title: Identification of Spodoptera exigua nucleopolyhedrovirus genes involved in pathogenicity and virulence.
abstract: 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.
authors: Instituto de Agrobiotecnología, CSIC-UPNA, Avda de Pamplona 123, 31192 Mutilva, Spain; Laboratory of Virology, Wageningen University, Wageningen, The Netherlands.
authors: Amaya
authors: A
authors: Serrano
authors: Laboratory of Virology, Wageningen University, Wageningen, The Netherlands.
authors: Gorben P
authors: GP
authors: Pijlman
authors: Laboratory of Virology, Wageningen University, Wageningen, The Netherlands.
authors: Just M
authors: JM
authors: Vlak
authors: Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain.
authors: Delia
authors: D
authors: Muñoz
authors: Instituto de Ecología A.C., Xalapa, Veracruz 91070, Mexico.
authors: Trevor
authors: T
authors: Williams
authors: Instituto de Agrobiotecnología, CSIC-UPNA, Avda de Pamplona 123, 31192 Mutilva, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain. Electronic address: pcm92@unavarra.es.
authors: Primitivo
authors: P
authors: Caballero
mesh_terms: D000818:Animals; D002460:Cell Line; D004279:DNA, Viral / Q000737:chemistry; D055786:Gene Knockout Techniques; D005814:Genes, Viral / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D016297:Mutagenesis, Site-Directed; D017924:Nucleopolyhedroviruses / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D010572:Pest Control, Biological; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000821:virology*; D014774:Virulence / Q000235:genetics
chemical_list: D004279:DNA, Viral
keywords: Pathogenicity; SeMNPV; SeMNPV bacmid; Spodoptera exigua; Virulence