title: Iflavirus increases its infectivity and physical stability in association with baculovirus.
abstract: Virus transmission and the prevalence of infection depend on multiple factors, including the interaction with other viral pathogens infecting the same host. In this study, active replication of an iflavirus, Spodoptera exigua iflavirus 1 (order Picornavirales) was observed in the offspring of insects that survived following inoculation with a pathogenic baculovirus, Spodoptera exigua multiple nucleopolyhedrovirus. Tracking the origin of the iflavirus suggested the association of this virus with the occlusion bodies of the baculovirus. Here we investigated the effect of this association on the stability and infectivity of both viruses. A reduction in baculovirus pathogenicity, without affecting its infectivity and productivity, was observed when associated with the iflavirus. In contrast, viral association increased the infectivity of the iflavirus and its resistance to ultraviolet radiation and high temperature, two of the main factors affecting virus stability in the field. In addition, electron microscopy analysis revealed the presence of particles resembling iflavirus virions inside the occlusion bodies of the baculovirus, suggesting the possible co-occlusion of both viruses. Results reported here are indicative of facultative phoresis of a virus and suggest that virus-virus interactions may be more common than currently recognized, and may be influential in the ecology of baculovirus and host populations and in consequence in the use of baculoviruses as biological insecticides.
authors.affiliation: Department of Genetics, Universitat de València, Burjassot, Valencia, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI-BIOTECMED), Universitat de València, Burjassot, Valencia, Spain.
authors.forename: Agata K
authors.initials: AK
authors.lastname: Jakubowska
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra, Pamplona, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, Pamplona, Navarra, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Murillo
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra, Pamplona, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, Pamplona, Navarra, Spain.
authors.forename: Arkaitz
authors.initials: A
authors.lastname: Carballo
authors.affiliation: Instituto de Ecología AC , Xalapa , Mexico.
authors.forename: Trevor
authors.initials: T
authors.lastname: Williams
authors.affiliation: Laboratory of Virology, Dept. of Plant Sciences, Wageningen Agricultural University , Wageningen , Netherlands.
authors.forename: Jan W M
authors.initials: JW
authors.lastname: van Lent
authors.affiliation: Instituto de Agrobiotecnología, Universidad Pública de Navarra, Pamplona, Spain; Departamento de Producción Agraria, Universidad Pública de Navarra, Pamplona, Navarra, Spain.
authors.forename: Primitivo
authors.initials: P
authors.lastname: Caballero
authors.affiliation: Department of Genetics, Universitat de València, Burjassot, Valencia, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI-BIOTECMED), Universitat de València, Burjassot, Valencia, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Herrero
keywords: Baculovirus; Co-infection; Iflavirus; Insect virus; Virus parasitism; Virus–virus interaction