title: Characterization of mycoviruses and analyses of chitinase secretion in the biocontrol fungus Metarhizium anisopliae.
abstract: Metarhizium anisopliae is the best-characterized entomopathogen and is used to control insect pests in sugar cane plantations in Brazil on a commercial scale. We have previously reported the infection of some M. anisopliae strains by dsRNA mycoviruses. Here we describe the purification and characterization of the viruses (MaV-A1, MaV-M5, MaV-RJ) in terms of dsRNA content, capsid proteins, electron microscopy, Western blot, and hybridization patterns. One spontaneous mutant lost some of the high molecular weight dsRNA components and showed significant alterations in colony morphology and spore production, suggesting that viral genes interfere with fungal phenotype. A comparison between dsRNA mycovirus-free and infected M. anisopliae isolates showed that virus-free isolates have increased endochitinase secretion. By comparing the following parameters: the buoyant density in CsCl of the presumed virions; the number and estimated molecular weight of the dsRNA components and the molecular mass of the capsid proteins to other mycoviruses previously described, we suggest the inclusion of MaV-A1 and MaV-M5 in the family Totiviridae and MaV-RJ in the family Partitiviridae.
authors.affiliation: INTA, Instituto de Fitopatología y Fisología Vegetal, Camino 60 cuadras, Km 51/2, (5119) Córdoba, Argentina.
authors.forename: María
authors.initials: M
authors.lastname: De La Paz Giménez-Pecci
authors.forename: Maurício R
authors.initials: MR
authors.lastname: Bogo
authors.forename: Lucélia
authors.initials: L
authors.lastname: Santi
authors.forename: Caroline Kriger de
authors.initials: CK
authors.lastname: Moraes
authors.forename: Cláudia Tatiana
authors.initials: CT
authors.lastname: Corrêa
authors.forename: Marilene
authors.initials: M
authors.lastname: Henning Vainstein
authors.forename: Augusto
authors.initials: A
authors.lastname: Schrank
mesh_terms: D000914:Antibodies, Viral / Q000097:blood; D015153:Blotting, Western; D001938:Brazil; D036022:Capsid Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002688:Chitinases / Q000378:metabolism*; D008854:Microscopy, Electron; D003904:Mitosporic Fungi / Q000201:enzymology* / Q000821:virology*; D009693:Nucleic Acid Hybridization; D010572:Pest Control, Biological; D012328:RNA Viruses / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000914:Antibodies, Viral; D036022:Capsid Proteins; D012367:RNA, Viral; D002688:Chitinases