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Yuan C, Xing L, Wang M, Hu Z, Zou Z. Microbiota modulates gut immunity and promotes baculovirus infection in Helicoverpa armigera. INSECT SCIENCE 2021; 28:1766-1779. [PMID: 33463036 DOI: 10.1111/1744-7917.12894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/07/2020] [Accepted: 11/29/2020] [Indexed: 06/12/2023]
Abstract
Baculoviruses are natural enemies of agricultural and forest insect pests and play an important role in biological pest control. Oral infection by baculovirus in the insect midgut is necessary for establishing systemic infection and eventually killing the insect. Since the insect midgut continuously encounters microbiota, the gut microbiota could affect baculovirus infection. Here, we demonstrated that gut microbiota modulates immune responses and promotes baculovirus infection in the cotton bollworm, Helicoverpa armigera. After oral infection, numerous host immunity-related genes including genes encoding Toll and immune deficiency (IMD) pathway components were upregulated in the midgut. Elimination of the gut microbiota significantly increased the resistance to viral infection in H. armigera. Quantitative real-time reverse transcription polymerase chain reaction and proteomic analysis showed that downregulation of the antiviral factor prophenoloxidase (PPO) could be mediated by microbiota during infection. It implied that midgut microbiota diminishes the expression of PPO to facilitate viral infection in H. armigera. Our findings revealed that the microbiota plays an important role in modulating the resistance of H. armigera to baculovirus infection, providing new insights in applying biopesticide.
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Affiliation(s)
- Chuanfei Yuan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Tropical Translational Medicine of Ministry of Education, NHC Key Laboratory of Control of Tropical Diseases, School of Tropical Medicine and Laboratory Medicine, Hainan Medical University, Haikou, 571199, China
| | - Longsheng Xing
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, 100049, China
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Boogaard B, Evers F, van Lent JWM, van Oers MM. The baculovirus Ac108 protein is a per os infectivity factor and a component of the ODV entry complex. J Gen Virol 2019; 100:669-678. [DOI: 10.1099/jgv.0.001200] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Bob Boogaard
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Felix Evers
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jan W. M. van Lent
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Monique M. van Oers
- Laboratory of Virology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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Liu Z, Wang X, Dai Y, Wei X, Ni M, Zhang L, Zhu Z. Expressing Double-Stranded RNAs of Insect Hormone-Related Genes Enhances Baculovirus Insecticidal Activity. Int J Mol Sci 2019; 20:E419. [PMID: 30669419 PMCID: PMC6359566 DOI: 10.3390/ijms20020419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 12/16/2022] Open
Abstract
Baculoviruses have already been used for insect pest control, but the slow killing speed limits their further promotion and application. Here we provide a strategy for improving baculovirus insecticidal activity using Helicoverpa armigera nucleopolyhedrovirus (HearNPV) to express double-stranded RNAs (dsRNAs) targeting cotton bollworm (Helicoverpa armigera) juvenile hormone (JH)-related genes. Droplet-feeding bioassays show that the 50% lethal concentration (LC50) values of recombinant baculoviruses expressing the dsRNA of JH acid methyl transferase gene (HaJHAMT) and the JH acid binding protein gene (HaJHBP) were 1.24 × 10⁴ polyhedral inclusion bodies (PIB)/mL and 2.26 × 10⁴ PIB/mL, respectively. Both were much lower than the control value (8.12 × 10⁴ PIB/mL). Meanwhile, the LT50 of recombinant baculovirus expressing dsRNA of HaJHBP was only 54.2% of the control value, which means that larval death was accelerated. Furthermore, the mRNA level of target genes was reduced in recombinant baculovirus-treated cotton bollworm larvae. Transcription of several key genes involved in hormone signaling pathways-for example, ecdysone receptor gene (HaEcR)-was also altered. This study establishes a new strategy for pest management by interfering with insect hormone-related gene expression via baculoviruses, and the engineered baculoviruses have great potential application in cotton production.
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Affiliation(s)
- Zheming Liu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xiaofang Wang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yan Dai
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xiaoli Wei
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
| | - Mi Ni
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
| | - Lei Zhang
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
| | - Zhen Zhu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.
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Inhibition of melanization by serpin-5 and serpin-9 promotes baculovirus infection in cotton bollworm Helicoverpa armigera. PLoS Pathog 2017; 13:e1006645. [PMID: 28953952 PMCID: PMC5633200 DOI: 10.1371/journal.ppat.1006645] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 10/09/2017] [Accepted: 09/12/2017] [Indexed: 12/13/2022] Open
Abstract
Melanization, an important insect defense mechanism, is mediated by clip-domain serine protease (cSP) cascades and is regulated by serpins. Here we show that proteolytic activation of prophenoloxidase (PPO) and PO-catalyzed melanization kill the baculovirus in vitro. Our quantitative proteomics and biochemical experiments revealed that baculovirus infection of the cotton bollworm, Helicoverpa armigera, reduced levels of most cascade members in the host hemolymph and PO activity. By contrast, serpin-9 and serpin-5 were sequentially upregulated after the viral infection. The H. armigera serpin-5 and serpin-9 regulate melanization by directly inhibiting their target proteases cSP4 and cSP6, respectively and cSP6 activates PPO purified from hemolymph. Furthermore, serpin-5/9-depleted insects exhibited high PO activities and showed resistance to baculovirus infection. Together, our results characterize a part of the melanization cascade in H. armigera, and suggest that natural insect virus baculovirus has evolved a distinct strategy to suppress the host immune system. Melanization is one of important modules in insect defense system. It consists of a cascade of clip-domain serine proteases (cSPs) that converts the zymogen prophenoloxidase (PPO) to active phenoloxidase (PO), which is negatively regulated by serpins. PO then catalyses the formation of melanin that physically encapsulates certain pathogens. Parasites and bacteria have evolved to produce specific proteins or antibiotic to suppress the melanization response of host insects for survival. However, the mechanisms by which virus persists in the face of the insect melanization are poorly understood. In this study, we show that a DNA virus baculovirus infection of the cotton bollworm, Helicoverpa armigera, reduced the levels of most cascade members in the host hemolymph and PO activity. By contrast, serpin-9 and serpin-5 were sequentially upregulated after the viral infection. Our results also reveal that melanization kills baculovirus in vitro. Serpin-5 and serpin-9 regulate melanization by directly inhibiting their target proteases cSP4 and cSP6, respectively and cSP6 activates PPO purified from hemolymph. Moreover, serpin-5/9-depleted insects show resistance to baculovirus infection. Our findings have enriched the understanding of molecular mechanisms by which pathogens suppress the melanization response of host insect for survival.
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Xing L, Yuan C, Wang M, Lin Z, Shen B, Hu Z, Zou Z. Dynamics of the Interaction between Cotton Bollworm Helicoverpa armigera and Nucleopolyhedrovirus as Revealed by Integrated Transcriptomic and Proteomic Analyses. Mol Cell Proteomics 2017; 16:1009-1028. [PMID: 28404795 DOI: 10.1074/mcp.m116.062547] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 03/17/2017] [Indexed: 01/23/2023] Open
Abstract
Over the past decades, Helicoverpa armigera nucleopolyhedrovirus (HearNPV) has been widely used for biocontrol of cotton bollworm, which is one of the most destructive pest insects in agriculture worldwide. However, the molecular mechanism underlying the interaction between HearNPV and host insects remains poorly understood. In this study, high-throughput RNA-sequencing was integrated with label-free quantitative proteomics analysis to examine the dynamics of gene expression in the fat body of H. armigera larvae in response to challenge with HearNPV. RNA sequencing-based transcriptomic analysis indicated that host gene expression was substantially altered, yielding 3,850 differentially expressed genes (DEGs), whereas no global transcriptional shut-off effects were observed in the fat body. Among the DEGs, 60 immunity-related genes were down-regulated after baculovirus infection, a finding that was consistent with the results of quantitative real-time RT-PCR. Gene ontology and functional classification demonstrated that the majority of down-regulated genes were enriched in gene cohorts involved in energy, carbohydrate, and amino acid metabolic pathways. Proteomics analysis identified differentially expressed proteins in the fat body, among which 76 were up-regulated, whereas 373 were significantly down-regulated upon infection. The down-regulated proteins are involved in metabolic pathways such as energy metabolism, carbohydrate metabolism (CM), and amino acid metabolism, in agreement with the RNA-sequence data. Furthermore, correlation analysis suggested a strong association between the mRNA level and protein abundance in the H. armigera fat body. More importantly, the predicted gene interaction network indicated that a large subset of metabolic networks was significantly negatively regulated by viral infection, including CM-related enzymes such as aldolase, enolase, malate dehydrogenase, and triose-phosphate isomerase. Taken together, transcriptomic data combined with proteomic data elucidated that baculovirus established systemic infection of host larvae and manipulated the host mainly by suppressing the host immune response and down-regulating metabolism to allow viral self-replication and proliferation. Therefore, this study provided important insights into the mechanism of host-baculovirus interaction.
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Affiliation(s)
- Longsheng Xing
- From the ‡State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101.,§University of Chinese Academy of Sciences, Beijing 100049
| | - Chuanfei Yuan
- §University of Chinese Academy of Sciences, Beijing 100049.,¶State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071; and
| | - Manli Wang
- ¶State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071; and
| | - Zhe Lin
- From the ‡State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101
| | - Benchang Shen
- ‖Guangzhou Medical University, Guangzhou 510182, China
| | - Zhihong Hu
- ¶State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071; and
| | - Zhen Zou
- From the ‡State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101; .,§University of Chinese Academy of Sciences, Beijing 100049
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The Autographa californica multiple nucleopolyhedrovirus ac110 gene encodes a new per os infectivity factor. Virus Res 2016; 221:30-7. [DOI: 10.1016/j.virusres.2016.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 05/17/2016] [Accepted: 05/18/2016] [Indexed: 11/21/2022]
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7
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Yin F, Du R, Kuang W, Yang G, Wang H, Deng F, Hu Z, Wang M. Characterization of the viral fibroblast growth factor homolog of Helicoverpa armigera single nucleopolyhedrovirus. Virol Sin 2016; 31:240-8. [PMID: 27142667 DOI: 10.1007/s12250-016-3710-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 04/07/2016] [Indexed: 10/21/2022] Open
Abstract
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.
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Affiliation(s)
- Feifei Yin
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.,School of Tropical and Laboratory Medicine, Hainan Medical University, Haikou, 571101, China
| | - Ruikun Du
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Wenhua Kuang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Guang Yang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Hualin Wang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Fei Deng
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhihong Hu
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Manli Wang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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8
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Du R, Yin F, Wang M, Hu Z, Wang H, Deng F. Glycoprotein E of the Japanese encephalitis virus forms virus-like particles and induces syncytia when expressed by a baculovirus. J Gen Virol 2015; 96:1006-1014. [PMID: 25593161 DOI: 10.1099/vir.0.000052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 01/07/2015] [Indexed: 11/18/2022] Open
Abstract
The prM glycoprotein is thought to be a chaperone for the proper folding, membrane association and assembly of the envelope protein (E) of flaviviruses. The prM-E and E proteins of the Japanese encephalitis virus (JEV) were expressed in insect cells using both the baculovirus-expression system and the transient expression method. Protein expression was analysed by Western blotting and the cytopathic effect was observed by microscopy. In the baculovirus-expression system the E protein, with or without the prM protein, induced syncytial formation in Sf9 cells. Transient expression of prM-E also induced syncytia in Sf9 cells. Immunofluorescence revealed that in presence of prM, E proteins were endoplasmic reticulum-like in distribution, while in the absence of prM, E proteins were located on the cell surface. Sucrose gradient sedimentation and Western blot analysis indicated that the E protein expressed with or without the prM protein was secreted into the culture medium in particulate form. The formation of virus-like particles (VLPs) in the medium was confirmed by electron microscopy and immunoelectron microscopy. The results suggest that the E protein of JEV in the absence of prM, retained its fusion ability, by either cell surface expression or formation of VLPs. Moreover, based on the observation that co-expression of prM-E in Sf9 cells induced considerable syncytial formation, a novel, safe and simple antiviral screening approach is proposed for studying inhibitory antibodies, peptides or small molecules targeting the JEV E protein.
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Affiliation(s)
- Ruikun Du
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Feifei Yin
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
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Zhu Z, Yin F, Liu X, Hou D, Wang J, Zhang L, Arif B, Wang H, Deng F, Hu Z. Genome sequence and analysis of Buzura suppressaria nucleopolyhedrovirus: a group II Alphabaculovirus. PLoS One 2014; 9:e86450. [PMID: 24475121 PMCID: PMC3901692 DOI: 10.1371/journal.pone.0086450] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 12/10/2013] [Indexed: 12/15/2022] Open
Abstract
The genome of Buzura suppressaria nucleopolyhedrovirus (BusuNPV) was sequenced by 454 pyrosequencing technology. The size of the genome is 120,420 bp with 36.8% G+C content. It contains 127 hypothetical open reading frames (ORFs) covering 90.7% of the genome and includes the 37 conserved baculovirus core genes, 84 genes found in other baculoviruses, and 6 unique ORFs. No typical baculoviral homologous repeats (hrs) were present but the genome contained a region of repeated sequences. Gene Parity Plots revealed a 28.8 kb region conserved among the alpha- and beta-baculoviruses. Overall comparisons of BusuNPV to other baculoviruses point to a distinct species in group II Alphabaculovirus.
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Affiliation(s)
- Zheng Zhu
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Feifei Yin
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoping Liu
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Dianhai Hou
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jun Wang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Lei Zhang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Basil Arif
- Canadian Forest Service, Great Lakes Forestry Centre, Sault Ste Marie, Ontario, Canada
| | - Hualin Wang
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Fei Deng
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Zhihong Hu
- State Key Laboratory of Virology and China Center for Virus Culture Collection, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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Tang Q, Li G, Yao Q, Chen L, Lv P, Lian C, Chen K. Bm91 is an envelope component of ODV but is dispensable for the propagation of Bombyx mori nucleopolyhedrovirus. J Invertebr Pathol 2013; 113:70-7. [PMID: 23391406 DOI: 10.1016/j.jip.2013.01.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 01/06/2013] [Accepted: 01/14/2013] [Indexed: 10/27/2022]
Abstract
Orf91 (Bm91) of Bombyx mori nucleopolyhedrovirus (BmNPV) is a highly conserved gene that encodes a predicted 105-amino-acid protein, but its function remains unknown. In the current study, 5'-RACE revealed that the transcription initiation site of Bm91 was - 12 nucleotides upstream of the start codon ATG, transcription of Bm91 was detected from 12 to 96 h postinfection (p.i.) and Bm91 protein was detected from 24 to 96 h p.i. in BmNPV-infected BmN cells. Furthermore, Western blot analysis revealed that Bm91 was in occlusion-derived virus (ODV) but not in budded virus (BV). To investigate the role of Bm91 in baculovirus life cycle, a Bm91-knockout virus was constructed by bacmid recombination in E. coli. Fluorescence and light microscopy showed that the production of BV and occlusion bodies (OBs) in Bm91-deficient-virus-infected BmN cells were similar to those in wild-type-virus-infected ones. Bioassay results showed that genetic deletion of Bm91 did not significantly affect BmNPV infectivity, but extended the median lethal time (LT50). Taken together, these results indicate that Bm91 is not essential for viral propagation in vitro, but absence of the gene may affect the virulence of ODVs in silkworm larvae.
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Affiliation(s)
- Qi Tang
- School of Food and Biological Engineering, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
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11
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Chen Y, Zheng F, Tao L, Zheng Z, Liu Y, Wang H. Helicoverpa armaigera nucleopolyhedrovirus ORF50 is an early gene not essential for virus propagation in vitro and in vivo. Virus Genes 2012; 45:149-60. [PMID: 22581445 DOI: 10.1007/s11262-012-0754-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/27/2012] [Indexed: 11/29/2022]
Abstract
Homologs of Helicoverpa armigera nucleopolyhedrovirus ORF50 (HA50) are found in most alphabaculoviruses, but their functions remain unknown. Here, we characterized whether Ha50 is indispensable for virus progration. Ha50 transcript was first detected at 3 h post-infection from HearNPV-infected HzAM1 cells. 3'RACE analysis showed that Ha50 transcript was polyadenlylated. 5'RACE analysis revealed two transcription initiation sites, one of which was mapped to the canonical baculovirus early transcription initiator motif CAGT. HA50 protein could be detected from infected cells harvested at 12 h post-infection. Transient expression assays showed that GFP-fused HA50 localized in the cytoplasm and nucleus of HzAM1 cells with or without superinfection. To further examine the role of Ha50 in the virus life cycle, a Ha50 knockout bacmid and a repair bacmid carrying Ha50 under the control of its native promoter elements were constructed using bacmid technology. One-step growth curve analysis showed that the kinetics of infectious budded virus production of Ha50 knockout virus was similar to that of the parental virus or the repair virus. Analysis of the expression of viral early protein IE-1, late protein VP39 and very late protein suggested that viral protein expression was not affected by Ha50 inactivation. Electron microscopy revealed that HaBacΔ50-PH-G occluded viruses (ODVs) and occlusion bodies were indistinguishable from those of the wild-type virus. Similarly, bioassays showed no significant difference in the LC(50) values between Ha50 deletion virus and wild-type virus. Our results together demonstrate that Ha50 is an early gene dispensable for virus propagation in vitro and in vivo.
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Affiliation(s)
- Yao Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Xiaohongshan No 44, Wuhan 430071, People's Republic of China
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Simón O, Palma L, Williams T, López-Ferber M, Caballero P. Analysis of a naturally-occurring deletion mutant of Spodoptera frugiperda multiple nucleopolyhedrovirus reveals sf58 as a new per os infectivity factor of lepidopteran-infecting baculoviruses. J Invertebr Pathol 2012; 109:117-26. [PMID: 22041202 DOI: 10.1016/j.jip.2011.10.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 10/13/2011] [Accepted: 10/17/2011] [Indexed: 11/19/2022]
Affiliation(s)
- Oihane Simón
- Instituto de Agrobiotecnología, CSIC, Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain
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