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Suppression of Chitin-Triggered Immunity by a New Fungal Chitin-Binding Effector Resulting from Alternative Splicing of a Chitin Deacetylase Gene. J Fungi (Basel) 2022; 8:jof8101022. [PMID: 36294587 PMCID: PMC9605236 DOI: 10.3390/jof8101022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/24/2022] [Accepted: 09/25/2022] [Indexed: 11/16/2022] Open
Abstract
Phytopathogenic fungi have evolved mechanisms to manipulate plant defences, such as chitin-triggered immunity, a plant defensive response based on the recognition of chitin oligomers by plant-specific receptors. To cope with chitin resistance, fungal pathogens have developed different strategies to prevent chitin recognition, such as binding, breaking, or modifying immunogenic oligomers. In powdery mildew fungi, the activity of chitin deacetylase (CDA) is crucial for this purpose, since silencing of the CDA gene leads to a rapid activation of chitin signalling and the subsequent suppression of fungal growth. In this work, we have identified an unusually short CDA transcript in Podosphaera xanthii, the cucurbit powdery mildew pathogen. This transcript, designated PxCDA3, appears to encode a truncated version of CDA resulting from an alternative splicing of the PxCDA gene, which lacked most of the chitin deacetylase activity domain but retained the carbohydrate-binding module. Experiments with the recombinant protein showed its ability to bind to chitin oligomers and prevent the activation of chitin signalling. Furthermore, the use of fluorescent fusion proteins allowed its localization in plant papillae at pathogen penetration sites. Our results suggest the occurrence of a new fungal chitin-binding effector, designated CHBE, involved in the manipulation of chitin-triggered immunity in powdery mildew fungi.
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Ismail S, Aboutabl M, Fayed B. Investigation of chitosan, its depolymerized products, and nanoformulation as novel anticonvulsants. EGYPTIAN PHARMACEUTICAL JOURNAL 2022. [DOI: 10.4103/epj.epj_58_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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3
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Mart Nez-Cruz JS, Romero D, Hierrezuelo JS, Thon M, de Vicente A, P Rez-Garc A A. Effectors with chitinase activity (EWCAs), a family of conserved, secreted fungal chitinases that suppress chitin-triggered immunity. THE PLANT CELL 2021; 33:1319-1340. [PMID: 33793825 DOI: 10.1093/plcell/koab011] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 12/11/2020] [Indexed: 05/23/2023]
Abstract
In plants, chitin-triggered immunity is one of the first lines of defense against fungi, but phytopathogenic fungi have developed different strategies to prevent the recognition of chitin. Obligate biotrophs such as powdery mildew fungi suppress the activation of host responses; however, little is known about how these fungi subvert the immunity elicited by chitin. During epiphytic growth, the cucurbit powdery mildew fungus Podosphaera xanthii expresses a family of candidate effector genes comprising nine members with an unknown function. In this work, we examine the role of these candidates in the infection of melon (Cucumis melo L.) plants, using gene expression analysis, RNAi silencing assays, protein modeling and protein-ligand predictions, enzymatic assays, and protein localization studies. Our results show that these proteins are chitinases that are released at pathogen penetration sites to break down immunogenic chitin oligomers, thus preventing the activation of chitin-triggered immunity. In addition, these effectors, designated effectors with chitinase activity (EWCAs), are widely distributed in pathogenic fungi. Our findings reveal a mechanism by which fungi suppress plant immunity and reinforce the idea that preventing the perception of chitin by the host is mandatory for survival and development of fungi in plant environments.
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Affiliation(s)
- Jes S Mart Nez-Cruz
- Departamento de Microbiolog�a, Facultad de Ciencias, Universidad de M�laga, M�laga 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterr�nea "La Mayora", Universidad de M�laga, Consejo Superior de Investigaciones Cient�ficas (IHSM‒UMA‒CSIC), M�laga 29071, Spain
| | - Diego Romero
- Departamento de Microbiolog�a, Facultad de Ciencias, Universidad de M�laga, M�laga 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterr�nea "La Mayora", Universidad de M�laga, Consejo Superior de Investigaciones Cient�ficas (IHSM‒UMA‒CSIC), M�laga 29071, Spain
| | - Jes S Hierrezuelo
- Departamento de Microbiolog�a, Facultad de Ciencias, Universidad de M�laga, M�laga 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterr�nea "La Mayora", Universidad de M�laga, Consejo Superior de Investigaciones Cient�ficas (IHSM‒UMA‒CSIC), M�laga 29071, Spain
| | - Michael Thon
- Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Universidad de Salamanca, Salamanca 37185, Spain
| | - Antonio de Vicente
- Departamento de Microbiolog�a, Facultad de Ciencias, Universidad de M�laga, M�laga 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterr�nea "La Mayora", Universidad de M�laga, Consejo Superior de Investigaciones Cient�ficas (IHSM‒UMA‒CSIC), M�laga 29071, Spain
| | - Alejandro P Rez-Garc A
- Departamento de Microbiolog�a, Facultad de Ciencias, Universidad de M�laga, M�laga 29071, Spain
- Instituto de Hortofruticultura Subtropical y Mediterr�nea "La Mayora", Universidad de M�laga, Consejo Superior de Investigaciones Cient�ficas (IHSM‒UMA‒CSIC), M�laga 29071, Spain
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Polonio Á, Fernández‐Ortuño D, de Vicente A, Pérez‐García A. A haustorial-expressed lytic polysaccharide monooxygenase from the cucurbit powdery mildew pathogen Podosphaera xanthii contributes to the suppression of chitin-triggered immunity. MOLECULAR PLANT PATHOLOGY 2021; 22:580-601. [PMID: 33742545 PMCID: PMC8035642 DOI: 10.1111/mpp.13045] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/04/2021] [Accepted: 02/04/2021] [Indexed: 05/06/2023]
Abstract
Podosphaera xanthii is the main causal agent of cucurbit powdery mildew and a limiting factor of crop productivity. The lifestyle of this fungus is determined by the development of specialized parasitic structures inside epidermal cells, termed haustoria, that are responsible for the acquisition of nutrients and the release of effectors. A typical function of fungal effectors is the manipulation of host immunity, for example the suppression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). Chitin is a major component of fungal cell walls, and chitin oligosaccharides are well-known PAMP elicitors. In this work, we examined the role of PHEC27213, the most highly expressed, haustorium-specific effector candidate of P. xanthii. According to different computational predictions, the protein folding of PHEC27213 was similar to that of lytic polysaccharide monooxygenases (LPMOs) and included a conserved histidine brace; however, PHEC27213 had low sequence similarity with LPMO proteins and displayed a putative chitin-binding domain that was different from the canonical carbohydrate-binding module. Binding and enzymatic assays demonstrated that PHEC27213 was able to bind and catalyse colloidal chitin, as well as chitooligosaccharides, acting as an LPMO. Furthermore, RNAi silencing experiments showed the potential of this protein to prevent the activation of chitin-triggered immunity. Moreover, proteins with similar features were found in other haustorium-forming fungal pathogens. Our results suggest that this protein is a new fungal LPMO that catalyses chitooligosaccharides, thus contributing to the suppression of plant immunity during haustorium development. To our knowledge, this is the first mechanism identified in the haustorium to suppress chitin signalling.
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Affiliation(s)
- Álvaro Polonio
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
| | - Dolores Fernández‐Ortuño
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
| | - Antonio de Vicente
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
| | - Alejandro Pérez‐García
- Departamento de MicrobiologíaFacultad de CienciasUniversidad de MálagaMálagaSpain
- Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’Universidad de MálagaConsejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC)MálagaSpain
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Ismail SA, Hassan ME, Hashem AM. Single step hydrolysis of chitin using thermophilic immobilized exochitinase on carrageenan-guar gum gel beads. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.101281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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6
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Das S, Dey P, Roy D, Maiti MK, Sen R. N-Acetyl-d-glucosamine Production by a Chitinase of Marine Fungal Origin: a Case Study of Potential Industrial Significance for Valorization of Waste Chitins. Appl Biochem Biotechnol 2018; 187:407-423. [DOI: 10.1007/s12010-018-2822-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 06/15/2018] [Indexed: 10/28/2022]
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7
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Ishimwe E, Hodgson JJ, Clem RJ, Passarelli AL. Reaching the melting point: Degradative enzymes and protease inhibitors involved in baculovirus infection and dissemination. Virology 2015; 479-480:637-49. [PMID: 25724418 DOI: 10.1016/j.virol.2015.01.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 01/13/2015] [Accepted: 01/30/2015] [Indexed: 10/24/2022]
Abstract
Baculovirus infection of a host insect involves several steps, beginning with initiation of virus infection in the midgut, followed by dissemination of infection from the midgut to other tissues in the insect, and finally culminating in "melting" or liquefaction of the host, which allows for horizontal spread of infection to other insects. While all of the viral gene products are involved in ultimately reaching this dramatic infection endpoint, this review focuses on two particular types of baculovirus-encoded proteins: degradative enzymes and protease inhibitors. Neither of these types of proteins is commonly found in other virus families, but they both play important roles in baculovirus infection. The types of degradative enzymes and protease inhibitors encoded by baculoviruses are discussed, as are the roles of these proteins in the infection process.
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Affiliation(s)
- Egide Ishimwe
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506-4901, United States
| | - Jeffrey J Hodgson
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506-4901, United States
| | - Rollie J Clem
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506-4901, United States.
| | - A Lorena Passarelli
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506-4901, United States.
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Wang Q, Qu L, Zhang Z, Wang Y, Zhang Y. Characterization of a novel chitinase, DkChi, from Dendrolimus kikuchii nucleopolyhedrovirus. Arch Virol 2013; 158:2523-30. [DOI: 10.1007/s00705-013-1775-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 05/21/2013] [Indexed: 11/24/2022]
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Oh S, Kim DH, Patnaik BB, Jo YH, Noh MY, Lee HJ, Lee KH, Yoon KH, Kim WJ, Noh JY, Jeong HC, Lee YS, Zhang CX, Song YS, Jung WJ, Ko K, Han YS. Molecular and immunohistochemical characterization of the chitinase gene from Pieris rapae granulovirus. Arch Virol 2013; 158:1701-18. [PMID: 23512574 DOI: 10.1007/s00705-013-1649-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 01/24/2013] [Indexed: 11/30/2022]
Abstract
The chitinase gene of baculoviruses is expressed in the late phase of virus replication in insects and possesses high exo- and endochitinase activity, which can hydrolyze chitin in the body of the insect, thus promoting terminal host liquefaction. Alphabaculovirus viral chitinases (vChitA) have been well analyzed, but information regarding viral chitinases from betabaculoviruses is limited. Whole-genome sequencing of a Korean isolate of Pieris rapae GV (PiraGV-K) predicted a putative chitinase gene corresponding to ORF10. The PiraGV-K chitinase gene had a coding sequence of 1,761 bp, encoding a protein of 586 amino acid (aa) residues, including an 18-aa putative signal peptide. Time course induction pattern observed by SDS-PAGE and subsequent Western blot with anti-PiraGV-K chitinase antibody revealed the cleavage of the signal peptide from the intact chitinase. Edman sequencing analysis was further conducted to confirm the exact nature of the mature chitinase, and the N-terminal amino acid sequence (KPGAP) exactly matched the sequence following the signal peptide sequence. The transcriptomics of PiraGV-K chitinase in infected P. rapae larvae, examined by real-time PCR, revealed a significant 75-fold increase after four days of feeding with PiraGV-K-treated leaves, with a subsequent decline at the later stages of infection. Confocal microscopic analysis showed that PiraGV-K chitinase possibly exists as a secreted protein, with strong chitinase-specific signals in fat body cells and integument at four days postinfection. Furthermore, immunogold labeling and electron microscopy studies localized the PiraGV-K chitinase in the cytoplasm and sparsely within vacuolar structures in the fat body apart from the extensive aggregation in the cuticular lining of the integument.
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Affiliation(s)
- Seunghan Oh
- Division of Plant Biotechnology, College of Agriculture and Life Science, Chonnam National University, Gwangju, 500-757, Korea
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10
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Insect-Derived Chitinases. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 136:19-50. [DOI: 10.1007/10_2013_207] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Structural Analysis of Chi1 Chitinase from Yen-Tc: The Multisubunit Insecticidal ABC Toxin Complex of Yersinia entomophaga. J Mol Biol 2012; 415:359-71. [DOI: 10.1016/j.jmb.2011.11.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/03/2011] [Accepted: 11/08/2011] [Indexed: 10/15/2022]
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12
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Young V, Sneddon K, Ward V. Establishment of a neonate cell line from Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) that supports replication of E. postvittana nucleopolyhedrovirus. J Invertebr Pathol 2010; 104:147-9. [DOI: 10.1016/j.jip.2010.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 02/04/2010] [Accepted: 02/12/2010] [Indexed: 11/28/2022]
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Suckling DM, Brockerhoff EG. Invasion biology, ecology, and management of the light brown apple moth (Tortricidae). ANNUAL REVIEW OF ENTOMOLOGY 2010; 55:285-306. [PMID: 19728834 DOI: 10.1146/annurev-ento-112408-085311] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), the light brown apple moth (LBAM), is an important leafroller pest with an exceptionally wide host range that includes many horticultural crops and other woody and herbaceous plants. LBAM is native to southeastern Australia but has invaded Western Australia, New Zealand, Hawaii, much of England, and in 2007, it was confirmed as established in California. The discovery of this pest in California has led to a major detection and regulatory effort because of concerns about economic and environmental impacts. Its recent discovery in Sweden is also of note. LBAM has often been intercepted on imports of fruit and other plant parts, and it has the potential to become a successful invader in temperate and subtropical regions worldwide. The importance of the insect has prompted development of classical biological control programs together with a wide variety of other management interventions that can be used in integrated pest management or integrated pest eradication.
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Affiliation(s)
- D M Suckling
- The New Zealand Institute for Plant & Food Research Limited, Christchurch, New Zealand.
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Daimon T, Katsuma S, Kang WK, Shimada T. Functional characterization of chitinase from Cydia pomonella granulovirus. Arch Virol 2007; 152:1655-64. [PMID: 17557135 DOI: 10.1007/s00705-007-1000-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 04/27/2007] [Indexed: 11/29/2022]
Abstract
Baculovirus chitinases (V-CHIAs) play a crucial role in the terminal liquefaction of virus-infected larvae after death. Although v-chiAs from nucleopolyhedroviruses (NPVs) have been well characterized, little is known about v-chiAs from granuloviruses (GVs). We characterized the v-chiA of Cydia pomonella GV (CpGV) by constructing a recombinant Bombyx mori NPV (BmNPV) in which BmNPV v-chiA was replaced by CpGV v-chiA (103CpGV virus). CpGV v-chiA encoded an approximately 70-kDa chitinase with an exo-type substrate preference. CpGV V-CHIA lacked a C-terminal KDEL endoplasmic reticulum retention motif and was suggested to be a secretory protein. Terminal host liquefaction of B. mori larvae and proper folding of BmNPV-encoded cysteine protease (BmNPV V-CATH) were observed following infection with 103CpGV, indicating that CpGV v-chiA is able to compensate for the absence of its BmNPV counterpart. Our data suggest that the molecular interaction between V-CHIA and V-CATH may be conserved across a broad range of lepidopteran GVs and NPVs.
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Affiliation(s)
- T Daimon
- Graduate School of Agricultural and Life Sciences, Department of Agricultural and Environmental Biology, The University of Tokyo, Tokyo, Japan
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Abstract
Insect viruses have evolved to counter physiological barriers to infection presented by the host insect. For the Lepidoptera (butterflies and moths), these barriers include (1) the peritrophic membrane (PM) lining the gut, which presents a physical barrier to virus infection of the midgut epithelial cells, (2) the basement membrane (BM) that overlies the gut thereby restricting secondary infection of other tissues, and (3) the immune system of the host insect. Hence, insect viruses provide a resource for genes that disrupt host physiology in a specific manner, and these genes in turn serve as a resource both for the study of physiological processes, and for disruption of these processes for pest management purposes. There are several examples of the application of genes used by an insect virus to overcome the PM barrier for production of insect-resistant transgenic plants. There are other examples of intrahemocoelic effectors, such as BM-degrading proteases that can only be used with an appropriate system for delivery of the agent from the gut into the hemocoel (body cavity) of the insect pest. In this chapter, we describe (1) baculovirus- and entomopoxvirus-derived genes that alter the physiology of the host insect, (2) use of these and homologous genes for production of insect-resistant transgenic plants, (3) other viral genes that have potential for use in development of insect-resistant transgenic plants, and (4) the use of plant lectins for delivery of intrahemocoelic toxins from transgenic plants. Plant expression of polydnavirus-derived genes is described by Gill et al. (this volume, pp. 393-426).
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Affiliation(s)
- Sijun Liu
- Department of Entomology, Iowa State University, Ames, Iowa 50011, USA
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Daimon T, Katsuma S, Kang W, Shimada T. Comparative studies of Bombyx mori nucleopolyhedrovirus chitinase and its host ortholog, BmChi-h. Biochem Biophys Res Commun 2006; 345:825-33. [PMID: 16701557 DOI: 10.1016/j.bbrc.2006.04.112] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Accepted: 04/18/2006] [Indexed: 11/18/2022]
Abstract
Baculovirus-encoded chitinases (V-CHIAs) were first proposed to be acquired from a bacterium via horizontal gene transfer. However, we have recently reported that lepidopteran hosts also encode v-chiA orthologs. Here we describe comparative studies of Bombyx mori nucleopolyhedrovirus (BmNPV) chitinase and its host ortholog, BmChi-h. We constructed recombinant BmNPVs in which native and modified forms of BmChi-h were driven under the polyhedrin promoter and the authentic v-chiA was deleted. Western blot analysis indicated that BmCHI-h was rapidly secreted from virus-infected BmN cells whereas BmNPV CHIA was localized within the virus-infected cells; probably because of the presence of a C-terminal endoplasmic reticulum retention motif on BmNPV CHIA. Enzymological studies showed that BmNPV CHIA was able to retain much higher chitinolytic activity under alkaline conditions. For B. mori larvae infected with v-chiA-deleted BmNPV, the terminal liquefaction of dead larvae and the activation of baculovirus-encoded cysteine protease were not observed, and the introduction of BmChi-h did not rescue these defects. Our findings show that BmNPV chiA possesses unique features that are not shared by host orthologs, which may reflect functional specialization of baculovirus chitinases.
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Affiliation(s)
- Takaaki Daimon
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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