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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 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

  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

    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. 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

  13. 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

  14. 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

  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. 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

  5. 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

  6. 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

  7. 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 ...

  8. 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

  9. 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

  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. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  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. 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

  7. 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

  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. 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

  10. 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

  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. 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

  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. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  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. 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

  6. 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

  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. 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

  9. 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

  10. 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

  11. 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

  12. 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

  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. 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

  2. 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

  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. 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

  5. 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

  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 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

  10. 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

  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. 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

  13. 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

  14. 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

  15. 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

  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. 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

  20. 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

  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. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  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. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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

  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. 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

  5. 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

  6. 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

  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)

    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.

  9. 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

  10. 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.

  11. 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

  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. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  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

    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 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

  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

    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

  8. 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

  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

    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

  12. 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

  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. 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

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  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 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...

  12. 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...

  13. 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...

  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. 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

  3. 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...

  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. 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 ...

  6. 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 ...

  7. 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...

  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

  11. Analysis of defective genomes of bombyx mori nucleopolyhedrovirus generated by serial undiluted passage in cell culture.

    PubMed

    Yanase, T; Hashimoto, Y; Matsumoto, T

    1998-04-01

    Viral DNA was extracted from cells infected with bombyx mori nucleopolyhedrovirus (BmNPV) D1 strain after 34 serial undiluted passages (P34). P34 DNA was subjected to restriction analysis and Southern blot hybridisation using standard D1 DNA and P34 DNA of BmNPV as probes. Based on hybridisation profiles, the BmNPV DNA regions retained in the P34 DNA were localised on HindIII and PstI restriction maps. Two regions of BmNPV DNA located at 0-12.8 and 40.2-65.0 map unit (m.u.) were highly conserved in P34 DNA. These regions contained two of three interspersed homologous sequences (ihss), but only one of five homologous regions (hrs). This suggests that ihss may have an essential role in BmNPV replication. PMID:9770071

  12. Reduced expression of Autographa californica nucleopolyhedrovirus ORF34, an essential gene, enhances heterologous gene expression

    SciTech Connect

    Salem, Tamer Z.; Zhang, Fengrui; Thiem, Suzanne M.

    2013-01-20

    Autographa californica multiple nucleopolyhedrovirus ORF34 is part of a transcriptional unit that includes ORF32, encoding a viral fibroblast growth factor (FGF) and ORF33. We identified ORF34 as a candidate for deletion to improve protein expression in the baculovirus expression system based on enhanced reporter gene expression in an RNAi screen of virus genes. However, ORF34 was shown to be an essential gene. To explore ORF34 function, deletion (KO34) and rescue bacmids were constructed and characterized. Infection did not spread from primary KO34 transfected cells and supernatants from KO34 transfected cells could not infect fresh Sf21 cells whereas the supernatant from the rescue bacmids transfection could recover the infection. In addition, budded viruses were not observed in KO34 transfected cells by electron microscopy, nor were viral proteins detected from the transfection supernatants by western blots. These demonstrate that ORF34 is an essential gene with a possible role in infectious virus production.

  13. Classification, genetic variation and pathogenicity of Lymantria dispar nucleopolyhedrovirus isolates from Asia, Europe, and North America.

    PubMed

    Harrison, Robert L; Keena, Melody A; Rowley, Daniel L

    2014-02-01

    Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) has been formulated and applied to control outbreaks of the gypsy moth, L. dispar. To classify and determine the degree of genetic variation among isolates of L. dispar NPVs from different parts of the range of the gypsy moth, partial sequences of the lef-8, lef-9, and polh genes were determined for Lymantria spp. virus samples from host populations throughout the world. Sequence analysis confirmed that all L. dispar virus samples tested contained isolates of the species Lymantria dispar multiple nucleopolyhedrovirus (Baculoviridae: Alphabaculovirus). Phylogenetic inference based on the lef-8 sequences indicated that the LdMNPV isolates formed two groups, one consisting primarily of isolates from Asia, and one consisting primarily of isolates from Europe and North America. The complete genome sequence was determined for an isolate from the Asian group, LdMNPV-2161 (S. Korea). The LdMNPV-2161 genome was 163,138bp in length, 2092bp larger than the previously determined genome of LdMNPV isolate 5-6 (CT, USA). The two genome sequences were co-linear, with an overall nucleotide sequence identity of 97.5% and some differences in ORF content. In droplet-feeding bioassays against neonate L. dispar larvae, isolates LdMNPV-3029 (Virin-ENSh/Russia) and LdMNPV-Ab-a624 (MA, USA) killed neonate larvae with an LC50 values that were 1.8- to 3.2-fold lower than a sample of Gypchek® (CT, USA) and isolates LdMNPV-3041 (Japan) and LdMNPV-2161. This study expands our knowledge about genetic variation among LdMNPV isolates and provides novel information on the distinct groups in which these NPVs occur. PMID:24370838

  14. Hierarchical spatial structure of genetically variable nucleopolyhedroviruses infecting cyclic populations of western tent caterpillars.

    PubMed

    Cooper, Dawn; Cory, Jenny S; Myers, Judith H

    2003-04-01

    The cyclic population dynamics of western tent caterpillars, Malacosoma californicum pluviale, are associated with epizootics of a nucleopolyhedrovirus, McplNPV. Given the dynamic fluctuations in host abundance and levels of viral infection, host resistance and virus virulence might be expected to change during different phases of the cycle. As a first step in determining if McplNPV virulence and population structure change with host density, we used restriction fragment length polymorphism (RFLP) analysis to examine the genetic diversity of McplNPV infecting western tent caterpillar populations at different spatial scales. Thirteen dominant genetic variants were identified in 39 virus isolates (individual larvae) collected from field populations during one year of low host density, and another distinct variant was discovered among nine additional isolates in two subsequent years of declining host density. The distribution of these genetic variants was not random and indicated that the McplNPV population was structured at several spatial levels. A high proportion of the variation could be explained by family grouping, which suggested that isolates collected within a family were more likely to be the same than isolates compared among populations. Additionally, virus variants from within populations (sites) were more likely to be the same than isolates collected from tent caterpillar populations on different islands. This may indicate that there is limited mixing of virus among tent caterpillar families and populations when host population density is low. Thus there is potential for the virus to become locally adapted to western tent caterpillar populations in different sites. However, no dominant genotype was observed at any site. Whether and how selection acts on the genetically diverse nucleopolyhedrovirus populations as host density changes will be investigated over the next cycle of tent caterpillar populations. PMID:12753209

  15. Phosphatase activity of Bombyx mori nucleopolyhedrovirus PTP is dispensable for enhanced locomotory activity in B. mori larvae.

    PubMed

    Katsuma, Susumu

    2015-11-01

    Baculovirus-induced enhanced locomotory activity (ELA) is not induced in caterpillars infected with a mutant Bombyx mori nucleopolyhedrovirus (BmNPV) or Autographa californica multiple nucleopolyhedrovirus (AcMNPV) lacking a functional protein tyrosine phosphatase gene (ptp). Previous studies suggest that the PTP proteins from BmNPV and AcMNPV act in different ways to induce ELA, i.e., BmNPV PTP is utilized as a virion structural component, whereas AcMNPV PTP requires its phosphatase activity. Here, I generated and characterized two new BmNPV mutants expressing enzymatically inactive PTP proteins and confirmed that the phosphatase activity of PTP is not required for ELA induction in BmNPV-infected B. mori larvae. PMID:26550695

  16. A new gland associated with the retrocerebral complex of the adult corn earworm, Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the discovery of a putative new gland associated with the retrocerebral complex in the adults of Helicoverpa zea. The gland was not observed in Manduca sexta and few other species of moths. The pair of glands, each 40-60 µm in diameter, is located on either side of the recurrent nerve. Eac...

  17. Microsatellite variation in Helicoverpa zea (Boddie) populations in the southern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven polymorphic microsatellite markers were used to analyze Helicoverpa zea (Boddie) populations from various host plants in four different locations in the southern United States. Linear distance between collection sites ranged from approximately 150 to 900 km. Mean number of alleles per locus ...

  18. Regional Assessment of Helicoverpa zea (Lepidoptera: Noctuidae) Populations on Cotton and Non-Cotton Crop Hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selection pressure on bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), by cotton, Gossypium hirsutum (L.) (Malvaceae), that produces one or more Bacillus thuringiensis (Bt) Berliner proteins is reduced by plantings of non-Bt refuge cotton that produce non-selected individuals. However, ...

  19. Molecular identification and expression analysis of a diapause hormone receptor in the corn earworm, Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diapause hormone (DH) is an insect neuropeptide that is highly effective in terminating the overwintering pupal diapause in members of the Helicoverpa/Heliothis complex of agricultural pests, thus DH and related compounds have promise as tools for pest management. To augment our development of effe...

  20. Long distance migration in Helicoverpa zea: What we know and need to know

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper identifies knowledge and knowledge gaps in the areas of biology and ecology, and migratory flight of corn earworm, Helicoverpa zea (Boddie). The paper focuses on results from studies of H. zea population dynamics and migration in Texas during a period of substantial irrigated corn produc...

  1. Effect of Hexaflumuron on feeding response and reproduction of bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hexaflumuron (Consult® 100 EC, Dow AgroSciences) is an insect growth regulator that inhibits chitin synthesis. The efficacy of hexaflumuron mixed with 2.5 M sucrose (ppm) was evaluated in the laboratory against bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) for toxicity, proboscis exten...

  2. Development of the cursorial spider, Cheiracanthium inclusum (Araneae: Miturgidae), on eggs of Helicoverpa zea (Lepidoptera: Noctuidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of the cursorial spider Cheiricanthium inclusum (Hentz) (Araneae: Miturgidae) from emergence to maturity on a diet of eggs of the lepidopteran pest Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) was characterized. C. inclusum developed to adulthood with no mortality while feeding on ...

  3. Molecular cloning and functional characterization of the diapause hormone receptor in the corn earworm Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diapause hormone (DH) in the heliothine moth has shown its activity in termination of pupal diapause, while the orthology in the silkworm is known to induce embryonic diapause. In the current study, we cloned the diapause hormone receptor from the corn earworm Helicoverpa zea (HzDHr) and tested ...

  4. Autographa californica multiple nucleopolyhedrovirus gene ac81 is required for nucleocapsid envelopment.

    PubMed

    Dong, Fang; Wang, Jinwen; Deng, Riqiang; Wang, Xunzhang

    2016-08-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly pathogenic Baculoviridae that targets insects, whose core gene, ac81, has an unknown function. To determine the role of ac81 in the life cycle of AcMNPV, an ac81-knockout (Ac-81KO-GP) was constructed through homologous recombination in Escherichia coli. We determined that no budded virions were produced in Ac-81KO-GP-transfected Sf9 cells, while there was no effect on viral DNA replication. Electron microscopy (EM) analysis revealed that occlusion-derived virions (ODVs) envelopment and the subsequent embedding of virions into occlusion bodies (OBs) were aborted due to ac81 deletion. Interestingly, confocal microscopy and immunofluorescence analysis revealed that Ac81 was predominantly localized to the ring zone of nuclei during the late phase of infection. In addition, Ac81 was localized to the mature and premature ODVs in virus-infected cells within the ring zone as revealed by immuno-electron microscopy (IEM) analysis. Furthermore, we determined that Ac81 contained a functional hydrophobic transmembrane (TM) domain, whose deletion resulted in a phenotype similar to that of Ac-81KO-GP. These results suggest that Ac81 might be a TM protein that played an important role in nucleocapsid envelopment. PMID:27212683

  5. Autographa californica multiple nucleopolyhedrovirus ac53 plays a role in nucleocapsid assembly

    SciTech Connect

    Liu Chao; Li Zhaofei Wu Wenbi; Li Lingling; Yuan Meijin; Pan Lijing; Yang Kai Pang Yi

    2008-12-05

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf53 (ac53) is a highly conserved gene existing in all sequenced Lepidoptera and Hymenoptera baculoviruses, but its function remains unknown. To investigate its role in the baculovirus life cycle, an ac53 deletion virus (vAc{sup ac53KO-PH-GFP}) was generated through homologous recombination in Escherichia coli. Fluorescence and light microscopy and titration analysis revealed that vAc{sup ac53KO-PH-GFP} could not produce infectious budded virus in infected Sf9 cells. Real-time PCR demonstrated that the ac53 deletion did not affect the levels of viral DNA replication. Electron microscopy showed that many lucent tubular shells devoid of the nucleoprotein core are present in the virogenic stroma and ring zone, indicating that the ac53 knockout affected nucleocapsid assembly. With a recombinant virus expressing an Ac53-GFP fusion protein, we observed that Ac53 was distributed within the cytoplasm and nucleus at 24 h post-infection, but afterwards accumulated predominantly near the nucleus-cytoplasm boundary. These data demonstrate that ac53 is involved in nucleocapsid assembly and is an essential gene for virus production.

  6. The Autographa californica multiple nucleopolyhedrovirus ac110 gene encodes a new per os infectivity factor.

    PubMed

    Jiantao Liu; Zhu, Leyuan; Zhang, Shan; Deng, Zihao; Huang, Zhihong; Yuan, Meijin; Wu, Wenbi; Yang, Kai

    2016-08-01

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac110 gene is especially conserved in lepidopteran-specific baculoviruses and is uncharacterized. To investigate the role of ac110 in the baculovirus life cycle, an ac110-knockout (vAc110KO) and a repair (vAc110:HA) viruses were constructed in this study. Budded virion production and occlusion body formation were unaffected in vAc110KO-transfected or infected Sf9 cells. Intrahemocoelic injection of budded virions of vAc110KO killed Trichoplusia ni larvae as efficiently as the repair or the wild-type viruses. However, per os inoculation of occlusion bodies of vAc110KO failed to establish infection in T. ni larvae, while the repair virus was as efficient as the wild-type virus. Treatment with calcofluor white, a reagent that damages the peritrophic membrane, did not rescue the oral infectivity of vAc110KO. These results suggested that Ac110 is a new per os infectivity factor that may play a role after occlusion-derived virions pass through the peritrophic membrane during oral infection. PMID:27212681

  7. Threshold concentrations of nucleopolyhedrovirus in soil to initiate infections in Heliothis virescens on cotton plants.

    PubMed

    Fuxa, James R

    2008-04-01

    The purpose of the research was to determine threshold concentrations of nucleopolyhedrovirus (NPV) in soil for abiotic transport to cotton plants in the field and under conducive and nonconducive conditions in the greenhouse. Under the assumption that 2% mortality would suffice to initiate foci of infection in Heliothis virescens larvae on the plants, thresholds ranged from 25 to 2,311 viral occlusion bodies (OB)/g soil in the greenhouse. Thresholds generally were smaller for rain on sandy soil and wind on clay soil than for wind on sand or rain on clay. Thresholds generally increased with height of the plant above the soil surface. In field plots, percentage mortality in bioassays of cotton plants was greatest on leaves versus other tissues, and mortality increased with soil dosage and decreased with plant height and over time. Season-long soil-NPV-transport thresholds for 2% plant-bioassay mortality of larvae ranged from 1 OB/g to 7.4 x 10(8) OB/g soil based on the amounts of NPV applied to the soil at planting time, and they ranged from 8 OB/g to 1.2 x 10(5) OB/g soil based on bioassays of soil samples collected concurrently with plant samples throughout the growing season. These results should contribute to NPV epizootiology, biological control, and risk assessment through better understanding of viral soil-to-plant transport. PMID:17647052

  8. Lymantria mathura nucleopolyhedrovirus: Identification, occurrence and genetic diversity in Iwate Prefecture, Japan.

    PubMed

    Takatsuka, Jun

    2016-07-01

    A high prevalence of nuclear polyhedrosis has been observed in larval outbreaks of Lymantria mathura in Iwate Prefecture, Japan. However, the virus responsible has not been identified. Here the virus was designated Lymantria mathura nucleopolyhedrovirus (LymaNPV), based on partial sequence results of the lef-8, lef-9, and polh genes and transmission electron microscopic observations. Diagnosis by polymerase chain reaction targeting of the partial polh gene and a subsequent restriction fragment length polymorphism (RFLP) analysis indicated that LymaNPV was an exclusive causative agent for the nuclear polyhedrosis of the L. mathura larvae. LymaNPV was also detected from a very small fraction of L. dispar larvae that co-occurred with L. mathura larvae where the prevalence of LymaNPV-caused disease was high. A bioassay using LymaNPV against L. dispar larvae produced infection with the inoculated virus. This finding was consistent with the results of the field sample analysis. LymaNPV contained six genome types in the L. mathura populations sampled, as determined by RFLP of LymaNPV genomic DNA and southern blot hybridization analyses. None of the genome types was unique to any sampling site, indicating that some flow had occurred among sites. However, genome-type composition seemed to differ among sites. This study provides basic information about the interaction between L. mathura and LymaNPV. PMID:27234422

  9. Complete Sequence, Analysis and Organization of the Orgyia leucostigma Nucleopolyhedrovirus Genome

    PubMed Central

    Thumbi, David K.; Eveleigh, Robert J. M.; Lucarotti, Christopher J.; Lapointe, Renée; Graham, Robert I.; Pavlik, Lillian; Lauzon, Hilary A. M.; Arif, Basil M.

    2011-01-01

    The complete genome of the Orgyia leucostigma nucleopolyhedrovirus (OrleNPV) isolated from the whitemarked tussock moth (Orgyia leucostigma, Lymantridae: Lepidoptera) was sequenced, analyzed, and compared to other baculovirus genomes. The size of the OrleNPV genome was 156,179 base pairs (bp) and had a G+C content of 39%. The genome encoded 135 putative open reading frames (ORFs), which occupied 79% of the entire genome sequence. Three inhibitor of apoptosis (ORFs 16, 43 and 63), and five baculovirus repeated ORFs (bro-a through bro-e) were interspersed in the OrleNPV genome. In addition to six direct repeat (drs), a common feature shared among most baculoviruses, OrleNPV genome contained three homologous regions (hrs) that are located in the latter half of the genome. The presence of an F-protein homologue and the results from phylogenetic analyses placed OrleNPV in the genus Alphabaculovirus, group II. Overall, OrleNPV appears to be most closely related to group II alphabaculoviruses Ectropis obliqua (EcobNPV), Apocheima cinerarium (ApciNPV), Euproctis pseudoconspersa (EupsNPV), and Clanis bilineata (ClbiNPV). PMID:22163346

  10. Functional characterization of Autographa californica multiple nucleopolyhedrovirus gp16 (ac130)

    SciTech Connect

    Yang, Ming; Huang, Cui; Qian, Duo-Duo; Li, Lu-Lin

    2014-09-15

    To investigate the function of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) gp16, multiple gp16-knockout and repair mutants were constructed and characterized. No obvious difference in productivity of budded virus, DNA synthesis, late gene expression and morphogenesis was observed between gp16-knockout and repair viruses, but gp16 deletion resulted in six hours of lengthening in ST{sub 50} to the third instar Spodoptera exigua larvae in bioassays. GP16 was fractionated mainly in the light membrane fraction, by subcellular fractionation. A GP16-EGFP fusion protein was predominantly localized close around the nuclear membrane in infected cells, being coincident with formation of the vesicles associated with the nuclear membrane, which hosted nucleocapsids released from the nucleus. These data suggest that gp16 is not required for viral replication, but may be involved in membrane trafficking associated with the envelopment/de-envelopment of budded viruses when they cross over the nuclear membrane and pass through cytoplasm. - Highlights: • gp16 knockout and repair mutants of AcMNPV were constructed and characterized. • AcMNPV gp16 is not essential to virus replication. • Deletion of gp16 resulted in time lengthening to kill S. exigua larvae. • GP16 was localized close around the nuclear membrane of infected cells. • GP16 was fractionated in the light membrane fraction in subcellular fractionation.

  11. Occurrence and characterization of a tetrahedral nucleopolyhedrovirus from Spilarctia obliqua (Walker).

    PubMed

    Senthil Kumar, C M; Jacob, T K; Devasahayam, S; D'Silva, Sharon; Jinsha, J; Rajna, S

    2015-11-01

    Spilarctia obliqua Walker (Lepidoptera: Arctiidae) is a polyphagous insect pest damaging pulses, oil seeds, cereals, vegetables and medicinal and aromatic plants in India. The pest also infests turmeric and ginger sporadically in Kerala. We observed an epizootic caused by a nucleopolyhedrovirus (NPV) in field populations of the insects in December 2013. The NPV was purified and characterized. The isolate was tetrahedral in shape and belonged to multicapsid NPV. The REN profile of the SpobNPV genome with Pst I, Xho I and HindIII enzymes showed a genome size of 99.1±3.9 kbp. Partialpolh, lef-8 and lef-9 gene sequences of the isolate showed a close relationship with HycuNPV and SpphNPV. Phylogram and K-2-P distances between similar isolates suggested inclusion of the present SpobNPV isolate to group I NPV. The biological activity of the isolate was tested under laboratory conditions against third instar larvae of S. obliqua and the LC50 was 4.37×10(3)OBs/ml occlusion bodies (OBs) per ml. The median survival time (ST50) was 181 h at a dose of 1×10(6)OBs/ml and 167 h at a dose of 1×10(8)OBs/ml. SpobNPV merits further field evaluation as a potential biological control agent of S. obliqua, a serious pest of many agriculturally important crops in the Oriental region. PMID:26449395

  12. Identification of nucleopolyhedrovirus that infect Nymphalid butterflies Agraulis vanillae and Dione juno.

    PubMed

    Rodríguez, Vanina Andrea; Belaich, Mariano Nicolás; Gómez, Diego Luis Mengual; Sciocco-Cap, Alicia; Ghiringhelli, Pablo Daniel

    2011-02-01

    Dione juno and Agraulis vanillae are very common butterflies in natural gardens in South America, and also bred worldwide. In addition, larvae of these butterflies are considered as pests in crops of Passiflora spp. For these reasons, it is important to identify and describe pathogens of these species, both for preservation purposes and for use in pest control. Baculoviridae is a family of insect viruses that predominantly infect species of Lepidoptera and are used as bioinsecticides. Larvae of D. juno and A. vanillae exhibiting symptoms of baculovirus infection were examined for the presence of baculoviruses by PCR and transmission electron microscopy. Degenerate primers were designed and used to amplify partial sequences from the baculovirus p74, cathepsin, and chitinase genes, along with previously designed primers for amplification of lef-8, lef-9, and polh. Sequence data from these six loci, along with ultrastructural observations on occlusion bodies isolated from the larvae, confirmed that the larvae were infected with nucleopolyhedroviruses from genus Alphabaculovirus. The NPVs from the two different larval hosts appear to be variants of the same, previously undescribed baculovirus species. Phylogenetic analysis of the sequence data placed these NPVs in Alphabaculovirus group I/clade 1b. PMID:21047512

  13. Nucleopolyhedroviruses (NPV) induce the expression of small heat shock protein 25.4 in Antheraea pernyi.

    PubMed

    Zhang, Congfen; Zhu, Baojian; Dai, Li Shang; Liu, Chaoliang; Luo, Xuegang

    2016-10-15

    Nucleopolyhedroviruses (NPVs) is one group of Baculoviruses. The infection of NPV in silkworm is often lethal. To investigate the effective measures to stop the infection of NPV, we cloned cDNA encoding small heat shock protein 25.4 in Antheraea pernyi (Ap-HSP25.4). The translated amino acid sequence consisted of 223 residues with a calculated molecular mass of 25.4kDa and an isoelectronic point (pI) of 4.93. Quantitative real-time PCR was used to investigate the expression patterns and distribution profiles of Ap-sHSP25.4 before and after challenged with NPV. We found that the inhibitors of eicosanoid synthesis could suppress the transcription of Ap-sHSP25.4 in the fat body in a dose dependent manner. And arachidonic acid induced the expression of Ap-sHSP25.4. Thus, we concluded that sHSPs may be promising candidates to boost insect immunity in practice. PMID:27265031

  14. Screening and optimization of an efficient Bombyx mori nucleopolyhedrovirus inducible promoter.

    PubMed

    Cao, Ming-Ya; Kuang, Xiu-Xiu; Li, Hai-Qing; Lei, Xue-Jiao; Xiao, Wen-Fu; Dong, Zhan-Qi; Zhang, Jun; Hu, Nan; Chen, Ting-Ting; Lu, Cheng; Pan, Min-Hui

    2016-08-10

    Pathogen-inducible promoters have been studied extensively and widely used in resistance breeding and gene therapy. However, few reports have been published that explore the efficacy of Bombyx mori nucleopolyhedrovirus (BmNPV)-inducible promoters in antiviral research in the Bombyx mori (Lepidoptera). Here, we screened BmNPV promoters (VP1054, P33, Bm21, Bm122, 39K, P143, and P6.9) and found that the 39K promoter had the highest BmNPV-induced transcriptional activity by dual-luciferase reporter assays system. By 5' truncation analysis, two regions of 39K promoter were critical for optimal virus-inducible activity, indicated that they could serve as a candidate to produce synthetic pathogen-induced promoters. Furthermore, we enhanced the virus-inducible activity of BmNPV 39K promoter using a hybrid enhancer comprising hr3 and polh-up (designated as HP39K). Finally, we showed that RNAi regulated by HP39K promoter could significantly inhibit the proliferation of BmNPV in silkworm cells. Taken together, our results have practical value in antiviral research of silkworm and baculovirus expression system. PMID:27245143

  15. Genome Sequencing and Analysis of Catopsilia pomona nucleopolyhedrovirus: A Distinct Species in Group I Alphabaculovirus

    PubMed Central

    Wang, Jun; Zhu, Zheng; Zhang, Lei; Hou, Dianhai; Wang, Manli; Arif, Basil; Kou, Zheng; Wang, Hualin; Deng, Fei; Hu, Zhihong

    2016-01-01

    The genome sequence of Catopsilia pomona nucleopolyhedrovirus (CapoNPV) was determined by the Roche 454 sequencing system. The genome consisted of 128,058 bp and had an overall G+C content of 40%. There were 130 hypothetical open reading frames (ORFs) potentially encoding proteins of more than 50 amino acids and covering 92% of the genome. Among all the hypothetical ORFs, 37 baculovirus core genes, 23 lepidopteran baculovirus conserved genes and 10 genes conserved in Group I alphabaculoviruses were identified. In addition, the genome included regions of 8 typical baculoviral homologous repeat sequences (hrs). Phylogenic analysis showed that CapoNPV was in a distinct branch of clade “a” in Group I alphabaculoviruses. Gene parity plot analysis and overall similarity of ORFs indicated that CapoNPV is more closely related to the Group I alphabaculoviruses than to other baculoviruses. Interesting, CapoNPV lacks the genes encoding the fibroblast growth factor (fgf) and ac30, which are conserved in most lepidopteran and Group I baculoviruses, respectively. Sequence analysis of the F-like protein of CapoNPV showed that some amino acids were inserted into the fusion peptide region and the pre-transmembrane region of the protein. All these unique features imply that CapoNPV represents a member of a new baculovirus species. PMID:27166956

  16. Inactivation of the budded virus of Autographa californica M nucleopolyhedrovirus by gloverin

    PubMed Central

    Moreno-Habel, Daniela A.; Biglang-awa, Ivan M.; Dulce, Angelica; DeeLuu, Dee; Garcia, Peter; Weers, Paul M. M.; Haas-Stapleton, Eric J.

    2012-01-01

    Antimicrobial peptides are generated in insects exposed to pathogens for combating infection. Gloverin is a small cationic antibacterial protein whose expression is induced in the hemocytes and fat body cells of Trichoplusia ni larvae exposed to bacteria. The purpose of this study was to determine the role of gloverin during baculovirus infection. We found that gloverin expression is induced in T. ni systemically infected with the baculovirus Autographa californica M nucleopolyhedrovirus (AcMNPV). Two gloverin genes were cloned using RNA isolated from the hemocytes of T. ni larvae that were systemically infected AcMNPV budded virus (BV) and C-terminal 6x-His and V5 epitope tags were incorporated to facilitate gloverin isolation, detection and functional studies. The supernatants of Sf9 cells stably transfected with the two gloverin expression plasmids and affinity purified gloverin proteins reduced the quantity of infectious AcMNPV BV as measured in vitro by plaque assay with untransfected Sf9 cells. Nanomolar concentrations of affinity column purified gloverin protein caused calcein to be rapidly released from unilamellar vesicles comprised of phosphatidylglycerol, but not from vesicles made up of phosphatidylcholine, suggesting that gloverin interaction with membranes is rapid and affected by membrane charge. Both the BV inactivation and calcein release activities of gloverin increased with higher concentrations of gloverin. These results demonstrate that gloverin is an antiviral protein that interacts with vesicle membranes to cause the contents to be released. PMID:22401766

  17. Cell Culture for Production of Insecticidal Viruses.

    PubMed

    Reid, Steven; Chan, Leslie C L; Matindoost, Leila; Pushparajan, Charlotte; Visnovsky, Gabriel

    2016-01-01

    While large-scale culture of insect cells will need to be conducted using bioreactors up to 10,000 l scale, many of the main challenges for cell culture-based production of insecticidal viruses can be studied using small-scale (20-500 ml) shaker/spinner flasks, either in free suspension or using microcarrier-based systems. These challenges still relate to the development of appropriate cell lines, stability of virus strains in culture, enhancing virus yields per cell, and the development of serum-free media and feeds for the desired production systems. Hence this chapter presents mainly the methods required to work with and analyze effectively insect cell systems using small-scale cultures. Outlined are procedures for quantifying cells and virus and for establishing frozen cells and virus stocks. The approach for maintaining cell cultures and the multiplicity of infection (MOI) and time of infection (TOI) parameters that should be considered for conducting infections are discussed.The methods described relate, in particular, to the suspension culture of Helicoverpa zea and Spodoptera frugiperda cell lines to produce the baculoviruses Helicoverpa armigera nucleopolyhedrovirus, HearNPV, and Anticarsia gemmatalis multicapsid nucleopolyhedrovirus, AgMNPV, respectively, and the production of the nonoccluded Oryctes nudivirus, OrNV, using an adherent coleopteran cell line. PMID:27565495

  18. The Trichoplusia ni single nucleopolyhedrovirus tn79 gene encodes a functional sulfhydryl oxidase enzyme that is able to support the replication of Autographa californica multiple nucleopolyhedrovirus lacking the sulfhydryl oxidase ac92 gene

    PubMed Central

    Clem, Stian A.; Wu, Wenbi; Lorena Passarelli, A.

    2014-01-01

    The Autographa californica multiple nucleopolyhedrovirus ac92 is a conserved baculovirus gene with homology to flavin adenine dinucleotide-linked sulfhydryl oxidases. Its product, Ac92, is a functional sulfhydryl oxidase. Deletion of ac92 results in almost negligible levels of budded virus (BV) production, defects in occlusion-derived virus (ODV) co-envelopment and their inefficient incorporation into occlusion bodies. To determine the role of sulfhydryl oxidation in the production of BV, envelopment of nucleocapsids, and nucleocapsid incorporation into occlusion bodies, the Trichoplusia ni single nucleopolyhedrovirus ortholog, Tn79, was substituted for ac92. Tn79 was found to be an active sulfhydryl oxidase that substituted for Ac92, resulting in the production of infectious BV, albeit about 10-fold less than an ac92-containing virus. Tn79 rescued defects in ODV morphogenesis caused by a lack of ac92. Active Tn79 sulfhydryl oxidase activity is required for efficient BV production, ODV envelopment, and their subsequent incorporation into occlusion bodies in the absence of ac92. PMID:25010286

  19. Slow cell infection, inefficient primary infection and inability to replicate in fat body determine host-range of Thysanoplusia orichalcea M Nucleopolyhedrovirus (ThorMNPV)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An enhanced green fluorescence protein (EGFP) gene expression cassette was inserted at the gp37 locus of Thysanoplusia orichacea M nucleopolyhedrovirus (ThorMNPV) to produce vThGFP to study host-range mechanisms. Using EGFP to monitor infection in vitro, many cell lines showed EGFP expression sugges...

  20. DNA hybridization assay for detection of nucleopolyhedrovirus in whitemarked tussock moth (Orgyia leucostigma) larvae.

    PubMed

    Ebling, P M; Smith, P A; van Frankenhuyzen, K

    2001-01-01

    DNA dot-blot hybridization assays utilizing a horseradish peroxidase-labelled whole genomic DNA probe and enhanced chemiluminescence were conducted to quantify detection thresholds of nucleopolyhedrovirus (NPV) in whitemarked tussock moth (Orgyia leucostigma) larvae. The minimum detection thresholds for an aqueous suspension of occlusion bodies (OBs), OBs added to macerates of non-infected larvae and OBs in macerates of diseased larvae were 7.8 x 10(3), 7.8 x 10(3), and 1.5 x 10(3) OBs, respectively. Purified viral DNA was detected at a concentration of 1.6 x 10(-1) ng in a 20 microliters volume. The presence of pre-occluded viral nucleocapsids and DNA, inherent to infected larvae, improved the detection threshold five-fold compared with OBs alone. Larval tissues did not block the detection system utilized, nor did they bind non-specifically to the probe. Detection thresholds, upon sequential hybridization of the same membrane, on average deteriorated two-fold between the first and second hybridization and an additional six-fold between the second and third hybridization. NPV infection was detected two days post-inoculation (pi) in about one-third of the larvae examined and in almost all larvae three days pi. Microscopic analysis of stained larval smears missed NPV infection in almost all larvae two days pi and about two-thirds of the larvae three days pi. Results from the two methods of analysis were not comparable until four days pi. The detection system utilized is a reliable, efficient and simple method for the early detection of NPV infection in large numbers of larvae and may be used for further studies quantifying the role of this baculovirus in the ecology of whitemarked tussock moth populations. PMID:11455634

  1. The Pangenome of the Anticarsia gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV)

    PubMed Central

    de Brito, Anderson Fernandes; Braconi, Carla Torres; Weidmann, Manfred; Dilcher, Meik; Alves, João Marcelo Pereira; Gruber, Arthur; Zanotto, Paolo Marinho de Andrade

    2016-01-01

    The alphabaculovirus Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) is the world’s most successful viral bioinsecticide. Through the 1980s and 1990s, this virus was extensively used for biological control of populations of Anticarsia gemmatalis (Velvetbean caterpillar) in soybean crops. During this period, genetic studies identified several variable loci in the AgMNPV; however, most of them were not characterized at the sequence level. In this study we report a full genome comparison among 17 wild-type isolates of AgMNPV. We found the pangenome of this virus to contain at least 167 hypothetical genes, 151 of which are shared by all genomes. The gene bro-a that might be involved in host specificity and carrying transporter is absent in some genomes, and new hypothetical genes were observed. Among these genes there is a unique rnf12-like gene, probably implicated in ubiquitination. Events of gene fission and fusion are common, as four genes have been observed as single or split open reading frames. Gains and losses of genomic fragments (from 20 to 900 bp) are observed within tandem repeats, such as in eight direct repeats and four homologous regions. Most AgMNPV genes present low nucleotide diversity, and variable genes are mainly located in a locus known to evolve through homologous recombination. The evolution of AgMNPV is mainly driven by small indels, substitutions, gain and loss of nucleotide stretches or entire coding sequences. These variations may cause relevant phenotypic alterations, which probably affect the infectivity of AgMNPV. This work provides novel information on genomic evolution of the AgMNPV in particular and of baculoviruses in general. PMID:26615220

  2. The Lymantria dispar Nucleopolyhedrovirus Enhancins Are Components of Occlusion-Derived Virus

    PubMed Central

    Slavicek, James M.; Popham, Holly J. R.

    2005-01-01

    Enhancins are metalloproteinases, first identified in granuloviruses, that can enhance nucleopolyhedrovirus (NPV) potency. We had previously identified two enhancin genes (E1 and E2) in the Lymantria dispar multinucleocapsid NPV (LdMNPV) and showed that both were functional. For this study, we have extended our analysis of LdMNPV enhancin genes through an immunocytochemical analysis of E1 and E2 expression and localization. E1 and E2 peptide antibodies recognized proteins of ∼84 kDa and 90 kDa, respectively, on Western blots of extracts from L. dispar 652Y cells infected with wild-type virus. The 84- and 90-kDa proteins were first detected at 48 h postinfection (p.i.) and were present through 96 h p.i. E1 and E2 peptide antibodies detected E1 and E2 in polyhedron extracts, and the antibodies were shown to be specific for E1 and E2, respectively, through the use of recombinant virus strains lacking the enhancin genes. E1 and E2 were further localized to occlusion-derived virus (ODV). The enhancins were not found in budded virus. Immunoelectron microscopy indicated that E1 and E2 were present in ODV envelopes and possibly in nucleocapsids. Fractionation studies with several detergents suggested that the enhancins were present in ODV envelopes in association with nucleocapsids. In contrast, enhancins in granuloviruses are located within the granulin matrix. The presence of LdMNPV enhancins within ODV provides a position for the proteins to interact directly on the peritrophic membrane as ODV traverses this host defense barrier. PMID:16051850

  3. Isolation and characterization of plaque-purified strains of Malacosoma disstria Nucleopolyhedrovirus.

    PubMed

    Erlandson, Martin A; Baldwin, Doug; Haveroen, Melissa; Keddie, B Andrew

    2006-03-01

    Seven plaque-purified genotypic variants or strains, derived from a previously described field isolate of the Malacosoma disstria Nucleopolyhedrovirus (MadiNPV) from Alberta populations of forest tent caterpillar, were characterized based on distinctive restriction endonuclease fragment patterns. Two strains, MadiNPV-pp3 and MadiNPV-pp11, were selected for further characterization, as they represented strains producing high and low budded virus (BV) titres, respectively, in the M. disstria cell line UA-Md203. Analysis of restriction endonuclease fragment profiles indicated the genomes differed significantly in size, 133.8 +/- 2.4 kb for MadiNPV-pp3 and 118.1 +/- 3.5 kb for MadiNPV-pp11. These strains were characterized based on their BV production in three different cell lines derived from M. disstria haemocytes. Compared with MadiNPV-pp11, MadiNPV-pp3 produced two- to three-fold more BVs in UA-Md203 and 210 other cell lines; however, BV production was only marginally higher for MadiNPV-pp3 in the UA-Md221 cell line. Similarly, the yield of polyhedral inclusion bodies was significantly higher for MadiNPV-pp3 in UA-Md203 and 210 cell lines than for MadiNPV-pp11 but not in the UA-Md221 cell line. This data, although derived from a limited number of cell lines, suggested MadiNPV-pp3 may have a broader tissue tropism than MadiNPV-pp11. PMID:16604123

  4. Identification of Spodoptera exigua nucleopolyhedrovirus genes involved in pathogenicity and virulence.

    PubMed

    Serrano, Amaya; Pijlman, Gorben P; Vlak, Just M; Muñoz, Delia; Williams, Trevor; Caballero, Primitivo

    2015-03-01

    Genome sequence analysis of seven different Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) isolates that differed in insecticidal phenotype permitted the identification of genes likely to be involved in pathogenicity of occlusion bodies (OBs) and speed of kill (virulence) of this virus: se4 (hoar), se5 (unknown function), se28 (unknown function), se76 (cg30), se87 (p26) and se129 (p26). To study the role of these genes experimentally on the insecticidal phenotype, a bacmid-based recombination system was constructed to delete selected genes from a SeMNPV isolate, VT-SeAL1, designated as SeBacAL1. All of the knockout viruses were viable and the repair viruses behaved like the wild-type control, vSeBacAL1. Deletion of se4, se5, se76 and se129 resulted in decreased OB pathogenicity compared to vSeBacAL1 OBs. In contrast, deletion of se87 did not significantly affect OB pathogenicity, whereas deletion of se28 resulted in significantly increased OB pathogenicity. Deletion of se4, se28, se76, se87 and se129 did not affect speed of kill compared to the bacmid vSeBacAL1, whereas speed of kill was significantly extended following deletion of se5 and in the wild-type isolate (SeAL1), compared to that of the bacmid. Therefore, biological assays confirmed that several genes had effects on virus insecticidal phenotype. Se5 is an attractive candidate gene for further studies, as it affects both biological parameters of this important biocontrol virus. PMID:25644432

  5. Transport of Wild-Type and Recombinant Nucleopolyhedroviruses by Scavenging and Predatory Arthropods.

    PubMed

    Lee; Fuxa

    2000-05-01

    Wild-type and recombinant nucleopolyhedroviruses (NPVs) were compared in their capability to be transported over limited distances by the predator Podisus maculiventris (Say) and scavengers Sarcophaga bullata (Parker) and Acheta domesticus (Linnaeus) in Trichoplusia ni (Hübner) larvae infesting collards in a greenhouse microcosm. Viruses tested were variants of Autographa californica (Speyer) NPV (AcNPV): wild-type virus (AcNPV.WT), AcNPV expressing a scorpion toxin (AcNPV.AaIT), and AcNPV expressing juvenile hormone esterase (AcJHE.SG). Podisus maculiventris transported AcNPV.WT and S. bullata transported AcNPV.WT and AcNPV.AaIT. Prevalence and transport of AcNPV.WT were greater than those of AcNPV.AaIT and AcJHE.SG, regardless of whether the nontarget organism carriers were present or absent. Podisus maculiventris and S. bullata transported recombinant and wild-type NPVs at a rate of up to 62.5 cm/day, and A. domesticus transported wild-type NPV at 125 cm/day. The infected host insects, T. ni, undoubtedly contributed to viral transport in the current research. In every experiment, both the wild-type and recombinant virus spread to some degree in the plots without predators or scavengers. The relative amounts of NPVs that accumulated in soil, as indicated by bioassay mortality percentages, generally exhibited spatial patterns similar to those of T. ni mortality due to NPV on the collards plants. Thus, the predator and scavengers in the current research demonstrated some capacity to transport wild-type as well as recombinant viruses at significant rates in a greenhouse microcosm. PMID:10882435

  6. Transcriptome Analysis of the SL221 Cells at the Early Stage during Spodoptera litura Nucleopolyhedrovirus Infection

    PubMed Central

    Yu, Qian; Xiong, Youhua; Liu, Jianliang; Wen, Dongling; Wu, Xiaohui; Yin, Hanqi

    2016-01-01

    Spodoptera litura (S. litura) is one of the most destructive agricultural pests worldwide. There is urgent need for a nuclear polyhedrosis virus that is specific to S. litura. To date, there have been no reports regarding the responses of S. litura cells to early Spodoptera litura nucleopolyhedrovirus (SpltNPV) infection due to the lack of a reference genome and transcriptome for S. litura. In this study, a cell transcriptome from the host S. litura was assembled and used for Illumina strand-specific RNA sequencing (RNA-seq) to generate 99180 unigenes, representing the 18 hour infection cycle. More than 2000 S. litura genes were significant differentially regulated throughout the infection. The levels of viral mRNAs began to increase dramatically at 6 hpi, and this increase continued throughout the remainder of the infection. We focused on the expression of genes related to stress responses, apoptosis, metabolic enzymes and host cell innate immune system. A small subset of genes related to host stress response, especially for 62 ones being able to annotated as enzyme, ligand and receptor genes, were observed to be specifically differentially expressed at 6 hpi. At 18 hpi, 104 unigenes were continuously significantly changing from 0 hpi to 18 hpi, considered to be viral multiplication related genes, including 3 annotated SL221 unigenes and 81 viral genes, such as tetraspanin and iap gene. This information and further studies on the regulation of host gene expression by baculovirus infection at early stage will provide the tools needed to enhance the utility of this virus as an effective insecticide. PMID:26840182

  7. Mechanism of Enhanced Bombyx mori Nucleopolyhedrovirus-Resistance by Titanium Dioxide Nanoparticles in Silkworm

    PubMed Central

    Zhang, Hua; Ni, Min; Hong, Fashui; Shen, Weide; Li, Bing

    2015-01-01

    The infection of Bombyx mori nucleopolyhedrovirus (BmNPV) in silkworms is often lethal. It is difficult to prevent, and its lethality is correlated with both viral particle characteristics and silkworm strains. Low doses of titanium dioxide nanoparticles (TiO2 NPs) can promote silkworm growth and improve its resistance to organophosphate pesticides. In this study, TiO2 NPs’ effect on BmNPV resistance was investigated by analyzing the characteristics of BmNPV proliferation and transcriptional differences in silkworm midgut and the transcriptional changes of immunity related genes after feeding with TiO2 NPs. We found that low doses of TiO2 NPs improved the resistance of silkworm against BmNPV by 14.88-fold, with the mortalities of the experimental group and control group being 0.56% and 8.33% at 144 h, respectively. The proliferation of BmNPV in the midgut was significantly increased 72 h after infection in both experimental and control groups; the control group reached the peak at 120 h, while the experimental group took 24 more hours to reach the maximal value that was 12.63 times lower than the control, indicating that TiO2 NPs can inhibit BmNPV proliferation in the midgut. Consistently, the expression of the BmNPV-resistant gene Bmlipase-1 had the same increase pattern as the proliferation changes. Immune signaling pathway analysis revealed that TiO2 NPs inhibited the proliferation of silkworm BmNPV to reduce the activation levels of janus kinase/signal transducer and activator of transcription (JAK/STAT) and phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway, while promoting the expression of Bmakt to improve the immunity. Overall, our results demonstrate that TiO2 NPs increase silkworm resistance against BmNPV by inhibiting virus proliferation and improving immunity in silkworms. PMID:25692869

  8. A Hypothetical Model of Crossing Bombyx mori Nucleopolyhedrovirus through Its Host Midgut Physical Barrier

    PubMed Central

    Cheng, Yang; Wang, Xue-Yang; Hu, Hao; Killiny, Nabil; Xu, Jia-Ping

    2014-01-01

    Bombyx mori nucleopolyhedrovirus (BmNPV) is a primary pathogen of silkworm (B. mori) that causes severe economic losses each year. However, the molecular mechanisms of silkworm-BmNPV interactions, especially the silkworm proteins that can interact with the virus, are still largely unknown. In this study, the total and membrane proteins of silkworm midguts were displayed using one- and two-dimensional electrophoresis. A virus overlay assay was used to detect B. mori proteins that specifically bind to BmNPV particles. Twelve proteins were located and identified using mass spectrometry, and the different expression of the corresponding genes in BmNPV susceptible and resistant silkworm strains also indicated their involvement in BmNPV infection. The 12 proteins are grouped based on their potential roles in viral infection, for example, endocytosis, intracellular transportation, and host responses. Based on these results, we hypothesize the following: I) vacuolar ATP synthase catalytic subunit A and subunit B may be implicated in the process of the membrane fusion of virus and the release of the nucleocapsid into cytoplasm; II) actin, enolase and phosphoglycerate kinase are cytoskeleton associated proteins and may play an important role in BmNPV intracellular transportation; III) mitochondrial prohibitin complex protein 2, ganglioside-induced differentiation-associated protein, calreticulin, regucalcin-like isoform X1 and 60 kDa heat shock protein are involved in cell apoptosis regulation during BmNPV infection in larvae midguts; IV) ribosomal P0 may be associated with BmNPV infection by regulating gene expression of BmNPV; V) arginine kinase has a role in the antiviral activities against BmNPV. Our work should prove informative by providing multiple protein targets and a novel direction to investigate the molecular mechanisms of the interactions between silkworms and BmNPV. PMID:25502928

  9. ERK- and JNK-Dependent Signaling Pathways Contribute to Bombyx mori Nucleopolyhedrovirus Infection▿

    PubMed Central

    Katsuma, Susumu; Mita, Kazuei; Shimada, Toru

    2007-01-01

    Mitogen-activated protein kinases (MAPKs) often play important roles in virus infection. To explore intracellular signaling pathways induced by baculovirus infection, we examined the involvement of MAPKs in Bombyx mori nucleopolyhedrovirus (BmNPV) infection of BmN cells. We found that specific inhibitors of extracellular signal-regulated kinase (ERK) kinase and c-Jun NH2-terminal kinase (JNK) significantly reduced occlusion body (OB) formation and budded virus (BV) production. Next, we quantified OB and BV production after applying the inhibitors at different times postinfection (p.i.). The inhibitors significantly reduced OB and BV production to various extents when applied at 12 h p.i., indicating that the reduction of BmNPV infectivity by these inhibitors occurs at the late stage of infection. Also, we observed that these inhibitors markedly repressed or deregulated the expression of delayed early, late, and very late gene products. Western blot analysis using phospho-MAPK-specific antibodies showed that ERK and JNK were activated at the late stage of BmNPV infection. In addition, the magnitude and pattern of MAPK activation were dependent on the multiplicity of infection. To verify the effects of the inhibitors on BmNPV infection, we also attempted to knock down the B. mori genes BmErk and BmJnk, which encode ERK and JNK, respectively. Knockdown of BmErk and BmJnk resulted in the reduced production of OBs and BVs, confirming that BmERK and BmJNK are involved in the BmNPV infection process. Taken together, these results indicate that the activation of MAPK signaling pathways is required for efficient infection by BmNPV. PMID:17913811

  10. The Pangenome of the Anticarsia gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV).

    PubMed

    Brito, Anderson Fernandes de; Braconi, Carla Torres; Weidmann, Manfred; Dilcher, Meik; Alves, João Marcelo Pereira; Gruber, Arthur; Zanotto, Paolo Marinho de Andrade

    2016-01-01

    The alphabaculovirus Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) is the world's most successful viral bioinsecticide. Through the 1980s and 1990s, this virus was extensively used for biological control of populations of Anticarsia gemmatalis (Velvetbean caterpillar) in soybean crops. During this period, genetic studies identified several variable loci in the AgMNPV; however, most of them were not characterized at the sequence level. In this study we report a full genome comparison among 17 wild-type isolates of AgMNPV. We found the pangenome of this virus to contain at least 167 hypothetical genes, 151 of which are shared by all genomes. The gene bro-a that might be involved in host specificity and carrying transporter is absent in some genomes, and new hypothetical genes were observed. Among these genes there is a unique rnf12-like gene, probably implicated in ubiquitination. Events of gene fission and fusion are common, as four genes have been observed as single or split open reading frames. Gains and losses of genomic fragments (from 20 to 900 bp) are observed within tandem repeats, such as in eight direct repeats and four homologous regions. Most AgMNPV genes present low nucleotide diversity, and variable genes are mainly located in a locus known to evolve through homologous recombination. The evolution of AgMNPV is mainly driven by small indels, substitutions, gain and loss of nucleotide stretches or entire coding sequences. These variations may cause relevant phenotypic alterations, which probably affect the infectivity of AgMNPV. This work provides novel information on genomic evolution of the AgMNPV in particular and of baculoviruses in general. PMID:26615220

  11. Proteomic analyses of baculovirus Anticarsia gemmatalis multiple nucleopolyhedrovirus budded and occluded virus.

    PubMed

    Braconi, Carla Torres; Ardisson-Araújo, Daniel Mendes Pereira; Paes Leme, Adriana Franco; Oliveira, Juliana Velasco de Castro; Pauletti, Bianca Alves; Garcia-Maruniak, Alejandra; Ribeiro, Bergmann Morais; Maruniak, James E; Zanotto, Paolo Marinho de Andrade

    2014-04-01

    Baculoviruses infect insects, producing two distinct phenotypes during the viral life cycle: the budded virus (BV) and the occlusion-derived virus (ODV) for intra- and inter-host spread, respectively. Since the 1980s, several countries have been using Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) as a biological control agent against the velvet bean caterpillar, A. gemmatalis. The genome of AgMNPV isolate 2D (AgMNPV-2D) carries at least 152 potential genes, with 24 that possibly code for structural proteins. Proteomic studies have been carried out on a few baculoviruses, with six ODV and two BV proteomes completed so far. Moreover, there are limited data on virion proteins carried by AgMNPV-2D. Therefore, structural proteins of AgMNPV-2D were analysed by MALDI- quadrupole-TOF and liquid chromatography MS/MS. A total of 44 proteins were associated with the ODV and 33 with the BV of AgMNPV-2D. Although 38 structural proteins were already known, we found six new proteins in the ODV and seven new proteins carried by the AgMNPV-2D BV. Eleven cellular proteins that were found on several other enveloped viruses were also identified, which are possibly carried with the virion. These findings may provide novel insights into baculovirus biology and their host interaction. Moreover, our data may be helpful in subsequent applied studies aiming to improve AgMNPV use as a biopesticide and a biotechnology tool for gene expression or delivery. PMID:24443474

  12. A hypothetical model of crossing Bombyx mori nucleopolyhedrovirus through its host midgut physical barrier.

    PubMed

    Cheng, Yang; Wang, Xue-Yang; Hu, Hao; Killiny, Nabil; Xu, Jia-Ping

    2014-01-01

    Bombyx mori nucleopolyhedrovirus (BmNPV) is a primary pathogen of silkworm (B. mori) that causes severe economic losses each year. However, the molecular mechanisms of silkworm-BmNPV interactions, especially the silkworm proteins that can interact with the virus, are still largely unknown. In this study, the total and membrane proteins of silkworm midguts were displayed using one- and two-dimensional electrophoresis. A virus overlay assay was used to detect B. mori proteins that specifically bind to BmNPV particles. Twelve proteins were located and identified using mass spectrometry, and the different expression of the corresponding genes in BmNPV susceptible and resistant silkworm strains also indicated their involvement in BmNPV infection. The 12 proteins are grouped based on their potential roles in viral infection, for example, endocytosis, intracellular transportation, and host responses. Based on these results, we hypothesize the following: I) vacuolar ATP synthase catalytic subunit A and subunit B may be implicated in the process of the membrane fusion of virus and the release of the nucleocapsid into cytoplasm; II) actin, enolase and phosphoglycerate kinase are cytoskeleton associated proteins and may play an important role in BmNPV intracellular transportation; III) mitochondrial prohibitin complex protein 2, ganglioside-induced differentiation-associated protein, calreticulin, regucalcin-like isoform X1 and 60 kDa heat shock protein are involved in cell apoptosis regulation during BmNPV infection in larvae midguts; IV) ribosomal P0 may be associated with BmNPV infection by regulating gene expression of BmNPV; V) arginine kinase has a role in the antiviral activities against BmNPV. Our work should prove informative by providing multiple protein targets and a novel direction to investigate the molecular mechanisms of the interactions between silkworms and BmNPV. PMID:25502928

  13. Genome sequence of Perigonia lusca single nucleopolyhedrovirus: insights into the evolution of a nucleotide metabolism enzyme in the family Baculoviridae.

    PubMed

    Ardisson-Araújo, Daniel M P; Lima, Rayane Nunes; Melo, Fernando L; Clem, Rollie J; Huang, Ning; Báo, Sônia Nair; Sosa-Gómez, Daniel R; Ribeiro, Bergmann M

    2016-01-01

    The genome of a novel group II alphabaculovirus, Perigonia lusca single nucleopolyhedrovirus (PeluSNPV), was sequenced and shown to contain 132,831 bp with 145 putative ORFs (open reading frames) of at least 50 amino acids. An interesting feature of this novel genome was the presence of a putative nucleotide metabolism enzyme-encoding gene (pelu112). The pelu112 gene was predicted to encode a fusion of thymidylate kinase (tmk) and dUTP diphosphatase (dut). Phylogenetic analysis indicated that baculoviruses have independently acquired tmk and dut several times during their evolution. Two homologs of the tmk-dut fusion gene were separately introduced into the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) genome, which lacks tmk and dut. The recombinant baculoviruses produced viral DNA, virus progeny, and some viral proteins earlier during in vitro infection and the yields of viral occlusion bodies were increased 2.5-fold when compared to the parental virus. Interestingly, both enzymes appear to retain their active sites, based on separate modeling using previously solved crystal structures. We suggest that the retention of these tmk-dut fusion genes by certain baculoviruses could be related to accelerating virus replication and to protecting the virus genome from deleterious mutation. PMID:27273152

  14. The utility of camptothecin as a synergist of Bacillus thuringiensis var. kurstaki and nucleopolyhedroviruses against Trichoplusia ni and Spodoptera exigua.

    PubMed

    Sun, Shifeng; Cheng, Zhongshan; Fan, Jing; Cheng, Xinghu; Pang, Yi

    2012-08-01

    We studied the effect of combining microbial pesticides with camptothecin (CPT) on the mortality of two lepidopteran insects: Trichoplusia ni (Hübner) and Spodoptera exigua (Hübner). CPT is an alkaloid that is often used as an anticancer agent. Here, CPT was evaluated as a microbial pesticide synergist of Bacillus thuringiensis (Bt) and insect baculovirus. The toxicity of CPT and its synergistic effects on two microbial pesticides were studied using the diet overlay method. Bioassay results showed that CPT significantly enhances the toxicity of Bt variety kurstaki to S. exigua and T ni. In addition, CPT strongly enhanced the infectivity of Autographa californica (Speyer) multinucleocapsid nucleopolyhedrovirus (AcMNPV) and S. exigua nucleopolyhedrovirus (SeMNPV). Using light microscopy, we found that CPT disrupts the peritrophic membrane of T. ni larvae and severely affects the structure of the midgut, resulting in an abnormal gut lumen morphology. We speculate that CPT increases toxicity by affecting the permeability of the peritrophic membrane. PMID:22928294

  15. Genome sequence of Perigonia lusca single nucleopolyhedrovirus: insights into the evolution of a nucleotide metabolism enzyme in the family Baculoviridae

    PubMed Central

    Ardisson-Araújo, Daniel M. P.; Lima, Rayane Nunes; Melo, Fernando L.; Clem, Rollie J.; Huang, Ning; Báo, Sônia Nair; Sosa-Gómez, Daniel R.; Ribeiro, Bergmann M.

    2016-01-01

    The genome of a novel group II alphabaculovirus, Perigonia lusca single nucleopolyhedrovirus (PeluSNPV), was sequenced and shown to contain 132,831 bp with 145 putative ORFs (open reading frames) of at least 50 amino acids. An interesting feature of this novel genome was the presence of a putative nucleotide metabolism enzyme-encoding gene (pelu112). The pelu112 gene was predicted to encode a fusion of thymidylate kinase (tmk) and dUTP diphosphatase (dut). Phylogenetic analysis indicated that baculoviruses have independently acquired tmk and dut several times during their evolution. Two homologs of the tmk-dut fusion gene were separately introduced into the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) genome, which lacks tmk and dut. The recombinant baculoviruses produced viral DNA, virus progeny, and some viral proteins earlier during in vitro infection and the yields of viral occlusion bodies were increased 2.5-fold when compared to the parental virus. Interestingly, both enzymes appear to retain their active sites, based on separate modeling using previously solved crystal structures. We suggest that the retention of these tmk-dut fusion genes by certain baculoviruses could be related to accelerating virus replication and to protecting the virus genome from deleterious mutation. PMID:27273152

  16. Complete sequence and organization of Antheraea pernyi nucleopolyhedrovirus, a dr-rich baculovirus

    PubMed Central

    Nie, Zuo-Ming; Zhang, Zhi-Fang; Wang, Dan; He, Ping-An; Jiang, Cai-Ying; Song, Li; Chen, Fang; Xu, Jie; Yang, Ling; Yu, Lin-Lin; Chen, Jian; Lv, Zheng-Bing; Lu, Jing-Jing; Wu, Xiang-Fu; Zhang, Yao-Zhou

    2007-01-01

    Background The completion and reporting of baculovirus genomes is extremely important as it advances our understanding of gene function and evolution. Due to the large number of viral genomes now sequenced it is very important that authors present significantly detailed analyses to advance the understanding of the viral genomes. However, there is no report of the Antheraea pernyi nucleopolyhedrovirus (AnpeNPV) genome. Results The genome of AnpeNPV, which infects Chinese tussah silkworm (Antheraea pernyi), was sequenced and analyzed. The genome was 126,629 bp in size. The G+C content of the genome, 53.4%, was higher than that of most of the sequenced baculoviruses. 147 open reading frames (ORFs) that putatively encode proteins of 50 or more amino acid residues with minimal overlap were determined. Of the 147 ORFs, 143 appeared to be homologous to other baculovirus genes, and 4 were unique to AnpeNPV. Furthermore, there are still 29 and 33 conserved genes present in all baculoviruses and all lepidopteran baculoviruses respectively. In addition, the total number of genes common to all lepidopteran NPVs is sill 74, however the 74 genes are somewhat different from the 74 genes identified before because of some new sequenced NPVs. Only 6 genes were found exclusively in all lepidopteran NPVs and 12 genes were found exclusively in all Group I NPVs. AnpeNPV encodes v-trex(Anpe115, a 3' to 5' repair exonuclease), which was observed only in CfMNPV and CfDEFNPV in Group I NPVs. This gene potentially originated by horizontal gene transfer from an ancestral host. In addition, AnpeNPV encodes two conotoxin-like gene homologues (ctls), ctl1 and ctl2, which were observed only in HycuNPV, OpMNPV and LdMNPV. Unlike other baculoviruses, only 3 typical homologous regions (hrs) were identified containing 2~9 repeats of a 30 bp-long palindromic core. However, 24 perfect or imperfect direct repeats (drs) with a high degree of AT content were found within the intergenic spacer regions that

  17. The Host Specificities of Baculovirus per os Infectivity Factors

    PubMed Central

    Song, Jingjiao; Wang, Xi; Hou, Dianhai; Huang, Huachao; Liu, Xijia; Deng, Fei; Wang, Hualin; Arif, Basil M.; Hu, Zhihong; Wang, Manli

    2016-01-01

    Baculoviruses are insect-specific pathogens with a generally narrow host ranges. Successful primary infection is initiated by the proper interaction of at least 8 conserved per os infectivity factors (PIFs) with the host’s midgut cells, a process that remains largely a mystery. In this study, we investigated the host specificities of the four core components of the PIF complex, P74, PIF1, PIF2 and PIF3 by using Helicoverpa armigera nucleopolyhedrovirus (HearNPV) backbone. The four pifs of HearNPV were replaced by their counterparts from a group I Autographa californica multiple nucleopolyhedrovirus (AcMNPV) or a group II Spodoptera litura nucleopolyhedrovirus (SpltNPV). Transfection and infection assays showed that all the recombinant viruses were able to produce infectious budded viruses (BVs) and were lethal to H. armigera larvae via intrahaemocoelic injection. However, feeding experiments using very high concentration of occlusion bodies demonstrated that all the recombinant viruses completely lost oral infectivity except SpltNPV pif3 substituted pif3-null HearNPV (vHaBacΔpif3-Sppif3-ph). Furthermore, bioassay result showed that the median lethal concentration (LC50) value of vHaBacΔpif3-Sppif3-ph was 23-fold higher than that of the control virus vHaBacΔpif3-Hapif3-ph, indicating that SpltNPV pif3 can only partially substitute the function of HearNPV pif3. These results suggested that most of PIFs tested have strict host specificities, which may account, at least in part, for the limited host ranges of baculoviruses. PMID:27454435

  18. Prevalence of Helicoverpa zea (Lepidoptera: Noctuidae) on late season volunteer corn in Mississippi: implications on Bt resistance management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The southern United States has a long growing period between corn harvest and first winter frost, so volunteer corn which germinates after corn harvest has a growing period sufficient for corn earworm, Helicoverpa zea (Boddie) to feed on these plants. However, lower air temperatures can limit larval...

  19. Complete mitochondrial genome of Helicoverpa zea (Boddie) and expression profiles of mitochondrial-encoded genes in early and late embryos

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The mitochondrial genome of the bollworm, Helicoverpa zea, 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 mitogen...

  20. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Newly emerged bollworm adults, Helicoverpa zea (Boddie) require carbohydrate source from plant exudates and nectars for reproduction. Adults actively seek such feeding sites upon eclosion in their natural habitat. We wanted to evaluate this nocturnal behavior of the bollworm for potential use as a p...

  1. Genetic Variation for Resistance to Bacillus thuringiensis Toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in Eastern North Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to evaluate resistance to Bacillus thuringiensis Berliner toxins, female bollworm moths, Helicoverpa zea (Boddie), were collected from four light trap locations in two eastern North Carolina counties from August-October during 2001 and 2002. Moths were allowed to oviposit, and upon hatch, ...

  2. Risk assessment for Helicoverpa zea (Lepidoptera: Noctuidae) resistance on dual-gene versus single-gene corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent changes in EPA regulations have prompted concern in some experts that transgenic corn expressing two lepidopteran-active genes from the soil bacterium Bacillus thuringiensis (Bt) (dual-gene) may result in more rapid selection for resistance in Helicoverpa zea (Boddie) than corn expressing a s...

  3. Engineering a Recombinant Baculovirus with a Peptide Hormone Gene and its Effect on the Corn Earworm, Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The helicokinins are peptides identified from Helicoverpa zea that when injected into the larvae were found to cause excessive diuresis and loss of feeding activity. Of the three peptides, helicokinin II (HezK-II) was found to be most potent. A synthetic gene encoding HezK-II was constructed based o...

  4. Detection and Evolution of Resistance to the Pyrethroid Cypermethrin in Bollworm, Helicoverpa zea (Lepidoptera, Noctuidae) in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The bollworm Helicoverpa zea (Boddie) is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn and soybeans. A statewide program that evaluated cypermethrin resist...

  5. Field efficacy and transmission of fast- and slow-killing nucleopolyhedroviruses that are infectious to Adoxophyes honmai (Lepidoptera: Tortricidae).

    PubMed

    Takahashi, Maho; Nakai, Madoka; Saito, Yasumasa; Sato, Yasushi; Ishijima, Chikara; Kunimi, Yasuhisa

    2015-03-01

    The smaller tea tortrix, Adoxophyes honmai (Lepidoptera: Tortricidae), is an economically important pest of tea in Japan. Previous work showed that a fast-killing nucleopolyhedrovirus (NPV) isolated from A. orana (AdorNPV) and a slow-killing NPV isolated from A. honmai (AdhoNPV) are both infectious to A. honmai larvae. Field application of these different NPVs was conducted against an A. honmai larval population in tea plants, and the control efficacy and transmission rate of the two NPVs were compared. The slow-killing AdhoNPV showed lower field efficacy, in terms of preventing damage caused by A. honmai larvae against the tea plants, than the fast-killing AdorNPV. However, AdhoNPV had a significantly higher horizontal transmission rate than AdorNPV. These results show that AdorNPV is suitable as an inundative agent, while AdhoNPV is an appropriate inoculative agent. PMID:25793940

  6. Field Efficacy and Transmission of Fast- and Slow-Killing Nucleopolyhedroviruses that Are Infectious to Adoxophyes honmai (Lepidoptera: Tortricidae)

    PubMed Central

    Takahashi, Maho; Nakai, Madoka; Saito, Yasumasa; Sato, Yasushi; Ishijima, Chikara; Kunimi, Yasuhisa

    2015-01-01

    The smaller tea tortrix, Adoxophyes honmai (Lepidoptera: Tortricidae), is an economically important pest of tea in Japan. Previous work showed that a fast-killing nucleopolyhedrovirus (NPV) isolated from A. orana (AdorNPV) and a slow-killing NPV isolated from A. honmai (AdhoNPV) are both infectious to A. honmai larvae. Field application of these different NPVs was conducted against an A. honmai larval population in tea plants, and the control efficacy and transmission rate of the two NPVs were compared. The slow-killing AdhoNPV showed lower field efficacy, in terms of preventing damage caused by A. honmai larvae against the tea plants, than the fast-killing AdorNPV. However, AdhoNPV had a significantly higher horizontal transmission rate than AdorNPV. These results show that AdorNPV is suitable as an inundative agent, while AdhoNPV is an appropriate inoculative agent. PMID:25793940

  7. The BRO proteins of Bombyx mori nucleopolyhedrovirus are nucleocytoplasmic shuttling proteins that utilize the CRM1-mediated nuclear export pathway

    SciTech Connect

    Kang, Won Kyung . E-mail: wkkang@riken.jp; Kurihara, Masaaki . E-mail: mkuri@riken.jp; Matsumoto, Shogo . E-mail: smatsu@riken.jp

    2006-06-20

    The BRO proteins of Bombyx mori nucleopolyhedrovirus (BmNPV) display a biphasic pattern of intracellular localization during infection. At early times, they reside in the nucleus but then show both cytoplasmic and nuclear localization as the infection proceeds. Therefore, we examined the possibility of nuclear export. Using inhibitors, we reveal that BmNPV BRO proteins shuttle between the nucleus and cytoplasm. Mutations on the leucine-rich region of BRO proteins resulted in nuclear accumulation of transiently expressed proteins, suggesting that this region functions as a CRM1-dependent nuclear export signal (NES). On the contrary, mutant BRO-D with an altered NES did not show nuclear accumulation in infected cells, although protein production seemed to be reduced. RT-PCR analysis showed that the lower level of protein production was due to a reduction in RNA synthesis. Taken together, our results suggest that BRO proteins are nucleocytoplasmic shuttling proteins that utilize the CRM1-mediated nuclear export pathway.

  8. Analysis of the Genome of the Sexually Transmitted Insect Virus Helicoverpa zea Nudivirus 2

    PubMed Central

    Burand, John P.; Kim, Woojin; Afonso, Claudio L.; Tulman, Edan R.; Kutish, Gerald F.; Lu, Zhiqiang; Rock, Daniel L.

    2012-01-01

    The sexually transmitted insect virus Helicoverpa zea nudivirus 2 (HzNV-2) was determined to have a circular double-stranded DNA genome of 231,621 bp coding for an estimated 113 open reading frames (ORFs). HzNV-2 is most closely related to the nudiviruses, a sister group of the insect baculoviruses. Several putative ORFs that share homology with the baculovirus core genes were identified in the viral genome. However, HzNV-2 lacks several key genetic features of baculoviruses including the late transcriptional regulation factor, LEF-1 and the palindromic hrs, which serve as origins of replication. The HzNV-2 genome was found to code for three ORFs that had significant sequence homology to cellular genes which are not generally found in viral genomes. These included a presumed juvenile hormone esterase gene, a gene coding for a putative zinc-dependent matrix metalloprotease, and a major facilitator superfamily protein gene; all of which are believed to play a role in the cellular proliferation and the tissue hypertrophy observed in the malformation of reproductive organs observed in HzNV-2 infected corn earworm moths, Helicoverpa zea. PMID:22355451

  9. Engineered chloroplast dsRNA silences cytochrome p450 monooxygenase, V-ATPase and chitin synthase genes in the insect gut and disrupts Helicoverpa armigera larval development and pupation

    PubMed Central

    Jin, Shuangxia; Singh, Nameirakpam D.; Li, Lebin; Zhang, Xianlong; Daniell, Henry

    2015-01-01

    Summary In the past two decades, chloroplast genetic engineering has been advanced to achieve high-level protein accumulation but not for down-regulation of targeted genes. Therefore, in this report, lepidopteran chitin synthase (Chi), cytochrome P450 monooxygenase (P450) and V-ATPase dsRNAs were expressed via the chloroplast genome to study RNA interference (RNAi) of target genes in intended hosts. PCR and Southern blot analysis confirmed homoplasmy and site-specific integration of transgene cassettes into the chloroplast genomes. Northern blots and real-time qRT-PCR confirmed abundant processed and unprocessed dsRNA transcripts (up to 3.45 million copies of P450 dsRNAs/μg total RNA); the abundance of cleaved dsRNA was greater than the endogenous psbA transcript. Feeding of leaves expressing P450, Chi and V-ATPase dsRNA decreased transcription of the targeted gene to almost undetectable levels in the insect midgut, likely after further processing of dsRNA in their gut. Consequently, the net weight of larvae, growth and pupation rates were significantly reduced by chloroplast-derived dsRNAs. Taken together, successful expression of dsRNAs via the chloroplast genome for the first time opens the door to study RNA interference/processing within plastids. Most importantly, dsRNA expressed in chloroplasts can be utilized for gene inactivation to confer desired agronomic traits or for various biomedical applications, including down-regulation of dysfunctional genes in cancer or autoimmune disorders, after oral delivery of dsRNA bioencapsulated within plant cells. PMID:25782349

  10. Engineered chloroplast dsRNA silences cytochrome p450 monooxygenase, V-ATPase and chitin synthase genes in the insect gut and disrupts Helicoverpa armigera larval development and pupation.

    PubMed

    Jin, Shuangxia; Singh, Nameirakpam D; Li, Lebin; Zhang, Xianlong; Daniell, Henry

    2015-04-01

    In the past two decades, chloroplast genetic engineering has been advanced to achieve high-level protein accumulation but not for down-regulation of targeted genes. Therefore, in this report, lepidopteran chitin synthase (Chi), cytochrome P450 monooxygenase (P450) and V-ATPase dsRNAs were expressed via the chloroplast genome to study RNA interference (RNAi) of target genes in intended hosts. PCR and Southern blot analysis confirmed homoplasmy and site-specific integration of transgene cassettes into the chloroplast genomes. Northern blots and real-time qRT-PCR confirmed abundant processed and unprocessed dsRNA transcripts (up to 3.45 million copies of P450 dsRNAs/μg total RNA); the abundance of cleaved dsRNA was greater than the endogenous psbA transcript. Feeding of leaves expressing P450, Chi and V-ATPase dsRNA decreased transcription of the targeted gene to almost undetectable levels in the insect midgut, likely after further processing of dsRNA in their gut. Consequently, the net weight of larvae, growth and pupation rates were significantly reduced by chloroplast-derived dsRNAs. Taken together, successful expression of dsRNAs via the chloroplast genome for the first time opens the door to study RNA interference/processing within plastids. Most importantly, dsRNA expressed in chloroplasts can be utilized for gene inactivation to confer desired agronomic traits or for various biomedical applications, including down-regulation of dysfunctional genes in cancer or autoimmune disorders, after oral delivery of dsRNA bioencapsulated within plant cells. PMID:25782349

  11. Efficient isolation, purification, and characterization of the Helicoverpa zea VHDL receptor.

    PubMed

    Persaud, Deryck R; Yousefi, Vandad; Haunerland, Norbert

    2003-12-01

    The study of fat body receptors (e.g., VHDL receptor) in Lepidoptera has been irksome due to the fact that isolation and purification of these proteins are difficult and resulted in extremely low yields. A rapid and efficient method is presented for the purification of Helicoverpa zea VHDL receptor by the use of VHDL-biotin ligand complexed to streptavidin coated magnetic beads. The technique can be easily applied to other ligands and allows for the purification of membrane proteins with higher yields compared to previously used methods involving immunopurification. Although the purified protein can be characterized by Western and non-radioactive ligand blots using enhanced chemiluminescence (ECL), a non-radioactive ligand blot method using VHDL-FITC is presented, which allows for the quick analysis of the receptor directly from the blot under standard UV light. Sufficient receptor protein has been derived for amino acid analysis, receptor-ligand and xenobiotic binding studies. PMID:14965772

  12. Molecular identification and expression analysis of a diapause hormone receptor in the corn earworm, Helicoverpa zea.

    PubMed

    Zhang, Qirui; Piermarini, Peter M; Nachman, Ronald J; Denlinger, David L

    2014-03-01

    Diapause hormone (DH) is an insect neuropeptide that is highly effective in terminating the overwintering pupal diapause in members of the Helicoverpa/Heliothis complex of agricultural pests, thus DH and related compounds have promise as tools for pest management. To augment our development of effective DH analogs and antagonists that could be used as diapause disruptors this study focuses on the cloning and identification of the DH receptor (DHR) in the corn earworm, Helicoverpa zea. The full-length dhr cDNA contains 2153 nucleotides encoding 511 amino acids. Our results suggest there are at least two splicing variants of Hezea-DHR. Hydrophobicity analysis and sequence alignment indicate that Hezea-DHR has 7 transmembrane regions and a highly conserved C-terminal region that is also present in related receptors. Hezea-DHR has 95%, 82% and 79% identity to a partial DHR sequence from Heliothis virescens, a full-length DHR in Orgyia thyellina, and DHR-1 in Bombyx mori, but only 45-49% identity to pheromone biosynthesis activating neuropeptide receptor (PBANR). Expression of dhr mRNA remained low in whole body extracts throughout diapause and in young nondiapausing pupae, but was distinctly elevated as development ensued in pharate adults 7 days after pupation. The highest expression of dhr mRNA we noted was in the ovary. A DHR fusion protein with enhanced-green fluorescent protein was successfully expressed heterologously in X. laevis oocytes, as verified by fluorescent imaging and Western blots, but an electrophysiological assay failed to detect receptor-ligand binding activity, which suggests that an essential cofactor and/or accessory protein is required for functional activity of the DHR. PMID:24345336

  13. Characterization of the RNA-binding regions in protein p36 of Heliothis armigera cypovirus 14.

    PubMed

    Chen, Wuguo; Hu, Yuanyang; Li, Yang; Yu, Zheng; Dong, Changjin; Cai, Dawei; Zhang, Jiamin

    2007-05-01

    Some proteins of cypovirus (CPV) bind to RNA, probably contributing to the replication of viral genome. However, little is known about whether any protein from Heliothis armigera cypovirus (HaCPV) could bind to RNA. In this study, we cloned the ORF of segment 9 (S9) of HaCPV, serotype 14, into pMAL-c2X for the generation and purification of maltose binding protein (MBP) fused protein p36 (MBP-p36). The analysis of the RNA-binding properties of MBP-p36 revealed that p36, but not MBP alone, bound to ssRNA of CPV. Furthermore, the ssRNA-binding activities of p36 were significantly inhibited or completely eliminated by protein denaturants or unsuitable concentrations of NaCl. Importantly, the formation of ssRNA/p36 was only competitively inhibited by a heavy dose of competitive non-viral ssRNA or dsRNA, but not by ssDNA and dsDNA, suggesting that p36 bound to both ssRNA and dsRNA, but not DNA. Moreover, the characterization of different mutants of p36 revealed that the regions 1-26aa, 154-170aa, and 229-238aa, but not region 291-320aa, may be crucial for the ssRNA-binding ability of p36. Conceivably, the sensitivity of p36 to denaturants and the synergetic effect of different regions suggest that the RNA-binding ability of p36 may be conformation-dependent. Thus, our findings provide new insights into understanding the genomic function of HaCPV-14. PMID:17350708

  14. Autographa californica Multiple Nucleopolyhedrovirus DNA Polymerase C Terminus Is Required for Nuclear Localization and Viral DNA Replication

    PubMed Central

    Feng, Guozhong

    2014-01-01

    ABSTRACT The DNA polymerase (DNApol) of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is essential for viral DNA replication. The DNApol exonuclease and polymerase domains are highly conserved and are considered functional in DNA replication. However, the role of the DNApol C terminus has not yet been characterized. To identify whether only the exonuclease and polymerase domains are sufficient for viral DNA replication, several DNApol C-terminal truncations were cloned into a dnapol-null AcMNPV bacmid with a green fluorescent protein (GFP) reporter. Surprisingly, most of the truncation constructs, despite containing both exonuclease and polymerase domains, could not rescue viral DNA replication and viral production in bacmid-transfected Sf21 cells. Moreover, GFP fusions of these same truncations failed to localize to the nucleus. Truncation of the C-terminal amino acids 950 to 984 showed nuclear localization but allowed for only limited and delayed viral spread. The C terminus contains a typical bipartite nuclear localization signal (NLS) motif at residues 804 to 827 and a monopartite NLS motif at residues 939 to 948. Each NLS, as a GFP fusion peptide, localized to the nucleus, but both NLSs were required for nuclear localization of DNApol. Alanine substitutions in a highly conserved baculovirus DNApol sequence at AcMNPV DNApol amino acids 972 to 981 demonstrated its importance for virus production and DNA replication. Collectively, the data indicated that the C terminus of AcMNPV DNApol contains two NLSs and a conserved motif, all of which are required for nuclear localization of DNApol, viral DNA synthesis, and virus production. IMPORTANCE The baculovirus DNA polymerase (DNApol) is a highly specific polymerase that allows viral DNA synthesis and hence virus replication in infected insect cells. We demonstrated that the exonuclease and polymerase domains of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) alone are

  15. Trichoplusia ni Kinesin-1 Associates with Autographa californica Multiple Nucleopolyhedrovirus Nucleocapsid Proteins and Is Required for Production of Budded Virus

    PubMed Central

    Biswas, Siddhartha; Blissard, Gary W.

    2016-01-01

    ABSTRACT The mechanism by which nucleocapsids of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) egress from the nucleus to the plasma membrane, leading to the formation of budded virus (BV), is not known. AC141 is a nucleocapsid-associated protein required for BV egress and has previously been shown to be associated with β-tubulin. In addition, AC141 and VP39 were previously shown by fluorescence resonance energy transfer by fluorescence lifetime imaging to interact directly with the Drosophila melanogaster kinesin-1 light chain (KLC) tetratricopeptide repeat (TPR) domain. These results suggested that microtubule transport systems may be involved in baculovirus nucleocapsid egress and BV formation. In this study, we investigated the role of lepidopteran microtubule transport using coimmunoprecipitation, colocalization, yeast two-hybrid, and small interfering RNA (siRNA) analyses. We show that nucleocapsid AC141 associates with the lepidopteran Trichoplusia ni KLC and kinesin-1 heavy chain (KHC) by coimmunoprecipitation and colocalization. Kinesin-1, AC141, and microtubules colocalized predominantly at the plasma membrane. In addition, the nucleocapsid proteins VP39, FP25, and BV/ODV-C42 were also coimmunoprecipitated with T. ni KLC. Direct analysis of the role of T. ni kinesin-1 by downregulation of KLC by siRNA resulted in a significant decrease in BV production. Nucleocapsids labeled with VP39 fused with three copies of the mCherry fluorescent protein also colocalized with microtubules. Yeast two-hybrid analysis showed no evidence of a direct interaction between kinesin-1 and AC141 or VP39, suggesting that either other nucleocapsid proteins or adaptor proteins may be required. These results further support the conclusion that microtubule transport is required for AcMNPV BV formation. IMPORTANCE In two key processes of the replication cycle of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV), nucleocapsids are

  16. Development of a multiplex polymerase chain reaction for the simultaneous detection of microsporidians, nucleopolyhedrovirus, and densovirus infecting silkworms.

    PubMed

    Ravikumar, G; Raje Urs, S; Vijaya Prakash, N B; Rao, C G P; Vardhana, K V

    2011-07-01

    We have developed a novel PCR-based assay for individual and simultaneous detection of three major pathogens (microsporidians, nucleopolyhedrovirus (NPV) and densovirus (DNV)) infecting the silkworm, Bombyx mori. Multiplex PCR, using three primer pairs, two of which were designed from the conserved regions of 16S small subunit ribosomal RNA gene of microsporidians, and polyhedrin gene of NPVs respectively, and a third primer pair designed from the internal sequences of B. mori DNVs (BmDNV), showed discrete and pathogen specific PCR products. The assay showed high specificity and sensitivity for the pathogenic DNA. Under optimized PCR conditions, the assay yielded a 794bp DNA fragment from Nosema bombycis, 471bp fragment from B. mori NPV (BmNPV) and 391bp fragment from BmDNV. Further, this detection method was successfully applied to other silkworm species such as Antheraea mylitta and Samia cynthia ricini, in detecting same or similar pathogens infecting them. This method is a valuable supplement to the conventional microscopic diagnostic methods and can be used for the early detection of pathogens infecting silkworms. Furthermore it can assist research and extension centers for the safe supply of disease-free silkworms to farmers. PMID:21570404

  17. Betabaculovirus F proteins showed different efficiencies when rescuing the infectivity of gp64-null Autographa californica nucleopolyhedrovirus.

    PubMed

    Yin, Feifei; Wang, Manli; Tan, Ying; Deng, Fei; Vlak, Just M; Hu, Zhihong; Wang, Hualin

    2013-02-01

    The Agrotis segetum granulovirus (AgseGV) F protein was previously identified as the first betabaculovirus F protein with functional homology to Autographa californica nucleopolyhedrovirus (AcMNPV) GP64. In the current study, F proteins from Xestia c-nigrum granulovirus (XecnGV), Cydia pomonella granulovirus (CpGV), Phthorimaea operculella granulovirus (PhopGV), Choristoneura occidentalis granulovirus (ChocGV) and Plutella xylostella GV (PlxyGV) were studied for their ability to rescue the infectivity of gp64-null AcMNPV. Our results showed that most studied betabaculovirus F proteins could replace the function of AcMNPV GP64, however, their efficiencies to rescue the infectivity of gp64-null AcMNPV were substantially different. PlxyF, although fusogenic, was the only protein that failed to substitute the function of AcMNPV GP64. Further studies using Sf9(0p1D) cell line showed that PlxyF appeared to be properly incorporated into AcMNPV virions and underwent correct post-translational cleavage and N-linked glycosylation. However, the gp64-null AcMNPV containing PlxyF could not be propagated in either Sf9 or P. xylostella cells. PMID:23245471

  18. Cloning and Characterization of Sf9 Cell Lamin and the Lamin Conformational Changes during Autographa californica multiple nucleopolyhedrovirus Infection.

    PubMed

    Wei, Wenqiang; Wang, Hongju; Li, Xiaoya; Fang, Na; Yang, Shili; Liu, Hongyan; Kang, Xiaonan; Sun, Xiulian; Ji, Shaoping

    2016-01-01

    At present, the details of lamina alterations after baculovirus infection remain elusive. In this study, a lamin gene in the Sf9 cell line of Spodoptera frugiperda was cloned. The open reading frame (orf) of the Sf9 lamin was 1860 bp and encoded a protein with a molecular weight of 70 kDa. A transfection assay with a red fluorescence protein (rfp)-lamin fusion protein indicated that Sf9 lamin was localized in the nuclear rim. Transmission electron microscopy observations indicated that Autographa californica multiple nucleopolyhedrovirus (AcMNPV) nucleocapsids may pass through the nuclear envelope. Immunofluorescence assay indicated that the lamina showed a ruffled staining pattern with the formation of invaginations in the Sf9 cells infected with AcMNPV, while it was evenly distributed at the nuclear periphery of mock-infected cells. Western blotting results indicated that the total amount of lamin in the baculovirus-infected Sf9 cells was significantly decreased compared with the mock-infected cells. These results imply that AcMNPV infection induces structural and biochemical rearrangements of lamina of Sf9 cells. PMID:27164127

  19. Bombyx mori nucleopolyhedrovirus orf8 encodes a nucleic acid binding protein that colocalizes with IE1 during infection.

    PubMed

    Imai, N; Kurihara, M; Matsumoto, S; Kang, W-K

    2004-08-01

    This report describes the characterization of the Bombyx mori nucleopolyhedrovirus (BmNPV) orf8 gene. Immunoblot analyses demonstrated that orf8 was expressed as an early gene. The ORF8 protein accumulated in the nucleus, and was maintained at relatively constant levels from 4 to 24 h postinfection. Immunoblot analysis failed to detect ORF8 protein associated with budded virus and occlusion derived virus. In addition, immunohistochemical analysis by confocal microscopy showed that ORF8 protein colocalized with IE1 to specific nuclear foci throughout infection. To further examine the function of ORF8, a reporter gene was inserted into the orf8 reading frame. One orf8 disruption mutant (BmD8), which expressed the N-terminal half of ORF8, was isolated. However, it was not possible to isolate a null mutant, suggesting that orf8 may have an important role during viral infection. Single-step growth curves showed that BV production was reduced in BmD8 infected cells. Biochemical analyses indicated that ORF8 bound to nucleic acids. Together, these results suggest that BmNPV ORF8 may be involved in viral DNA replication and/or transcription. PMID:15290382

  20. Autographa californica multiple nucleopolyhedrovirus GP64 protein: Analysis of domain I and V amino acid interactions and membrane fusion activity.

    PubMed

    Yu, Qianlong; Blissard, Gary W; Liu, Tong-Xian; Li, Zhaofei

    2016-01-15

    The Autographa californica multiple nucleopolyhedrovirus GP64 is a class III viral fusion protein. Although the post-fusion structure of GP64 has been solved, its pre-fusion structure and the detailed mechanism of conformational change are unknown. In GP64, domain V is predicted to interact with two domain I segments that flank fusion loop 2. To evaluate the significance of the amino acids involved in these interactions, we examined 24 amino acid positions that represent interacting and conserved residues within domains I and V. In several cases, substitution of a single amino acid involved in a predicted interaction disrupted membrane fusion activity, but no single amino acid pair appears to be absolutely required. We identified 4 critical residues in domain V (G438, W439, T452, and T456) that are important for membrane fusion, and two residues (G438 and W439) that appear to be important for formation or stability of the pre-fusion conformation of GP64. PMID:26655244

  1. Cloning and Characterization of Sf9 Cell Lamin and the Lamin Conformational Changes during Autographa californica multiple nucleopolyhedrovirus Infection

    PubMed Central

    Wei, Wenqiang; Wang, Hongju; Li, Xiaoya; Fang, Na; Yang, Shili; Liu, Hongyan; Kang, Xiaonan; Sun, Xiulian; Ji, Shaoping

    2016-01-01

    At present, the details of lamina alterations after baculovirus infection remain elusive. In this study, a lamin gene in the Sf9 cell line of Spodoptera frugiperda was cloned. The open reading frame (orf) of the Sf9 lamin was 1860 bp and encoded a protein with a molecular weight of 70 kDa. A transfection assay with a red fluorescence protein (rfp)-lamin fusion protein indicated that Sf9 lamin was localized in the nuclear rim. Transmission electron microscopy observations indicated that Autographa californica multiple nucleopolyhedrovirus (AcMNPV) nucleocapsids may pass through the nuclear envelope. Immunofluorescence assay indicated that the lamina showed a ruffled staining pattern with the formation of invaginations in the Sf9 cells infected with AcMNPV, while it was evenly distributed at the nuclear periphery of mock-infected cells. Western blotting results indicated that the total amount of lamin in the baculovirus-infected Sf9 cells was significantly decreased compared with the mock-infected cells. These results imply that AcMNPV infection induces structural and biochemical rearrangements of lamina of Sf9 cells. PMID:27164127

  2. Autographa californica multiple nucleopolyhedrovirus ac142, a core gene that is essential for BV production and ODV envelopment

    SciTech Connect

    McCarthy, Christina B.; Da, Xiaojiang; Donly, Cam; Theilmann, David A.

    2008-03-15

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac142 is a baculovirus core gene and encodes a protein previously shown to associate with occlusion-derived virus (ODV). To determine its role in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac142 deletion virus (AcBAC{sup ac142KO-PH-GFP}). Fluorescence and light microscopy revealed that AcBAC{sup ac142KO-PH-GFP} exhibits a single-cell infection phenotype. Titration assays and Western blot confirmed that AcBAC{sup ac142KO-PH-GFP} is unable to produce budded virus (BV). However, viral DNA replication is unaffected and the development of occlusion bodies in AcBAC{sup ac142KO-PH-GFP}-transfected cells evidenced progression to very late phases of the viral infection. Western blot analysis showed that AC142 is expressed in the cytoplasm and nucleus throughout infection and that it is a structural component of BV and ODV which localizes to nucleocapsids. Electron microscopy indicates that ac142 is required for nucleocapsid envelopment to form ODV and their subsequent occlusion, a fundamental process to all baculoviruses.

  3. Bm59 is an early gene, but is unessential for the propagation and assembly of Bombyx mori nucleopolyhedrovirus.

    PubMed

    Hu, Xiaolong; Shen, Yunwang; Zheng, Qin; Wang, Guobao; Wu, Xiaofeng; Gong, Chengliang

    2016-02-01

    Bombyx mori nucleopolyhedrovirus (BmNPV) is a major pathogen that specifically infects the domestic silkworm and causes serious economic loss to sericulture around the world. The function of BmNPV Bm59 gene in the viral life cycle is inconclusive. To investigate the role of Bm59 during viral infection, the transcription initiation site and temporal expression of Bm59 were analyzed, and Bm59-knockout virus was generated through homologous recombination in Escherichia coli. The results showed that Bm59 is an early transcription gene with an atypia early transcriptional start motif. Budded virion (BV) production and DNA replication in the BmN cells transfected with the Bm59-knockout virus bacmid were similar to those in the cells transfected with the wild-type virus. Electron microscopy revealed that the occlusion-derived virus can be produced in cells infected with the Bm59-knockout virus. These results indicated that Bm59 is an early gene and is not essential for viral replication or assembly of BmNPV. These findings suggested that non-essential gene (Bm59) remained in the viral genome, which may interact with other viral/host genes in a certain situation. PMID:26210473

  4. Abortive replication of Bombyx mori nucleopolyhedrovirus in Sf9 and High Five cells: Defective nuclear transport of the virions

    SciTech Connect

    Katou, Yasuhiro; Ikeda, Motoko; Kobayashi, Michihiro . E-mail: michihir@agr.nagoya-u.ac.jp

    2006-04-10

    Despite close genetic relationship, Bombyx mori nucleopolyhedrovirus (BmNPV) and Autographa californica multicapsid NPV (AcMNPV) display a distinct host range property. Here, BmNPV replication was examined in Sf9 and High Five cells that were nonproductive for BmNPV infection but supported high titers of AcMNPV replication. Recombinant BmNPV, vBm/gfp/lac, containing bm-ie1 promoter-driven egfp showed that few Sf9 and High Five cells infected with vBm/gfp/lac expressed EGFP, while large proportion of EGFP-expressing cells was observed when transfected with vBm/gfp/lac DNA. Immunocytochemical analysis showed that BmNPV was not imported into the nucleus of these two cell lines, while recombinant BmNPV, vBm{delta}64/ac-gp64 possessing AcMNPV gp64 was imported into the nucleus, yielding progeny virions in High Five cells, but not Sf9 cells. These results indicate that the defective nuclear import of infected virions due to insufficient BmNPV GP64 function is involved in the restricted BmNPV replication in Sf9 and High Five cells.

  5. Sequence analysis of the complete genome of Trichoplusia ni single nucleopolyhedrovirus and the identification of a baculoviral photolyase gene

    SciTech Connect

    Willis, Leslie G.; Siepp, Robyn; Stewart, Taryn M.; Erlandson, Martin A.; Theilmann, David A. . E-mail: TheilmannD@agr.gc.ca

    2005-08-01

    The genome of the Trichoplusia ni single nucleopolyhedrovirus (TnSNPV), a group II NPV which infects the cabbage looper (T. ni), has been completely sequenced and analyzed. The TnSNPV DNA genome consists of 134,394 bp and has an overall G + C content of 39%. Gene analysis predicted 144 open reading frames (ORFs) of 150 nucleotides or greater that showed minimal overlap. Comparisons with previously sequenced baculoviruses indicate that 119 TnSNPV ORFs were homologues of previously reported viral gene sequences. Ninety-four TnSNPV ORFs returned an Autographa californica multiple NPV (AcMNPV) homologue while 25 ORFs returned poor or no sequence matches with the current databases. A putative photolyase gene was also identified that had highest amino acid identity to the photolyase genes of Chrysodeixis chalcites NPV (ChchNPV) (47%) and Danio rerio (zebrafish) (40%). In addition unlike all other baculoviruses no obvious homologous repeat (hr) sequences were identified. Comparison of the TnSNPV and AcMNPV genomes provides a unique opportunity to examine two baculoviruses that are highly virulent for a common insect host (T. ni) yet belong to diverse baculovirus taxonomic groups and possess distinct biological features. In vitro fusion assays demonstrated that the TnSNPV F protein induces membrane fusion and syncytia formation and were compared to syncytia formed by AcMNPV GP64.

  6. Tightly Regulated Expression of Autographa californica Multicapsid Nucleopolyhedrovirus Immediate Early Genes Emerges from Their Interactions and Possible Collective Behaviors

    PubMed Central

    Taka, Hitomi; Asano, Shin-ichiro; Matsuura, Yoshiharu; Bando, Hisanori

    2015-01-01

    To infect their hosts, DNA viruses must successfully initiate the expression of viral genes that control subsequent viral gene expression and manipulate the host environment. Viral genes that are immediately expressed upon infection play critical roles in the early infection process. In this study, we investigated the expression and regulation of five canonical regulatory immediate-early (IE) genes of Autographa californica multicapsid nucleopolyhedrovirus: ie0, ie1, ie2, me53, and pe38. A systematic transient gene-expression analysis revealed that these IE genes are generally transactivators, suggesting the existence of a highly interactive regulatory network. A genetic analysis using gene knockout viruses demonstrated that the expression of these IE genes was tolerant to the single deletions of activator IE genes in the early stage of infection. A network graph analysis on the regulatory relationships observed in the transient expression analysis suggested that the robustness of IE gene expression is due to the organization of the IE gene regulatory network and how each IE gene is activated. However, some regulatory relationships detected by the genetic analysis were contradictory to those observed in the transient expression analysis, especially for IE0-mediated regulation. Statistical modeling, combined with genetic analysis using knockout alleles for ie0 and ie1, showed that the repressor function of ie0 was due to the interaction between ie0 and ie1, not ie0 itself. Taken together, these systematic approaches provided insight into the topology and nature of the IE gene regulatory network. PMID:25816136

  7. Development of a Microbial-Based Integrated Pest Management Program for Helicoverpa spp. (Lepidoptera: Noctuidae) and Beneficial Insects on Conventional Cotton Crops in Australia

    PubMed Central

    Mensah, Robert K.; Young, Alison; Rood-England, Leah

    2015-01-01

    Entomopathogenic fungi, when used as a microbial control agent against cotton pests, such as Helicoverpa spp., may have the potential to establish and spread in the environment and to have an impact on both pests and beneficial insects. Information on the effect of entomopathogenic fungi on pests and beneficial insects is crucial for a product to be registered as a biopesticide. The effect of the entomopathogenic fungus BC 639 (Aspergillus sp.) against Helicoverpa spp. and beneficial insects (mostly predatory insects) was studied in the laboratory and in cotton field trials. The results show that when Helicoverpa spp. second instar larvae were exposed to increasing concentrations (from 102 to 109) of the entomopathogenic fungus BC 639, the optimum dose required to kill over 50% of the insects was 1.0 × 107 spores/mL. In the field trials, the number of Helicoverpa spp. per metre on plots treated with 1.0 or 0.50 L/ha of BC 639 was the same as on plots treated with the recommended rate of the commercial insecticide, Indoxacarb. However, when plots were treated with 0.25 L/ha of BC 639, this was not as effective at controlling Helicoverpa spp. as 1.0 or 0.5 L/ha BC 639 or Indoxacarb. BC 639 had less effect on predatory insects when applied at lower rates (0.50 and 0.25 L/ha) than at higher rates (1.0 L/ha). Thus, BC 639 was more selective against predators when applied at lower rates than at the higher rate, but was also more selective than Indoxacarb. Thus, the ability of BC 639 to control Helicoverpa spp. effectively with a minimal effect on predatory insects indicates its potential for enhancing integrated pest management programs and to sustain cotton production. PMID:26463189

  8. Autographa californica multiple nucleopolyhedrovirus ODV-E56 is a per os infectivity factor, but is not essential for binding and fusion of occlusion-derived virus to the host midgut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) occlusion-derived virus (ODV) envelope protein ODV-E56 is essential for oral infection of neonate Heliothis virescens larvae. Here, we present a more detailed study of ODV-E56 function. Bioassays with recombinant clones of AcMNPV lack...

  9. Quantification of soil-to-plant transport of recombinant nucleopolyhedrovirus: effects of soil type and moisture, air currents, and precipitation.

    PubMed

    Fuxa, J R; Richter, A R

    2001-11-01

    Significantly more occlusion bodies (OB) of DuPont viral construct HzSNPV-LqhIT2, expressing a scorpion toxin, were transported by artificial rainfall to cotton plants from sandy soil (70:15:15 sand-silt-clay) than from silt (15:70:15) and significantly more from silt than from clay (15:15:70). The amounts transported by 5 versus 50 mm of precipitation were the same, and transport was zero when there was no precipitation. In treatments that included precipitation, the mean number of viable OB transported to entire, 25- to 35-cm-tall cotton plants ranged from 56 (clay soil, 5 mm of rain) to 226 (sandy soil, 50 mm of rain) OB/plant. In a second experiment, viral transport increased with increasing wind velocity (0, 16, and 31 km/h) and was greater in dry (-1.0 bar of matric potential) than in moist (-0.5 bar) soil. Wind transport was greater for virus in a clay soil than in silt or sand. Only 3.3 x 10(-7) (clay soil, 5 mm rain) to 1.3 x 10(-6) (sandy soil, 50 mm rain) of the OB in surrounding soil in experiment 1 or 1.1 x 10(-7) (-0.5 bar sandy soil, 16-km/h wind) to 1.3 x 10(-6) (-1.0 bar clay soil, 31-km/h wind) in experiment 2 were transported by rainfall or wind to cotton plants. This reduces the risk of environmental release of a recombinant nucleopolyhedrovirus (NPV), because only a very small proportion of recombinant virus in the soil reservoir is transported to vegetation, where it can be ingested by and replicate in new host insects. PMID:11679341

  10. Proteomics of the 26S proteasome in Spodoptera frugiperda cells infected with the nucleopolyhedrovirus, AcMNPV.

    PubMed

    Lyupina, Yulia V; Zatsepina, Olga G; Serebryakova, Marina V; Erokhov, Pavel A; Abaturova, Svetlana B; Kravchuk, Oksana I; Orlova, Olga V; Beljelarskaya, Svetlana N; Lavrov, Andrey I; Sokolova, Olga S; Mikhailov, Victor S

    2016-06-01

    Baculoviruses are large DNA viruses that infect insect species such as Lepidoptera and are used in biotechnology for protein production and in agriculture as insecticides against crop pests. Baculoviruses require activity of host proteasomes for efficient reproduction, but how they control the cellular proteome and interact with the ubiquitin proteasome system (UPS) of infected cells remains unknown. In this report, we analyzed possible changes in the subunit composition of 26S proteasomes of the fall armyworm, Spodoptera frugiperda (Sf9), cells in the course of infection with the Autographa californica multiple nucleopolyhedrovirus (AcMNPV). 26S proteasomes were purified from Sf9 cells by an immune affinity method and subjected to 2D gel electrophoresis followed by MALDI-TOF mass spectrometry and Mascot search in bioinformatics databases. A total of 34 homologues of 26S proteasome subunits of eukaryotic species were identified including 14 subunits of the 20S core particle (7 α and 7 β subunits) and 20 subunits of the 19S regulatory particle (RP). The RP contained homologues of 11 of RPN-type and 6 of RPT-type subunits, 2 deubiquitinating enzymes (UCH-14/UBP6 and UCH-L5/UCH37), and thioredoxin. Similar 2D-gel maps of 26S proteasomes purified from uninfected and AcMNPV-infected cells at 48hpi confirmed the structural integrity of the 26S proteasome in insect cells during baculovirus infection. However, subtle changes in minor forms of some proteasome subunits were detected. A portion of the α5(zeta) cellular pool that presumably was not associated with the proteasome underwent partial proteolysis at a late stage in infection. PMID:26945516

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

    PubMed

    Harrison, Robert L; Rowley, Daniel L; Keena, Melody A

    2016-06-01

    Isolates of the baculovirus species Lymantria dispar multiple nucleopolyhedrovirus have been formulated and applied to suppress outbreaks of the gypsy moth, L. dispar. To evaluate the genetic diversity in this species at the genomic level, the genomes of three isolates from Massachusetts, USA (LdMNPV-Ab-a624), Spain (LdMNPV-3054), and Japan (LdMNPV-3041) were sequenced and compared with four previously determined LdMNPV genome sequences. The LdMNPV genome sequences were collinear and contained the same homologous repeats (hrs) and clusters of baculovirus repeat orf (bro) gene family members in the same relative positions in their genomes, although sequence identities in these regions were low. Of 146 non-bro ORFs annotated in the genome of the representative isolate LdMNPV 5-6, 135 ORFs were found in every other LdMNPV genome, including the 37 core genes of Baculoviridae and other genes conserved in genus Alphabaculovirus. Phylogenetic inference with an alignment of the core gene nucleotide sequences grouped isolates 3041 (Japan) and 2161 (Korea) separately from a cluster containing isolates from Europe, North America, and Russia. To examine phenotypic diversity, bioassays were carried out with a selection of isolates against neonate larvae from three European gypsy moth (Lymantria dispar dispar) and three Asian gypsy moth (Lymantria dispar asiatica and Lymantria dispar japonica) colonies. LdMNPV isolates 2161 (Korea), 3029 (Russia), and 3041 (Japan) exhibited a greater degree of pathogenicity against all L. dispar strains than LdMNPV from a sample of Gypchek. This study provides additional information on the genetic diversity of LdMNPV isolates and their activity against the Asian gypsy moth, a potential invasive pest of North American trees and forests. PMID:27090923

  12. Identification of the Lymantria dispar Nucleopolyhedrovirus Envelope Fusion Protein Provides Evidence for a Phylogenetic Division of the Baculoviridae†

    PubMed Central

    Pearson, Margot N.; Groten, Christoph; Rohrmann, George F.

    2000-01-01

    The complete genome sequences of a number of diverse members of the Baculoviridae including both nucleopolyhedroviruses (NPVs) and granuloviruses (GVs) revealed that they lack a homolog of GP64, the envelope fusion protein of the budded form of Autographa californica multinucleocapsid NPV (AcMNPV) and its close relatives. Computer-assisted analyses of the genome of one of these viruses, Lymantria dispar MNPV (LdMNPV), revealed a single open reading frame (ld130) whose product had the predicted properties of a membrane protein. Characterization of the localization of the products of the full-length ld130 gene and of an ld130-enhanced green fluorescent protein gene (egfp) fusion using both immunofluorescence and fluorescence microscopy revealed that LD130 accumulates at the plasma membranes of cells infected with LdMNPV or transfected with ld130-egfp. In addition, cells transfected with either ld130 or ld130-egfp or infected with wild-type virus undergo membrane fusion at pH 5. Western blot analyses indicate that LD130 is present in infected cells as an 83-kDa protein and is also present in budded virions as a protein doublet containing bands of 81 and 83 kDa. Tunicamycin treatment of infected cells resulted in an immunoreactive band of about 72 kDa, indicating that LD130 is N-glycosylated. Whereas the distribution of gp64 appears to be confined to a relatively closely related group of NPVs, homologs of ld130 are present in a diverse number of both NPVs and GVs. This suggests that LD130 may be the primordial baculovirus envelope fusion protein. PMID:10846096

  13. A Chrysodeixis chalcites Single-Nucleocapsid Nucleopolyhedrovirus Population from the Canary Islands Is Genotypically Structured To Maximize Survival

    PubMed Central

    Bernal, Alexandra; Simón, Oihane; Williams, Trevor; Muñoz, Delia

    2013-01-01

    A Chrysodeixis chalcites single-nucleocapsid nucleopolyhedrovirus wild-type isolate from the Canary Islands, Spain, named ChchSNPV-TF1 (ChchTF1-wt), appears to have great potential as the basis for a biological insecticide for control of the pest. An improved understanding of the genotypic structure of this wild-type strain population should facilitate the selection of genotypes for inclusion in a bioinsecticidal product. Eight genetically distinct genotypes were cloned in vitro: ChchTF1-A to ChchTF1-H. Quantitative real-time PCR (qPCR) analysis confirmed that ChchTF1-A accounted for 36% of the genotypes in the wild-type population. In bioassays, ChchTF1-wt occlusion bodies (OBs) were significantly more pathogenic than any of the component single-genotype OBs, indicating that genotype interactions were likely responsible for the pathogenicity phenotype of wild-type OBs. However, the wild-type population was slower killing and produced higher OB yields than any of the single genotypes alone. These results strongly suggested that the ChchTF1-wt population is structured to maximize its transmission efficiency. Experimental OB mixtures and cooccluded genotype mixtures containing the most abundant and the rarest genotypes, at frequencies similar to those at which they were isolated, revealed a mutualistic interaction that restored the pathogenicity of OBs. In OB and cooccluded mixtures containing only the most abundant genotypes, ChchTF1-ABC, OB pathogenicity was even greater than that of wild-type OBs. The ChchTF1-ABC cooccluded mixture killed larvae 33 h faster than the wild-type population and remained genotypically and biologically stable throughout five successive passages in vivo. In conclusion, the ChchTF1-ABC mixture shows great potential as the active ingredient of a bioinsecticide to control C. chalcites in the Canary Islands. PMID:24096419

  14. The Baculovirus Core Gene ac83 Is Required for Nucleocapsid Assembly and Per Os Infectivity of Autographa californica Nucleopolyhedrovirus

    PubMed Central

    Zhu, Shimao; Wang, Wei; Wang, Yan; Yuan, Meijin

    2013-01-01

    Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac83 is a baculovirus core gene whose function in the AcMNPV life cycle is unknown. In the present study, an ac83-knockout AcMNPV (vAc83KO) was constructed to investigate the function of ac83 through homologous recombination in Escherichia coli. No budded virions were produced in vAc83KO-transfected Sf9 cells, although viral DNA replication was unaffected. Electron microscopy revealed that nucleocapsid assembly was aborted due to the ac83 deletion. Domain-mapping studies revealed that the expression of Ac83 amino acid residues 451 to 600 partially rescued the ability of AcMNPV to produce infectious budded virions. Bioassays indicated that deletion of the chitin-binding domain of Ac83 resulted in the failure of oral infection of Trichoplusia ni larvae by AcMNPV, but AcMNPV remained infectious following intrahemocoelic injection, suggesting that the domain is involved in the binding of occlusion-derived virions to the peritrophic membrane and/or to other chitin-containing insect tissues. It has been demonstrated that Ac83 is the only component with a chitin-binding domain in the per os infectivity factor complex on the occlusion-derived virion envelope. Interestingly, a functional inner nuclear membrane sorting motif, which may facilitate the localization of Ac83 to the envelopes of occlusion-derived virions, was identified by immunofluorescence analysis. Taken together, these results demonstrate that Ac83 plays an important role in nucleocapsid assembly and the establishment of oral infection. PMID:23864639

  15. Comparative proteomics analysis of apoptotic Spodoptera frugiperda cells during p35 knockout Autographa californica multiple nucleopolyhedrovirus infection.

    PubMed

    Yu, Qian; Xiong, Youhua; Liu, Jianliang; Wang, Qin; Qiu, Yuanxin; Wen, Dongling

    2016-06-01

    Infection with Autographa californica multiple nucleopolyhedrovirus (AcMNPV) mutants lacking a functional p35 gene can induce host cell apoptosis, which provides the possibility to use the potential of these viruses in the biological control of pest insects. Nonetheless, the proteomics or the protein changes of Spodoptera frugiperda (Sf9) cells infected with p35 knockout AcMNPV have not yet been studied. To further improve the use of AcMNPV, we set out to analyze the protein composition and protein changes of Sf9 cells of different infection stages by isobaric tag for relative and absolute quantification (iTRAQ) techniques. A total of 4004 sf9 proteins were identified by iTRAQ. After comparation of the significantly expressed 483 proteins from p35koAcMNPV-infected Sf9 cells and the significantly expressed 413 proteins from wtAcMNPV-infected Sf9 cells, we found that 226 proteins were specific to p35koAcMNPV-infected Sf9 cells. The 226 proteins were categorized according to GO classification for insects and were categorized into: biological processes, molecular functions and cellular components. Of interest, the most up-regulated proteins related to Epstein-Barr virus infection, RNA transport, Calcium signaling pathway, cGMP-PKG signaling pathway, oxidative phosphorylation and N-Glycan biosynthesis. Determination of the protein changes in p35 knockout AcMNPV-infected Sf9 cells would facilitate the better use of this virus-host cell interaction in pest insect control and other related fields. PMID:26922645

  16. Nucleopolyhedrovirus infection and/or parasitism by Microplitis pallidipes Szepligeti affect hemocyte apoptosis of Spodoptera exigua (Hübner) larvae.

    PubMed

    Wan, Nian-Feng; Ji, Xiang-Yun; Zhang, Hao; Yang, Jun-Hua; Jiang, Jie-Xian

    2015-11-01

    We determined the effects of parasitism by the endoparasitoid Microplitis pallidipes Szepligeti and/or nucleopolyhedrovirus (NPV) infection on hemocyte apoptosis of Spodoptera exigua (Hübner) larvae. Compared to healthy (control) larvae, larvae that were parasitized, virus-infected, or both all showed a significant increase in hemocyte apoptosis during 48-h observation period. The peaks of hemocyte apoptosis in parasitized, virus-infected and parasitized+infected larvae were at 12, 24 and 48 h after treatment, and were 86.7±1.9, 87.4±3.6 and 76.5±1.6%, respectively. Meanwhile, compared to parasitized larvae, hemocyte apoptosis in jointly parasitized and infected larvae increased by 12.9%, 18.7% and 2.8% at 8, 36 and 48 h respectively, and decreased by 39.0% and 9.1% at 12 and 24h. Compared to virus-infected larvae, hemocyte apoptosis in jointly parasitized and infected larvae increased by 13.4%, 2.4% and 15.3% at 8, 36 and 48 h, respectively, and decreased by 4.0% and 29.9% at 12 and 24h. Our study found that joint and separate parasitism and SeNPV infection induced hemocyte apoptosis of S. exigua larvae. It also revealed that NPV infection promoted host hemocyte apoptosis induced by parasitism at early egg and larval stages of M. pallidipes in host larvae, but inhibited the same effect at late egg stage of M. pallidipes in host larvae, and that parasitism promoted host hemocyte apoptosis induced by NPV infection at early egg and larval stages of M. pallidipes in host larvae, but inhibited the same effect at late egg stage of M. pallidipes in host larvae. PMID:26470677

  17. On the susceptibility of the box tree moth Cydalima perspectalis to Anagrapha falcifera nucleopolyhedrovirus (AnfaNPV).

    PubMed

    Rose, Jana; Kleespies, Regina G; Wang, Yongjie; Wennmann, Jörg T; Jehle, Johannes A

    2013-07-01

    The box tree moth Cydalima perspectalis is an invasive insect pest in many European countries. Caterpillars of this species cause widespread damage on box tree plants. In this study, a new opportunity to control this pest with the baculovirus Anagrapha falcifera nucleopolyhedrovirus (AnfaNPV) was investigated. Initially, AnfaNPV was identified to infect larvae of Diaphania nitidalis by determining the partial nucleotide sequence of the three highly conserved genes polh, lef-8 and lef-9 of the infection causing agent. Two AnfaNPV isolates, termed Dn10 and BI-235, were then propagated in larvae of C. perspectalis and purified by sucrose density centrifugation. A bioassay using leaf disks of box tree was established to evaluate the virulence of both AnfaNPV isolates to neonate C. perspectalis larvae. After 7days, the mortality of larvae was scored and median lethal concentrations (LC50) were determined to 7.8×10(5)OBs/ml for isolate BI-235 and 2.3×10(6)OBs/ml for isolate Dn10 by using probit analysis. Thus, AnfaNPV BI-235 was significantly more virulent to neonate C. perspectalis larvae than Dn10 based on a three times higher LC50 value. Additionally, light and transmission electron microscopic investigations verified high rates of infection in fat body, epidermis and tracheal matrix of C. perspectalis by both AnfaNPV isolates BI-235 and Dn10. In conclusion, the performed laboratory experiments indicate the susceptibility of C. perspectalis to AnfaNPV. PMID:23562977

  18. Deletion Genotypes Reduce Occlusion Body Potency but Increase Occlusion Body Production in a Colombian Spodoptera frugiperda Nucleopolyhedrovirus Population

    PubMed Central

    Barrera, Gloria; Williams, Trevor; Villamizar, Laura; Caballero, Primitivo; Simón, Oihane

    2013-01-01

    A Colombian field isolate (SfCOL-wt) of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is a mixture of different genotypes. To evaluate the insecticidal properties of the different genotypic variants, 83 plaque purified virus were characterized. Ten distinct genotypes were identified (named A through J). SfCOL-A was the most prevalent (71±2%; mean ± SE) showing a PstI restriction profile indistinguishable to that of SfCOL-wt. The remaining nine genotypes presented genomic deletions of 3.8 - 21.8 Kb located mainly between nucleotides 11,436 and 33,883 in the reference genome SfMNPV-B, affecting the region between open reading frames (ORFs) sf20 and sf33. The insecticidal activity of each genotype from SfCOL-wt and several mixtures of genotypes was compared to that of SfCOL-wt. The potency of SfCOL-A occlusion bodies (OBs) was 4.4-fold higher than SfCOL-wt OBs, whereas the speed of kill of SfCOL-A was similar to that of SfCOL-wt. Deletion genotype OBs were similarly or less potent than SfCOL-wt but six deletion genotypes were faster killing than SfCOL-wt. The potency of genotype mixtures co-occluded within OBs were consistently reduced in two-genotype mixtures involving equal proportions of SfCOL-A and one of three deletion genotypes (SfCOL-C, -D or -F). Speed of kill and OB production were improved only when the certain genotype mixtures were co-occluded, although OB production was higher in the SfCOL-wt isolate than in any of the component genotypes, or mixtures thereof. Deleted genotypes reduced OB potency but increased OB production of the SfCOL-wt population, which is structured to maximize the production of OBs in each infected host. PMID:24116220

  19. A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea.

    PubMed

    Brévault, Thierry; Tabashnik, Bruce E; Carrière, Yves

    2015-01-01

    Widely grown transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) can benefit agriculture, but adaptation by pests threatens their continued success. Refuges of host plants that do not make Bt toxins can promote survival of susceptible insects and delay evolution of resistance, particularly if resistance is inherited as a recessive trait. However, data have been lacking to compare the dominance of resistance when Bt and non-Bt seeds are planted in random mixtures versus separate blocks. Here we report results from greenhouse experiments with transgenic cotton producing Bt toxin Cry1Ac and the bollworm, Helicoverpa zea, showing that the dominance of resistance was significantly higher in a seed mixture relative to a block of Bt cotton. The proportion of larvae on non-Bt cotton plants in the seed mixture was also significantly higher than expected under the null hypothesis of random distribution. In simulations based on observed survival, resistance evolved 2- to 4.5-fold faster in the seed mixture relative to separate blocks of Bt and non-Bt cotton. These findings support previous modelling results indicating that block refuges may be more effective than seed mixtures for delaying resistance in pests with mobile larvae and inherently low susceptibility to the toxins in Bt crops. PMID:25950459

  20. Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States

    PubMed Central

    Onstad, David; Crain, Philip; Crespo, Andre; Hutchison, William; Buntin, David; Porter, Pat; Catchot, Angus; Cook, Don; Pilcher, Clint; Flexner, Lindsey; Higgins, Laura

    2016-01-01

    We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton. PMID:26637533

  1. Molecular cloning and functional characterization of the diapause hormone receptor in the corn earworm Helicoverpa zea

    PubMed Central

    Jiang, Hongbo; Wei, Zhaojun; Nachman, Ronald J.; Park, Yoonseong

    2013-01-01

    The diapause hormone (DH) in the heliothine moth has shown its activity in termination of pupal diapause, while the orthology in the silkworm is known to induce embryonic diapause. In the current study, we cloned the diapause hormone receptor from the corn earworm Helicoverpa zea (HzDHr) and tested its ligand specificities in a heterologous reporter system. HzDHr was expressed in Chinese Hamster Ovary (CHO) cells, which were co-transfected with the aequorin reporter, and was used to measure the ligand activities. A total of 68 chemicals, including natural DH analogs and structurally similar peptide mimetics, were tested for agonistic and antagonistic activities. Several peptide mimetics with a 2-amino-7-bromofluorene-succinoyl (2Abf-Suc) N-terminal modification showed strong agonistic activities; these mimetics included 2Abf-Suc-F[dA]PRLamide, 2Abf-Suc-F[dR]PRLamide, 2Abf-Suc-FKPRLamide and 2Abf-Suc-FGPRLamide. Antagonistic activity was found in the ecdysis triggering hormone in Drosophila melanogaster (FFLKITKNVPRLamide). Interestingly, HzDHr does not discriminate between DH (WFGPRLamide C-terminal motif) and another closely related endogenous peptide, pyrokinin 1 (FXPRXamide; a C-terminal motif that is separate from WFGPRLamide). We provide large-scale in vitro data that serve as a reference for the development of agonists and antagonists to disrupt the DH signaling pathway. PMID:24257143

  2. Incipient Resistance of Helicoverpa punctigera to the Cry2Ab Bt Toxin in Bollgard II® Cotton

    PubMed Central

    Downes, Sharon; Parker, Tracey; Mahon, Rod

    2010-01-01

    Combinations of dissimilar insecticidal proteins (“pyramids”) within transgenic plants are predicted to delay the evolution of pest resistance for significantly longer than crops expressing a single transgene. Field-evolved resistance to Bacillus thuringiensis (Bt) transgenic crops has been reported for first generation, single-toxin varieties and the Cry1 class of proteins. Our five year data set shows a significant exponential increase in the frequency of alleles conferring Cry2Ab resistance in Australian field populations of Helicoverpa punctigera since the adoption of a second generation, two-toxin Bt cotton expressing this insecticidal protein. Furthermore, the frequency of cry2Ab resistance alleles in populations from cropping areas is 8-fold higher than that found for populations from non-cropping regions. This report of field evolved resistance to a protein in a dual-toxin Bt-crop has precisely fulfilled the intended function of monitoring for resistance; namely, to provide an early warning of increases in frequencies that may lead to potential failures of the transgenic technology. Furthermore, it demonstrates that pyramids are not ‘bullet proof’ and that rapid evolution to Bt toxins in the Cry2 class is possible. PMID:20830203

  3. Incipient resistance of Helicoverpa punctigera to the Cry2Ab Bt toxin in Bollgard II cotton.

    PubMed

    Downes, Sharon; Parker, Tracey; Mahon, Rod

    2010-01-01

    Combinations of dissimilar insecticidal proteins ("pyramids") within transgenic plants are predicted to delay the evolution of pest resistance for significantly longer than crops expressing a single transgene. Field-evolved resistance to Bacillus thuringiensis (Bt) transgenic crops has been reported for first generation, single-toxin varieties and the Cry1 class of proteins. Our five year data set shows a significant exponential increase in the frequency of alleles conferring Cry2Ab resistance in Australian field populations of Helicoverpa punctigera since the adoption of a second generation, two-toxin Bt cotton expressing this insecticidal protein. Furthermore, the frequency of cry2Ab resistance alleles in populations from cropping areas is 8-fold higher than that found for populations from non-cropping regions. This report of field evolved resistance to a protein in a dual-toxin Bt-crop has precisely fulfilled the intended function of monitoring for resistance; namely, to provide an early warning of increases in frequencies that may lead to potential failures of the transgenic technology. Furthermore, it demonstrates that pyramids are not 'bullet proof' and that rapid evolution to Bt toxins in the Cry2 class is possible. PMID:20830203

  4. Susceptibilities of Helicoverpa zea and Heliothis virescens (Lepidoptera: Noctuidae) populations to Cry1Ac insecticidal protein.

    PubMed

    Ali, M I; Luttrell, R G; Young, S Y

    2006-02-01

    Susceptibilities of bollworm, Helicoverpa zea (Boddie) and tobacco budworm, Heliothis virescens (F.) to Cry1Ac were measured via a diet-incorporated assay with MPV II at the University of Arkansas during 2002-2004. Lethal concentration-mortality (LC50) estimates of five laboratory, seven laboratory-cross, and 10 field populations of H. virescens varied 12-fold. Pooled susceptibilities of H. virescens across all laboratory and field populations varied five-fold. The LC50 estimates for H. virescens were higher than those reported by previous research before the introduction of transgenic crops. However, the ratio of susceptibility of laboratory and field populations was similar, suggesting no change in overall species susceptibility. Individual LC50 estimates of five laboratory, nine laboratory-cross, and 57 field populations of H. zea varied over 130-fold. Pooled susceptibilities across laboratory and field populations varied widely. Among the field populations, colonies from non-Bacillus thuringiensis (Bt) crops were generally more susceptible than those from Bt crops. Across the Bt crops expressing Cry protein, colonies from Bollgard (Monsanto Company) cotton had lower susceptibility to CrylAc than those from Bt corn and those from non-Bt crops. PMID:16573337

  5. Characteristics of morphology, electrophysiology, and central projections of two sensilla styloconica in Helicoverpa assulta larvae.

    PubMed

    Tang, Qing-Bo; Hong, Zhen-Zhen; Cao, Huan; Yan, Feng-Ming; Zhao, Xin-Cheng

    2015-08-19

    The medial and lateral styloconic sensilla, constituting the main taste organs of lepidopterous caterpillars, were investigated in the oligophagous species, Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae). In this paper, the two sensilla were morphologically and physiologically characterized by scanning electron microscopy and tip recordings, respectively. The central projections of their respective sensory neurons were mapped by anterograde staining experiments combined with confocal laser scanning microscopy. The results showed that the two sensilla are in general morphologically similar. However, the size of the peg on the medial sensillum is significantly greater than that of the lateral. Tobacco leaf saps, sinigrin, and nicotine elicited strong responses from neurons housed by the medial sensillum, whereas sucrose activated primarily the lateral sensillum. All stained neurons in either sensillum showed a projection pattern involving axons entering the subesophageal ganglion through the ipsilateral maxillary and passing further on through the ipsilateral circumesophageal connective to the tritocerebrum of the brain. In the subesophageal ganglion, the axons targeted two areas: the ventrolateral section and the region near the neuromere midline. One distinction between the staining patterns originating from the two sensilla, however, is that axons arising from the medial sensillum, and not the lateral, give off some additional neural branches in the subesophageal ganglion including a few arborizations surrounding a tract, plus a long process extending posteriorly along the midline. Differences in the central projections derived from the two sensilla styloconica have not been reported previously. PMID:26164458

  6. A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea

    PubMed Central

    Brévault, Thierry; Tabashnik, Bruce E.; Carrière, Yves

    2015-01-01

    Widely grown transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) can benefit agriculture, but adaptation by pests threatens their continued success. Refuges of host plants that do not make Bt toxins can promote survival of susceptible insects and delay evolution of resistance, particularly if resistance is inherited as a recessive trait. However, data have been lacking to compare the dominance of resistance when Bt and non-Bt seeds are planted in random mixtures versus separate blocks. Here we report results from greenhouse experiments with transgenic cotton producing Bt toxin Cry1Ac and the bollworm, Helicoverpa zea, showing that the dominance of resistance was significantly higher in a seed mixture relative to a block of Bt cotton. The proportion of larvae on non-Bt cotton plants in the seed mixture was also significantly higher than expected under the null hypothesis of random distribution. In simulations based on observed survival, resistance evolved 2- to 4.5-fold faster in the seed mixture relative to separate blocks of Bt and non-Bt cotton. These findings support previous modelling results indicating that block refuges may be more effective than seed mixtures for delaying resistance in pests with mobile larvae and inherently low susceptibility to the toxins in Bt crops. PMID:25950459

  7. Larval Helicoverpa zea Transcriptional, Growth and Behavioral Responses to Nicotine and Nicotiana tabacum

    PubMed Central

    Gog, Linus; Vogel, Heiko; Hum-Musser, Sue M.; Tuter, Jason; Musser, Richard O.

    2014-01-01

    The polyphagous feeding habits of the corn earworm, Helicoverpa zea (Boddie), underscore its status as a major agricultural pest with a wide geographic distribution and host plant repertoire. To study the transcriptomic response to toxins in diet, we conducted a microarray analysis of H. zea caterpillars feeding on artificial diet, diet laced with nicotine and Nicotiana tabacum (L.) plants. We supplemented our analysis with growth and aversion bioassays. The transcriptome reflects an abundant expression of proteases, chitin, cytochrome P450 and immune-related genes, many of which are shared between the two experimental treatments. However, the tobacco treatment tended to elicit stronger transcriptional responses than nicotine-laced diet. The salivary factor glucose oxidase, known to suppress nicotine induction in the plant, was upregulated by H. zea in response to tobacco but not to nicotine-laced diet. Reduced caterpillar growth rates accompanied the broad regulation of genes associated with growth, such as juvenile hormone epoxide hydrolase. The differential expression of chemosensory proteins, such as odorant binding-protein-2 precursor, as well as the neurotransmitter nicotinic-acetylcholine-receptor subunit 9, highlights candidate genes regulating aversive behavior towards nicotine. We suggest that an observed coincidental rise in cannibalistic behavior and regulation of proteases and protease inhibitors in H. zea larvae signify a compensatory response to induced plant defenses. PMID:26462833

  8. A single amino acid substitution modulates low-pH-triggered membrane fusion of GP64 protein in Autographa californica and Bombyx mori nucleopolyhedroviruses

    SciTech Connect

    Katou, Yasuhiro; Yamada, Hayato; Ikeda, Motoko; Kobayashi, Michihiro

    2010-09-01

    We have previously shown that budded viruses of Bombyx mori nucleopolyhedrovirus (BmNPV) enter the cell cytoplasm but do not migrate into the nuclei of non-permissive Sf9 cells that support a high titer of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) multiplication. Here we show, using the syncytium formation assay, that low-pH-triggered membrane fusion of BmNPV GP64 protein (Bm-GP64) is significantly lower than that of AcMNPV GP64 protein (Ac-GP64). Mutational analyses of GP64 proteins revealed that a single amino acid substitution between Ac-GP64 H155 and Bm-GP64 Y153 can have significant positive or negative effects on membrane fusion activity. Studies using bacmid-based GP64 recombinant AcMNPV harboring point-mutated ac-gp64 and bm-gp64 genes showed that Ac-GP64 H155Y and Bm-GP64 Y153H substitutions decreased and increased, respectively, the multiplication and cell-to-cell spread of progeny viruses. These results indicate that Ac-GP64 H155 facilitates the low-pH-triggered membrane fusion reaction between virus envelopes and endosomal membranes.

  9. Production of recombinant Bombyx mori nucleopolyhedrovirus in silkworm by intrahaemocoelic injection with invasive diaminopimelate auxotrophic Escherichia coli containing BmNPV-Bacmid.

    PubMed

    Sun, Jingchen; Yao, Lunguang; Yao, Ning; Xu, Hua; Jin, Pengfei; Kan, Yunchao

    2010-12-01

    The present study elaborates a cost-effective and transfectant-free method for generating recombinant Bombyx mori (silkworm) nucleopolyhedrovirus in silkworm larvae and pupae by injecting invasive Escherichia coli carrying BmBacmid [BmNPV (B. mori nucleopolyhedrovirus)-Bacmid] into larval haemocoel. Up to 109 PFU (plaque-forming units)/ml of infective recombinant baculovirus was generated in the silkworm by intrahaemocoelic injection with 106 DAP (diaminopimelic acid) auxotrophic and BmBacmid containing E. coli cells expressing both invasin and listeriolysin. Thus 1 ml of overnight culture of E. coli is sufficient to inject more than 2000 larvae, while DAP costing up to $1 is enough to inject about 4000 larvae. Recombinant proteins can be controlled to be expressed mainly in pupae by adjusting the injection dose, too. In this new method, many original manipulations have been eliminated, including BmBacmid preparation and the subsequent complex transfection procedures. Hence it is a time- and cost-saving means for large-scale injection of B. mori for recombinant baculovirus production in comparison with the traditional transfection methods, which may play an important role in the industrial development of the BmNPV-silkworm bioreactor. PMID:20979580

  10. Influence of virus inoculation method and host larval age on productivity of the nucleopolyhedrovirus of the teak defoliator, Hyblaea puera (Cramer).

    PubMed

    Biji, C P; Sudheendrakumar, V V; Sajeev, T V

    2006-04-01

    Hyblaea puera nucleopolyhedrovirus (HpNPV) is a potential biocontrol agent against the teak defoliator H. puera (Cramer) (Lepidoptera: Hyblaeidae). As part of optimization of the mass production of this nucleopolyhedrovirus, three methods of inoculation were evaluated against the host larvae with various yield parameters as selection criteria. The inoculation methods compared were controlled dose on diet in rearing tubes using a micropipette, controlled dose on leaf discs (prepared from teak leaves) using a micropipette and spraying onto diet filled rearing tubes using an atomizer. Fifth instar H. puera larvae of the weight classes 75-100, 101-125, 126-150, 151-175 and 176-200mg were used for the bioassay. With reference to percentage of harvested larvae, virus production per larva and virus production per inoculated larva (VPIL), spraying viral suspension into rearing tubes filled with artificial diet using a hand sprayer was found to be the most efficient method of inoculation. It was observed that the method of inoculation and age of the larvae has discrete as well as interactive influence on the virus yield parameters. PMID:16384613

  11. Spatial and Temporal Variability in Host Use by Helicoverpa zea as Measured by Analyses of Stable Carbon Isotope Ratios and Gossypol Residues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concerns with resistance evolution in tobacco budworm, Heliothis virescens (F.) and bollworm, Helicoverpa zea (Boddie), to transgenic insecticidal crops that produce Bacillus thuringiensis proteins led to the adoption of the high dose/refuge strategy for managing cotton insect resistance in the Unit...

  12. Diapause hormone in the Helicoverpa/Heliothis complex: a review of gene expression, peptide structure and activity, analog and antagonist development, and the receptor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review summarizes recent studies focusing on diapause hormone (DH) in the Helicoverpa/Heliothis complex of agricultural pests. Moths in this complex overwinter in pupal diapause, a form of developmental arrest used to circumvent unfavorable seasons. DH was originally reported in the silkmoth ...

  13. Seasonal patterns of capture of Helicoverpa zea (Boddie) and Heliothis phloxiphaga (Grote and Robinson)(Lepidoptera: Noctuidae) in pheromone traps in Washington State

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In each of the 6 years of this study in south central Washington state, male corn earworm moths, Helicoverpa zea (Boddie), first appeared in pheromone traps in late May to early June, and were present continuously until mid to late October. Maximum numbers of corn earworm moths captured in pheromon...

  14. Temporal and spatial distribution of Helicoverpa zea and Heliothis virescens (Lepidoptera: noctuidae) moths in pheromone traps across agricultural landscapes in Arkansas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pheromone trap captures of Helicoverpa zea (Boddie) and Heliothis virescens (F.) from 2002-2005 were used to examine the distribution of these species across a multiple crop environment in southeast Arkansas. The greatest number of H. virescens moths was collected during 2003, but densities were lo...

  15. Diapause hormone in the corn earworm, Helicoverpa zea: Optimum temperature for activity, structure-activity relationships, and efficacy in accelerating flesh fly pupariation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diapause hormone (DH) effectively terminated pupal diapause in Helicoverpa zea. This effect was temperature-dependent, with an optimum of 21 degrees C. The dose-response curve indicated an ED50 of DH for diapause termination of approximately 100 pmol. The core sequence and essential amino acids w...

  16. Evaluating legume species as alternative trap crops to chickpea for management of Helicoverpa spp. (Lepidoptera: Noctuidae) in central Queensland cotton cropping systems.

    PubMed

    Grundy, P R; Sequeira, R V; Short, K S

    2004-12-01

    Mounting levels of insecticide resistance within Australian Helicoverpa spp. populations have resulted in the adoption of non-chemical IPM control practices such as trap cropping with chickpea, Cicer arietinum (L.). However, a new leaf blight disease affecting chickpea in Australia has the potential to limit its use as a trap crop. Therefore this paper evaluates the potential of a variety of winter-active legume crops for use as an alternative spring trap crop to chickpea as part of an effort to improve the area-wide management strategy for Helicoverpa spp. in central Queensland's cotton production region. The densities of Helicoverpa eggs and larvae were compared over three seasons on replicated plantings of chickpea, Cicer arietinum (L.), field pea Pisum sativum (L), vetch, Vicia sativa (L.) and faba bean, Vicia faba (L.). Of these treatments, field pea was found to harbour the highest densities of eggs. A partial life table study of the fate of eggs oviposited on field pea and chickpea suggested that large proportions of the eggs laid on field pea suffered mortality due to dislodgment from the plants after oviposition. Plantings of field pea as a replacement trap crop for chickpea under commercial conditions confirmed the high level of attractiveness of this crop to ovipositing moths. The use of field pea as a trap crop as part of an area-wide management programme for Helicoverpa spp. is discussed. PMID:15541187

  17. Phenotypic impacts of PBAN RNA interference in an ant, Solenopsis invicta, and a moth, Helicoverpa zea.

    PubMed

    Choi, Man-Yeon; Vander Meer, Robert K; Coy, Monique; Scharf, Michael E

    2012-08-01

    Insect neuropeptide hormones represent more than 90% of all insect hormones. The PBAN/pyrokinin family is a major group of insect neuropeptides, and they are expected to be found from all insect groups. These species-specific neuropeptides have been shown to have a variety of functions from embryo to adult. PBAN is well understood in moth species relative to sex pheromone biosynthesis, but other potential functions are yet to be determined. Recently, we focused on defining the PBAN gene and peptides in fire ants in preparation for an investigation of their function(s). RNA interference (RNAi) technology is a convenient tool to investigate unknown physiological functions in insects, and it is now an emerging method for development of novel biologically-based control agents as alternatives to insecticides. This could be a paradigm shift that will avoid many problems associated with conventional chemical insecticides. In this study, we selected the PBAN gene and its neuropeptide products as an RNAi target from two insect groups; a social insect, the fire ant (Solenopsis invicta) and a non-social insect, the corn earworm (Helicoverpa zea). Both insects are economically important pests. We report negative impacts after PBAN dsRNA treatment to suppress PBAN gene transcription during developmental and adult stages of both species, e.g. increased adult and larval mortality, delayed pupal development and decreased sex pheromone production in the moth. This is an important first step in determining the multiple functions of the PBAN gene in these two insects. This work illustrates the variety of phenotypic effects observed after RNAi silencing of the PBAN gene and suggests the possibility of novel biologically-based insect pest control methods. PMID:22705256

  18. Role of juvenile hormone esterase and epoxide hydrolase in reproduction of the cotton bollworm, Helicoverpa zea.

    PubMed

    Khalil, Sayed M S; Anspaugh, Douglas D; Michael Roe, R

    2006-07-01

    The role of juvenile hormone (JH) esterase (JHE) and epoxide hydrolase (EH) in reproduction of the cotton bollworm, Helicoverpa zea, was investigated. Peak emergence of male and female bollworm adults occurred early in the scotophase. Female adults were added to males in a 1:2 ratio, respectively, at the beginning of the first photophase after emergence (d0). The highest oviposition rates for mated females were noted on d 2-4. The in vitro JH III esterase and JH III EH activity was measured in whole body homogenates of virgin and mated females from d0 to d8 post-emergence. Maximal JHE activity for virgin females occurred on d2 (1.09+/-0.14(+/-1 SEM) nmol of JH III degraded/min/mg protein), which was approximately twice that of mated females on the same day. The same results were observed for EH where the activity peaked on d2 at 0.053+/-0.003 as compared to 0.033+/-0.003 nmol of JH III degraded/min/mg protein, respectively. By d4, both JHE and JH EH activities declined significantly in virgin and mated females and were the same through d7. The developmental changes and effects of mating on JH degradation were similar when measured per insect. The highest levels of JHE and JH EH activity/min/mg protein in d2 virgin and mated females was found in ovaries followed by the carcass and then haemolymph; no EH activity was found in haemolymph as expected. For ovary, the JHE and JH EH activity was highest in virgin compared to mated females. The role of both enzymes in the regulation of reproduction is discussed. PMID:16678198

  19. Modeling the impact of alternative hosts on Helicoverpa zea adaptation to bollgard cotton.

    PubMed

    Gustafson, David I; Head, Graham P; Caprio, Michael A

    2006-12-01

    For highly polyphagous cotton, Gossypium hirsutum L., pests such as Helicoverpa zea (Boddie), a substantial portion of the larval population develops on noncotton alternative hosts. These noncotton hosts potentially provide a natural refuge for H. zea, thereby slowing the evolution of resistance to the Bacillus thuringiensis Berliner (Bt)-derived Cry1Ac protein present in Bollgard cotton. Here, we demonstrate how the measured contribution of such alternative hosts can be included in estimating the "effective refuge" present for H. zea and in modeling resistance evolution in this species. A single-gene, two-compartment model was used in which one compartment represented corn, Zea mays L., and cotton that express the Cry1Ac protein or similar proteins, and the other compartment was the effective refuge, made up of a weighted average of non-Bt cotton and noncotton hosts. The effective refuge was estimated for each of six generations of H. zea based upon available data on larval population densities on different hosts and cropping patterns. Model runs were performed for regions centered on three states: Georgia, Mississippi, and North Carolina. Three sets of fitness cost assumptions for the putative resistance gene were used: none, low, and moderate, with either recessive or additive inheritance for resistance and fitness costs. For Georgia and North Carolina, resistance was predicted to take >30 yr to evolve except in the absence of fitness costs. For Mississippi, results were sensitive to fitness costs: >30 yr with moderate costs, 7-14 yr with low costs, and 6-10 yr without such costs. PMID:17195681

  20. Yield response of dual-toxin Bt cotton to Helicoverpa zea infestations.

    PubMed

    Gore, J; Adamczyk, J J; Catchot, A; Jackson, R

    2008-10-01

    Field cage experiments were conducted to determine the impact of bollworms, Helicoverpa zea (Boddie), on yields of Bollgard II and Widestrike cotton, Gossypium hirsutum L. One-day-old bollworm larvae were infested in white flowers of Bollgard II and in white flowers and terminals of Widestrike cotton. The infestation levels included 0, 50, and 100% of white flowers for each type of cotton. Terminal infestations included one or two larvae per terminal on Widestrike cotton. Larvae were placed in flowers of Bollgard II cotton each day for 1 to 4 wk during the first 4 wk of flowering during 2003, 2004, and 2005 seasons and in the flowers or terminals of Widestrike cotton each day for 1 to 3 wk. Averaged across years and durations of infestation, yields of Bollgard II cotton were significantly reduced compared with noninfested Bollgard II cotton when 100% of white flowers were infested. For Widestrike cotton, there was a reduction in yield when 100% of white flowers were infested in 2005, but not in 2006. There was a significant relationship for cumulative numbers of white flowers infested on seedcotton yield of Bollgard II during one of the 3 yr of the experiment. The regression equation during that year had a slope of -0.77. No significant relationships were observed for cumulative numbers of white flowers infested on yields of Widestrike cotton. Results of the current experiment suggest bollworms will rarely cause yield losses of Bollgard II and Widestrike cotton. Future research will need to focus on developing specific thresholds for bollworms on Bollgard II and Widestrike cotton. PMID:18950041

  1. Revisiting macronutrient regulation in the polyphagous herbivore Helicoverpa zea (Lepidoptera: Noctuidae): New insights via nutritional geometry.

    PubMed

    Deans, Carrie A; Sword, Gregory A; Behmer, Spencer T

    2015-10-01

    Insect herbivores that ingest protein and carbohydrates in physiologically-optimal proportions and concentrations show superior performance and fitness. The first-ever study of protein-carbohydrate regulation in an insect herbivore was performed using the polyphagous agricultural pest Helicoverpa zea. In that study, experimental final instar caterpillars were presented two diets - one containing protein but no carbohydrates, the other containing carbohydrates but no protein - and allowed to self-select their protein-carbohydrate intake. The results showed that H. zea selected a diet with a protein-to-carbohydrate (p:c) ratio of 4:1. At about this same time, the geometric framework (GF) for the study of nutrition was introduced. The GF is now established as the most rigorous means to study nutrient regulation (in any animal). It has been used to study protein-carbohydrate regulation in several lepidopteran species, which exhibit a range of self-selected p:c ratios between 0.8 and 1.5. Given the economic importance of H. zea, and it is extremely protein-biased p:c ratio of 4:1 relative to those reported for other lepidopterans, we decided to revisit its protein-carbohydrate regulation. Our results, using the experimental approach of the GF, show that H. zea larvae self-select a p:c ratio of 1.6:1. This p:c ratio strongly matches that of its close relative, Heliothis virescens, and is more consistent with self-selected p:c ratios reported for other lepidopterans. Having accurate protein and carbohydrate regulation information for an insect herbivore pest such as H. zea is valuable for two reasons. First, it can be used to better understand feeding patterns in the field, which might lead to enhanced management. Second, it will allow researchers to develop rearing diets that more accurately reflect larval nutritional needs, which has important implications for resistance bioassays and other measures of physiological stress. PMID:26141409

  2. Production and characterization of Bacillus thuringiensis Cry1Ac-resistant cotton bollworm Helicoverpa zea (Boddie).

    PubMed

    Anilkumar, Konasale J; Rodrigo-Simón, Ana; Ferré, Juan; Pusztai-Carey, Marianne; Sivasupramaniam, Sakuntala; Moar, William J

    2008-01-01

    Laboratory-selected Bacillus thuringiensis-resistant colonies are important tools for elucidating B. thuringiensis resistance mechanisms. However, cotton bollworm, Helicoverpa zea, a target pest of transgenic corn and cotton expressing B. thuringiensis Cry1Ac (Bt corn and cotton), has proven difficult to select for stable resistance. Two populations of H. zea (AR and MR), resistant to the B. thuringiensis protein found in all commercial Bt cotton varieties (Cry1Ac), were established by selection with Cry1Ac activated toxin (AR) or MVP II (MR). Cry1Ac toxin reflects the form ingested by H. zea when feeding on Bt cotton, whereas MVP II is a Cry1Ac formulation used for resistance selection and monitoring. The resistance ratio (RR) for AR exceeded 100-fold after 11 generations and has been maintained at this level for nine generations. This is the first report of stable Cry1Ac resistance in H. zea. MR crashed after 11 generations, reaching only an RR of 12. AR was only partially cross-resistant to MVP II, suggesting that MVP II does not have the same Cry1Ac selection pressure as Cry1Ac toxin against H. zea and that proteases may be involved with resistance. AR was highly cross-resistant to Cry1Ab toxin but only slightly cross-resistant to Cry1Ab expressing corn leaf powder. AR was not cross-resistant to Cry2Aa2, Cry2Ab2-expressing corn leaf powder, Vip3A, and cypermethrin. Toxin-binding assays showed no significant differences, indicating that resistance was not linked to a reduction in binding. These results aid in understanding why this pest has not evolved B. thuringiensis resistance, and highlight the need to choose carefully the form of B. thuringiensis protein used in experiments. PMID:18024681

  3. Naturally Occurring Deletion Mutants Are Parasitic Genotypes in a Wild-Type Nucleopolyhedrovirus Population of Spodoptera exigua

    PubMed Central

    Muñoz, Delia; Castillejo, Juan I.; Caballero, Primitivo

    1998-01-01

    A wild-type nucleopolyhedrovirus (NPV) isolate from Spodoptera exigua from Florida (Se-US2) is a variant of the SeMNPV type strain since it has a unique DNA profile but is closely related to other known geographical isolates of SeMNPV. It consists of several genotypic variants, of which seven were identified in a Se-US2 virus stock by a modification of the in vivo cloning method developed by Smith and Crook (Virology 166:240–244, 1988). The US2A variant was the most prevalent genotype, and it was designated the prototype Se-US2 variant, while four of the variants (US2B, US2D, US2F, and US2H) were found at low frequency. US2C and US2E were also very abundant, and their diagnostic bands were easily observed in wild-type isolate restriction endonuclease patterns. The analysis of each variant, compared to the prototype US2A, showed that US2B and US2H presented minor differences, while US2D and US2F contained slightly larger insertions or deletions. Variants US2C and US2E contained major deletions of 21.1 and 14 kb, respectively, mapping at the same genomic region (between 14.5 and 30.2 map units [m.u.] and between 12.8 and 23 m.u., respectively). This is the first report of such deletion mutants in a natural baculovirus population. Variants US2A, US2B, US2D, US2F, and US2H were isolated as pure genotypes, but we failed to clone US2C and US2E in vivo. When these two variants appeared without apparent contamination with any other variant, they lost their pathogenicity for Spodoptera exigua larvae. A further biological characterization showed evidence that these two naturally occurring deletion mutants act as parasitic genotypes in the virus population. Bioassay data also demonstrated that pure US2A is significantly more pathogenic against second-instar S. exigua larvae than the wild-type isolate. The need for precise genotypic characterization of a baculovirus prior to its development as a bioinsecticide is discussed. PMID:9797293

  4. Functional Analysis of the Autographa californica Multiple Nucleopolyhedrovirus GP64 Terminal Fusion Loops and Interactions with Membranes

    PubMed Central

    Dong, Sicong

    2012-01-01

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) glycoprotein GP64 is the major envelope protein of the budded virus (BV). GP64 is a class III fusion protein that mediates BV attachment to the cell surface and low-pH-triggered membrane fusion between the BV envelope and the endosome membrane during entry. Class III fusion proteins contain terminal looped structures that are believed to interact with membranes. To examine the functions of 3 loops found at the apex of the GP64 postfusion structure, we generated 2-alanine substitutions that scanned the two so-called fusion loops (loop 1 and loop 2) plus an adjacent loop structure (loop 3) that is closely attached to loop 2 and is also found at the apex of the GP64 postfusion structure. We identified essential residues from Y75 to T86 (loop 1) and N149 to H156 (loop 2) that are required for fusion activity, but no essential residues in loop 3. Further analysis revealed that critical fusion loop residues fall within two groups that are associated with either membrane merger (hemifusion) or fusion pore expansion. We next examined the interactions of soluble GP64 proteins and BV with membranes composed of various phospholipids. BV interacted directly with small unilamellar vesicles (SUVs) comprised of phospholipids phosphatidylcholine and phosphatidic acid (PC/PA) or phosphatidylcholine and phosphatidylserine (PC/PS) under neutral and acidic pH. We also examined the interactions of soluble GP64 constructs containing substitutions of the most hydrophobic residues within each of the two fusion loops. We found that a 2-residue substitution in either single loop (loop 1 [positions 81 and 82] or loop 2 [positions 153 and 154]) was not sufficient to substantially reduce the GP64-liposome interaction, but the same substitutions in both fusion loops severely reduced the GP64-liposome association at neutral pH. These results suggest that critical hydrophobic residues in both fusion loops may be involved in the

  5. Analysis of an Autographa californica Nucleopolyhedrovirus lef-11 Knockout: LEF-11 Is Essential for Viral DNA Replication

    PubMed Central

    Lin, Guangyun; Blissard, Gary W.

    2002-01-01

    The Autographa californica nucleopolyhedrovirus (AcMNPV) lef-11 gene was previously identified by transient late expression assays as a gene important for viral late gene expression. The lef-11 gene was not previously identified as necessary for DNA replication in transient origin-dependent plasmid DNA replication assays. To examine the role of lef-11 in the context of the infection cycle, we generated a deletion of the lef-11 gene by recombination in an AcMNPV genome propagated as a BACmid in Escherichia coli. The resulting AcMNPV lef-11-null BACmid (vAclef11KO) was unable to propagate in cell culture, although a “repair” AcMNPV BACmid (vAclef11KO-REP), which was generated by transposition of the lef-11 gene into the polyhedrin locus of the vAclef11KO BACmid, was able to replicate in a manner similar to wild-type or control AcMNPV viruses. Thus, the lef-11 gene is essential for viral replication in Sf9 cells. The vAclef11KO BACmid was examined to determine if the defect in viral replication resulted from a defect in DNA replication or from a defect in late transcription. The lef-11-null BACmid and control BACmids were transfected into Sf9 cells, and viral DNA replication was monitored. The viral DNA genome of the lef-11-null BACmid (vAclef11KO) was not amplified, whereas replication and amplification of the genomes of the repair BACmid (vAclef11KO-REP), wild-type AcMNPV, and a nonpropagating gp64-null control BACmid (vAcGUSgp64KO) were readily detected. Northern blot analysis of transcripts from selected early, late, and very late genes showed that late and very late transcription was absent in cells transfected with the lef-11-null BACmid. Thus, in contrast to prior studies using transient replication and late expression assays, studies of a lef-11-null BACmid indicate that LEF-11 is required for viral DNA replication during the infection cycle. PMID:11861844

  6. Autographa californica Multiple Nucleopolyhedrovirus orf132 Encodes a Nucleocapsid-Associated Protein Required for Budded-Virus and Multiply Enveloped Occlusion-Derived Virus Production

    PubMed Central

    Yang, Ming; Wang, Shuo; Yue, Xiu-Li

    2014-01-01

    ABSTRACT Autographa californica multiple nucleopolyhedrovirus orf132 (named ac132) has homologs in all genome-sequenced group I nucleopolyhedroviruses. Its role in the viral replication cycle is unknown. In this study, ac132 was shown to express a protein of around 28 kDa, which was determined to be associated with the nucleocapsids of both occlusion-derived virus and budded virus. Confocal microscopy showed that AC132 protein appeared in central region of the nucleus as early as 12 h postinfection with the virus. It formed a ring zone at the periphery of the nucleus by 24 h postinfection. To investigate its role in virus replication, ac132 was deleted from the viral genome by using a bacmid system. In the Sf9 cell culture transfected by the ac132 knockout bacmid, infection was restricted to single cells, and the titer of infectious budded virus was reduced to an undetectable level. However, viral DNA replication and the expression of late genes vp39 and odv-e25 and a reporter gene under the control of the very late gene p10 promoter were unaffected. Electron microscopy showed that nucleocapsids, virions, and occlusion bodies were synthesized in the cells transfected by an ac132 knockout bacmid, but the formation of the virogenic stroma and occlusion bodies was delayed, the numbers of enveloped nucleocapsids were reduced, and the occlusion bodies contained mainly singly enveloped nucleocapsids. AC132 was found to interact with envelope protein ODV-E18 and the viral DNA-binding protein P6.9. The data from this study suggest that ac132 possibly plays an important role in the assembly and envelopment of nucleocapsids. IMPORTANCE To our knowledge, this is the first report on a functional analysis of ac132. The data presented here demonstrate that ac132 is required for production of the budded virus and multiply enveloped occlusion-derived virus of Autographa californica multiple nucleopolyhedrovirus. This article reveals unique phenotypic changes induced by ac132

  7. Spodoptera frugiperda resistance to oral infection by Autographa californica multiple nucleopolyhedrovirus linked to aberrant occlusion-derived virus binding in the midgut.

    PubMed

    Haas-Stapleton, Eric J; Washburn, Jan O; Volkman, Loy E

    2005-05-01

    Spodoptera frugiperda larvae are highly resistant to oral infection by Autographa californica multiple nucleopolyhedrovirus (AcMNPV) (LD(50), approximately 9200 occlusions), but extremely susceptible to budded virus within the haemocoel (LD(50), <1 p.f.u.). The inability of AcMNPV occlusion-derived virus (ODV) to establish primary infections readily within midgut cells accounts for a major proportion of oral resistance. To determine whether inappropriate binding of AcMNPV ODV to S. frugiperda midgut cells contributes to lack of oral infectivity, the binding and fusion properties of AcMNPV ODV were compared with those of the ODV of a new isolate of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) obtained from a field-collected larva (oral LD(50), 12 occlusions). By using a fluorescence-dequenching assay conducted in vivo, it was found that AcMNPV ODV bound to the midgut epithelia of S. frugiperda larvae at approximately 15 % of the level of SfMNPV ODV, but that, once bound, the efficiencies of fusion for the two ODVs were similar: 60 % for AcMNPV and 53 % for SfMNPV. Whilst the difference in binding efficiencies was significant, it could not account entirely for the observed differences in infectivity. Competition experiments, however, revealed that, in S. frugiperda larvae, SfMNPV ODV bound to a midgut cell receptor that was not bound by AcMNPV ODV, indicating that ODV interaction with a specific receptor(s) was necessary for productive infection of midgut columnar epithelial cells. Fusion in the absence of this ligand-receptor interaction did not result in productive infections. PMID:15831946

  8. Multiple acyl-CoA desaturase-encoding transcripts in pheromone glands of Helicoverpa assulta, the oriental tobacco budworm.

    PubMed

    Jeong, Seong Eun; Rosenfield, Claire-Lise; Marsella-Herrick, Patricia; Man You, Kyung; Knipple, Douglas C

    2003-06-01

    Seven desaturase cDNAs were isolated from pheromone glands of Helicoverpa assulta, a moth producing a sex pheromone blend with high Z9-16:Ald and low Z11-16:Ald, opposite to what is found in other heliothine moths such as Helicoverpa zea. Six of the seven sequences map onto recently defined lepidopteran desaturase sequence lineages and the other is orthologous to a desaturase sequence previously reported only in H. zea. The levels of desaturase-encoding transcripts in pheromone glands were determined and the three most abundant ones were functionally expressed in a desaturase-deficient mutant strain of Saccharomyces cerevisiae. The HassNPVE transcript, shown to encode a delta9 desaturase producing more Z9-18:Acid than Z9-16:Acid, was the most abundant, followed by the HassKPSE transcript, shown to encode a delta9 desaturase producing more Z9-16:Acid than Z9-18:Acid, and by the HassLPAQ transcript, shown to encode a delta11 desaturase producing only Z11-16:Acid. Thus, the relative amounts of transcripts encoding two delta9 desaturases and a single delta11 desaturase in H. assulta pheromone glands were consistent with the relative amounts of unsaturated fatty acid precursors required to produce the major and minor sex pheromone components of this species. Desaturase transcript levels in pheromone glands were also found to be as high during scotophase as during light phase, when pheromone production ceases. The other four transcripts were present at extremely low levels in H. assulta pheromone glands and the functional roles of their encoded desaturase-homologous proteins could not be determined. PMID:12770579

  9. A comparative study on the efficacy of a pest-specific and prey marking enzyme-linked immunosorbent assay for detection of predation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficacy of two different antigen-antibody combinations to detect predation on eggs of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) was compared, The first method was an indirect ELISA that detects H. armigera egg protein. The second method was a sandwich ELISA that detects an exotic p...

  10. Unique synteny and alternate splicing of the chitin synthases in closely related heliothine moths

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two chitin synthase genes were characterized in the genomes of two heliothine moths: the corn earworm/cotton bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) and the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). In both moths, the coding sequences for the two ge...

  11. Expression of the Cydia pomonella granulovirus matrix metalloprotease enhances Autographa californica multiple nucleopolyhedrovirus virulence and can partially substitute for viral cathepsin

    PubMed Central

    Ishimwe, Egide; Hodgson, Jeffrey J.; Passarelli, A. Lorena

    2015-01-01

    The Cydia pomonella granulovirus open reading frame 46 (CpGV-ORF46) contains predicted domains found in matrix metalloproteases (MMPs), a family of zinc-dependent endopeptidases that degrade extracellular matrix proteins. We showed that CpGV-MMP was active in vitro. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) expressing CpGV-ORF46 replicated similarly to a control virus lacking CpGV-ORF46 in cultured cells. The effects of AcMNPV expressing CpGV-MMP on virus infection in cultured cells and Trichoplusia ni larvae in the presence or absence of other viral degradative enzymes, cathepsin and chitinase, were evaluated. In the absence of cathepsin and chitinase or cathepsin alone, larval time of death was significantly delayed. This delay was compensated by the expression of CpGV-MMP. CpGV-MMP was also able to promote larvae melanization in the absence of cathepsin and chitinase. In addition, CpGV-MMP partially substituted for cathepsin in larvae liquefaction when chitinase, which is usually retained in the endoplasmic reticulum, was engineered to be secreted. PMID:25795312

  12. The Homologous Regions of Spodoptera litura (Lepidoptera: Noctuidae) Nucleopolyhedrovirus II Have Both the Function as Origin of DNA Replication and Enhancer

    PubMed Central

    Liu, Huifen; Gao, Huiju; Guo, Guang; Li, Yunzhi; Li, Yinü; Wang, Jinhui; Zhang, Zhifang; Yu, Zhencheng

    2015-01-01

    In the genome sequence of the Spodoptera litura nucleopolyhedrovirus II (SpltNPVII), seven homologous regions (hrs), Sphr1-7, were identified. Each of them composed of three to eight 64-bp highly conserved sequences, and each contained a 24-bp imperfect palindrome. A transient expression assay demonstrated that the expression of SpltNPVII-ie1 promoter-driven luciferase gene was enhanced between 3- and 13-fold by infection of SpltNPVII in Spli221 cells. Real-time polymerase chain reaction confirmed each of seven hrs could function as origin (ori) of viral DNA replication. This suggests that these hrs are bifunctional, having both ori and enhancer activities for transcription. In addition, the potential of seven hrs as origins had a significantly positive correlation with the number of their palindromes (r = 0.847, Sig: 0.016 < 0.05), and enhancer efficiency had a significantly positive correlation with the number of characteristic motifs (r = 0.893, Sig: 0.007 < 0.01). The efficiency of replication and enhancement of each hr both increased with increasing total numbers of palindromes, repeat sequences, and characteristic motifs. In addition, a single 64-bp highly conserved consensus sequence cannot very good support to the function as origin and enhancer, and require the assistance of other cis-elements in hrs.

  13. Comparative Studies of Lepidopteran Baculovirus-Specific Protein FP25K: Development of a Novel Bombyx mori Nucleopolyhedrovirus-Based Vector with a Modified fp25K Gene▿

    PubMed Central

    Nakanishi, Tadashi; Goto, Chie; Kobayashi, Michihiro; Kang, WonKyung; Suzuki, Takehiro; Dohmae, Naoshi; Matsumoto, Shogo; Shimada, Toru; Katsuma, Susumu

    2010-01-01

    Lepidopteran baculovirus-specific protein FP25K performs many roles during the infection cycle, including functions in the production of occlusion bodies (OBs) and budded viruses (BVs), oral infection, and postmortem host degradation. To explore the common and specific functions of FP25K proteins among lepidopteran baculoviruses, we performed comparative analyses of FP25K proteins from group I and group II nucleopolyhedroviruses (NPVs) and granulovirus (GV). Using recombinant Bombyx mori NPVs (BmNPVs), we showed that the FP25Ks from NPVs were able to eliminate all the phenotypic defects observed in an infection with a BmNPV mutant lacking functional fp25K but that FP25K from GV did not show abilities to recover oral infectivity and postmortem host degradation. We also observed that introduction of Autographa californica multiple NPV (AcMNPV) fp25K into the BmNPV genome enhanced OB and BV production. According to these results, we generated a novel BmNPV-based expression vector with AcMNPV fp25K and examined its potential in BmN cells and B. mori larvae. Our results showed that the introduction of AcMNPV fp25K significantly increases the expression of foreign gene products in cultured cells and shortens the time for obtaining the secreted recombinant proteins from larval hemolymph. PMID:20219904

  14. The role of the PI3K-Akt signal transduction pathway in Autographa californica multiple nucleopolyhedrovirus infection of Spodoptera frugiperda cells

    SciTech Connect

    Xiao Wei; Yang Yi; Weng Qingbei; Lin Tiehao; Yuan Meijin; Yang Kai; Pang Yi

    2009-08-15

    Many viruses activate the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway, thereby modulating diverse downstream signaling pathways associated with antiapoptosis, proliferation, cell cycling, protein synthesis and glucose metabolism, in order to augment their replication. To date, the role of the PI3K-Akt pathway in Baculovirus replication has not been defined. In the present study, we demonstrate that infection of Sf9 cells with Autographa californica multiple nucleopolyhedrovirus (AcMNPV) elevated cellular Akt phosphorylation at 1 h post-infection. The maximum Akt phosphorylation occurred at 6 h post-infection and remained unchanged until 18 h post-infection. The PI3K-specific inhibitor, LY294002, suppressed Akt phosphorylation in a dose-dependent manner, suggesting that AcMNPV-induced Akt phosphorylation is PI3K-dependent. The inhibition of PI3K-Akt activation by LY294002 significantly reduced the viral yield, including a reduction in budded viruses and occlusion bodies. The virus production was reduced only when the inhibitor was added within 24 h of infection, implying that activation of PI3K occurred early in infection. Correspondingly, both viral DNA replication and late (VP39) and very late (POLH) viral protein expression were impaired by LY294002 treatment; LY294002 had no effect on immediate-early (IE1) and early-late (GP64) protein expression. These results demonstrate that the PI3K-Akt pathway is required for efficient Baculovirus replication.

  15. Three-dimensional visualization of the Autographa californica multiple nucleopolyhedrovirus occlusion-derived virion envelopment process gives new clues as to its mechanism

    SciTech Connect

    Shi, Yang; Li, Kunpeng; Tang, Peiping; Li, Yinyin; Zhou, Qiang; Yang, Kai; Zhang, Qinfen

    2015-02-15

    Baculoviruses produce two virion phenotypes, occlusion-derived virion (ODV) and budded virion (BV). ODV envelopment occurs in the nucleus. Morphogenesis of the ODV has been studied extensively; however, the mechanisms underlying microvesicle formation and ODV envelopment in nuclei remain unclear. In this study, we used electron tomography (ET) together with the conventional electron microscopy to study the envelopment of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ODV. Our results demonstrate that not only the inner but also the outer nuclear membrane can invaginate and vesiculate into microvesicles and that intranuclear microvesicles are the direct source of the ODV membrane. Five main events in the ODV envelopment process are summarized, from which we propose a model to explain this process. - Highlights: • Both the inner and outer nuclear membranes could invaginate. • Both the inner and outer nuclear membranes could vesiculate into microvesicles. • Five main events in the ODV envelopment process are summarized. • A model is proposed to explain this ODV envelopment.

  16. Mortality of Cutworm Larvae Is Not Enhanced by Agrotis segetum Granulovirus and Agrotis segetum Nucleopolyhedrovirus B Coinfection Relative to Single Infection by Either Virus

    PubMed Central

    Wennmann, Jörg T.; Köhler, Tim; Gueli Alletti, Gianpiero

    2015-01-01

    Mixed infections of insect larvae with different baculoviruses are occasionally found. They are of interest from an evolutionary as well as from a practical point of view when baculoviruses are applied as biocontrol agents. Here, we report mixed-infection studies of neonate larvae of the common cutworm, Agrotis segetum, with two baculoviruses, Agrotis segetum nucleopolyhedrovirus B (AgseNPV-B) and Agrotis segetum granulovirus (AgseGV). By applying quantitative PCR (qPCR) analysis, coinfections of individual larvae were demonstrated, and occlusion body (OB) production within singly infected and coinfected larvae was determined in individual larvae. Mixtures of viruses did not lead to changes in mortality rates compared with rates of single-virus treatments, indicating an independent action within host larvae under our experimental conditions. AgseNPV-B-infected larvae showed an increase in OB production during 2 weeks of infection, whereas the number of AgseGV OBs did not change from the first week to the second week. Fewer OBs of both viruses were produced in coinfections than in singly infected larvae, suggesting a competition of the two viruses for larval resources. Hence, no functional or economic advantage could be inferred from larval mortality and OB production from mixed infections of A. segetum larvae with AgseNPV-B and AgseGV. PMID:25681187

  17. Interactions among insect-resistant soybean genotypes extracts with populations of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) susceptible and resistant to its nucleopolyhedrovirus.

    PubMed

    Piubelli, Giorla C; Moscardi, Flávio; Hoffmann-Campo, Clara B

    2009-12-01

    Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV) is being used in Brazil as a biological insecticide. Host plant resistance of soybean to insects is been searched for and some authors have mentioned the interference of plant chemistry in virus efficiency. Interactions among soybean extracts of genotypes used as a source of resistance (PI 274454 and PI 227687) with different AgMNPV concentrations in populations of A. geatalis susceptible (S) and resistant (R) to the virus were studied at laboratory condition. Higher mortality was observed when larvae fed on diets with extracts of the soybean genotypes compared with those fed on a plain diet (control). The mean lethal concentration (LC50) was reduced about 10 ties in the S-population fed on diets containing PI 274454 extracts and different concentrations of AgMNPV, compared to control diet. Additive effect was predominantly observed when larvae fed on diets with extracts of soybean genotypes (PI 274454 and PI 227687) and AgMNPV for both larval populations. The pupal weight was negatively influenced by the extracts incorporated to the diets compared to control, for both larval populations, notably for R-population. The results suggest that, in general, leaf extracts of soybean resistant genotype did not cause any harmful effect on virus efficiency. PMID:19893908

  18. The Ac124 protein is not essential for the propagation of Autographa californica multiple nucleopolyhedrovirus, but it is a viral pathogenicity factor.

    PubMed

    Liang, Changyong; Lan, Dandan; Zhao, Shuling; Liu, Lulu; Xue, Yanan; Zhang, Yongli; Wang, Yun; Chen, Xinwen

    2015-01-01

    orf124 (ac124) of AcMNPV is one of the highly conserved unique genes in group I lepidopteran nucleopolyhedroviruses. So far, its function remains unknown. In this study, infection with a virus expressing an ac124-gfp fusion showed that Ac124 localized to the cytoplasm throughout the infection. In addition, an ac124 knockout virus was generated to determine the role of ac124 in the baculovirus life cycle. Our results showed that an ac124 knockout AcMNPV could produce infectious budded viruses (BVs) and occlusion bodies (OBs) like those produced by the wild virus and ac124 repair virus. These three viruses had similar growth kinetics during the infection phase. There was no significant difference in nucleocapsids, occlusion-derived viruses and OBs visualized by electron microscopy. The ac124 deletion mutant did not reduce AcMNPV infectivity for S. exigua in an LD50 bioassay. However, it took 20 h longer for the ac124 deletion mutant to kill S. exigua than wild-type virus in the LT50 bioassay. Altogether, these results demonstrate that ac124 is not required for viral replication, but it accelerates the killing of infected larvae. PMID:25380680

  19. Autographa californica multiple nucleopolyhedrovirus Ac92 (ORF92, P33) is required for budded virus production and multiply enveloped occlusion-derived virus formation.

    PubMed

    Wu, Wenbi; Passarelli, A Lorena

    2010-12-01

    The Autographa californica multiple nucleopolyhedrovirus orf92 (p33), ac92, is one of 31 genes carried in all sequenced baculovirus genomes, thus suggesting an essential function. Ac92 has homology to the family of flavin adenine dinucleotide-linked sulfhydryl oxidases and is related to the ERV/ALR family of sulfhydryl oxidases. The role of ac92 during virus replication is unknown. Ac92 was associated with the envelope of both budded and occlusion-derived virus (ODV). To investigate the role of Ac92 during virus replication, an ac92-knockout bacmid was generated through homologous recombination in Escherichia coli. Titration and plaque assays showed no virus spread in ac92-knockout bacmid DNA-transfected insect cells. Deletion of ac92 did not affect viral DNA replication. However, ac92-knockout bacmid DNA-transfected cells lacked multiply enveloped occlusion-derived nucleocapsids; instead, singly enveloped nucleocapsids were detected. To gain insight into the requirement for sulfhydryl oxidation during virus replication, a virus was constructed in which the Ac92 C(155)XXC(158) amino acids, important for sulfhydryl oxidase activity, were mutated to A(155)XXA(158). The mutant virus exhibited a phenotype similar to that of the knockout virus, suggesting that the C-X-X-C motif was essential for sulfhydryl oxidase activity and responsible for the altered ODV phenotype. PMID:20861245

  20. The Differential Expression of BmGlcNAcase2 in Strains of Bombyx mori (Lepidoptera: Bombycidae) With Different Susceptibility to Bombyx mori (Lepidoptera: Bombycidae) Nucleopolyhedrovirus Infection

    PubMed Central

    Hao, Zhu; Quanbing, Ma

    2015-01-01

    GlcNAcase is a glycosyl hydrolase located in the lysosomes of numerous organisms. Levels of the protein, β-N-acetylglucosaminidase 2 (GlcNAcase2), which is a member of the GlcNAcase family, are different in two strains of the silkworm Bombyx mori that have different resistance to Bombyx mori nucleopolyhedroviruses (BmNPVs). We identified six single-nucleotide differences in the GlcNAcase2 coding sequence between the 306 and NB strains. Five are silent changes, but one is a nonsynonymous mutation. Reverse transcription-polymerase chain reaction analysis showed that GlcNAcase2 mRNA levels in the NB strain were nearly 2.57 times higher compared with those in the 306 strain. In addition, GlcNAcase2 enzyme activity was much higher in the NB strain compared with that in the 306 strain. Together, these results indicate that GlcNAcase2 may be involved in variable BmNPV resistance in B. mori. PMID:25765316

  1. Autographa californica multiple nucleopolyhedrovirus ac66 is required for the efficient egress of nucleocapsids from the nucleus, general synthesis of preoccluded virions and occlusion body formation

    SciTech Connect

    Ke Jianhao Wang Jinwen; Deng Riqiang; Wang Xunzhang

    2008-05-10

    Although orf66 (ac66) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is conserved in all sequenced lepidopteran baculovirus genomes, its function is not known. This paper describes generation of an ac66 knockout AcMNPV bacmid mutant and analyses of the influence of ac66 deletion on the virus replication in Sf-9 cells so as to determine the role of ac66 in the viral life cycle. Results indicated that budded virus (BV) yields were reduced over 99% in ac66-null mutant infected cells in comparison to that in wild-type virus infected cells. Optical microscopy revealed that occlusion body synthesis was significantly reduced in the ac66 knockout bacmid-transfected cells. In addition, ac66 deletion interrupted preoccluded virion synthesis. The mutant phenotype was rescued by an ac66 repair bacmid. On the other hand, real-time PCR analysis indicated that ac66 deletion did not affect the levels of viral DNA replication. Electron microscopy revealed that ac66 is not essential for nucleocapsid assembly, but for the efficient transport of nucleocapsids from the nucleus to the cytoplasm. These results suggested that ac66 plays an important role for the efficient exit of nucleocapsids from the nucleus to the cytoplasm for BV synthesis as well as for preoccluded virion and occlusion synthesis.

  2. Field testing Chinese and Japanese gypsy moth nucleopolyhedrovirus and disparvirus against a Chinese population of Lymantria dispar asiatica in Huhhot, Inner Mongolia, People's Republic of China.

    PubMed

    Duan, L Q; Otvos, I S; Xu, L B; Conder, N; Wang, Y

    2012-04-01

    The activity of three geographic isolates of the gypsy moth nucleopolyhedrovirus (LdMNPV) was evaluated in field trials against larvae of the Chinese population of Lymantria dispar asiatica Vnukovskij in Inner Mongolia, People's Republic of China, in 2004, 2005, and 2006. Although the Chinese isolate of the virus, LdMNPV-H, was the most pathogenic of the isolates tested, having the lowest mean lethal concentration causing 50% and 95% larval mortality, the increase in efficacy that would be obtained by incorporating this isolate into a commercial product does not justify the time or expense required to register it for use in the United States or Canada. The commercially available North American isolate, LdMNPV-D, was moderately pathogenic, whereas the Japanese isolate, LdMNPV-J, was the least pathogenic. The slopes of the dose-response regression lines for the three virus isolates indicated that the Chinese gypsy moth larvae were more homogenously susceptible to LdMNPV-H and LdMNPV-D than to LdMNPV-J. Time-response data showed that LdMNPV-J was significantly more virulent, but at a much higher dose, than the other two isolates, causing 50% mortality in the shortest time, followed by LdMNPV-H and LdMNPV-D. Rainfall immediately after the application of LdMNPV-D in 2005 resulted in significantly reduced gypsy moth larval mortality. PMID:22606802

  3. Cloning and expression of the VHDL receptor from fat body of the corn ear worm, Helicoverpa zea

    PubMed Central

    Persaud, Deryck R.; Haunerland, Norbert H.

    2004-01-01

    In Noctuids, storage proteins are taken up into fat body by receptor-mediated endocytosis. These include arylphorin and a second, structurally unrelated very high-density lipoprotein (VHDL). Previously, we have isolated a single storage protein receptor from the corn earworm, Helicoverpa zea, which binds both VHDL and arylphorin. The receptor protein is a basic, N-terminally blocked, ∼80 kDa protein that is associated with fat body membranes. Microsequencing of proteolytic fragments of the isolated receptor protein revealed internal sequences that were used to clone the complete cDNA of the VHDL receptor by 3′ and 5′ RACE techniques. The receptor protein, when expressed in vitro via a suitable insect expression vector, reacted with antibodies against the native VHDL receptor and bound strongly to its ligand VHDL, thus confirming that the cloned cDNA represents indeed the previously purified VHDL receptor. The receptor protein and a second, similar protein also found associated with the fat body membrane show considerable homology to putative basic juvenile hormone suppressible proteins cloned previously from other Noctuid species. Sequence analysis revealed that the receptor is likely a peripheral membrane protein that may mediate the selective uptake of VHDL. Abbreviation: BJHSP basic juvenile hormone suppressible protein FITC fluorescein isothiocyanate HRP horseraddish peroxidase RACE rapid amplification of cDNA ends VHDL very high density lipoprotein PMID:15861222

  4. DNA Barcoding the Heliothinae (Lepidoptera: Noctuidae) of Australia and Utility of DNA Barcodes for Pest Identification in Helicoverpa and Relatives.

    PubMed

    Mitchell, Andrew; Gopurenko, David

    2016-01-01

    Helicoverpa and Heliothis species include some of the world's most significant crop pests, causing billions of dollars of losses globally. As such, a number are regulated quarantine species. For quarantine agencies, the most crucial issue is distinguishing native species from exotics, yet even this task is often not feasible because of poorly known local faunas and the difficulties of identifying closely related species, especially the immature stages. DNA barcoding is a scalable molecular diagnostic method that could provide the solution to this problem, however there has been no large-scale test of the efficacy of DNA barcodes for identifying the Heliothinae of any region of the world to date. This study fills that gap by DNA barcoding the entire heliothine moth fauna of Australia, bar one rare species, and comparing results with existing public domain resources. We find that DNA barcodes provide robust discrimination of all of the major pest species sampled, but poor discrimination of Australian Heliocheilus species, and we discuss ways to improve the use of DNA barcodes for identification of pests. PMID:27509042

  5. APN1 is a functional receptor of Cry1Ac but not Cry2Ab in Helicoverpa zea

    PubMed Central

    Wei, Jizhen; Zhang, Min; Liang, Gemei; Wu, Kongming; Guo, Yuyuan; Ni, Xinzhi; Li, Xianchun

    2016-01-01

    Lepidopteran midgut aminopeptidases N (APNs) are phylogenetically divided into eight clusters, designated as APN1–8. Although APN1 has been implicated as one of the receptors for Cry1Ac in several species, its potential role in the mode of action of Cry2Ab has not been functionally determined so far. To test whether APN1 also acts as one of the receptors for Cry1Ac in Helicoverpa zea and even for Cry2Ab in this species, we conducted a gain of function analysis by heterologously expressing H. zea APN1 (HzAPN1) in the midgut and fat body cell lines of H. zea and the ovarian cell line of Spodoptera frugiperda (Sf9) and a loss of function analysis by RNAi (RNA interference) silencing of the endogenous APN1 in the three cell lines using the HzAPN1 double strand RNA (dsRNA). Heterologous expression of HzAPN1 significantly increased the susceptibility of the three cell lines to Cry1Ac, but had no effects on their susceptibility to Cry2Ab. Knocking down of the endogenous APN1 made the three cell lines resistant to Cry1Ac, but didn’t change cell lines susceptibility to Cry2Ab. The findings from this study demonstrate that HzAPN1 is a functional receptor of Cry1Ac, but not Cry2Ab. PMID:26755166

  6. Efficacy of insecticides of different chemistries against Helicoverpa zea (Lepidoptera: Noctuidae) in transgenic Bacillus thuringiensis and conventional cotton.

    PubMed

    Brickle, D S; Turnipseed, S G; Sullivan, M J

    2001-02-01

    Six insecticides of different chemistries were evaluated against the cotton bollworm, Helicoverpa zea (Boddie), in non-B.t. (Deltapine 'DP 5415', Deltapine 'DP 5415RR') and transgenic Bacillus thuringiensis (Berliner) (B.t.) (Deltapine 'NuCOTN 33B', Deltapine 'DP 458 B/RR') cotton. In 1998, treatments consisted of three rates each of a pyrethroid (lambda-cyhalothrin), spinosyn (spinosad), carbamate (thiodicarb), pyrrole (chlorfenapyr), oxadiazine (indoxacarb), and avermectin (emamectin benzoate) in a nonirrigated field. In 1999, treatments consisted of three rates each of lambda-cyhalothrin, spinosad, thiodicarb, and indoxacarb in an irrigated and a nonirrigated (dryland) field. The highest rate of each insecticide corresponded to normal grower-use rates. Spinosad and thiodicarb controlled H. zea in non-B.t. cotton, whereas other materials were less effective. Even though H. zea is becoming increasingly resistant to pyrethroid insecticides, lambda-cyhalothrin was highly effective in dryland B. thuringiensis cotton. Spinosad and thiodicarb were equally effective. Data indicated that reduced rates of lambda-cyhalothrin, spinosad, and thiodicarb could be used for control of H. zea in dryland B.t. cotton systems. However, reduced rates of these insecticides in a heavily irrigated B.t. cotton system did not provide adequate control. PMID:11233138

  7. Development of bollworms, Helicoverpa zea, on two commercial Bollgard® cultivars that differ in overall Cry1Ac levels

    PubMed Central

    Adamczyk, John J.; Gore, Jeffrey

    2004-01-01

    Research was conducted to quantify the development of the corn earworm (= bollworm), Helicoverpa zea (Boddie), on two different transgenic cotton cultivars (DP 50B and NuCOTN 33B) that contained different levels of the Cry1Ac endotoxin from the soil bacterium, Bacillus thuringiensis Berliner. Using a field cage, an inverse relationship between the amount of Cry1Ac among cultivars versus the weight of bollworm larvae was observed. Larvae that were recovered from the DP 50B cultivar expressing lower Cry1Ac weighed significantly more than larvae collected from the higher expressing NuCOTN 33B cultivar. Cotton plants from NuCOTN 33B were measured as expressing 300% more Cry1Ac than DP 50B plants. The distribution of larval weights indicates that more late-instars (> 200 mg) were collected from the lower expressing DP50B cultivar than the higher expressing NuCOTN 33B cultivar. Within a single population, bollworm larvae were highly variable in their development when feeding on Bollgard® cotton. Possible reasons and consequences for this variation are discussed. PMID:15861247

  8. DNA Barcoding the Heliothinae (Lepidoptera: Noctuidae) of Australia and Utility of DNA Barcodes for Pest Identification in Helicoverpa and Relatives

    PubMed Central

    Gopurenko, David

    2016-01-01

    Helicoverpa and Heliothis species include some of the world’s most significant crop pests, causing billions of dollars of losses globally. As such, a number are regulated quarantine species. For quarantine agencies, the most crucial issue is distinguishing native species from exotics, yet even this task is often not feasible because of poorly known local faunas and the difficulties of identifying closely related species, especially the immature stages. DNA barcoding is a scalable molecular diagnostic method that could provide the solution to this problem, however there has been no large-scale test of the efficacy of DNA barcodes for identifying the Heliothinae of any region of the world to date. This study fills that gap by DNA barcoding the entire heliothine moth fauna of Australia, bar one rare species, and comparing results with existing public domain resources. We find that DNA barcodes provide robust discrimination of all of the major pest species sampled, but poor discrimination of Australian Heliocheilus species, and we discuss ways to improve the use of DNA barcodes for identification of pests. PMID:27509042

  9. Development of bollworms, Helicoverpa zea, on two commercial Bollgard cultivars that differ in overall Cry1Ac levels.

    PubMed

    Adamczyk, John J; Gore, Jeffrey

    2004-01-01

    Research was conducted to quantify the development of the corn earworm (= bollworm), Helicoverpa zea (Boddie), on two different transgenic cotton cultivars (DP 50B and NuCOTN 33B) that contained different levels of the Cry1Ac endotoxin from the soil bacterium, Bacillus thuringiensis Berliner. Using a field cage, an inverse relationship between the amount of Cry1Ac among cultivars versus the weight of bollworm larvae was observed. Larvae that were recovered from the DP 50B cultivar expressing lower Cry1Ac weighed significantly more than larvae collected from the higher expressing NuCOTN 33B cultivar. Cotton plants from NuCOTN 33B were measured as expressing 300% more Cry1Ac than DP 50B plants. The distribution of larval weights indicates that more late-instars (> 200 mg) were collected from the lower expressing DP50B cultivar than the higher expressing NuCOTN 33B cultivar. Within a single population, bollworm larvae were highly variable in their development when feeding on Bollgard cotton. Possible reasons and consequences for this variation are discussed. PMID:15861247

  10. VHDL, a larval storage protein from the corn earworm, Helicoverpa zea, is a member of the vitellogenin gene family.

    PubMed

    Sum, Herbert; Haunerland, Norbert H

    2007-10-01

    The hemolymph of last instar larvae of the corn earworm, Helicoverpa zea contains a blue very high-density lipoprotein (VHDL) that is selectively taken up into fat body prior to pupation. Its amino-terminal sequence was determined by Edman degradation, and used to design a degenerate primer for PCR amplification. With 5' and 3' RACE techniques, the entire cDNA coding for VHDL was amplified and sequenced. Conceptual translation reveals a 173 kDa protein that contains a 15 amino acid signal sequence immediately before the experimentally determined N-terminus of the mature protein. The protein contains a typical lipoprotein N-terminal domain, and shows high sequence similarity to vitellogenins from Lepidoptera and other insect species. VHDL mRNA was not detectable in adult H. zea, and antibodies raised against VHDL did not react with adult hemolymph or yolk proteins. Therefore VHDL, although a member of the vitellogenin gene family, seems to be distinct from the vitellogenin expressed in adult females. PMID:17785196

  11. Cloning and expression of the VHDL receptor from fat body of the corn ear worm, Helicoverpa zea.

    PubMed

    Persaud, Deryck R; Haunerland, Norbert H

    2004-01-01

    In Noctuids, storage proteins are taken up into fat body by receptor-mediated endocytosis. These include arylphorin and a second, structurally unrelated very high-density lipoprotein (VHDL). Previously, we have isolated a single storage protein receptor from the corn earworm, Helicoverpa zea, which binds both VHDL and arylphorin. The receptor protein is a basic, N-terminally blocked, approximately 80 kDa protein that is associated with fat body membranes. Microsequencing of proteolytic fragments of the isolated receptor protein revealed internal sequences that were used to clone the complete cDNA of the VHDL receptor by 3' and 5' RACE techniques. The receptor protein, when expressed in vitro via a suitable insect expression vector, reacted with antibodies against the native VHDL receptor and bound strongly to its ligand VHDL, thus confirming that the cloned cDNA represents indeed the previously purified VHDL receptor. The receptor protein and a second, similar protein also found associated with the fat body membrane show considerable homology to putative basic juvenile hormone suppressible proteins cloned previously from other Noctuid species. Sequence analysis revealed that the receptor is likely a peripheral membrane protein that may mediate the selective uptake of VHDL. PMID:15861222

  12. Managing the Sugarcane Borer, Diatraea saccharalis, and Corn Earworm, Helicoverpa zea, using Bt Corn and Insecticide Treatments

    PubMed Central

    Farias, Juliano R.; Costa, Ervandil C.; Guedes, Jerson V. C.; Arbage, Alessandro P.; Neto, Armando B.; Bigolin, Mauricio; Pinto, Felipe F.

    2013-01-01

    The sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) and the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are important pests of corn in Brazil and have not been successfully managed, because of the difficulty of managing them with pesticides. The objective of this study was to evaluate the effect of Bt corn MON810, transformed with a gene from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) insecticide seed treatment, and foliar insecticide spray using treatments developed for control of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is the major pest of corn. The experiments were done under field conditions in early- and late-planted corn in the state of Rio Grande do Sul, Brazil, and in the laboratory. The MON810 corn reduced infestations and damage by D. saccharalis and H. zea. The insecticides used in seed treatments or foliar sprays did not affect D. saccharalis and H. zea infestations or damage levels. The exception was the insecticide seed treatment in non-transformed corn, which reduced early infestations of D. saccharalis. The MON810 corn, therefore, can be used for managing these two pest species, especially D. saccharalis. PMID:24735131

  13. Managing the sugarcane borer, Diatraea saccharalis, and corn earworm, Helicoverpa zea, using Bt corn and insecticide treatments.

    PubMed

    Farias, Juliano R; Costa, Ervandil C; Guedes, Jerson V C; Arbage, Alessandro P; Neto, Armando B; Bigolin, Mauricio; Pinto, Felipe F

    2013-01-01

    The sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) and the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are important pests of corn in Brazil and have not been successfully managed, because of the difficulty of managing them with pesticides. The objective of this study was to evaluate the effect of Bt corn MON810, transformed with a gene from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) insecticide seed treatment, and foliar insecticide spray using treatments developed for control of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is the major pest of corn. The experiments were done under field conditions in early- and late-planted corn in the state of Rio Grande do Sul, Brazil, and in the laboratory. The MON810 corn reduced infestations and damage by D. saccharalis and H. zea. The insecticides used in seed treatments or foliar sprays did not affect D. saccharalis and H. zea infestations or damage levels. The exception was the insecticide seed treatment in non-transformed corn, which reduced early infestations of D. saccharalis. The MON810 corn, therefore, can be used for managing these two pest species, especially D. saccharalis. PMID:24735131

  14. The heptad repeats region is essential for AcMNPV P10 filament formation and not the proline-rich or the C-terminus basic regions

    SciTech Connect

    Dong Chunsheng; Deng Fei; Li Dan; Wang Hualin; Hu Zhihong

    2007-09-01

    Baculovirus P10 protein is a small conserved protein and is expressed as bundles of filaments in the host cell during the late phase of virus infection. So far the published results on the domain responsible for filament structural formation have been contradictory. Electron microscopy revealed that the C-terminus basic region was involved in filament structural formation in the Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV) [van Oers, M.M., Flipsen, J.T., Reusken, C.B., Sliwinsky, E.L., Vlak, J.M., 1993. Functional domains of the p10 protein of Autographa californica nuclear polyhedorsis virus. J. Gen. Virol. 74, 563-574.]. While in the Helicoverpa armigera nucleopolyhedrovirus (HearNPV), the heptad repeats region but not the C-terminus domain was proven to be responsible for filament formation [Dong, C., Li, D., Long, G., Deng, F., Wang, H., Hu, Z., 2005. Identification of functional domains required for HearNPV P10 filament formation. Virology 338, 112-120.]. In this manuscript, fluorescence confocal microscopy was applied to study AcMNPV P10 filament formation. A set of plasmids containing different P10 structural domains fused with a fluorescent protein were constructed and transfected into Sf-9 cells. The data indicated that the heptad repeats region, but not the proline-rich region or the C-terminus basic region, is essential for AcMNPV P10 filament formation. Co-transfection of P10s tagged with different fluorescent revealed that P10s with defective heptad repeats region could not interact with intact heptad repeats region or even full-length P10s to form filament structure. Within the heptad repeats region, deletion of the three amino acids spacing of AcMNPV P10 appeared to have no significant impact on the formation of filament structures, but the content of the heptad repeats region appeared to play a role in the morphology of the filaments.

  15. Improvement in the UV resistance of baculoviruses by displaying nano-zinc oxide-binding peptides on the surfaces of their occlusion bodies.

    PubMed

    Li, Jin; Zhou, Yin; Lei, Chengfeng; Fang, Wei; Sun, Xiulian

    2015-08-01

    The sensitivity of baculoviruses to UV radiation severely limits their large-scale application as biological insecticides. The polyhedron envelope of a baculovirus, which is composed of carbohydrate and polyhedron envelope protein (PEP), is a significant structure for the stability and persistence of occlusion bodies (OBs) under environmental conditions. The results of this study revealed that the rough pitted surface phenotype of a pep-null Autographa californica multiple nucleopolyhedrovirus (AcMNPV) could not be rescued by any of its homologues, such as Helicoverpa armigera nucleopolyhedrovirus pep or Cydia pomonella granulovirus putative peps. In contrast, the N-terminal and middle flexible region (NM region, 1-167 aa) of AcMNPV PEP were able to form an intact OB envelope. Furthermore, this region was capable of carrying eGFP to the surfaces of the OBs. To improve the UV resistance of AcMNPV OBs, two peptides capable of specifically binding to nano-ZnO were separately fused to the NM region of PEP. Under laboratory conditions, infectivity of the recombinant viruses binding to nano-ZnO particles was about ninefold higher than that without the nano-ZnO particles after UV-B irradiation. Pot experiments revealed that the half-life of the recombinant baculovirus binding nano-ZnO particles was 3.3 ± 0.15 days, which was significantly longer than that of the control virus (0.49 ± 0.06 days). These results therefore represent a new approach for the protection the baculoviral insecticides against UV irradiation in the field. PMID:25895092

  16. New measures of insecticidal efficacy and safety obtained with the 39K promoter of a recombinant baculovirus.

    PubMed

    Regev, Avital; Rivkin, Hadassah; Gurevitz, Michael; Chejanovsky, Nor

    2006-12-22

    Baculoviruses are orally infectious to insects and considered to be natural insecticides. To enhance their speed-of-kill these viruses were engineered to express arthropod neurotoxins under the control of various strong promoters. Although this strategy proved to be efficient, it raised recently concerns about safety. We analyzed the speed-of-kill and safety of Autographa californica multiple nucleopolyhedrovirus expressing the insecticidal scorpion neurotoxin AaIT and found that the mortality of Helicoverpa armigera larvae was enhanced significantly when the expression was controlled by the baculovirus delayed-early promoter 39K rather than the very late promoter p10. This improvement was also reflected in better protection of cotton leaves on which these insects were fed. Using lacZ as a sensitive reporter we also found that expression driven by the 39K promoter was detected in insect but not in mammalian cells. These results imply that by selection of an appropriate viral promoter, engineered baculoviruses may comply with the high standard biosafety requirements from a genetically modified organism (GMO). Our results provide further support for the potential use of engineered baculoviruses in insect pest control in a safely manner. PMID:17141223

  17. Novel Apoptosis Suppressor Apsup from the Baculovirus Lymantria dispar Multiple Nucleopolyhedrovirus Precludes Apoptosis by Preventing Proteolytic Processing of Initiator Caspase Dronc

    PubMed Central

    Yamada, Hayato; Kitaguchi, Koji; Hamajima, Rina; Kobayashi, Michihiro

    2013-01-01

    We previously identified a novel baculovirus-encoded apoptosis suppressor, Apsup, from the baculovirus Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV). Apsup inhibits the apoptosis of L. dispar Ld652Y cells triggered by infection with p35-defective Autographa californica MNPV (vAcΔp35) and exposure to actinomycin D or UV light. Here, we examined the functional role of Apsup in apoptosis regulation in insect cells. Apsup prevented apoptosis and the proteolytic processing of L. dispar initiator caspase Dronc (Ld-Dronc) in Ld652Y cells triggered by overexpression of Ld-Dronc, LdMNPV inhibitor-of-apoptosis 3 (IAP3), or Hyphantria cunea MNPV IAP1. In vAcΔp35-infected apoptotic Ld652Y cells, Apsup restricted apoptosis induction and prevented processing of endogenous Ld-Dronc. Conversely, upon RNA interference (RNAi)-mediated silencing of apsup, LdMNPV-infected Ld652Y cells, which typically support high-titer virus replication, underwent apoptosis, accompanied by the processing of endogenous Ld-Dronc. Furthermore, endogenous Ld-Dronc coimmunoprecipitated with transiently expressed Apsup, indicating that Apsup physically interacts with Ld-Dronc. Apsup prevented the apoptosis of Sf9 cells triggered by vAcΔp35 infection but did not inhibit apoptosis or activation of caspase-3-like protease in vAcΔp35-infected Drosophila melanogaster S2 cells. Apsup also inhibited the proteolytic processing of L. dispar effector caspase Ld-caspase-1 in the transient expression assay but did not physically interact with Ld-caspase-1. These results demonstrate that Apsup inhibits apoptosis in Ld652Y cells by preventing the proteolytic processing of Ld-Dronc. Together with our previous findings showing that Apsup prevents the processing of both overexpressed Ld-Dronc and Bombyx mori Dronc, these results also demonstrate that Apsup functions as an effective apoptotic suppressor in various lepidopteran, but not dipteran, insect cells. PMID:24067961

  18. Translational enhancement of recombinant protein synthesis in transgenic silkworms by a 5'-untranslated region of polyhedrin gene of Bombyx mori Nucleopolyhedrovirus.

    PubMed

    Iizuka, Masashi; Tomita, Masahiro; Shimizu, Katsuhiko; Kikuchi, Yutaka; Yoshizato, Katsutoshi

    2008-06-01

    Previously, we established a method to produce recombinant proteins (r-proteins) in cocoons of germline transgenic silkworms, and showed that a step(s) in post-transcription processes was rate-limiting in obtaining a high yield of r-proteins. In this study, we examined whether the 5'-untranslated region (5'-UTR) of the polyhedrin gene (pol) of nucleopolyhedrovirus (NPV) has a translational enhancer activity in the r-protein expression by middle silk gland (MSG) cells of silkworm Bombyx mori (Bm). Sericin 1 gene (ser1) promoter-driven transformation vectors were constructed in which pol5'-UTRs of NPVs isolated from four different species, Bm, Spodoptera frugiperda, Ectropis oblique, and Malacosoma neustria, were each placed upstream of a reporter gene. Transient expression assays in MSGs showed that these pol5'-UTRs all enhanced the protein expression of reporter genes, and the pol5'-UTR of Bm NPV (pol5'-UTR/Bm) was the most effective among them. Thus, transgenic silkworms were generated, which bore the ser1 promoter-driven His-tagged secretory EGFP (sEGFP-His) gene under the control of pol5'-UTR/Bm. The synthesis of sEGFP-His proteins in MSGs of the transgenic worms was approximately 1.5-fold higher than that in those bearing null vectors. However, its mRNA expression levels were 67% of the control worms, indicating that the pol5'-UTR/Bm specifically enhanced the translational level. In conclusion, pol5'-UTR/Bm increased the yield of r-protein production in transgenic silkworms by enhancing the translational activity and this 5'-UTR could be useful for the mass production of r-proteins in germline transgenic silkworms. PMID:18640598

  19. Quantitative and ultrastructural changes in the haemocytes of Spodoptera littoralis (Boisd.) treated individually or in combination with Spodoptera littoralis multicapsid nucleopolyhedrovirus (SpliMNPV) and azadirachtin.

    PubMed

    Shaurub, El-Sayed H; Abd El-Meguid, Afaf; Abd El-Aziz, Nahla M

    2014-10-01

    The total haemocyte count (THC) and the possible ultrastructural alterations induced in the haemocytes of the fourth larval instars of the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae), 96 h post-feeding on a semi-synthetic diet, treated with the LC50 of Spodoptera littoralis multicapsid nucleopolyhedrovirus (SpliMNPV) and the LC50 of azadirachtin alone, and the LC25 of SpliMNPV combined with the LC25 of azadirachtin were studied and compared to the control. Single treatment with the virus and azadirachtin or combined treatment significantly decreased the THC compared to the control. There are five types of haemocytes in S. littoralis: prohaemocytes, plasmatocytes, granulocytes, spherulocytes and oenocytoids. The most common symptoms in granulocytes and plasmatocytes, the main affected cell types, due to viral infection were the presence of virogenic stroma, peripheral dispersion of the chromatin and disappearance of the nucleoli. However, the most common symptoms in these two types of haemocytes due to treatment with azadirachtin were the presence of rough endoplasmic reticulum filled with fibrous materials, due to probably apoptosis, in their cisternae and disorganization of mitochondria (looped, vacuolated and swollen). In addition, the cytoplasm of granulocytes was vacuolated with the appearance of autophagic lysosomes, while plasmatocytes showed ruptured cell membrane and folded nuclear envelope. Combined treatment with the NPV and azadirachtin induced the same pathological changes which were recorded from individual treatment with the virus or azadirachtin to the same haemocytes. It can be concluded that the change in the THC and ultrastructure of granulocytes and plasmatocytes may affect the cellular-mediated immune response in S. littoralis. Moreover, it seems likely that mitochondria were the target site of azadirachtin, as they were affected in both granulocytes and plasmatocytes treated with azadirachtin alone or in

  20. Functional characterization of Bombyx mori nucleopolyhedrovirus late gene transcription and genome replication factors in the non-permissive insect cell line SF-21

    SciTech Connect

    Berretta, Marcelo F.; Deshpande, Mandar; Crouch, Erin A.; Passarelli, A. Lorena . E-mail: lpassar@ksu.edu

    2006-04-25

    We compared the abilities of late gene transcription and DNA replication machineries of the baculoviruses Autographa californica nucleopolyhedrovirus (AcMNPV) and Bombyx mori NPV (BmNPV) in SF-21 cells, an insect-derived cell line permissive for AcMNPV infection. It has been well established that 19 AcMNPV late expression factors (lefs) stimulate substantial levels of late gene promoter activity in SF-21 cells. Thus, we constructed a set of clones containing the BmNPV homologs of the AcMNPV lefs under control of the constitutive Drosophila heat shock 70 protein promoter and tested their ability to activate an AcMNPV late promoter-reporter gene cassette in SF-21 cells. We tested the potential of individual or predicted functional groups of BmNPV lefs to successfully replace the corresponding AcMNPV gene(s) in transient late gene expression assays. We found that most, but not all, BmNPV lefs were able to either fully or partially substitute for the corresponding AcMNPV homolog in the context of the remaining AcMNPV lefs with the exception of BmNPV p143, ie-2, and p35. BmNPV p143 was unable to support late gene expression or be imported into the nucleus of cells in the presence of the AcMNPV or the BmNPV LEF-3, a P143 nuclear shuttling factor. Our results suggest that host-specific factors may affect the function of homologous proteins.

  1. Development of quenching and washing protocols for quantitative intracellular metabolite analysis of uninfected and baculovirus-infected insect cells.

    PubMed

    Tran, Trinh T B; Dietmair, Stefanie; Chan, Leslie C L; Huynh, Hoai T; Nielsen, Lars K; Reid, Steven

    2012-03-01

    Metabolomics refer to the global analysis of small molecule metabolites in a biological system, and can be a powerful tool to elucidate and optimize cellular processes, particularly when integrated into a systems biology framework. Determining the endometabolome in cultured animal cells is especially challenging, due to the conflicting demands for rapid quenching of metabolism and retention of membrane integrity, while cells are separated from the complex medium. The challenge is magnified in virus infected cells due to increased membrane fragility. This paper describes an effective methodology for quantitative intracellular metabolite analysis of the baculovirus-insect cell expression system, an important platform for the production of heterologous proteins and baculovirus-based biopesticides. These two applications were represented by Spodoptera frugiperda (Sf9) and Helicoverpa zea (HzAM1) cells infected with recombinant Autographa californica and wild-type Helicoverpa armigera nucleopolyhedroviruses (AcMNPV and HaSNPV), respectively. Specifically, an ice-cold quenching solution comprising 1.1% w/v NaCl and 0.2% w/v Pluronic® F-68 (NaCl+P) was found to be efficacious in preserving cell viability and minimizing cell leakage during quenching and centrifugation-based washing procedures (prior to extraction using cold 50% v/v acetonitrile). Good recoveries of intracellular adenosine triphosphate, total adenosine phosphates and amino acids were obtained after just one wash step, for both uninfected and infected insect cells. The ability to implement wash steps is critical, as insect cell media are metabolites-rich, while infected insect cells are much more fragile than their uninfected counterparts. Hence, a promising methodology has been developed to facilitate endometabolomic analysis of insect cell-baculovirus systems for bioprocess optimization. PMID:22166686

  2. Insect Eggs Can Enhance Wound Response in Plants: A Study System of Tomato Solanum lycopersicum L. and Helicoverpa zea Boddie

    PubMed Central

    Kim, Jinwon; Tooker, John F.; Luthe, Dawn S.; De Moraes, Consuelo M.; Felton, Gary W.

    2012-01-01

    Insect oviposition on plants frequently precedes herbivory. Accumulating evidence indicates that plants recognize insect oviposition and elicit direct or indirect defenses to reduce the pressure of future herbivory. Most of the oviposition-triggered plant defenses described thus far remove eggs or keep them away from the host plant or their desirable feeding sites. Here, we report induction of antiherbivore defense by insect oviposition which targets newly hatched larvae, not the eggs, in the system of tomato Solanum lycopersicum L., and tomato fruitworm moth Helicoverpa zea Boddie. When tomato plants were oviposited by H. zea moths, pin2, a highly inducible gene encoding protease inhibitor2, which is a representative defense protein against herbivorous arthropods, was expressed at significantly higher level at the oviposition site than surrounding tissues, and expression decreased with distance away from the site of oviposition. Moreover, more eggs resulted in higher pin2 expression in leaves, and both fertilized and unfertilized eggs induced pin2 expression. Notably, when quantified daily following deposition of eggs, pin2 expression at the oviposition site was highest just before the emergence of larvae. Furthermore, H. zea oviposition primed the wound-induced increase of pin2 transcription and a burst of jasmonic acid (JA); tomato plants previously exposed to H. zea oviposition showed significantly stronger induction of pin2 and higher production of JA upon subsequent simulated herbivory than without oviposition. Our results suggest that tomato plants recognize H. zea oviposition as a signal of impending future herbivory and induce defenses to prepare for this herbivory by newly hatched neonate larvae. PMID:22616005

  3. Association of Cry1Ac Toxin Resistance in Helicoverpa zea (Boddie) with Increased Alkaline Phosphatase Levels in the Midgut Lumen

    PubMed Central

    Caccia, Silvia; Moar, William J.; Chandrashekhar, Jayadevi; Oppert, Cris; Anilkumar, Konasale J.; Jurat-Fuentes, Juan Luis

    2012-01-01

    Resistance to Bacillus thuringiensis Cry1Ac toxin was characterized in a population of Helicoverpa zea larvae previously shown not to have an alteration in toxin binding as the primary resistance mechanism to this toxin. Cry1Ac-selected larvae (AR1) were resistant to protoxins and toxins of Cry1Ab, Cry1Ac, and the corresponding modified proteins lacking helix α-1 (Cry1AbMod and Cry1AcMod). When comparing brush border membrane vesicles (BBMVs) prepared from susceptible (LC) and AR1 larval midguts, there were only negligible differences in overall Cry1Ac toxin binding, though AR1 had 18% reversible binding, in contrast to LC, in which all binding was irreversible. However, no differences were detected in Cry1Ac-induced pore formation activity in BBMVs from both strains. Enzymatic activities of two putative Cry1Ac receptors (aminopeptidase N [APN] and alkaline phosphatase [ALP]) were significantly reduced (2-fold and 3-fold, respectively) in BBMVs from AR1 compared to LC larvae. These reductions corresponded to reduced protein levels in midgut luminal contents only in the case of ALP, with an almost 10-fold increase in specific ALP activity in midgut fluids from AR1 compared to LC larvae. Partially purified H. zea ALP bound Cry1Ac toxin in ligand blots and competed with Cry1Ac toxin for BBMV binding. Based on these results, we suggest the existence of at least one mechanism of resistance to Cry1A toxins in H. zea involving binding of Cry1Ac toxin to an ALP receptor in the larval midgut lumen of resistant larvae. PMID:22685140

  4. Association of Cry1Ac toxin resistance in Helicoverpa zea (Boddie) with increased alkaline phosphatase levels in the midgut lumen.

    PubMed

    Caccia, Silvia; Moar, William J; Chandrashekhar, Jayadevi; Oppert, Cris; Anilkumar, Konasale J; Jurat-Fuentes, Juan Luis; Ferré, Juan

    2012-08-01

    Resistance to Bacillus thuringiensis Cry1Ac toxin was characterized in a population of Helicoverpa zea larvae previously shown not to have an alteration in toxin binding as the primary resistance mechanism to this toxin. Cry1Ac-selected larvae (AR1) were resistant to protoxins and toxins of Cry1Ab, Cry1Ac, and the corresponding modified proteins lacking helix α-1 (Cry1AbMod and Cry1AcMod). When comparing brush border membrane vesicles (BBMVs) prepared from susceptible (LC) and AR1 larval midguts, there were only negligible differences in overall Cry1Ac toxin binding, though AR1 had 18% reversible binding, in contrast to LC, in which all binding was irreversible. However, no differences were detected in Cry1Ac-induced pore formation activity in BBMVs from both strains. Enzymatic activities of two putative Cry1Ac receptors (aminopeptidase N [APN] and alkaline phosphatase [ALP]) were significantly reduced (2-fold and 3-fold, respectively) in BBMVs from AR1 compared to LC larvae. These reductions corresponded to reduced protein levels in midgut luminal contents only in the case of ALP, with an almost 10-fold increase in specific ALP activity in midgut fluids from AR1 compared to LC larvae. Partially purified H. zea ALP bound Cry1Ac toxin in ligand blots and competed with Cry1Ac toxin for BBMV binding. Based on these results, we suggest the existence of at least one mechanism of resistance to Cry1A toxins in H. zea involving binding of Cry1Ac toxin to an ALP receptor in the larval midgut lumen of resistant larvae. PMID:22685140

  5. Development of neuropeptide analogs capable of traversing the integument: A case study using diapause hormone analogs in Helicoverpa zea.

    PubMed

    Zhang, Qirui; Nachman, Ronald J; Kaczmarek, Krzysztof; Kierus, Krzysztof; Zabrocki, Janusz; Denlinger, David L

    2015-12-01

    Diapause hormone and its analogs terminate pupal diapause in Helicoverpa zea when injected, but if such agents are to be used as effective diapause disruptors it will be essential to develop simple techniques for administering active compounds that can exert their effect by penetrating the insect epidermis. In the current study, we used two molecules previously shown to have high diapause-terminating activity as lead molecules to rationally design and synthesize new amphiphilic compounds with modified hydrophobic components. An assay for diapause termination identified 13 active compounds with EC50's ranging from 0.9 to 46.0 pmol per pupa. Three compounds, Decyl-1963, Dodecyl-1967, and Heptyl-1965, selected from the 13 compounds most active in breaking diapause following injection, also successfully prevented newly-formed pupae from entering diapause when applied topically. These compounds feature straight-chain, aliphatic hydrocarbons from 7 to 12 carbons in length; DH analogs with either a short-chain length of 4 or an aromatic phenethyl group failed to act topically. Compared to a high diapause incidence of 80-90% in controls, diapause incidence in pupae receiving a 10 nmole topical application of Decyl-1963, Dodecyl-1967, or Heptyl-1965 dropped to 30-45%. Decyl-1963 and Dodecyl-1967 also remained effective when topically applied at the 1 nmole level. These results suggest the feasibility of developing DH agonists that can be applied topically and suggest the identity of new lead molecules for development of additional topically-active DH analogs. The ability to penetrate the insect epidermis and/or midgut lining is critical if such agents are to be considered for future use as pest management tools. PMID:25753318

  6. Optimizing Helicoverpa zea (Lepidoptera: Noctuidae) insecticidal efficacy in Minnesota sweet corn: a logistic regression to assess timing parameters.

    PubMed

    Burkness, Eric C; Galvan, Tederson L; Hutchison, W D

    2009-04-01

    Late-season plantings of sweet corn in Minnesota result in an abundant supply of silking corn, Zea mays L., throughout August to early September that is highly attractive to the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae). During a 10-yr period, 1997-2006, insecticide efficacy trials were conducted in late-planted sweet corn in Minnesota for management of H. zea. These data were used to develop a logistic regression model to identify the variables and interactions that most influenced efficacy (proportion control) of late-instar H. zea. The pyrethroid lambdacyhalothrin (0.028 kg [AI]/ha) is a commonly used insecticide in sweet corn and was therefore chosen for use in parameter evaluation. Three variables were found to be significant (alpha = 0.05), the percentage of plants silking at the time of the first insecticide application, the interval between the first and second insecticide applications, and the interval between the last insecticide application and harvest. Odds ratio estimates indicated that as the percentage of plants silking at the time of first application increased, control of H. zea increased. As the interval between the first and second insecticide application increased, control of H. zea decreased. Finally, as the interval between the last insecticide application and harvest increased, control of H. zea increased. An additional timing trial was conducted in 2007 by using lambda-cyhalothrin, to evaluate the impact of the percentage of plants silking at the first application. The results indicated no significant differences in efficacy against late-instar H. zea at 0, 50, 90, and 100% of plants silking at the first application (regimes of five or more sprays). The implications of these effects are discussed within the context of current integrated pest management programs for late-planted sweet corn in the upper midwestern United States. PMID:19449649

  7. Influence of Dual-Bt Protein Corn on Bollworm, Helicoverpa zea (Boddie), Survivorship on Bollgard II Cotton

    PubMed Central

    Gore, J.; Catchot, A.; Cook, D.; Musser, F.; Caprio, M.

    2016-01-01

    Similar Cry proteins are expressed in both Bt corn, Zea mays L., and cotton, Gossypium hirsutum (L.), commercial production systems. At least one generation of corn earworm, Helicoverpa zea (Boddie), completes development on field corn in the Mid-South before dispersing across the landscape into other crop hosts like cotton. A concern is that Bt corn hybrids may result in selection for H. zea populations with a higher probability of causing damage to Bt cotton. The objective of this study was to determine the susceptibility of H. zea offspring from moths that developed on non-Bt and VT Triple Pro (VT3 PRO) field corn to lyophilized Bollgard II cotton tissue expressing Cry1Ac and Cry2Ab. Offspring of individuals reared on VT3 PRO expressing Cry1A.105 and Cry2Ab had a significantly higher LC50 two out of the three years this study was conducted. Excess larvae were placed on artificial diet and allowed to pupate to determine if there were any inheritable fitness costs associated with parental development on VT3 PRO corn. Offspring resulting from males collected from VT3 PRO had significantly lower pupal weight and longer pupal duration compared with offspring of individuals collected from non-Bt corn. However, offspring from females collected from VT3 PRO were not different from non-Bt offspring. Paternal influence on offspring in insects is not commonly observed, but illustrates the side effects of development on a transgenic plant expressing less than a high dose, 25 times the concentration needed to kill susceptible larvae. PMID:26809264

  8. Influence of Dual-Bt Protein Corn on Bollworm, Helicoverpa zea (Boddie), Survivorship on Bollgard II Cotton.

    PubMed

    Von Kanel, M B; Gore, J; Catchot, A; Cook, D; Musser, F; Caprio, M

    2016-04-01

    Similar Cry proteins are expressed in both Bt corn, Zea mays L., and cotton, Gossypium hirsutum (L.), commercial production systems. At least one generation of corn earworm, Helicoverpa zea (Boddie), completes development on field corn in the Mid-South before dispersing across the landscape into other crop hosts like cotton. A concern is that Bt corn hybrids may result in selection for H. zea populations with a higher probability of causing damage to Bt cotton. The objective of this study was to determine the susceptibility of H. zea offspring from moths that developed on non-Bt and VT Triple Pro (VT3 PRO) field corn to lyophilized Bollgard II cotton tissue expressing Cry1Ac and Cry2Ab. Offspring of individuals reared on VT3 PRO expressing Cry1A.105 and Cry2Ab had a significantly higher LC50 two out of the three years this study was conducted. Excess larvae were placed on artificial diet and allowed to pupate to determine if there were any inheritable fitness costs associated with parental development on VT3 PRO corn. Offspring resulting from males collected from VT3 PRO had significantly lower pupal weight and longer pupal duration compared with offspring of individuals collected from non-Bt corn. However, offspring from females collected from VT3 PRO were not different from non-Bt offspring. Paternal influence on offspring in insects is not commonly observed, but illustrates the side effects of development on a transgenic plant expressing less than a high dose, 25 times the concentration needed to kill susceptible larvae. PMID:26809264

  9. Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines.

    PubMed

    Dowd, Patrick F; Sattler, Scott E

    2015-01-01

    The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production. PMID:25601946

  10. Molecular characterization of two acetylcholinesterase genes from the oriental tobacco budworm, Helicoverpa assulta (Guenée).

    PubMed

    Lee, Dae-Weon; Kim, Sung-Su; Shin, Seung Won; Kim, Won Tae; Boo, Kyung Saeng

    2006-02-01

    Acetylcholinesterase (AChE) has been known to be the target of organophosphorous and carbamate insecticides. Only a single AChE, however, existed in insects and was involved in insecticide resistance, recently another AChE is reported in mosquitoes and aphids. We have cloned cDNAs encoding two ace genes, designated as Ha-ace1 and Ha-ace2 by a combined degenerate PCR and RACE strategy from adult heads of the oriental tobacco budworm, Helicoverpa assulta. The Ha-ace1 and Ha-ace2 genes encode 664 and 647 amino acids, respectively and have conserved motifs including a catalytic triad, a choline-binding site and an acyl pocket. Both Ha-AChEs were determined to be secretory proteins based on the existence of a signal peptide. The Ha-ace1 gene, the first reported ace1 in lepidopterans, belongs to the ace1 subfamily whereas the Ha-ace2 gene showed high similarity to those in the ace2 subfamily. Phylogenetic analysis showed that the Ha-ace1 gene was completely diverged from the Ha-ace2, suggesting that the Ha-ace genes are duplicated. Quantitative real time-PCR revealed that expression level of the Ha-ace1 gene was much higher than that of the Ha-ace2 in all body parts examined. The biochemical properties of purified proteins by affinity chromatography showed substrate specificity for acetylthiocholine iodide, and inhibitor specificity for BW284C51 and eserine and their peptide sequences partially identified by a MALDI-TOF mass spectrometer demonstrated that two Ha-AChEs were expressed in vivo. PMID:16352398

  11. Genetic variation for resistance to Bacillus thuringiensis toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in eastern North Carolina.

    PubMed

    Jackson, R E; Gould, F; Bradley, J R; Van Duyn, J W

    2006-10-01

    To evaluate resistance to Bacillus thuringiensis Berliner (Bt) toxins, adult female bollworms, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), were collected from four light trap locations in two eastern North Carolina counties from August to October during 2001 and 2002. Females were allowed to oviposit, and upon hatching, 24 neonates from each female (F1 lines) were screened for survival and growth rate on each of three diets: non-Bt diet, diet containing 5.0 microg/ml Cry1Ac toxin, or diet containing 5.0 microg/ml Cry2Ab toxin. These screens were designed to identify nonrecessive Bt resistance alleles present in field populations of bollworm. Of 561 and 691 families screened with both Cry1Ac- and Cry2Ab-containing diets in 2001 and 2002, respectively, no F1 lines were identified that seemed to carry a gene conferring substantial resistance to either Cry1Ac or Cry2Ab. Adults from F1 lines with growth scores in the highest (R) and lowest (S) quartiles were mated in four combinations, RxR, SxR, RxS, and SxS. Differences in growth rates of larvae from these crosses demonstrated that there is substantial quantitative genetic variation in eastern North Carolina populations for resistance to both Cry1Ac and Cry2Ab toxins. These findings, in addition to results suggesting partially dominant inheritance of resistance to Cry1Ac and Cry2Ab, are critically important for determining appropriate resistance management strategies that impact the sustainability of transgenic cotton, Gossypium hirsutum (L.). PMID:17066814

  12. Female sex pheromone of oriental tobacco budworm,Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae): Identification and field testing.

    PubMed

    Cork, A; Boo, K S; Dunkelblum, E; Hall, D R; Jee-Rajunga, K; Kehat, M; Kong Jie, E; Park, K C; Tepgidagarn, P; Xun, L

    1992-03-01

    Analysis of ovipositor washings from virgin femaleHelicoverpa assulta (Guenée) (Lepidoptere: Noctuidae) from Korea by gas chromatography (GC) linked to electroantennography and GC linked to mass spectrometry resulted in the identification of nine compounds, hexadecanal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, hexadecyl acetate, (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, hexadecan-l-ol, (Z)-9-hexadecen-l-ol, and (Z)-11-hexadecen-1-ol. However, ovipositor washings from females from Thailand contained mainly the 16-carbon aldehydes with very small amounts of (Z)-9-hexadecenyl acetate. Field tests conducted in Korea, China, and Thailand indicated that a binary blend of (Z)-9-hexadecenal and (Z)-11-hexadecenal was sufficient for attraction, although the most attractive ratio of compounds varied with location. In Korea a 20∶1 blend of compounds was the most attractive, while in Thailand a 7.5∶1 blend was most attractive. In China both blends of hexadecenal isomers were equally attractive. Addition of the hexadecenyl acetates to the 20∶1 blend of hexadecenals in the ratio of 1∶3.3 increased the trap catch of maleH. assulta compared to lures containing the aldehydes alone in Korea but reduced trap catch in China. Addition of the hexadecenyl acetates to the 7.5∶1 blend of hexadecenals had no significant effect on trap catch in Thailand or China compared to the aldehydes alone. The addition of the 16-carbon alcohols to the aldehydes had a significantly inhibitory effect in all three countries, suggesting they are not pheromone components. Taken together these results indicate thatH. assulta is polymorphic with at least two populations responding to different sex pheromones. PMID:24254945

  13. Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines

    PubMed Central

    Dowd, Patrick F.; Sattler, Scott E.

    2015-01-01

    The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production. PMID:25601946

  14. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    PubMed

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts. PMID:26318006

  15. Antifeedant and larvicidal activities of Rhein isolated from the flowers of Cassia fistula L.

    PubMed Central

    Duraipandiyan, V.; Ignacimuthu, S.; Gabriel Paulraj, M.

    2010-01-01

    Antifeedant and larvicidal activities of rhein (1,8-dihydroxyanthraquinone-3-carboxylic acid) isolated from the ethyl acetate extract of Cassia fistula flower were studied against lepidopteron pests Spodoptera litura and Helicoverpa armigera. Significant antifeedant activity was observed against H. armigera (76.13%) at 1000 ppm concentration. Rhein exhibited larvicidal activity against H. armigera (67.5), S. litura (36.25%) and the LC50 values was 606.50 ppm for H. armigera and 1192.55 ppm for S.litura. The survived larvae produced malformed adults. PMID:23961115

  16. Analysis of an Autographa californica Multicapsid Nucleopolyhedrovirus lef-6-Null Virus: LEF-6 Is Not Essential for Viral Replication but Appears To Accelerate Late Gene Transcription

    PubMed Central

    Lin, Guangyun; Blissard, Gary W.

    2002-01-01

    The Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) lef-6 gene was previously shown to be necessary for optimal transcription from an AcMNPV late promoter in transient late expression assays. In the present study, we examined the expression and cellular localization of lef-6 during the AcMNPV infection cycle and generated a lef-6-null virus for studies of the role of lef-6 in the infection cycle. Transcription of lef-6 was detected from 4 to 48 h postinfection, and the LEF-6 protein was identified in dense regions of infected cell nuclei, a finding consistent with its potential role as a late transcription factor. To examine lef-6 in the context of the AcMNPV infection cycle, we deleted the lef-6 gene from an AcMNPV genome propagated as an infectious BACmid in Escherichia coli. Unexpectedly, the resulting AcMNPV lef-6-null BACmid (vAclef6KO) was able to propagate in cell culture, although virus yields were substantially reduced. Thus, the lef-6 gene is not essential for viral replication in Sf9 cells. Two “repair” AcMNPV BACmids (vAclef6KO-REP-P and vAclef6KO-REP-ie1P) were generated by transposition of the lef-6 gene into the polyhedrin locus of the vAclef6KO BACmid. Virus yields from the two repair viruses were similar to those from wild-type AcMNPV or a control (BACmid-derived) virus. The lef-6-null BACmid (vAclef6KO) was further examined to determine whether the deletion of lef-6 affected DNA replication or late gene transcription in the context of an infection. The lef-6 deletion did not appear to affect viral DNA replication. Using Northern blot analysis, we found that although early transcription was apparently unaffected, both late and very late transcription were delayed in cells infected with the lef-6-null BACmid. This phenotype was rescued in viruses containing the lef-6 gene reinserted into the polyhedrin locus. Thus, the lef-6 gene was not essential for either viral DNA replication or late gene transcription, but the absence of

  17. Efficient expression of single chain variable fragment antibody against paclitaxel using the Bombyx mori nucleopolyhedrovirus bacmid DNA system and its characterizations.

    PubMed

    Yusakul, Gorawit; Sakamoto, Seiichi; Tanaka, Hiroyuki; Morimoto, Satoshi

    2016-07-01

    A single chain variable fragment (scFv), the smallest unit of functional recombinant antibody, is an attractive format of recombinant antibodies for various applications due to its small fragment and possibility of genetic engineering. Hybridoma clone 3A3 secreting anti-paclitaxel monoclonal antibody was used to construct genes encoding its variable domains of heavy (VH) and light (VL) chains. The VH and VL domains were linked to be the PT-scFv3A3 using flexible peptide linker in a format of VH-(GGGGS)5-VL. The PT-scFv3A3 was primarily expressed using the pET28a(+) vector in the Escherichia coli system, and was then further expressed by using the Bombyx mori nucleopolyhedrovirus (BmNPV) bacmid DNA system. Interestingly, the reactivity of PT-scFv3A3 expressed in the hemolymph of B. mori using the BmNPV bacmid DNA system was much higher than that expressed in the E. coli system. Using indirect competitive enzyme-linked immunosorbent assay (icELISA), the PT-scFv3A3 (B. mori) reacted not only with immobilized paclitaxel, but also with free paclitaxel in a concentration-dependent manner, with the linear range of free paclitaxel between 0.156 and 5.00 µg/ml. The PT-scFv3A3 (B. mori) exhibited less cross-reactivity (%) than its parental MAb clone 3A3 against paclitaxel-related compounds, including docetaxel (31.1 %), 7-xylosyltaxol (22.1 %), baccatin III (<0.68 %), 10-deacetylbaccatin III (<0.68 %), 1-hydroxybaccatin I (<0.68 %), and 1-acetoxy-5-deacetylbaccatin I (<0.68 %). With the exception of cephalomannine, the cross-reactivity was slightly increased to 8.50 %. The BmNPV bacmid DNA system was a highly efficient expression system of active PT-scFv3A3, which is applicable for PT-scFv3A3-based immunoassay of paclitaxel. In addition, the PT-scFv3A3 can be applied to evaluate its neutralizing property of paclitaxel or docetaxel toxicity. PMID:26940321

  18. Cross-resistance to toxins used in pyramided Bt crops and resistance to Bt sprays in Helicoverpa zea.

    PubMed

    Welch, Kara L; Unnithan, Gopalan C; Degain, Ben A; Wei, Jizhen; Zhang, Jie; Li, Xianchun; Tabashnik, Bruce E; Carrière, Yves

    2015-11-01

    To delay evolution of resistance by insect pests, farmers are rapidly increasing their use of transgenic crops producing two or more Bacillus thuringiensis (Bt) toxins that kill the same pest. A key condition favoring durability of these "pyramided" crops is the absence of cross-resistance between toxins. Here we evaluated cross-resistance in the major lepidopteran pest Helicoverpa zea (Boddie) to Bt toxins used in pyramids. In the laboratory, we selected a strain of this pest with Bt toxin Cry1Ac followed by selection with MVP II, a formulation containing a hybrid protoxin that is identical to Cry1Ac in the active portion of the toxin and 98.5% identical overall. We calculated the resistance ratio as the EC50 (concentration causing mortality or failure to develop beyond the first instar of 50% of larvae) for the laboratory-selected strain divided by the EC50 for its field-derived parent strain that was not selected in the laboratory. The resistance ratio was 20.0-33.9 (mean=27.0) for MVP II, 57.0 for Cry1Ac, 51.3 for Cry1A.105, 22.4 for Cry1Ab, 3.3 for Cry2Ab, 1.8 for Cry1Fa, and 1.6 for Vip3Aa. Resistance ratios were 2.9 for DiPel ES and 2.0 for Agree VG, which are commercial Bt spray formulations containing Cry1Ac, other Bt toxins, and Bt spores. By the conservative criterion of non-overlap of 95% fiducial limits, the EC50 was significantly higher for the selected strain than its parent strain for MVP II, Cry1Ac, Cry1A.105, Cry1Ab, Cry2Ab and DiPel ES. For Cry1Fa, Vip3Aa, and Agree VG, significantly lower susceptibility to a high concentration indicated low cross-resistance. The resistance ratio for toxins other than Cry1Ac was associated with their amino acid sequence similarity to Cry1Ac in domain II. Resistance to Cry1Ac and the observed cross-resistance to other Bt toxins could accelerate evolution of H. zea resistance to currently registered Bt sprays and pyramided Bt crops. PMID:26458274

  19. Distribution of bollworm, Helicoverpa zea (Boddie), injured reproductive structures on genetically engineered Bacillus thuringiensis var. kurstaki Berliner cotton.

    PubMed

    Gore, J; Leonard, B R; Gable, R H

    2003-06-01

    Bollworm, Helicoverpa zea (Boddie), larvae are commonly observed feeding in genetically engineered Bollgard cotton. Although no information is currently available characterizing the levels of injury bollworms cause, aproximately 25% of the Bollgard acreage in the United States receives at least one insecticide application annually targeting bollworm populations. Studies were conducted to determine the levels of fruiting form injury that can occur from bollworm larvae feeding on white flowers of two types of genetically engineered cotton. The two types of genetically engineered cotton included the original Bollgard that produces one protein (Cry1Ac) from Bacillus thuringiensis variety kurstaki Berliner and Bollgard II that produces two proteins (Cry1Ac + Cry2Ab) from B. thuringiensis kurstaki. In one study, individual larvae (24 +/- 6 h old) were placed in first position white flowers of Deltapine 5415 (non-Bollgard) and Deltapine NuCOTN 33B (Bollgard). Larval infestations were made on 50 plants for each of 5 d during 2000 and 2001. Each plant was visually examined at 3 d and every 2 d thereafter, until larvae were no longer recovered. Larvae injured a total of 46.6 fruiting forms per 50 plants on non-Bollgard cotton, compared with only 18.9 fruiting forms per 50 plants on Bollgard cotton. Mean larval injury per insect was 4.3 fruiting forms on non-Bollgard cotton compared with 2.7 fruiting forms on Bollgard cotton. In a second study, individual larvae (24 +/- 6 h old) were placed in first position white flowers of Deltapine 50 (non-Bollgard), Deltapine 50B (Bollgard), and an experimental Bollgard II line. Larval infestations were made on 10 plants per day for each of six consecutive days during 2001. Larvae injured a total of 25.0 fruiting forms per 10 plants on non-Bollgard, 11.5 on Bollgard, and 6.4 on Bollgard II cottons. Mean larval injury per insect was 6.6 fruiting forms on non-Bollgard, 3.5 on Bollgard, and 0.8 on Bollgard II cottons. These data indicate

  20. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea.

    PubMed

    López, Juan D; Latheef, M A; Hoffmann, W C

    2010-01-01

    Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult feeding approach. This approach entails the use of a feeding attractant and stimulant in combination with a toxicant that when ingested by the adult will either reduce fecundity/fertility at sub-lethal dosages or kill the adult. The intent of this study was to assess reproductive inhibition and toxicity of emamectin benzoate on H. zea when ingested by the adults when mixed in ppm active ingredient (wt:vol) with 2.5 M sucrose as a feeding stimulant. Because the mixture has to be ingested to function, the effect of emamectin benzoate was also evaluated at sub-lethal and lethal concentrations on proboscis extension and gustatory response of H. zea in the laboratory. Feral males captured in sex pheromone-baited traps in the field were used for toxicity evaluations because they were readily available and were more representative of the field populations than laboratory-reared adults. Laboratory-reared female moths were used for reproduction effects because it is very difficult to collect newly emerged feral females from the field. Emamectin benzoate was highly toxic to feral H. zea males with LC(50) values (95% CL) being 0.718 (0.532-0.878), 0.525 (0.316-0.751), and 0.182 (0.06-0.294) ppm for 24, 48 and 72 h responses, respectively. Sub-lethal concentrations of emamectin benzoate did not significantly reduce proboscis extension response of feral males and gustatory response of female H. zea. Sublethal concentrations of emamectin benzoate significantly reduced percent larval hatch of

  1. Isolation and identification of the cDNA encoding the pheromone biosynthesis activating neuropeptide and additional neuropeptides in the oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae).

    PubMed

    Choi, M Y; Tanaka, M; Kataoka, H; Boo, K S; Tatsuki, S

    1998-10-01

    The present study is concerned with cloning and characterizing Has-PBAN cDNA which is 756 nucleotides long, isolated from the brain and suboesophageal ganglion complex (Br-Sg) of Helicoverpa assulta adults. The 194-amino acid sequence deduced from this cDNA possessed the proteolytic endocleavage sites to generate multiple peptides. From the processing of the prepro-hormone, it can be predicted that the cDNA has a PBAN domain with 33 amino acids and four additional peptide domains: 24 amino acid-, 7 amino acid-, 18 amino acid- and 8 amino acid-long sequences, with FXPR (or K) L (X = G, T or S) amidated at their C-termini. The amino acid sequence of all five predicted peptides, including the PBAN, are identical to that of Helicoverpa zea (Raina, A.K., Jaffe, H., Kempe, T.G., Keim, P., Blacher, R.W., Fales, H.M., Riley, C.T., Klun, J.A., Ridgway, R.L., Hayes, D.K., 1989. Identification of a neuropeptide hormone that regulates sex pheromone production in female moths. Science 244, 796-798 and Ma, P.W.K., Knipple, D.C., Roelofs, W.L., 1994. Structural organization of the Helicoverpa zea gene encoding the precursor protein for pheromone biosynthesis-activating neuropeptide and other neuropeptides. Proc. Natl. Acad. Sci., U.S.A. 91, 506-510). A single mRNA species corresponding to the size of Has-PBAN cDNA was detected from the Br-Sg of 1-3-day old female and male adults, and their expression was also at a similar level. Pheromone production was induced upon injection of female or male Br-Sg extracts or synthetic PBAN into the haemocoel of decapitated 1-3-day old female adults during the photophase when they are not supposed to produce pheromone. From these results, H. assulta adult females seem to use their own PBAN for regulating sex pheromone biosynthesis. Functions of the four other peptides ending with FXPR (or K) L in the Has-PBAN cDNA and of the male PBAN remain to be elucidated. PMID:9807222

  2. Utilizing the assassin bug, Pristhesancus plagipennis (Hemiptera: Reduviidae), as a biological control agent within an integrated pest management programme for Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton.

    PubMed

    Grundy, P R

    2007-06-01

    Helicoverpa spp. and mirids, Creontiades spp., have been difficult to control biologically in cotton due to their unpredictable temporal abundance combined with a cropping environment often made hostile by frequent usage of broad spectrum insecticides. To address this problem, a range of new generation insecticides registered for use in cotton were tested for compatibility with the assassin bug, Pristhesancus plagipennis (Walker), a potential biological control agent for Helicoverpa spp. and Creontiades spp. Indoxacarb, pyriproxifen, buprofezin, spinosad and fipronil were found to be of low to moderate toxicity on P. plagipennis whilst emamectin benzoate, abamectin, diafenthiuron, imidacloprid and omethaote were moderate to highly toxic. Inundative releases of P. plagipennis integrated with insecticides identified as being of low toxicity were then tested and compared with treatments of P. plagipennis and the compatible insecticides used alone, conventionally sprayed usage practice and an untreated control during two field experiments in cotton. The biological control provided by P. plagipennis nymphs when combined with compatible insecticides provided significant (P<0.001) reductions in Helicoverpa and Creontiades spp. on cotton and provided equivalent yields to conventionally sprayed cotton with half of the synthetic insecticide input. Despite this, the utilization of P. plagipennis in cotton as part of an integrated pest management programme remains unlikely due to high inundative release costs relative to other control technologies such as insecticides and transgenic (Bt) cotton varieties. PMID:17524159

  3. Autographa californica multiple nucleopolyhedrovirus ODV-E56 is a per os infectivity factor, but is not essential for binding and fusion of occlusion-derived virus to the host midgut

    SciTech Connect

    Sparks, Wendy O.; Harrison, Robert L.; Bonning, Bryony C.

    2011-01-05

    The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) occlusion-derived virus (ODV) envelope protein ODV-E56 is essential for oral infection of larvae of Heliothis virescens. Bioassays with recombinant clones of AcMNPV lacking a functional odv-e56 gene showed that ODV-E56 was required for infectivity of both polyhedra and to a lesser extent, purified ODV. However, binding and fusion assays showed that ODV lacking ODV-E56 bound and fused to midgut cells at levels similar to ODV of wild-type virus. Fluorescence microscopy of midguts from larvae inoculated with ODV-E56-positive and -negative viruses that express GFP indicated that ODV-E56 was required for infection of the midgut epithelium. Purified ODV-E56 bound to several proteins in midgut-derived brush border membrane vesicles, but failed to rescue infectivity of ODV-E56-negative viruses in trans. These results indicate that ODV-E56 is a per os infectivity factor (pif-5) required for primary midgut infection at a point before or after virion binding and fusion.

  4. Efficient silkworm expression of single-chain variable fragment antibody against ginsenoside Re using Bombyx mori nucleopolyhedrovirus bacmid DNA system and its application in enzyme-linked immunosorbent assay for quality control of total ginsenosides.

    PubMed

    Sakamoto, Seiichi; Pongkitwitoon, Benyakan; Nakamura, Seiko; Maenaka, Katsumi; Tanaka, Hiroyuki; Morimoto, Satoshi

    2010-09-01

    A single-chain variable fragment (scFv) antibody against ginsenoside Re (G-Re) have been successfully expressed in the silkworm larvae using Bombyx mori nucleopolyhedrovirus (BmNPV) bacmid DNA system. The baculovirus donor vector for expression of scFv against G-Re (GRe-scFv) was constructed to contain honeybee melittin signal sequence to accelerate secretion of the recombinant GRe-scFv into the haemolymph of silkworm larvae. Functional recombinant GRe-scFv was purified by cation exchange chromatography followed by immobilized metal ion affinity chromatography. The yield of purified GRe-scFv was 6.5 mg per 13 silkworm larvae, which is equivalent to 650 mg/l of the haemolymph, exhibiting extremely higher yield than that expressed in Escherichia coli (1.7 mg/l of culture medium). It was revealed from characterization that GRe-scFv retained similar characteristic of the parental monoclonal antibody (MAb) against G-Re (MAb-4G10), making it possible to develop indirect competitive enzyme-linked immunosorbent assay (icELISA) for quality control of total ginsenosides in various ginsengs. The detectable range for calibration of G-Re by developed icELISA shows 0.05-10 microg/ml. These results clearly suggested that the silkworm expression system is quite useful for the expression of functional scFv that frequently required time- and cost-consuming re-folding when it expressed in E. coli. PMID:20592135

  5. Baculovirus induced transcripts in hemocytes from Heliothis virescens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using RNA-sequencing digital difference expression profiling methods we have assessed the gene expression profiles of hemocytes harvested from Heliothis virescens that were challenged with Helicoverpa zea single nucleopolyhedrovirus (HzSNPV). A reference transcriptome of hemocyte-expressed transcri...

  6. Supplemental control of lepidopterous pests on BT transgenic sweet corn with biologically based spray treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biologically based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie), on transgenic sweet corn, Zea mays (L.), expressing a Cry1Ab toxi...

  7. Improving the robustness of a low-cost insect cell medium for baculovirus biopesticides production, via hydrolysate streamlining using a tube bioreactor-based statistical optimization routine.

    PubMed

    Huynh, Hoai T; Chan, Leslie C L; Tran, Trinh T B; Nielsen, Lars K; Reid, Steven

    2012-01-01

    A critical component of an in vitro production process for baculovirus biopesticides is a growth medium that is efficacious, robust, and inexpensive. An in-house low-cost serum-free medium, VPM3, has been shown to be very promising in supporting Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) production in H. zea insect cell suspension cultures, for use as a biopesticide against the Heliothine pest complex. However, VPM3 is composed of a significant number of undefined components, including five different protein hydrolysates, which introduce a challenging lot-to-lot variability to the production process. In this study, an intensive statistical optimization routine was employed to reduce the number of protein hydrolysates in VPM3 medium. Nearly 300 runs (including replicates) were conducted with great efficiency by using 50 mL TubeSpin® bioreactors to propagate insect cell suspension cultures. Fractional factorial experiments were first used to determine the most important of the five default protein hydrolysates, and to screen for seven potential substitutes for the default meat peptone, Primatone RL. Validation studies informed by the screening tests showed that promising alternative media could be formulated based on just two protein hydrolysates, in particular the YST-AMP (Yeast Extract and Amyl Meat Peptone) and YST-POT (Yeast Extract and Lucratone Potato Peptone) combinations. The YST-AMP (meat-based) and YST-POT (meat-free) variants of VPM3 were optimized using response surface methodology, and were shown to be just as good as the default VPM3 and the commercial Sf-900 II media in supporting baculovirus yields, hence providing a means toward a more reproducible and scalable production process for HaSNPV biopesticides. PMID:22323401

  8. The Impact of Inter-Kernel Movement in the Evolution of Resistance to Dual-Toxin Bt-Corn Varieties in Helicoverpa zea (Lepidoptera: Noctuidae).

    PubMed

    Caprio, Michael A; Martinez, Jeannette C; Porter, Patrick A; Bynum, Ed

    2016-02-01

    Seeds or kernels on hybrid plants are primarily F(2) tissue and will segregate for heterozygous alleles present in the parental F(1) hybrids. In the case of plants expressing Bt-toxins, the F(2) tissue in the kernels will express toxins as they would segregate in any F(2) tissue. In the case of plants expressing two unlinked toxins, the kernels on a Bt plant fertilized by another Bt plant would express anywhere from 0 to 2 toxins. Larvae of corn earworm [Helicoverpa zea (Boddie)] feed on a number of kernels during development and would therefore be exposed to local habitats (kernels) that varied in their toxin expression. Three models were developed for plants expressing two Bt-toxins, one where the traits are unlinked, a second where the traits were linked and a third model assuming that maternal traits were expressed in all kernels as well as paternally inherited traits. Results suggest that increasing larval movement rates off of expressing kernels tended to increase durability while increasing movement rates off of nonexpressing kernels always decreased durability. An ideal block refuge (no pollen flow between blocks and refuges) was more durable than a seed blend because the refuge expressed no toxins, while pollen contamination from plants expressing toxins in a seed blend reduced durability. A linked-trait model in an ideal refuge model predicted the longest durability. The results suggest that using a seed-blend strategy for a kernel feeding insect on a hybrid crop could dramatically reduce durability through the loss of refuge due to extensive cross-pollination. PMID:26527792

  9. Comparative production of Helicoverpa zea (Lepidoptera: Noctuidae) from transgenic cotton expressing either one or two Bacillus thuringiensis proteins with and without insecticide oversprays.

    PubMed

    Jackson, R E; Bradley, J R; Van Duyn, J W; Gould, F

    2004-10-01

    Transgenic cotton, Gossypium hirsutum (L.), expressing either one or two Bacillus thuringiensis ssp. kurstaki Berliner (Bt) proteins was compared with the conventional sister line in field experiments with regard to production of bollworm, Helicoverpa zea (Boddie), and bolls damaged by bollworm. The relative numbers of bollworms that developed on Bollgard (Monsanto Co., St. Louis, MO), Bollgard II (Monsanto Co.), and conventional cotton were estimated under nontreated conditions in 2000 and both insecticide-treated and nontreated conditions in 2001-2002 in North Carolina tests. Averaged across seven field studies under nontreated conditions, Bollgard cotton generated statistically similar numbers of large (L4-L5) bollworm larvae compared with the conventional variety; however, Bollgard cotton produced significantly fewer damaged bolls and bollworm adults than the conventional variety. Production of large larvae, damaged bolls, and adults was decreased dramatically by Bollgard II cotton as compared with Bollgard and conventional varieties. When comparing insecticide-treated and nontreated cotton genotypes, both Bt cotton sustained less boll damage than the conventional variety averaged across insecticide regimes; furthermore, Bollgard II cotton had fewer damaged bolls than the Bollgard variety. When averaged across cotton genotypes, pyrethroid oversprays reduced the numbers of damaged bolls compared with the nontreated cotton. Insecticide-treated Bollgard cotton, along with insecticide-treated and nontreated Bollgard II cotton reduced production of bollworm larvae, pupae, and adults. However, the addition of pyrethroid oversprays to Bollgard II cotton seemed to be the best resistance management strategy available for bollworm because no bollworms were capable of completing development under these conditions. PMID:15568364

  10. Inhibition of Helicoverpa zea (Lepidoptera: Noctuidae) Growth by Transgenic Corn Expressing Bt Toxins and Development of Resistance to Cry1Ab.

    PubMed

    Reisig, Dominic D; Reay-Jones, Francis P F

    2015-08-01

    Transgenic corn, Zea mays L., that expresses the Bacillus thuringiensis (Bt) toxin Cry1Ab is only moderately toxic to Helicoverpa zea (Boddie) and has been planted commercially since 1996. Growth and development of H. zea was monitored to determine potential changes in susceptibility to this toxin over time. Small plots of corn hybrids expressing Cry1F, Cry1F × Cry1Ab, Cry1Ab × Cry3Bb1, Cry1A.105 × Cry2Ab2 × Cry3Bb1, Cry1A.105 × Cry2Ab2, and Vip3Aa20 × Cry1Ab × mCry3A were planted in both 2012 and 2013 inNorth and South Carolina with paired non-Bt hybrids from the same genetic background. H. zea larvae were sampled on three time periods from ears and the following factors were measured: kernel area injured (cm(2)) by H. zea larvae, larval number per ear, larval weight, larval length, and larval head width. Pupae were sampled on a single time period and the following factors recorded: number per ear, weight, time to eclosion, and the number that eclosed. There was no reduction in larval weight, number of insect entering the pupal stadium, pupal weight, time to eclosion, and number of pupae able to successfully eclose to adulthood in the hybrid expressing Cry1Ab compared with a non-Bt paired hybrid. As Cry1Ab affected these in 1996, H. zea may be developing resistance to Cry1Ab in corn, although these results are not comprehensive, given the limited sampling period, size, and geography. We also found that the negative impacts on larval growth and development were greater in corn hybrids with pyramided traits compared with single traits. PMID:26314074

  11. Silencing of the Baculovirus Op-iap3 Gene by RNA Interference Reveals that It Is Required for Prevention of Apoptosis during Orgyia pseudotsugata M Nucleopolyhedrovirus Infection of Ld652Y Cells†

    PubMed Central

    Means, John C.; Muro, Israel; Clem, Rollie J.

    2003-01-01

    The Op-iap3 gene from the baculovirus Orgyia pseudotsugata M nucleopolyhedrovirus (OpMNPV) inhibits apoptosis induced by a mutant of Autographa californica MNPV (AcMNPV) that lacks the antiapoptotic gene p35, as well as apoptosis induced by a wide range of other stimuli in both mammalian and insect cells. However, the role of Op-iap3 during OpMNPV infection has not been previously examined. To determine the function of the Op-IAP3 protein during OpMNPV infection, we used RNA interference (RNAi) to silence Op-iap3 expression during OpMNPV infection of Ld652Y cells. Infected cells treated with Op-iap3 double-stranded RNA (dsRNA) did not accumulate detectable Op-iap3 mRNA, confirming that the Op-iap3 gene was effectively silenced. Op-IAP3 protein was found to be a component of the budded virion; however, in OpMNPV-infected cells treated with Op-iap3 dsRNA, the Op-IAP3 protein that was introduced by the inoculum virus decreased to almost undetectable levels by 12 h after dsRNA addition. Apoptosis was observed in infected cells treated with Op-iap3 dsRNA beginning at 12 h, and by 48 h, almost all of the cells had undergone apoptosis. These results show for the first time that Op-IAP3 is necessary to prevent apoptosis during OpMNPV infection. In addition, our results demonstrate that the RNAi technique can be an effective tool for studying baculovirus gene function. PMID:12663755

  12. Biocontrol potential of Steinernema thermophilum and its symbiont Xenorhabdus indica against lepidopteran pests: virulence to egg and larval stages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Under laboratory conditions, the biocontrol potential of Steinernema thermophilum was tested against eggs and larval stages of two important lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura (polyphagous pests), as well as Galleria mellonella (used as a model host) . In terms of ...

  13. Molecular research and genetic engineering of resistance to Verticillium wilt in cotton: A review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Verticillium dahliae, a soil-borne pathogen, causes Verticillium wilt, one of the most serious diseases in cotton, deleteriously influencing the crop’s production and quality. Verticillium wilt has become a major obstacle in cotton production since Helicoverpa armigera, the cotton bollworm, became e...

  14. Development of Transgenics in Chickpea.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chickpea (Cicer arietinum L.) is an important food crop in much of the developing world and ranks third in production among food legumes. Chickpea production is limited worldwide by drought, insect damage from Helicoverpa armigera, Callosobruchus maculatus and C. chinensis and disease pressure from ...

  15. A Conserved Odorant Receptor Tuned to Floral Volatiles in Three Heliothinae Species

    PubMed Central

    Cao, Song; Liu, Yang; Guo, Mengbo; Wang, Guirong

    2016-01-01

    Odorant receptors (ORs) play an important role in insects to monitor and adapt to the external environment, such as host plant location, oviposition-site selection, mate recognition and natural enemy avoidance. In our study, we identified and characterized OR12 from three closely-related species, Helicoverpa armigera, Helicoverpa assulta, Heliothis virescens, sharing between 90 and 98% of their amino acids. The tissue expression pattern analysis in H. armigera showed that HarmOR12 was strongly expressed both in male and female antennae, but not in other tissues. Functional analysis performed in the heterologous Xenopus expression system showed that all three OR12 were tuned to six structurally related plant volatiles. Electroantennogram recordings from male and female antennae of H. armigera closely matched the data of in vitro functional studies. Our results revealed that OR12 has a conserved role in Heliothinae moths and might represent a suitable target for the control of these crop pests. PMID:27163122

  16. A Conserved Odorant Receptor Tuned to Floral Volatiles in Three Heliothinae Species.

    PubMed

    Cao, Song; Liu, Yang; Guo, Mengbo; Wang, Guirong

    2016-01-01

    Odorant receptors (ORs) play an important role in insects to monitor and adapt to the external environment, such as host plant location, oviposition-site selection, mate recognition and natural enemy avoidance. In our study, we identified and characterized OR12 from three closely-related species, Helicoverpa armigera, Helicoverpa assulta, Heliothis virescens, sharing between 90 and 98% of their amino acids. The tissue expression pattern analysis in H. armigera showed that HarmOR12 was strongly expressed both in male and female antennae, but not in other tissues. Functional analysis performed in the heterologous Xenopus expression system showed that all three OR12 were tuned to six structurally related plant volatiles. Electroantennogram recordings from male and female antennae of H. armigera closely matched the data of in vitro functional studies. Our results revealed that OR12 has a conserved role in Heliothinae moths and might represent a suitable target for the control of these crop pests. PMID:27163122

  17. Field efficacy of sweet corn hybrids expressing a Bacillus thuringiensis toxin for management of Ostrinia nubilalis (Lepidoptera: Crambidae) and Helicoverpa zea (Lepidoptera: Noctuidae).

    PubMed

    Burkness, E C; Hutchison, W D; Bolin, P C; Bartels, D W; Warnock, D F; Davis, D W

    2001-02-01

    Field studies were done in 1995-1996 to assess the efficacy of three sweet corn hybrids that express the Bacillus thuringiensis (Bt) toxin, CrylAb, against two lepidopteran pests, Ostrinia nubilalis (Hubner) and Helicoverpa zea (Boddie). The Bt hybrids tested were developed by Novartis Seeds, using the event BT-11, which expresses Bt toxin in green tissue as well as reproductive tissues including the tassel, silk, and kernel. Bt hybrids were compared with a standard non-Bt control or the non-Bt isoline for each hybrid; none of the hybrids were treated with insecticides during the study. Hybrid efficacy was based on larval control of each pest, as well as plant or ear damage associated with each pest. In both years, control of O. nubilalis larvae in primary ears of all Bt hybrids was 99-100% compared with the appropriate non-Bt check. Plant damage was also significantly reduced in all Bt hybrids. In 1996, control of H. zea in Bt hybrids ranged from 85 to 88% when compared with the appropriate non-Bt control. In 1996, a University of Minnesota experimental non-Bt hybrid (MN2 x MN3) performed as well as the Bt hybrids for control of O. nubilalis. Also, in 1996, two additional University of Minnesota experimental non-Bt hybrids (A684su X MN94 and MN2 X MN3) performed as well as Bt hybrids for percent marketable ears (ears with no damage or larvae). In addition, compared with the non-Bt hybrids, percent marketable ears were significantly higher for all Bt hybrids and in most cases ranged from 98 to 100%. By comparison, percent marketable ears for the non-Bt hybrids averaged 45.5 and 37.4% in 1995 and 1996, respectively. Results from the 2-yr study strongly suggest that Bt sweet corn hybrids will provide high levels of larval control for growers in both fresh and processing markets. Specifically, Bt sweet corn hybrids, in the absence of conventional insecticide use, provided excellent control of O. nubilalis, and very good control of H. zea. However, depending on

  18. Interaction of Autographa californica Multiple Nucleopolyhedrovirus Cathepsin Protease Progenitor (proV-CATH) with Insect Baculovirus Chitinase as a Mechanism for proV-CATH Cellular Retention▿†

    PubMed Central

    Hodgson, Jeffrey J.; Arif, Basil M.; Krell, Peter J.

    2011-01-01

    The insect baculovirus chitinase (CHIA) and cathepsin protease (V-CATH) enzymes cause terminal host insect liquefaction, enhancing the dissemination of progeny virions away from the host cadavers. Regulated and delayed cellular release of these host tissue-degrading enzymes ensures that liquefaction starts only after optimal viral replication has occurred. Baculoviral CHIA remains intracellular due to its C-terminal KDEL endoplasmic reticulum (ER) retention motif. However, the mechanism for cellular retention of the inactive V-CATH progenitor (proV-CATH) has not yet been determined. Signal peptide cleavage occurs upon cotranslational ER import of the v-cath-expressed protein, and ER-resident CHIA is needed for the folding of proV-CATH. Although this implies that CHIA and proV-CATH bind each other in the ER, the putative CHIA–proV-CATH interaction has not been experimentally verified. We demonstrate that the amino-terminal 22 amino acids (aa) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) preproV-CATH are responsible for the entry of proV-CATH into the ER. Furthermore, the CHIA–green fluorescent protein (GFP) and proV-CATH-red fluorescent protein (RFP) fusion proteins colocalize in the ER. Using monomeric RFP (mRFP)-based bimolecular fluorescence complementation (BiFC), we determined that CHIA and proV-CATH interact directly with each other in the ER during virus replication. Moreover, reciprocal Ni/His pulldowns of His-tagged proteins confirmed the CHIA–proV-CATH interaction biochemically. The reciprocal copurification of CHIA and proV-CATH suggests a specific CHIA–proV-CATH interaction and corroborates our BiFC data. Deletion of the CHIA KDEL motif allowed for premature CHIA secretion from cells, and proV-CATH was similarly prematurely secreted from cells along with ΔKDEL-CHIA. These data suggest that CHIA and proV-CATH interact directly with each other and that this interaction aids the cellular retention of proV-CATH. PMID:21289117

  19. Influence of life history differences of two tachinid parasitoids ofHelicoverpa zea (Boddie) (Lepidoptera: Noctuidae) on their interactions with glandular trichome/methyl ketone-based insect resistance in tomato.

    PubMed

    Farrar, R R; Kennedy, G G; Kashyap, R K

    1992-03-01

    The effects of glandular trichome/methyl ketone (2-tridecanone and 2-undecanone) -based insect resistance in the wild tomato,Lycopersicon hirsutum f.glabratum C.H. Mull, accession PI 134417, onArchytas marmoratus (Townsend) andEucelatoria bryani (Sabrosky) (Diptera: Tachinidae), both parasitoids ofHelicoverpa (=Heliothis)zea (Boddie) (Lepidoptera: Noctuidae), were investigated in the laboratory.A. marmoratus deposits larvae (planidia) on the foliage of its host's food plant; planidia attach to passing hosts, penetrate the cuticle, and develop in the host pupae.E. bryani larviposits directly into its host; its larvae develop in the host larva.A. marmoratus planidia are killed by glandular trichomes of PI 134417 and also by trichomes of hybrid lines with no methyl ketones. The methyl ketones are toxic to planidia, but at least part of the effect is due to other factors, possibly physical entanglement. Both species can be affected indirectly by methyl ketones in the diet of the host. 2-Undecanone reduces the percentage ofA. marmoratus larvae that reach pupation. This effect is evidently due to premature death and desiccation of the host pupa caused by 2-undecanone. 2-Tridecanone in host diets had no effect onA. marmoratus. InE. bryani, 2-tridecanone in the diet of the host reduced the number of parasitoids yielded by each parasitized host, although not the overall percentage of hosts parasitized. 2-Undecanone in the diet of the host had no effect onE. bryani. PMID:24254953

  20. Resistance to insecticides in Heliothine Lepidoptera: a global view

    PubMed Central

    McCaffery, A. R.

    1998-01-01

    The status of resistance to organophosphate, carbamate, cyclodiene and pyrethroid insecticides in the heliothine Lepidoptera is reviewed. In particular, resistance in the tobacco budworm, Heliothis virescens, and the corn earworm, Helicoverpa zea, from the New World, and the cotton bollworm, Helicoverpa armigera, from the Old World, are considered in detail. Particular emphasis has been placed on resistance to the most widely used of these insecticide groups, the pyrethroids. In each case, the incidence and current status of resistance are considered before a detailed view of the mechanisms of resistance is given. Controversial issues regarding the nature of mechanisms of resistance to pyrethroid insecticides are discussed. The implications for resistance management are considered.

  1. Electrophysiological and behavioral responses of Microplitis mediator (Hymenoptera: Braconidae) to caterpillar-induced volatiles from cotton.

    PubMed

    Yu, Huilin; Zhang, Yongjun; Wyckhuys, Kris A G; Wu, Kongming; Gao, Xiwu; Guo, Yuyuan

    2010-04-01

    Microplitis mediator Haliday (Hymenoptera: Braconidae) is an important larval endoparasitoid of various lepidopteran pests, including Helicoverpa armigera (Hübner). In China, H. armigera is a key pest of cotton and is currently the focus of several biological control efforts that use M. mediator as principal natural enemy of this pest. To improve the success of biological control efforts, behavioral studies are needed that shed light on the interaction between M. mediator and H. armigera. In this study, we determined M. mediator response to volatile compounds from undamaged, mechanically injured, or H. armigera--damaged plants and identified attractive volatiles. In Y-tube olfactometer assays, we found that mechanically damaged plants and/or plants treated with H. armigera oral secretions did not attract wasps. However, volatiles from H. armigera-damaged plants elicited a strong attraction of both M. mediator sexes. Headspace extracts from H. armigera-damaged cotton were analyzed by coupled gas chromatography-electroantennographic detection (GC-EAD), and a total of seven different compounds were found to elicit electroantennogram (EAG) responses, including an unknown compound. Six different EAD-active volatiles were identified from caterpillar-damaged cotton plants, of which 3, 7-dimethyl-1, 3, 6-octatriene and (Z)-3-hexenyl acetate were the principal compounds. Olfactometer assays indicated that individual synthetic compounds of 3, 7-dimethyl-1, 3, 6-octatriene, (Z)-3-hexenyl acetate, and nonanal were attractive to M. mediator. Field cage studies showed that parasitism of H. armigera larvae by M. mediator was higher on cotton plants to which 3,7-dimethyl-1,3, 6-octatriene was applied. Our results show that the combination of terpenoids and green leaf volatiles may not only facilitate host, mate, or food location but may also increase H. armigera parasitism by M. mediator. PMID:20388293

  2. Processing of Pheromone Information in Related Species of Heliothine Moths

    PubMed Central

    Berg, Bente G.; Zhao, Xin-Cheng; Wang, Guirong

    2014-01-01

    In heliothine moths, the male-specific olfactory system is activated by a few odor molecules, each of which is associated with an easily identifiable glomerulus in the primary olfactory center of the brain. This arrangement is linked to two well-defined behavioral responses, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecific females and the other inhibition of attraction via signal information emitted from heterospecifics. The chance of comparing the characteristic properties of pheromone receptor proteins, male-specific sensory neurons and macroglomerular complex (MGC)-units in closely-related species is especially intriguing. Here, we review studies on the male-specific olfactory system of heliothine moths with particular emphasis on five closely related species, i.e., Heliothis virescens, Heliothis subflexa, Helicoverpa zea, Helicoverpa assulta and Helicoverpa armigera. PMID:26462937

  3. Improvement of Pest Resistance in Transgenic Tobacco Plants Expressing dsRNA of an Insect-Associated Gene EcR

    PubMed Central

    Ma, Yao; Zhang, Jia-Qi; Qi, Hai-Sheng; Wei, Zhao-Jun; Yao, Qiong; Zhang, Wen-Qing; Li, Sheng

    2012-01-01

    The adoption of pest-resistant transgenic plants to reduce yield loss and pesticide utilization has been successful in the past three decades. Recently, transgenic plant expressing double-stranded RNA (dsRNA) targeting pest genes emerges as a promising strategy for improving pest resistance in crops. The steroid hormone, 20-hydroxyecdysone (20E), predominately controls insect molting via its nuclear receptor complex, EcR-USP. Here we report that pest resistance is improved in transgenic tobacco plants expressing dsRNA of EcR from the cotton bollworm, Helicoverpa armigera, a serious lepidopteran pest for a variety of crops. When H. armigera larvae were fed with the whole transgenic tobacco plants expressing EcR dsRNA, resistance to H. armigera was significantly improved in transgenic plants. Meanwhile, when H. armigera larvae were fed with leaves of transgenic tobacco plants expressing EcR dsRNA, its EcR mRNA level was dramatically decreased causing molting defects and larval lethality. In addition, the transgenic tobacco plants expressing H. armigera EcR dsRNA were also resistant to another lepidopteran pest, the beet armyworm, Spodoptera exigua, due to the high similarity in the nucleotide sequences of their EcR genes. This study provides additional evidence that transgenic plant expressing dsRNA targeting insect-associated genes is able to improve pest resistance. PMID:22685585

  4. Improvement of pest resistance in transgenic tobacco plants expressing dsRNA of an insect-associated gene EcR.

    PubMed

    Zhu, Jin-Qi; Liu, Shumin; Ma, Yao; Zhang, Jia-Qi; Qi, Hai-Sheng; Wei, Zhao-Jun; Yao, Qiong; Zhang, Wen-Qing; Li, Sheng

    2012-01-01

    The adoption of pest-resistant transgenic plants to reduce yield loss and pesticide utilization has been successful in the past three decades. Recently, transgenic plant expressing double-stranded RNA (dsRNA) targeting pest genes emerges as a promising strategy for improving pest resistance in crops. The steroid hormone, 20-hydroxyecdysone (20E), predominately controls insect molting via its nuclear receptor complex, EcR-USP. Here we report that pest resistance is improved in transgenic tobacco plants expressing dsRNA of EcR from the cotton bollworm, Helicoverpa armigera, a serious lepidopteran pest for a variety of crops. When H. armigera larvae were fed with the whole transgenic tobacco plants expressing EcR dsRNA, resistance to H. armigera was significantly improved in transgenic plants. Meanwhile, when H. armigera larvae were fed with leaves of transgenic tobacco plants expressing EcR dsRNA, its EcR mRNA level was dramatically decreased causing molting defects and larval lethality. In addition, the transgenic tobacco plants expressing H. armigera EcR dsRNA were also resistant to another lepidopteran pest, the beet armyworm, Spodoptera exigua, due to the high similarity in the nucleotide sequences of their EcR genes. This study provides additional evidence that transgenic plant expressing dsRNA targeting insect-associated genes is able to improve pest resistance. PMID:22685585

  5. Supplemental control of lepidopterous pests on Bt transgenic sweet corn with biologically-based spray treatments.

    PubMed

    Farrar, Robert R; Shepard, B Merle; Shapiro, Martin; Hassell, Richard L; Schaffer, Mark L; Smith, Chad M

    2009-01-01

    Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn. PMID:19611255

  6. Supplemental Control of Lepidopterous Pests on Bt Transgenic Sweet Corn with Biologically-Based Spray Treatments

    PubMed Central

    Farrar, Robert R.; Shepard, B. Merle; Shapiro, Martin; Hassell, Richard. L; Schaffer, Mark. L.; Smith, Chad. M.

    2009-01-01

    Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn. PMID:19611255

  7. Design, synthesis, and insecticidal activity of some novel diacylhydrazine and acylhydrazone derivatives.

    PubMed

    Sun, Jialong; Zhou, Yuanming

    2015-01-01

    In this study a series of diacylhydrazine and acylhydrazone derivatives were designed and synthesized according to the method of active group combination and the principles of aromatic group bioisosterism. The structures of the novel derivatives were determined on the basis on 1H-NMR, IR and ESI-MS spectral data. All of the compounds were evaluated for their in vivo insecticidal activity against the third instar larvae of Spodoptera exigua Hiibner, Helicoverpa armigera Hubner, Plutella xyllostella Linnaeus and Pieris rapae Linne, respectively, at a concentration of 10 mg/L. The results showed that all of the derivatives displayed high insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, metaflumizone and tolfenpyrad, and approximately identical insecticidal activity against H. armigera, P. xyllostella and P. rapae as the references metaflumizone and tolfenpyrad. PMID:25830791

  8. Reduced plant nutrition under elevated CO2 depresses the immunocompetence of cotton bollworm against its endoparasite

    PubMed Central

    Yin, Jin; Sun, Yucheng; Ge, Feng

    2014-01-01

    Estimating the immunocompetence of herbivore insects under elevated CO2 is an important step in understanding the effects of elevated CO2 on crop-herbivore-natural enemy interactions. Current study determined the effect of elevated CO2 on the immune response of Helicoverpa armigera against its parasitoid Microplitis mediator. H. armigera were reared in growth chambers with ambient or elevated CO2, and fed wheat grown in the concentration of CO2 corresponding to their treatment levels. Our results showed that elevated CO2 decreases the nutritional quality of wheat, and reduces the total hemocyte counts and impairs the capacity of hemocyte spreading of hemolymph of cotton bollworm larvae, fed wheat grown in the elevated CO2, against its parasitoid; however, this effect was insufficient to change the development and parasitism traits of M. mediator. Our results suggested that lower plant nutritional quality under elevated CO2 could decrease the immune response of herbivorous insects against their parasitoid natural enemies. PMID:24687002

  9. Reduced plant nutrition under elevated CO2 depresses the immunocompetence of cotton bollworm against its endoparasite

    NASA Astrophysics Data System (ADS)

    Yin, Jin; Sun, Yucheng; Ge, Feng

    2014-04-01

    Estimating the immunocompetence of herbivore insects under elevated CO2 is an important step in understanding the effects of elevated CO2 on crop-herbivore-natural enemy interactions. Current study determined the effect of elevated CO2 on the immune response of Helicoverpa armigera against its parasitoid Microplitis mediator. H. armigera were reared in growth chambers with ambient or elevated CO2, and fed wheat grown in the concentration of CO2 corresponding to their treatment levels. Our results showed that elevated CO2 decreases the nutritional quality of wheat, and reduces the total hemocyte counts and impairs the capacity of hemocyte spreading of hemolymph of cotton bollworm larvae, fed wheat grown in the elevated CO2, against its parasitoid; however, this effect was insufficient to change the development and parasitism traits of M. mediator. Our results suggested that lower plant nutritional quality under elevated CO2 could decrease the immune response of herbivorous insects against their parasitoid natural enemies.

  10. Assessment of Bt trait purity in different generations of transgenic cottons.

    PubMed

    Singh, B P; Sandhu, S S; Kalia, V K; Gujart, G T; Dhillon, M K

    2016-04-01

    Adequate expression of Bt (Bacillus thuringiensis) toxins and purity of seeds of Bt-transgenic cottons are important for controlling bollworms, and thereby increasing the cotton productivity. Therefore, we examined the variability in expression of Bt toxin proteins in the seeds and in leaves of different cotton (Gossypium hirsutum (L.) hybrids (JKCH 226, JKCH 1947, JKCH Durga, JKCH Ishwar, JKCH Varun KDCHH 441 and KDCHH 621) expressing Bt toxins in F₁ and F₂ generations, using bioassays against the cotton bollworm, Helicoverpa armigera (Hübner), and the lateral flow strip (LFS) test. Toxicity of Bt toxin proteins in the seeds of Bt-transgenic cottons to H. armigera correlated with their toxicity in the leaves in one- toxin Bt cotton hybrids. The Bt-F₁ and Bt-F₂ seeds of JKCH 1947 were more toxic to H. armigera than those of JKCH Varun seeds. The seeds and leaves of F₁s showed greater toxicity than the F2 seeds or leaves of one-toxin (cry1Ac) Bt cotton hybrids. However, no significant differences were observed for the two-toxin (cry1Ac and cry2Ab) hybrid, KDCHH 621. Toxicity of leaves to H. armigera increased with crop age, until 112 days after seedling emergence. The Bt trait purity in F₁ seeds of four two-toxin Bt cotton hybrids ranged from 86.7 to 100%. The present study emphasizes the necessity of 95% Bt trait purity in seeds of transgenic cotton for sustainable crop production. PMID:27295920

  11. Influence of Landscape Diversity and Composition on the Parasitism of Cotton Bollworm Eggs in Maize

    PubMed Central

    Liu, Bing; Yang, Long; Yang, Yizhong; Lu, Yanhui

    2016-01-01

    We deployed >50,000 Helicoverpa armigera eggs in maize fields to assess the rate of parasitism by Trichogramma chilonis across 33 sites during a three-year span (2012–2014) in northern China. Subsequently, we used a partial least squares (PLS) regression approach to assess the relationship of landscape diversity with composition and parasitism potential. The parasitism rate of H. armigera eggs by T. chilonis ranged from 0–25.8%, with a mean value of 5.6%. Landscape diversity greatly enhanced parasitism at all four different spatial scales (0.5, 1.0, 1.5 and 2.0 km radius). Both the proportion of arable area and the total planting area of two major crops (cotton and maize) had a negative correlation to the parasitism rate at each scale, whereas parasitism was positively correlated to the proportion of host crops of H. armigera other than cotton and maize at the 0.5 to 2.0 km radius scales as well as to that of non-crop habitat at the 0.5 and 1.0 km radius scales. The study indicated that maintaining landscape diversity provided an important biocontrol service by limiting H. armigera through the egg parasitoid T. chilonis, whereas rapid agricultural intensification would greatly reduce the presence and parasitism of T. chilonis in China. PMID:26881784

  12. Development of a novel-type transgenic cotton plant for control of cotton bollworm.

    PubMed

    Yue, Zhen; Liu, Xiaoguang; Zhou, Zijing; Hou, Guangming; Hua, Jinping; Zhao, Zhangwu

    2016-08-01

    The transgenic Bt cotton plant has been widely planted throughout the world for the control of cotton budworm Helicoverpa armigera (Hubner). However, a shift towards insect tolerance of Bt cotton is now apparent. In this study, the gene encoding neuropeptide F (NPF) was cloned from cotton budworm H. armigera, an important agricultural pest. The npf gene produces two splicing mRNA variants-npf1 and npf2 (with a 120-bp segment inserted into the npf1 sequence). These are predicted to form the mature NPF1 and NPF2 peptides, and they were found to regulate feeding behaviour. Knock down of larval npf with dsNPF in vitro resulted in decreases of food consumption and body weight, and dsNPF also caused a decrease of glycogen and an increase of trehalose. Moreover, we produced transgenic tobacco plants transiently expressing dsNPF and transgenic cotton plants with stably expressed dsNPF. Results showed that H. armigera larvae fed on these transgenic plants or leaves had lower food consumption, body size and body weight compared to controls. These results indicate that NPF is important in the control of feeding of H. armigera and valuable for production of potential transgenic cotton. PMID:26841044

  13. p13 from group II baculoviruses is a killing-associated gene

    PubMed Central

    Lu, Nan; Du, Enqi; Liu, Yangkun; Qiao, Hong; Yao, Lunguang; Pan, Zishu; Lu, Songya; Qi, Yipeng

    2012-01-01

    p13 gene was first described in Leucania separata multinuclear polyhedrosis virus (Ls-p13) several years ago, but the function of P13 protein has not been experimentally investigated to date. In this article, we indicated that the expression of p13 from Heliothis armigera single nucleocapsid nucleopolyhedrovirus (Ha-p13) was regulated by both early and late promoter. Luciferase assay demonstrated that the activity of Ha-p13 promoter with hr4 enhancer was more than 100 times in heterologous Sf9 cells than that in nature host Hz-AM1 cells. Both Ls-P13 and Ha-P13 are transmembrane proteins. Confocal microscopic analysis showed that both mainly located in the cytoplasm membrane at 48 h. Results of RNA interference indicated that Ha-p13 was a killing-associated gene for host insects H. armigera. The AcMNPV acquired the mentioned killing activity and markedly accelerate the killing rate when expressing Ls-p13. In conclusion, p13 is a killing associated gene in both homologous and heterologous nucleopolyhedrovirus. [BMB Reports 2012; 45(12): 730-735] PMID:23261060

  14. Ultraweak photon emission from herbivory-injured maize plants

    NASA Astrophysics Data System (ADS)

    Yoshinaga, Naoko; Kato, Kimihiko; Kageyama, Chizuko; Fujisaki, Kenji; Nishida, Ritsuo; Mori, Naoki

    2006-01-01

    Following perception of herbivory or infection, plants exhibit a wide range of inducible responses. In this study, we found ultraweak photon emissions from maize leaves damaged by Helicoverpa armigera (Noctuidae). Interestingly, mechanically damaged maize leaves treated with caterpillar regurgitants emitted the same intensity and pattern of photon emissions as those from maize leaves damaged by caterpillars. Furthermore, two-dimensional imaging of the leaf section treated with the oral secretions clearly shows that photon emissions were observed specifically at the lip of the wound exposed to the secretions. These results suggest that the direct interaction between maize leaf cells and chemicals contained in caterpillar regurgitants triggers these photon emissions.

  15. Cloning and characterization of an insecticidal crystal protein gene from Bacillus thuringiensis subspecies kenyae.

    PubMed

    Misra, Hari S; Khairnar, Nivedita P; Mathur, Manjula; Vijayalakshmi, N; Hire, Ramesh S; Dongre, T K; Mahajan, S K

    2002-04-01

    A sporulating culture of Bacillus thuringiensis subsp. kenyae strain HD549 is toxic to larvae of lepidopteran insect species such as Spodoptera litura, Helicoverpa armigera and Phthorimaea operculella, and a dipteran insect, Culex fatigans. A 1.9-kb DNA fragment, PCR-amplified from HD549 using cryII-gene-specific primers, was cloned and expressed in E. coli. The recombinant protein produced 92% mortality in first-instar larvae of Spodoptera litura and 86% inhibition of adult emergence in Phthorimaea operculella, but showed very low toxicity against Helicoverpa armigera, and lower mortality against third-instar larvae of dipteran insects Culex fatigans, Anopheles stephensi and Aedes aegypti. The sequence of the cloned crystal protein gene showed almost complete homology with a mosquitocidal toxin gene from Bacillus thuringiensis var. kurstaki, with only five mutations scattered in different regions. Amino acid alignment with different insecticidal crystal proteins using the MUTALIN program suggested presence of the conserved block 3 region in the sequence of this protein. A mutation in codon 409 of this gene that changes a highly conserved phenylalanine residue to serine lies in this block. PMID:12357073

  16. in silico identification of cross affinity towards Cry1Ac pesticidal protein with receptor enzyme in Bos taurus and sequence, structure analysis of crystal proteins for stability

    PubMed Central

    Ebenezer, King Solomon; Nachimuthu, Ramesh; Thiagarajan, Prabha; Velu, Rajesh Kannan

    2013-01-01

    Any novel protein introduced into the GM crops need to be evaluated for cross affinity on living organisms. Many researchers are currently focusing on the impact of Bacillus thuringiensis cotton on soil and microbial diversity by field experiments. In spite of this, in silico approach might be helpful to elucidate the impact of cry genes. The crystal a protein which was produced by Bt at the time of sporulation has been used as a biological pesticide to target the insectivorous pests like Cry1Ac for Helicoverpa armigera and Cry2Ab for Spodoptera sp. and Heliothis sp. Here, we present the comprehensive in silico analysis of Cry1Ac and Cry2Ab proteins with available in silico tools, databases and docking servers. Molecular docking of Cry1Ac with procarboxypeptidase from Helicoverpa armigera and Cry1Ac with Leucine aminopeptidase from Bos taurus has showed the 125th amino acid position to be the preference site of Cry1Ac protein. The structures were compared with each other and it showed 5% of similarity. The cross affinity of this toxin that have confirmed the earlier reports of ill effects of Bt cotton consumed by cattle. PMID:24023423

  17. In-Silico Determination of Insecticidal Potential of Vip3Aa-Cry1Ac Fusion Protein Against Lepidopteran Targets Using Molecular Docking.

    PubMed

    Ahmad, Aftab; Javed, Muhammad R; Rao, Abdul Q; Khan, Muhammad A U; Ahad, Ammara; Din, Salah Ud; Shahid, Ahmad A; Husnain, Tayyab

    2015-01-01

    Study and research of Bt (Bacillus thuringiensis) transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac) insecticidal protein and vegetative insecticidal protein (Vip3Aa) have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN) and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua, and Spodoptera litura) revealed that the Ser290, Ser293, Leu337, Thr340, and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein. PMID:26697037

  18. In-Silico Determination of Insecticidal Potential of Vip3Aa-Cry1Ac Fusion Protein Against Lepidopteran Targets Using Molecular Docking

    PubMed Central

    Ahmad, Aftab; Javed, Muhammad R.; Rao, Abdul Q.; Khan, Muhammad A. U.; Ahad, Ammara; Din, Salah ud; Shahid, Ahmad A.; Husnain, Tayyab

    2015-01-01

    Study and research of Bt (Bacillus thuringiensis) transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac) insecticidal protein and vegetative insecticidal protein (Vip3Aa) have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN) and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua, and Spodoptera litura) revealed that the Ser290, Ser293, Leu337, Thr340, and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein. PMID:26697037

  19. Tarsi of Male Heliothine Moths Contain Aldehydes and Butyrate Esters as Potential Pheromone Components.

    PubMed

    Choi, Man-Yeon; Ahn, Seung-Joon; Park, Kye-Chung; Meer, Robert Vander; Cardé, Ring T; Jurenka, Russell

    2016-05-01

    The Noctuidae are one of the most speciose moth families and include the genera Helicoverpa and Heliothis. Females use (Z)-11-hexadecenal as the major component of their sex pheromones except for Helicoverpa assulta and Helicoverpa gelotopoeon, both of which utilize (Z)-9-hexadecenal. The minor compounds found in heliothine sex pheromone glands vary with species, but hexadecanal has been found in the pheromone gland of almost all heliothine females so far investigated. In this study, we found a large amount (0.5-1.5 μg) of hexadecanal and octadecanal on the legs of males of four heliothine species, Helicoverpa zea, Helicoverpa armigera, H. assulta, and Heliothis virescens. The hexadecanal was found on and released from the tarsi, and was in much lower levels or not detected on the remaining parts of the leg (tibia, femur, trochanter, and coxa). Lower amounts (0.05-0.5 μg) of hexadecanal were found on female tarsi. This is the first known sex pheromone compound to be identified from the legs of nocturnal moths. Large amounts of butyrate esters (about 16 μg) also were found on tarsi of males with lower amounts on female tarsi. Males deposited the butyrate esters while walking on a glass surface. Decapitation did not reduce the levels of hexadecanal on the tarsi of H. zea males, indicating that hexadecanal production is not under the same neuroendocrine regulation system as the production of female sex pheromone. Based on electroantennogram studies, female antennae had a relatively high response to hexadecanal compared to male antennae. We consider the possible role of aldehydes and butyrate esters as courtship signals in heliothine moths. PMID:27155602

  20. Peripheral genetic structure of Helicoverpa zea indicates asymmetrical panmixia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seasonal climatic shifts create peripheral habitats that alternate between habitable and uninhabitable for migratory species. Such dynamic peripheral habitats are potential sites where migratory species could evolve high genetic diversity resulting from convergence of immigrants from multiple region...

  1. Hophornbeam copperleaf, an example wild host for Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Populations of Helicovepa zea (Boddie)and Heliothis virescens (Fabricies)were commonly found on hophornbeam copperleaf, Acalpha ostryaefolia, in Arkansas and Mississippi. From 2002-2009, more than 25 colonies of H. zea were established from collections made on the wild host plant. One colony of H...

  2. Challenges to monitoring Bt resistance in Helicoverpa zea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic crops that produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) are widely grown in many countries for the control of lepidopteran pests. The evolution of resistance in these pests to transgenic crops producing Bt toxins threatens the prolonged success of this imp...

  3. Monitoring and adaptive resistance management in Australia for Bt-cotton: current status and future challenges.

    PubMed

    Downes, Sharon; Mahon, Rod; Olsen, Karen

    2007-07-01

    In the mid-1990 s the Australian Cotton industry adopted an insect-resistant variety of cotton (Ingard) which expresses the Bt toxin Cry1Ac that is specific to a group of insects including the target Helicoverpa armigera. A conservative resistance management plan (RMP), that restricted the area planted to Ingard, was implemented to preserve the efficacy of Cry1Ac until two-gene transgenic cotton was available. In 2004/05 Bollgard II replaced Ingard as the transgenic cotton available in Australia. It improves on Ingard by incorporating an additional insecticidal protein (Cry2Ab). If an appropriate refuge is grown, there is no restriction on the area planted to Bollgard II. In 2004/05 and 2005/06 the Bollgard II acreage represented approximately 80 of the total area planted to cotton in Australia. The sensitivity of field-collected populations of H. armigera to Bt products was assayed before and subsequent to the widespread deployment of Ingard cotton. In 2002 screens against Cry2Ab were developed in preparation for replacement of Ingard with Bollgard II. There have been no reported field failures of Bollgard II due to resistance. However, while alleles that confer resistance to H. armigera in the field are rare for Cry1Ac, they are surprisingly common for Cry2Ab. We present an overview of the current approach adopted in Australia to monitor and adaptively manage resistance to Bt-cotton in field populations of H. armigera and discuss the implications of our findings to date. We also highlight future challenges for resistance management in Australia, many of which extend to other Bt-crop and pest systems. PMID:17470372

  4. Cloning, characterization and expression of a novel haplotype cry2A-type gene from Bacillus thuringiensis strain SWK1, native to Himalayan valley Kashmir.

    PubMed

    Reyaz, A L; Arulselvi, P Indra

    2016-05-01

    Bacillus thuringiensis (Bt) is a gram positive bacterium which is effectively being used in pest management strategies as an eco-friendly bioinsecticide. In the present study a new cry2A gene was cloned from a promising indigenous B. thuringiensis SWK1 strain previously characterized for its toxicity against Spodoptera litura and Helicoverpa armigera larvae. The nucleotide sequence of the cloned cry2A gene pointed out that the open reading frame has 1902 bases encoding a polypeptide of 634 amino acid residues with a probable molecular weight of 70kDa. Homology comparisons showed that the deduced amino acid sequence of Cry2A had a similarity of 94% compared to that of the known Cry2Aa protein in the NCBI database and this gene has been named as cry2Al1 by the B. thuringiensis δ-endotoxin Nomenclature Committee. cry2Al1 was ligated into pET 22b vector and expressed in Escherichia coli BL21 (DE3) pLysS under the control of T7 promoter induced by isopropyl-beta-d-thiogalactopyranoside (IPTG). SDS-PAGE analysis confirmed the expression of cry2Al1 as ∼65kDa protein. Insect pest bioassays with neonate larvae of S. litura and H. armigera showed that the purified Cry2Al1 are toxic to S. litura and H. armigera with LC50 2.448μg/ml and H. armigera with 3.374μg/ml respectively. PMID:26906447

  5. Cell lines derived from the black cutworm, Agrotis ipsilon, that support replication of the A. ipsilon multiple nucleopolyhedrovirus and several group I nucleopolyhedroviruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New cell lines were recently developed from the embryos of the black cutworm, Agrotis ipsilon (Lepidoptera: Noctuidae). A primary culture was initiated from 4 day-old A. ipsilon eggs in ExCell420 medium supplemented with 5% fetal bovine serum. This initial culture produced sufficient cell growth to ...

  6. Complete sequence and gene organization of the Nosema heliothidis ribosomal RNA gene region.

    PubMed

    Dong, Shinan; Shen, Zhongyuan; Zhu, Feng; Tang, Xudong; Xu, Li

    2011-01-01

    By sequencing the entire ribosomal RNA (rRNA) gene region of Nosema heliothidis isolated from cotton bollworm (Helicoverpa armigera), we showed that its gene organization is similar to the type species, Nosema bombycis: the 5'-large subunit rRNA (2,490 bp)-internal transcribed spacer (192 bp)-small subunit rRNA (1,232 bp)-intergenic spacer (274 bp)-5S rRNA (115 bp)-3'. We constructed two phylogenetic trees, analyzed phylogenetic relationships, examined rRNA organization of microsporidia, and compared the secondary structure of small subunit rRNA with closely related microsporidia. The latter two features may provide important information for the classification and phylogenetic analysis of microsporidia. PMID:21895841

  7. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    PubMed

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products. PMID:25721170

  8. Design, synthesis and insecticidal activity of novel phenylurea derivatives.

    PubMed

    Sun, Jialong; Zhou, Yuanming

    2015-01-01

    A series of novel phenylurea derivatives were designed and synthesized according to the method of active groups linkage and the principle of aromatic groups bioisosterism in this study. The structures of the novel phenylurea derivatives were confirmed based on ESI-MS, IR and 1H-NMR spectral data. All of the compounds were evaluated for the insecticidal activity against the third instars larvae of Spodoptera exigua Hiibner, Plutella xyllostella Linnaeus, Helicoverpa armigera Hubner and Pieris rapae Linne respectively, at the concentration of 10 mg/L. The results showed that all of the derivatives displayed strong insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, chlorbenzuron and metaflumizone. Among the synthesized compounds, 3b, 3d, 3f, 4b and 4g displayed broad spectrum insecticidal activity. PMID:25808149

  9. Toxicity of cinnamomin--a new type II ribosome-inactivating protein to bollworm and mosquito.

    PubMed

    Zhou, X; Li, X D; Yuan, J Z; Tang, Z H; Liu, W Y

    2000-03-01

    The toxicity of cinnamomin, a new type II ribosome-inactivating protein purified from the seeds of camphor tree (Cinnamomum camphora), to bollworm (Helicoverpa armigera) and mosquito (Culex pipines pallens) during larval stage was tested. The LC50 of cinnamomin to bollworm larvae fed on diet containing cinnamomin was 1839 ppm and the LC50 to larvae of mosquito was 168 ppm. The gut extract of bollworm larvae could apparently hydrolyze cinnamomin. The inhibition of protein synthesis by cinnamomin was tested in in vitro translation system of bollworm larvae, and its LC50 was determined to be approx. 14 nM. Bollworm larvae ribosome treated with cinnamomin produced a specific RNA fragment (R-fragment) characterized on urea-denatured polyacrylamide gel. Evidence was provided that hidden breaks exist in the largest ribosomal RNA of bollworm larvae. PMID:10732994

  10. GhDRIN1, a novel drought-induced gene of upland cotton (Gossypium hirsutum L.) confers abiotic and biotic stress tolerance in transgenic tobacco.

    PubMed

    Dhandapani, Gurusamy; Lakshmi Prabha, Azhagiyamanavalan; Kanakachari, Mogilicherla; Phanindra, Mullapudi Lakshmi Venkata; Prabhakaran, Narayanasamy; Gothandapani, Sellamuthu; Padmalatha, Kethireddy Venkata; Solanke, Amolkumar U; Kumar, Polumetla Ananda

    2015-04-01

    A novel stress tolerance cDNA fragment encoding GhDRIN1 protein was identified and its regulation was studied in cotton boll tissues and seedlings subjected to various biotic and abiotic stresses. Phylogenetic and conserved domain prediction indicated that GhDRIN1 was annotated with a hypothetical protein of unknown function. Subcellular localization showed that GhDRIN1 is localized in the chloroplasts. The promoter sequence was isolated and subjected to in silico study. Various cis-acting elements responsive to biotic and abiotic stresses and hormones were found. Transgenic tobacco seedlings exhibited better growth on amended MS medium and showed minimal leaf damage in insect bioassays carried out with Helicoverpa armigera larvae. Transgenic tobacco showed better tolerance to water-deficit and fast recovered upon rewatering. Present work demonstrated that GhDRIN1, a novel stress tolerance gene of cotton, positively regulates the response to biotic and abiotic stresses in transgenic tobacco. PMID:25413882

  11. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    PubMed

    Tay, Wee Tek; Mahon, Rod J; Heckel, David G; Walsh, Thomas K; Downes, Sharon; James, William J; Lee, Sui-Fai; Reineke, Annette; Williams, Adam K; Gordon, Karl H J

    2015-11-01

    The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton) expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests) to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC) marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC) transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the detailed mode

  12. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein

    PubMed Central

    Tay, Wee Tek; Mahon, Rod J.; Heckel, David G.; Walsh, Thomas K.; Downes, Sharon; James, William J.; Lee, Sui-Fai; Reineke, Annette; Williams, Adam K.; Gordon, Karl H. J.

    2015-01-01

    The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton) expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests) to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC) marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC) transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the detailed mode

  13. Tea, coffee, and cocoa as ultraviolet radiation protectants for beet armyworm nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The addition of 1% (wt/v) aqueous extracts of cocoa (Theobroma cacao L.) (Malvales: Malvaceae), coffee (Coffea arabica L.) (Gentianales: Rubiaceae), green, and black tea (Camellia sinensis L.) (Ericales: Theaceae) provided excellent ultraviolet (UV) radiation protection for the beet armyworm, Spodo...

  14. Autographa californica multiple nucleopolyhedrovirus PK-1 is essential for nucleocapsid assembly

    SciTech Connect

    Liang, Changyong; Li, Min; Dai, Xuejuan; Zhao, Shuling; Hou, Yanling; Zhang, Yongli; Lan, Dandan; Wang, Yun; Chen, Xinwen

    2013-09-01

    PK-1 (Ac10) is a baculovirus-encoded serine/threonine kinase and its function is unclear. Our results showed that a pk-1 knockout AcMNPV failed to produce infectious progeny, while the pk-1 repair virus could rescue this defect. qPCR analysis demonstrated that pk-1 deletion did not affect viral DNA replication. Analysis of the repaired recombinants with truncated pk-1 mutants demonstrated that the catalytic domain of protein kinases of PK-1 was essential to viral infectivity. Moreover, those PK-1 mutants that could rescue the infectious BV production defect exhibited kinase activity in vitro. Therefore, it is suggested that the kinase activity of PK-1 is essential in regulating viral propagation. Electron microscopy revealed that pk-1 deletion affected the formation of normal nucleocapsids. Masses of electron-lucent tubular structures were present in cell transfected with pk-1 knockout bacmid. Therefore, PK-1 appears to phosphorylate some viral or cellular proteins that are essential for DNA packaging to regulate nucleocapsid assembly. - Highlights: • A pk-1 knockout AcMNPV failed to produce infectious progeny. • The pk-1 deletion did not affect viral DNA replication. • The catalytic domain of protein kinases (PKc) of PK-1 was essential to viral infectivity. • The kinase activity of PK-1 is essential in regulating viral propagation. • PK-1 appears to phosphorylate some viral proteins that are essential for DNA packaging to regulate nucleocapsid assembly.

  15. The transcriptome of the baculovirus Autographa californica multiple nucleopolyhedrovirus in Trichoplusia ni cells.

    PubMed

    Chen, Yun-Ru; Zhong, Silin; Fei, Zhangjun; Hashimoto, Yoshifumi; Xiang, Jenny Z; Zhang, Shiying; Blissard, Gary W

    2013-06-01

    Baculoviruses are important insect pathogens that have been developed as protein expression vectors in insect cells and as transduction vectors for mammalian cells. They have large double-stranded DNA genomes containing approximately 156 tightly spaced genes, and they present significant challenges for transcriptome analysis. In this study, we report the first comprehensive analysis of AcMNPV transcription over the course of infection in Trichoplusia ni cells, by a combination of strand-specific RNA sequencing (RNA-Seq) and deep sequencing of 5' capped transcription start sites and 3' polyadenylation sites. We identified four clusters of genes associated with distinctive patterns of mRNA accumulation through the AcMNPV infection cycle. A total of 218 transcription start sites (TSS) and 120 polyadenylation sites (PAS) were mapped. Only 29 TSS were associated with a canonical TATA box, and 14 initiated within or near the previously identified CAGT initiator motif. The majority of viral transcripts (126) initiated within the baculovirus late promoter motif (TAAG), and late transcripts initiated precisely at the second position of the motif. Analysis of 3' ends showed that 92 (77%) of the 3' PAS were located within 30 nucleotides (nt) downstream of a consensus termination signal (AAUAAA or AUUAAA). A conserved U-rich region was found approximately 2 to 10 nt downstream of the PAS for 58 transcripts. Twelve splicing events and an unexpectedly large number of antisense RNAs were identified, revealing new details of possible regulatory mechanisms controlling AcMNPV gene expression. Combined, these data provide an emerging global picture of the organization and regulation of AcMNPV transcription through the infection cycle. PMID:23536684

  16. Proteotoxic stress induced by Autographa californica nucleopolyhedrovirus infection of Spodoptera frugiperda Sf9 cells.

    PubMed

    Lyupina, Yulia V; Abaturova, Svetlana B; Erokhov, Pavel A; Orlova, Olga V; Beljelarskaya, Svetlana N; Mikhailov, Victor S

    2013-02-01

    Baculovirus AcMNPV causes proteotoxicity in Sf9 cells as revealed by accumulation of ubiquitinated proteins and aggresomes in the course of infection. Inhibition of proteasomes by lactacystin increased markedly the stock of ubiquitinated proteins indicating a primary role of proteasomes in detoxication. The proteasomes were present in Sf9 cells as 26S and 20S complexes whose protease activity did not change during infection. Proteasome inhibition caused a delay in the initiation of viral DNA replication suggesting an important role of proteasomes at early stages in infection. However, lactacystin did not affect ongoing replication indicating that active proteasomes are not required for genome amplification. At late stages in infection (24-48 hpi), aggresomes containing the ubiquitinated proteins and HSP/HSC70s showed gradual fusion with the vacuole-like structures identified as lysosomes by antibody to cathepsin D. This result suggests that lysosomes may assist in protection against proteotoxicity caused by baculoviruses absorbing the ubiquitinated proteins. PMID:23123012

  17. Hyper-Enhanced Production of Foreign Recombinant Protein by Fusion with the Partial Polyhedrin of Nucleopolyhedrovirus

    PubMed Central

    Bae, Sung Min; Kim, Hee Jung; Lee, Jun Beom; Choi, Jae Bang; Shin, Tae Young; Koo, Hyun Na; Choi, Jae Young; Lee, Kwang Sik; Je, Yeon Ho; Jin, Byung Rae; Yoo, Sung Sik; Woo, Soo Dong

    2013-01-01

    To enhance the production efficiency of foreign protein in baculovirus expression systems, the effects of polyhedrin fragments were investigated by fusion expressing them with the enhanced green fluorescent protein (EGFP). Recombinant viruses were generated to express EGFP fused with polyhedrin fragments based on the previously reported minimal region for self-assembly and the KRKK nuclear localization signal (NLS). Fusion expressions with polyhedrin amino acids 19 to 110 and 32 to 110 lead to localization of recombinant protein into the nucleus and mediate its assembly. The marked increase of EGFP by these fusion expressions was confirmed through protein and fluorescence intensity analyses. The importance of nuclear localization for enhanced production was shown by the mutation of the NLS within the fused polyhedrin fragment. In addition, when the polyhedrin fragment fused with EGFP was not localized in the nucleus, some fragments increased the production of protein. Among these fragments, some degradation of only the fused polyhedrin was observed in the fusion of amino acids 19 to 85 and 32 to 85. The fusion of amino acids 32 to 85 may be more useful for the enhanced and intact production of recombinant protein. The production of E2 protein, which is a major antigen of classical swine fever virus, was dramatically increased by fusion expression with polyhedrin amino acids 19 to 110, and its preliminary immunogenicity was verified using experimental guinea pigs. This study suggests a new option for higher expression of useful foreign recombinant protein by using the partial polyhedrin in baculovirus. PMID:23593321

  18. Proteotoxic stress induced by Autographa californica nucleopolyhedrovirus infection of Spodoptera frugiperda Sf9 cells

    SciTech Connect

    Lyupina, Yulia V.; Abaturova, Svetlana B.; Erokhov, Pavel A.; Orlova, Olga V.; Beljelarskaya, Svetlana N.; Mikhailov, Victor S.

    2013-02-05

    Baculovirus AcMNPV causes proteotoxicity in Sf9 cells as revealed by accumulation of ubiquitinated proteins and aggresomes in the course of infection. Inhibition of proteasomes by lactacystin increased markedly the stock of ubiquitinated proteins indicating a primary role of proteasomes in detoxication. The proteasomes were present in Sf9 cells as 26S and 20S complexes whose protease activity did not change during infection. Proteasome inhibition caused a delay in the initiation of viral DNA replication suggesting an important role of proteasomes at early stages in infection. However, lactacystin did not affect ongoing replication indicating that active proteasomes are not required for genome amplification. At late stages in infection (24-48 hpi), aggresomes containing the ubiquitinated proteins and HSP/HSC70s showed gradual fusion with the vacuole-like structures identified as lysosomes by antibody to cathepsin D. This result suggests that lysosomes may assist in protection against proteotoxicity caused by baculoviruses absorbing the ubiquitinated proteins.

  19. Effects of Cucurbitacin on the Activity of Nucleopolyhedroviruses against Pickleworm Larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cucurbitacin-containing feeding stimulant (Invite® EC) was attractive to second instar pickleworm larvae in the absence of a food source. Second instar pickleworm larvae also fed preferentially on cucumber fruits that were treated with a 1% (0.01X) solution of Invite EC. However, 1% Invite did...

  20. Black Tea and Lignin as Ultraviolet Protectants for the Beet Armyworm Nucleopolyhedrovirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of major constraints to use baculoviruses for biocontrol of insect pests in field conditions is their sensitivity to breakdown by sunlight. In this study, we evaluated black tea and lignin (Reax 85A) as potential ultraviolet (UV) protectants for beet armyworm (BAW) Spodoptera exigua (Hübner) (L...

  1. A Highly Efficient and Simple Construction Strategy for Producing Recombinant Baculovirus Bombyx mori Nucleopolyhedrovirus

    PubMed Central

    Liu, Xingjian; Wei, Yonglong; Li, Yinü; Li, Haoyang; Yang, Xin; Yi, Yongzhu; Zhang, Zhifang

    2016-01-01

    The silkworm baculovirus expression system is widely used to produce recombinant proteins. Several strategies for constructing recombinant viruses that contain foreign genes have been reported. Here, we developed a novel defective-rescue BmNPV Bacmid (reBmBac) expression system. A CopyControl origin of replication was introduced into the viral genome to facilitate its genetic manipulation in Escherichia coli and to ensure the preparation of large amounts of high quality reBmBac DNA as well as high quality recombinant baculoviruses. The ORF1629, cathepsin and chitinase genes were partially deleted or rendered defective to improve the efficiency of recombinant baculovirus generation and the expression of foreign genes. The system was validated by the successful expression of luciferase reporter gene and porcine interferon γ. This system can be used to produce batches of recombinant baculoviruses and target proteins rapidly and efficiently in silkworms. PMID:27008267

  2. A Highly Efficient and Simple Construction Strategy for Producing Recombinant Baculovirus Bombyx mori Nucleopolyhedrovirus.

    PubMed

    Liu, Xingjian; Wei, Yonglong; Li, Yinü; Li, Haoyang; Yang, Xin; Yi, Yongzhu; Zhang, Zhifang

    2016-01-01

    The silkworm baculovirus expression system is widely used to produce recombinant proteins. Several strategies for constructing recombinant viruses that contain foreign genes have been reported. Here, we developed a novel defective-rescue BmNPV Bacmid (reBmBac) expression system. A CopyControl origin of replication was introduced into the viral genome to facilitate its genetic manipulation in Escherichia coli and to ensure the preparation of large amounts of high quality reBmBac DNA as well as high quality recombinant baculoviruses. The ORF1629, cathepsin and chitinase genes were partially deleted or rendered defective to improve the efficiency of recombinant baculovirus generation and the expression of foreign genes. The system was validated by the successful expression of luciferase reporter gene and porcine interferon γ. This system can be used to produce batches of recombinant baculoviruses and target proteins rapidly and efficiently in silkworms. PMID:27008267

  3. A DNA Binding Protein Is Required for Viral Replication and Transcription in Bombyx mori Nucleopolyhedrovirus

    PubMed Central

    Chen, Bin; Shi, Yanghui; Quan, Yanping; Nie, Zuoming; Zhang, Yaozhou; Yu, Wei

    2016-01-01

    A DNA-binding protein (DBP) [GenBank accession number: M63416] of Bombyx mori nuclear polyhedrosis virus (BmNPV) has been reported to be a regulatory factor in BmNPV, but its detailed functions remain unknown. In order to study the regulatory mechanism of DBP on viral proliferation, genome replication, and gene transcription, a BmNPV dbp gene knockout virus dbp-ko-Bacmid was generated by the means of Red recombination system. In addition, dbp-repaired virus dbp-re-Bacmid was constructed by the means of the Bac to Bac system. Then, the Bacmids were transfected into BmN cells. The results of this viral titer experiment revealed that the TCID50 of the dbp-ko-Bacmid was 0; however, the dbp-re-Bacmid was similar to the wtBacmid (p>0.05), indicating that the dbp-deficient would lead to failure in the assembly of virus particles. In the next step, Real-Time PCR was used to analyze the transcriptional phases of dbp gene in BmN cells, which had been infected with BmNPV. The results of the latter experiment revealed that the transcript of dbp gene was first detected at 3 h post-infection. Furthermore, the replication level of virus genome and the transcriptional level of virus early, late, and very late genes in BmN cells, which had been transfected with 3 kinds of Bacmids, were analyzed by Real-Time PCR. The demonstrating that the replication level of genome was lower than that of wtBacmid and dbp-re-Bacmid (p<0.01). The transcriptional level of dbp-ko-Bacmid early gene lef-3, ie-1, dnapol, late gene vp39 and very late gene p10 were statistically significantly lower than dbp-re-Bacmid and wtBacmid (p<0.01). The results presented are based on Western blot analysis, which indicated that the lack of dbp gene would lead to low expressions of lef3, vp39, and p10. In conclusion, dbp was not only essential for early viral replication, but also a viral gene that has a significant impact on transcription and expression during all periods of baculovirus life cycle. PMID:27414795

  4. Expansion of a bitter taste receptor family in a polyphagous insect herbivore.

    PubMed

    Xu, Wei; Papanicolaou, Alexie; Zhang, Hui-Jie; Anderson, Alisha

    2016-01-01

    The Insect taste system plays a central role in feeding behaviours and co-evolution of insect-host interactions. Gustatory receptors form the interface between the insect taste system and the environment. From genome and transcriptome sequencing we identified 197 novel gustatory receptor (GR) genes from the polyphagous pest Helicoverpa armigera. These GRs include a significantly expanded bitter receptor family (180 GRs) that could be further divided into three categories based on polypeptide lengths, gene structure and amino acid sequence. Type 1 includes 29 bitter Gr genes that possess introns. Type 2 includes 13 long intronless bitter Gr genes, while Type 3 comprises 131 short intronless bitter Gr genes. Calcium imaging analysis demonstrated that three Type 3 GRs (HarmGR35, HarmGR50 and HarmGR195) can be activated by a crude extract of cotton leaves. HarmGR195, a GR specifically and selectively expressed in adult tarsi, showed a specific response to proline, an amino acid widely present in plant tissues. We hypothesise that the expansion in the H. armigera GR family may be functionally tied to its polyphagous behavior. Understanding the molecular basis of polyphagy may provide opportunities for the development of new environmentally friendly pest control strategies. PMID:27032373

  5. Ignoring the irrelevant: auditory tolerance of audible but innocuous sounds in the bat-detecting ears of moths

    NASA Astrophysics Data System (ADS)

    Fullard, James H.; Ratcliffe, John M.; Jacobs, David S.

    2008-03-01

    Noctuid moths listen for the echolocation calls of hunting bats and respond to these predator cues with evasive flight. The African bollworm moth, Helicoverpa armigera, feeds at flowers near intensely singing cicadas, Platypleura capensis, yet does not avoid them. We determined that the moth can hear the cicada by observing that both of its auditory receptors (A1 and A2 cells) respond to the cicada’s song. The firing response of the A1 cell rapidly adapts to the song and develops spike periods in less than a second that are in excess of those reported to elicit avoidance flight to bats in earlier studies. The possibility also exists that for at least part of the day, sensory input in the form of olfaction or vision overrides the moth’s auditory responses. While auditory tolerance appears to allow H. armigera to exploit a food resource in close proximity to acoustic interference, it may render their hearing defence ineffective and make them vulnerable to predation by bats during the evening when cicadas continue to sing. Our study describes the first field observation of an eared insect ignoring audible but innocuous sounds.

  6. Reduced Levels of Membrane-Bound Alkaline Phosphatase Are Common to Lepidopteran Strains Resistant to Cry Toxins from Bacillus thuringiensis

    PubMed Central

    Jurat-Fuentes, Juan Luis; Karumbaiah, Lohitash; Jakka, Siva Rama Krishna; Ning, Changming; Liu, Chenxi; Wu, Kongming; Jackson, Jerreme; Gould, Fred; Blanco, Carlos; Portilla, Maribel; Perera, Omaththage; Adang, Michael

    2011-01-01

    Development of insect resistance is one of the main concerns with the use of transgenic crops expressing Cry toxins from the bacterium Bacillus thuringiensis. Identification of biomarkers would assist in the development of sensitive DNA-based methods to monitor evolution of resistance to Bt toxins in natural populations. We report on the proteomic and genomic detection of reduced levels of midgut membrane-bound alkaline phosphatase (mALP) as a common feature in strains of Cry-resistant Heliothis virescens, Helicoverpa armigera and Spodoptera frugiperda when compared to susceptible larvae. Reduced levels of H. virescens mALP protein (HvmALP) were detected by two dimensional differential in-gel electrophoresis (2D-DIGE) analysis in Cry-resistant compared to susceptible larvae, further supported by alkaline phosphatase activity assays and Western blotting. Through quantitative real-time polymerase chain reaction (qRT-PCR) we demonstrate that the reduction in HvmALP protein levels in resistant larvae are the result of reduced transcript amounts. Similar reductions in ALP activity and mALP transcript levels were also detected for a Cry1Ac-resistant strain of H. armigera and field-derived strains of S. frugiperda resistant to Cry1Fa. Considering the unique resistance and cross-resistance phenotypes of the insect strains used in this work, our data suggest that reduced mALP expression should be targeted for development of effective biomarkers for resistance to Cry toxins in lepidopteran pests. PMID:21390253

  7. Pollen-mediated gene flow from transgenic cotton under greenhouse conditions is dependent on different pollinators.

    PubMed

    Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Li, Zhen; Shelton, Anthony M; Luo, Junyu; Cui, Jinjie; Zhang, Qingwen; Liu, Xiaoxia

    2015-01-01

    With the large-scale release of genetically modified (GM) crops, there are ecological concerns on transgene movement from GM crops to non-GM counterparts and wild relatives. In this research, we conducted greenhouse experiments to measure pollen-mediated gene flow (PGF) in the absence and presence of pollinators (Bombus ignitus, Apis mellifera and Pieris rapae) in one GM cotton (resistant to the insect Helicoverpa armigera and the herbicide glyphosate) and two non-GM lines (Shiyuan321 and Hai7124) during 2012 and 2013. Our results revealed that: (1) PGF varied depending on the pollinator species, and was highest with B. ignitus (10.83%) and lowest with P. rapae (2.71%); (2) PGF with B. ignitus depended on the distance between GM and non-GM cottons; (3) total PGF to Shiyuan321 (8.61%) was higher than to Hai7124 (4.10%). To confirm gene flow, we tested hybrids carrying transgenes for their resistance to glyphosate and H. armigera, and most hybrids showed strong resistance to the herbicide and insect. Our research confirmed that PGF depended on pollinator species, distance between plants and the receptor plant. PMID:26525573

  8. Pollen-mediated gene flow from transgenic cotton under greenhouse conditions is dependent on different pollinators

    PubMed Central

    Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Li, Zhen; Shelton, Anthony M.; Luo, Junyu; Cui, Jinjie; Zhang, Qingwen; Liu, Xiaoxia

    2015-01-01

    With the large-scale release of genetically modified (GM) crops, there are ecological concerns on transgene movement from GM crops to non-GM counterparts and wild relatives. In this research, we conducted greenhouse experiments to measure pollen-mediated gene flow (PGF) in the absence and presence of pollinators (Bombus ignitus, Apis mellifera and Pieris rapae) in one GM cotton (resistant to the insect Helicoverpa armigera and the herbicide glyphosate) and two non-GM lines (Shiyuan321 and Hai7124) during 2012 and 2013. Our results revealed that: (1) PGF varied depending on the pollinator species, and was highest with B. ignitus (10.83%) and lowest with P. rapae (2.71%); (2) PGF with B. ignitus depended on the distance between GM and non-GM cottons; (3) total PGF to Shiyuan321 (8.61%) was higher than to Hai7124 (4.10%). To confirm gene flow, we tested hybrids carrying transgenes for their resistance to glyphosate and H. armigera, and most hybrids showed strong resistance to the herbicide and insect. Our research confirmed that PGF depended on pollinator species, distance between plants and the receptor plant. PMID:26525573

  9. Dominant resistance to Bt cotton and minor cross-resistance to Bt toxin Cry2Ab in cotton bollworm from China

    PubMed Central

    Jin, Lin; Wei, Yiyun; Zhang, Lei; Yang, Yihua; Tabashnik, Bruce E; Wu, Yidong

    2013-01-01

    Evolution of resistance by insect pests threatens the long-term benefits of transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt). Previous work has detected increases in the frequency of resistance to Bt toxin Cry1Ac in populations of cotton bollworm, Helicoverpa armigera, from northern China where Bt cotton producing Cry1Ac has been grown extensively for more than a decade. Confirming that trend, we report evidence from 2011 showing that the percentage of individuals resistant to a diagnostic concentration of Cry1Ac was significantly higher in two populations from different provinces of northern China (1.4% and 2.3%) compared with previously tested susceptible field populations (0%). We isolated two resistant strains: one from each of the two field-selected populations. Relative to a susceptible strain, the two strains had 460- and 1200-fold resistance to Cry1Ac, respectively. Both strains had dominant resistance to a diagnostic concentration of Cry1Ac in diet and to Bt cotton leaves containing Cry1Ac. Both strains had low, but significant cross-resistance to Cry2Ab (4.2- and 5.9-fold), which is used widely as the second toxin in two-toxin Bt cotton. Compared with resistance in other strains of H. armigera, the resistance in the two strains characterized here may be especially difficult to suppress. PMID:24478804

  10. Insecticidal Pilin Subunit from the Insect Pathogen Xenorhabdus nematophila

    PubMed Central

    Khandelwal, Puneet; Choudhury, Devapriya; Birah, Ajanta; Reddy, M. K.; Gupta, Gorakh Prasad; Banerjee, Nirupama

    2004-01-01

    Xenorhabdus nematophila is an insect pathogen and produces protein toxins which kill the larval host. Previously, we characterized an orally toxic, large, outer membrane-associated protein complex from the culture medium of X. nematophila. Here, we describe the cloning, expression, and characterization of a 17-kDa pilin subunit of X. nematophila isolated from that protein complex. The gene was amplified by PCR, cloned, and expressed in Escherichia coli. The recombinant protein was refolded in vitro in the absence of its cognate chaperone by using a urea gradient. The protein oligomerized during in vitro refolding, forming multimers. Point mutations in the conserved N-terminal residues of the pilin protein greatly destabilized its oligomeric organization, demonstrating the importance of the N terminus in refolding and oligomerization of the pilin subunit by donor strand complementation. The recombinant protein was cytotoxic to cultured Helicoverpa armigera larval hemocytes, causing agglutination and subsequent release of the cytoplasmic enzyme lactate dehydrogenase. The agglutination of larval cells by the 17-kDa protein was inhibited by several sugar derivatives. The biological activity of the purified recombinant protein indicated that it has a conformation similar to that of the native protein. The 17-kDa pilin subunit was found to be orally toxic to fourth- or fifth-instar larvae of an important crop pest, H. armigera, causing extensive damage to the midgut epithelial membrane. To our knowledge, this is first report describing an insecticidal pilin subunit of a bacterium. PMID:15375127

  11. Expansion of a bitter taste receptor family in a polyphagous insect herbivore

    PubMed Central

    Xu, Wei; Papanicolaou, Alexie; Zhang, Hui-Jie; Anderson, Alisha

    2016-01-01

    The Insect taste system plays a central role in feeding behaviours and co-evolution of insect-host interactions. Gustatory receptors form the interface between the insect taste system and the environment. From genome and transcriptome sequencing we identified 197 novel gustatory receptor (GR) genes from the polyphagous pest Helicoverpa armigera. These GRs include a significantly expanded bitter receptor family (180 GRs) that could be further divided into three categories based on polypeptide lengths, gene structure and amino acid sequence. Type 1 includes 29 bitter Gr genes that possess introns. Type 2 includes 13 long intronless bitter Gr genes, while Type 3 comprises 131 short intronless bitter Gr genes. Calcium imaging analysis demonstrated that three Type 3 GRs (HarmGR35, HarmGR50 and HarmGR195) can be activated by a crude extract of cotton leaves. HarmGR195, a GR specifically and selectively expressed in adult tarsi, showed a specific response to proline, an amino acid widely present in plant tissues. We hypothesise that the expansion in the H. armigera GR family may be functionally tied to its polyphagous behavior. Understanding the molecular basis of polyphagy may provide opportunities for the development of new environmentally friendly pest control strategies. PMID:27032373

  12. G-protein-coupled receptor participates in 20-hydroxyecdysone signaling on the plasma membrane

    PubMed Central

    2014-01-01

    Background Animal steroid hormones are conventionally known to initiate signaling via a genomic pathway by binding to the nuclear receptors. The mechanism by which 20E initiates signaling via a nongenomic pathway is unclear. Results We illustrate that 20E triggered the nongenomic pathway through a plasma membrane G-protein-coupled receptor (named ErGPCR) in the lepidopteran insect Helicoverpa armigera. The transcript of ErGPCR was increased at the larval molting stage and metamorphic molting stage by 20E regulation. Knockdown of ErGPCR via RNA interference in vivo blocked larval–pupal transition and suppressed 20E-induced gene expression. ErGPCR overexpression in the H. armigera epidermal cell line increased the 20E-induced gene expression. Through ErGPCR, 20E modulated Calponin nuclear translocation and phosphorylation, and induced a rapid increase in cytosolic Ca2+ levels. The inhibitors of T-type voltage-gated calcium channels and canonical transient receptor potential calcium channels repressed the 20E-induced Ca2+ increase. Truncation of the N-terminal extracellular region of ErGPCR inhibited its localization on the plasma membrane and 20E-induced gene expression. ErGPCR was not detected to bind with the steroid hormone analog [3H]Pon A. Conclusion These results suggest that ErGPCR participates in 20E signaling on the plasma membrane. PMID:24507557

  13. The characterization of microsporidian isolates (Nosematidae: Nosema) from five important lepidopteran pests in Taiwan.

    PubMed

    Tsai, Shu-Jen; Lo, Chu-Fang; Soichi, Yamane; Wang, Chung-Hsiung

    2003-05-01

    Microsporidian isolates from five lepidopteran pests-Spodoptera litura, Spodoptera exigua, Helicoverpa armigera, Plutella xylostella, and Pieris spp.-were compared by spore morphology, infectivity to S. litura, Western-blot banding patterns, the sequences of small subunit rRNA gene (SSUrRNA sequence), and random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). All the isolates could infect experimentally and multiply in the larvae of S. litura. The S. exigua isolate showed the highest virulence to the larvae of S. litura while the P. xylostella isolate showed the lowest. No significant differences either in spore morphology or in SSUrRNA sequences of these isolates were found. The SSUrRNA sequences of these isolates confirmed they are members of the genus Nosema. Based on the result of Western-blot hybridization with the rabbit anti-Nosema spodopterae spore antiserum, three serotypes could be distinguished: N. spodopterae (S. litura isolate) and Pi. spp. isolate; S. exigua and H. armigera isolates; and P. xylostella isolate. The amplicons of RAPD-PCR with 60 primers yielded clear patterns that were selected and used for identification and also for phylogenic analysis of these five isolates. Based on analysis by the computer, isolates could be clearly divided into three groups that were coincident with the serotypes; therefore we suggest that N. spodopterae and isolates of Pi. spp., S. exigua, and H. armigera are more closely related in phylogenesis. In addition, in the amplification with the Nosema bombycis specific primer set, only DNAs from P. xylostella isolate and N. bombycis yielded amplicons. Therefore, we suggest that four isolates, excluding the P. xylostella isolate, are N. spodopterae, and the taxonomic position of P. xylostella isolate needs to be elucidated. PMID:12725812

  14. Pheromone Lure and Trap Color Affects Bycatch in Agricultural Landscapes of Utah.

    PubMed

    Spears, Lori R; Looney, Chris; Ikerd, Harold; Koch, Jonathan B; Griswold, Terry; Strange, James P; Ramirez, Ricardo A

    2016-08-01

    Aerial traps, using combinations of color and attractive lures, are a critical tool for detecting and managing insect pest populations. Yet, despite improvements in trap efficacy, collection of nontarget species ("bycatch") plagues many insect pest surveys. Bycatch can influence survey effectiveness by reducing the available space for target species and increasing trap screening time, especially in areas where thousands of insects are captured as bycatch in a given season. Additionally, bycatch may negatively impact local nontarget insect populations, including beneficial predators and pollinators. Here, we tested the effect of pheromone lures on bycatch rates of Coccinellidae (Coleoptera), Apoidea (Hymenoptera), and nontarget Lepidoptera. Multicolored (primarily yellow and white) bucket traps containing a pheromone lure for capturing one of three survey target species, Spodoptera litura (F.), S. littoralis (Boisduval), or Helicoverpa armigera (Hübner), were placed in alfalfa and corn fields, and compared to multicolored traps without a pheromone lure. All-green traps with and without H. armigera lures were employed in a parallel study investigating the effect of lure and trap color on bycatch. Over 2,600 Coccinellidae representing seven species, nearly 6,400 bees in 57 species, and >9,000 nontarget moths in 17 genera were captured across 180 traps and seven temporal sampling events. Significant effects of lure and color were observed for multiple taxa. In general, nontarget insects were attracted to the H. armigera lure and multicolored trap, but further studies of trap color and pheromone lure specificity are needed to better understand these interactions and to minimize nontarget captures. PMID:27412193

  15. Binding Sites for Bacillus thuringiensis Cry2Ae Toxin on Heliothine Brush Border Membrane Vesicles Are Not Shared with Cry1A, Cry1F, or Vip3A Toxin ▿

    PubMed Central

    Gouffon, C.; Van Vliet, A.; Van Rie, J.; Jansens, S.; Jurat-Fuentes, J. L.

    2011-01-01

    The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane vesicles (BBMV) prepared from the target insect larvae. In this paper, we report on the specific binding of Cry2Ae toxin to binding sites on BBMV from larvae of the three most commercially relevant heliothine species, Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Using chromatographic purification under reducing conditions before labeling, we detected specific binding of radiolabeled Cry2Ae, which allowed us to perform competition assays using Cry1Ab, Cry1Ac, Cry1Fa, Vip3A, Cry2Ae, and Cry2Ab toxins as competitors. In these assays, Cry2Ae binding sites were shared with Cry2Ab but not with the tested Cry1 or Vip3A toxins. Our data support the use of Cry2Ae toxin in combination with Cry1 or Vip3A toxins in strategies to increase target range and delay the onset of heliothine resistance. PMID:21441333

  16. Comparative studies on the effects of Bt-transgenic and nontransgenic cotton on arthropod diversity, seedcotton yield and bollworms control.

    PubMed

    Dhillon, M K; Sharma, H C

    2013-01-01

    The effectiveness of commercial Bt-cotton in pest management, influence on arthropod diversity, natural enemies, and toxin flow in the insect fauna under field conditions were studied keeping in view the need to assess bioefficacy and biosafety of Bt-transgenic cotton. There were no significant differences in oviposition by Helicoverpa armigera on Bt-transgenic and non-transgenic cottons (9.2 versus 9.6 eggs plants(-100)), while the numbers of H. armigera larvae were significantly more on non-transgenic than on Bt-transgenic (10.4 versus 4.0 larvae plants(-100)) cotton. The Bt-cotton had significantly more number of mature opened bolls (9.6 versus 4.4 bolls plant(-1)), lower bollworm damage (12.8 versus 40.2% bolls damaged), and higher seedcotton yield (667.7 versus 231.7 kg ha