Genomic diversity in European Spodoptera exigua multiple nucleopolyhedrovirus isolates.
Key virus traits such as virulence and transmission strategies rely on genetic variation that results in functional changes in the interactions between hosts and viruses. Here, comparative genomic analyses of seven isolates of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) with differing phenotypes were employed to pinpoint candidate genes that may be involved in host-virus interactions. These isolates obtained after vertical or horizontal transmission of infection in insects differed in virulence. Apart from one genome containing a piggyBac transposon, all European SeMNPV isolates had a similar genome size and content. Complete genome analyses of single nucleotide polymorphisms and insertions/deletions identified mutations in 48 ORFs that could result in functional changes. Among these, 13 ORFs could be correlated with particular phenotypic characteristics of SeMNPV isolates. Mutations were found in all gene functional classes and most of the changes we highlighted could potentially be associated with differences in transmission. The regulation of DNA replication (helicase, lef-7) and transcription (lef-9, p47) might be important for the establishment of sublethal infection prior to and following vertical transmission. Virus-host cell interactions also appear instrumental in the modulation of viral transmission as significant mutations were detected in virion proteins involved in primary (AC150) or secondary infections (ME35) and in apoptosis inhibition (IAP2, AC134). Baculovirus populations naturally harbour high genomic variation located in genes involved at different levels of the complex interactions between virus and host during the course of an infection. The comparative analyses performed here suggest that the differences in baculovirus virulence and transmission phenotypes involve multiple molecular pathways.
Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais de Tours, UFR Sciences et Techniques, 37200 Tours, France.
Julien
J
Thézé
Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain.
Oihana
O
Cabodevilla
Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain.
Leopoldo
L
Palma
Instituto de Ecología AC, Xalapa, Veracruz 91070, Mexico.
Trevor
T
Williams
Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Navarra, Spain.|Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, 31192 Mutilva Baja, Navarra, Spain.
Primitivo
P
Caballero
Institut de Recherche sur la Biologie de l'Insecte, CNRS UMR 7261, Université François-Rabelais de Tours, UFR Sciences et Techniques, 37200 Tours, France.
Elisabeth A
EA
Herniou
D000818:Animals; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D016679:Genome, Viral; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
D004279:DNA, Viral; D014764:Viral Proteins; D037521:Virulence Factors