title: Horizontal transfer and hypovirulence associated with double-stranded RNA in Beauveria bassiana.
abstract: Beauveria bassiana strains from different hosts and geographic origins were assayed for the presence of double-stranded RNA (dsRNA). Two of them (15.4%) showed extra bands, with approximately 4.0-3.5 kb and 2-0.7 kb, respectively, after electrophoretic separation of undigested nucleic acids. Virus-like particles were approximately 28-30 nm diam. The dsRNA was maintained after conidiogenesis (vertical transmission) and was transmitted horizontally by hyphal anastomosis. Strains purged of dsRNA obtained after cycloheximide treatment showed increased conidial production when compared with strains carrying dsRNA particles. Bioassays demonstrated hypovirulence associated with dsRNA. The mean mortality against the insect Euschistus heros was reduced in strains containing dsRNA when compared with the isogenic dsRNA-free ones.
authors.affiliation: Universidade Federal do Paraná, Departamento de Patologia Básica, Rua Lourenco Mourão, 57 Seminário, Curitiba CEP 81531-990, Brazil. pdalzoto@terra.com.br
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Dalzoto
authors.forename: Chirlei
authors.initials: C
authors.lastname: Glienke-Blanco
authors.forename: Vanessa
authors.initials: V
authors.lastname: Kava-Cordeiro
authors.forename: Juliana Z
authors.initials: JZ
authors.lastname: Ribeiro
authors.forename: Elliot Watanabe
authors.initials: EW
authors.lastname: Kitajima
authors.forename: João Lúcio
authors.initials: JL
authors.lastname: Azevedo
mesh_terms: D000818:Animals; D052982:Beauveria / Q000472:pathogenicity* / Q000648:ultrastructure / Q000821:virology*; D003850:Deoxyribonuclease I / Q000378:metabolism; D007313:Insecta; D046529:Microscopy, Electron, Transmission; D012327:RNA Virus Infections / Q000821:virology*; D012328:RNA Viruses / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism / Q000648:ultrastructure; D012330:RNA, Double-Stranded / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism / Q000648:ultrastructure; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D012259:Ribonuclease, Pancreatic / Q000378:metabolism; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D014774:Virulence
chemical_list: D012330:RNA, Double-Stranded; D012367:RNA, Viral; D003850:Deoxyribonuclease I; D012259:Ribonuclease, Pancreatic; D015719:Single-Strand Specific DNA and RNA Endonucleases