiable homologues of the gene host range factor-1 (hrf-1), which appears to be involved in the susceptibility of L. dispar to NPV infection, were not present in LyxyMNPV. Additionally, two putative odv-e27 homologues were identified in LyxyMNPV. The LyxyMNPV genome encoded 14 bro genes compared with 16 in LdMNPV, which occupied more than 8% of the LyxyMNPV genome. Thirteen homologous regions (hrs) were identified containing 48 repeated sequences composed of 30-bp imperfect palindromes. However, they differed in the relative positions, number of repeats and orientation in the genome compared to LdMNPV. Conclusion The gene parity plot analysis

  15. Biosafety of recombinant and wild type nucleopolyhedroviruses as bioinsecticides.

    PubMed

    Ashour, Mohamed-Bassem; Ragheb, Didair A; El-Sheikh, El-Sayed A; Gomaa, El-Adarosy A; Kamita, Shizuo G; Hammock, Bruce D

    2007-06-01

    The entomopathogenic Autographa californica (Speyer) nucleopolyhedrovirus (AcMNPV) has been genetically modified to increase its speed of kill. The potential adverse effects of a recombinant AcMNPV (AcAaIT) as well as wild type AcMNPV and wild type Spodoptera littoralis NPV (SlNPV) were studied. Cotton plants were treated with these viruses at concentrations that were adjusted to resemble the recommended field application rate (4 x 10(12) PIBs/feddan, feddan = 4,200 m2) and 3rd instar larvae of S. littoralis were allowed to feed on the contaminated plants. SDS-PAGE, ELISA, and DNA analyses were used to confirm that larvae that fed on these plants were virus-infected. Polyhedra that were purified from the infected larvae were subjected to structural protein analysis. A 32 KDa protein was found in polyhedra that were isolated from all of the viruses. Subtle differences were found in the size and abundance of ODV proteins. Antisera against polyhedral proteins isolated from AcAaIT polyhedra were raised in rabbits. The terminal bleeds from rabbits were screened against four coating antigens (i.e., polyhedral proteins from AcAaIT, AcAaIT from field-infected larvae (AcAaIT-field), AcMNPV, and SlNPV) using a two-dimensional titration method with the coated antigen format. Competitive inhibition experiments were conducted in parallel to optimize antibody and coating antigen concentrations for ELISA. The IC50 values for each combination ranged from 1.42 to 163 microg/ml. AcAaIT-derived polyhedrin gave the lowest IC50 value, followed by those of SlNPV, AcAaIT-field, and AcMNPV. The optimized ELISA system showed low cross reactivity for AcMNPV (0.87%), AcAaIT-field (1.2%), and SlNPV (4.0%). Genomic DNAs isolated from AcAaIT that were passaged in larvae of S. littoralis that were reared in the laboratory or field did not show any detectable differences. Albino rats (male and female) that were treated with AcAaIT, AcMNPV or SlNPV (either orally or by intraperitoneal injection at

  16. Characterization of an Egyptian Spodoptera littoralis nucleopolyhedrovirus and a possible use of a highly conserved region from polyhedrin gene for nucleopolyhedrovirus detection

    PubMed Central

    Seufi, AlaaEddeen M

    2008-01-01

    An Egyptian isolate of Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) was tested for its potential as biocontrol agent in comparison to Autographa californica multiple nucleopolyhedrovirus (AcMNPV). Comparative assays of SpliNPV and AcMNPV against 2nd instar larvae of Spodoptera littoralis revealed 4-fold greater susceptibility of S. littoralis to AcMNPV than to SpliNPV based on LC50 values for the two viruses. The LT50s determined for SpliNPV and AcMNPV using LC50 of the virus against 2nd instar larvae were 4.2 and 5.8 days, respectively. A DNA segment of 405 bp containing highly conserved region from polyhedrin gene of SpliNPV (Polh-cr) was successfully amplified by PCR. Subsequently, this DNA segment was cloned and sequenced. Nucleotide sequence and its deduced amino acid sequence were compared to all available sequences in GenBank. Sequence alignment results revealed that Polh-cr showed significant similarities with 91 different baculovirus isolates. The percentage of homology ranged from 78% for Plusia orichalcea NPV to 99% for SpliNPV. This highly conserved region provides a candidate that could be used in easy, fast and economic prospective systems for virus detection as well as in biological control strategies. PMID:18215282

  17. Chemosensory receptor genes in the Oriental tobacco budworm Helicoverpa assulta.

    PubMed

    Xu, W; Papanicolaou, A; Liu, N-Y; Dong, S-L; Anderson, A

    2015-04-01

    The Oriental tobacco budworm (Helicoverpa assulta) is a specialist herbivore moth and its larvae feed on Solanaceous plants. (Z)-9-hexadecenal (Z9-16: Ald) is the major sex pheromone component in H. assulta but the specific pheromone receptor (PR) against Z9-16: Ald has not yet been identified. In the present study, we integrated transcriptomic, bioinformatic and functional characterization approaches to investigate the chemosensory receptor genes of H. assulta. We identified seven potential PRs with 44 olfactory receptors, 18 gustatory receptors and 24 ionotropic receptors, which were further studied by in silico gene expression profile, phylogenetic analysis, reverse transcription PCR and calcium imaging assays. The candidate PR, HassOR13, showed a strong response to the minor sex pheromone component, (Z)-11-hexadecenal, but not the major component, Z9-16: Ald, in calcium imaging assays. This study provides the molecular basis for comparative studies of chemosensory receptors between H. assulta and other Helicoverpa species and will advance our understanding of the evolution and function of Lepidoptera insect chemosensation. PMID:25430896

  18. Bacterial but not Baculoviral Infections Stimulate Hemolin Expression in Helicoverpa zea and Heliothis virescens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lepidopteran larvae are regularly infected by baculoviruses during feeding on infected plants. The differences in sensitivity to these infections can be substantial, even among closely related species. For example, the noctuids Cotton bollworm (Helicoverpa zea) and budworm (Heliothis virescens), whi...

  19. The Expression of Three Opsin Genes from the Compound Eye of Helicoverpa armigera (Lepidoptera: Noctuidae) Is Regulated by a Circadian Clock, Light Conditions and Nutritional Status

    PubMed Central

    Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Zhang, Xinfang; Li, Zhen; Liu, Xiaoxia; Zhang, Qingwen

    2014-01-01

    Visual genes may become inactive in species that inhabit poor light environments, and the function and regulation of opsin components in nocturnal moths are interesting topics. In this study, we cloned the ultraviolet (UV), blue (BL) and long-wavelength-sensitive (LW) opsin genes from the compound eye of the cotton bollworm and then measured their mRNA levels using quantitative real-time PCR. The mRNA levels fluctuated over a daily cycle, which might be an adaptation of a nocturnal lifestyle, and were dependent on a circadian clock. Cycling of opsin mRNA levels was disturbed by constant light or constant darkness, and the UV opsin gene was up-regulated after light exposure. Furthermore, the opsin genes tended to be down-regulated upon starvation. Thus, this study illustrates that opsin gene expression is determined by multiple endogenous and exogenous factors and is adapted to the need for nocturnal vision, suggesting that color vision may play an important role in the sensory ecology of nocturnal moths. PMID:25353953

  20. Effects of different Brush Border Membrane Vesicle isolation protocols on proteomic analysis of Cry1Ac binding proteins from the midgut of Helicoverpa armigera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The brush border membrane vesicles (BBMV) isolated from midgut cells of insect have been widely used for studying of the binding receptors and action mode of Cry proteins produced by Bacillus thuringiensis (Bt). There are several methods for isolating insect BBMV used in one-dimension electrophoresi...

  1. The autographa californica multiple nucleopolyhedrovirus ODV-E56 envelope protein is required for oral infectivity and can be functionally substituted by rachiplusia ou multiple nucleopolyhedrovirus ODV-E56

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) odv-e56 gene encodes an occlusion-derived virus (ODV)-specific envelope protein, ODV-E56. In a previous analysis, the odv-e56 gene was found to be under positive selection pressure, suggesting that it may be a determinant of viral ho...

  2. Genetic variation and biological activity of isolates of lymantria dispar multiple nucleopolyhedrovirus from north america, europe, and asia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about genetic variation of Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV; Baculoviridae: Alphabaculovirus) at the nucleotide sequence level. To obtain a more comprehensive view of genetic diversity among isolates of LdMNPV, partial sequences of the lef-8 gene were generated...

  3. A soluble form of P74 can act as a per os infectivity factor to the autographa californica multiple nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The baculovirus occlusion-derived virion (ODV) is required to spread virus infection among insect hosts via the per os route. The Autographa californica Multicapsid Nucleopolyhedrovirus (AcMNPV) P74 protein is an ODV envelope protein that is essential for ODVs to be infectious. P74 is anchored in ...

  4. Field Evaluation of a Kudzu/Cottonseed Oil Formulation on the Persistence of the Beet Armyworm Nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A plant extract (kudzu) was tested as a UV protectant for SeMNPV, with and without the addition of an oil/emulsifier (cottonseed oil/lecithin) formulation. Aqueous and oil emulsion formulations of the beet armyworm, Spodoptera exigua (Hübner), nucleopolyhedrovirus SeMNPV were applied to collards an...

  5. Complete Genome Sequence of the Strain of Lymantria dispar Multiple Nucleopolyhedrovirus Found in the Gypsy Moth Biopesticide Virin-ENSh.

    PubMed

    Harrison, Robert L; Rowley, Daniel L

    2015-01-01

    We report the genome sequence of an alphabaculovirus from the gypsy moth (Lymantria dispar) biopesticide Virin-ENSh. The genome sequence is 161,712 bp, and its structure and sequence similarity indicate that the virus used in Virin-ENSh is a strain of the species Lymantria dispar multiple nucleopolyhedrovirus. PMID:25593255

  6. Concentration- and time-response characteristics of plaque isolates of Agrotis ipsilon multiple nucleopolyhedrovirus derived from a field isolate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plaque isolates derived from the Illinois field isolate of Agrotis ipsilon multiple nucleopolyhedrovirus are distinguished by the presence or absence of a small deletion in the baculovirus egt (ecdysteroid UDP-glucosyltransferase) coding sequence. Dose-response and time-response bioassays were perf...

  7. Genomic analysis of five Lymantria dispar nucleopolyhedrovirus isolates and biological activity against different host strains of Lymantria dispar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To evaluate genetic diversity of Lymantria dispar nucleopolyhedrovirus (LdMNPV) at the genomic level, five isolates of LdMNPV from North America, Europe, and Asia were selected for complete genome sequence determination and analysis. These isolates consist of LdMNPV-2161 from Korea; LdMNPV-3029, a ...

  8. Involvement of Bombyx mori nucleopolyhedrovirus ORF41 (Bm41) in BV production and ODV envelopment

    SciTech Connect

    Tian Caihong; Zhao Jinfang; Xu Yipeng; Xue Jian; Zhang Baoqin; Cui Yingjun; Zhang Minjuan; Bao Yanyuan; Zhang Chuanxi

    2009-04-25

    Bombyx mori nucleopolyhedrovirus (BmNPV) ORF41 (Bm41), homologous to Ac52, is a gene present in most lepidopteran nucleopolyhedroviruses. Bm41 transcripts and encoded protein in BmNPV-infected cells can be detected from 3 and 6 h post-infection, respectively. Immunoassays have shown that Bm41 is not a viral structural protein and is detected in both the nuclei and cytoplasm of infected cells. A Bm41-disrupted virus (vBm{sup De}) and a repaired virus (vBm{sup Re}) were generated to investigate the function of Bm41. The results showed that Bm41 was essential for viral replication, and the disruption of Bm41 resulted in a much lower viral titer. Transmission electron microscopy revealed that disruption of Bm41 affected normal nucleocapsid envelopment and polyhedra formation in the nucleus. The disruption of Bm41 might severely affect odv-ec27 and polyhedrin expression. The disrupted virus reduced BmNPV infectivity in an LD{sub 50} bioassay and took 18-23 h longer to kill larvae than wild-type virus in an LT{sub 50} bioassay.

  9. ac18 is not essential for the propagation of Autographa californica multiple nucleopolyhedrovirus

    SciTech Connect

    Wang Yanjie; Wu Wenbi; Li Zhaofei; Yuan Meijin; Feng Guozhong; Yu Qian; Yang Kai Pang Yi

    2007-10-10

    orf18 (ac18) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved gene in lepidopteran nucleopolyhedroviruses, but its function remains unknown. In this study, an ac18 knockout AcMNPV bacmid was generated to determine the role of ac18 in baculovirus life cycle. After transfection of Sf-9 cells, the ac18-null mutant showed similar infection pattern to the parent virus and the ac18 repair virus with respect to the production of infectious budded virus, occlusion bodies, or the formation of nucleocapsids as visualized by electron microscopy. The deletion mutant did not reduce AcMNPV infectivity for Trichoplusia ni in LD{sub 50} bioassay; however, it did take 24 h longer for deleted mutant to kill T. ni larvae than wild-type virus in LT{sub 50} bioassay. Our results demonstrate that ac18 is not essential for viral propagation both in vitro and in vivo, but it may play a role in efficient virus infection in T. ni larvae.

  10. Antiviral activity and specific modes of action of bacterial prodigiosin against Bombyx mori nucleopolyhedrovirus in vitro.

    PubMed

    Zhou, Wei; Zeng, Cheng; Liu, RenHua; Chen, Jie; Li, Ru; Wang, XinYan; Bai, WenWen; Liu, XiaoYuan; Xiang, TingTing; Zhang, Lin; Wan, YongJi

    2016-05-01

    Prodigiosin, the tripyrrole red pigment, is a bacterial secondary metabolite with multiple bioactivities; however, the antiviral activity has not been reported yet. In the present study, we found the antiviral activity of bacterial prodigiosin on Bombyx mori nucleopolyhedrovirus (BmNPV)-infected cells in vitro, with specific modes of action. Prodigiosin at nontoxic concentrations selectively killed virus-infected cells, inhibited viral gene transcription, especially viral early gene ie-1, and prevented virus-mediated membrane fusion. Under prodigiosin treatment, both progeny virus production and viral DNA replication were significantly inhibited. Fluorescent assays showed that prodigiosin predominantly located in cytoplasm which suggested it might interact with cytoplasm factors to inhibit virus replication. In conclusion, the present study clearly indicates that prodigiosin possesses significant antiviral activity against BmNPV. PMID:26685856