title: Effects of double-stranded RNA in Metarhizium anisopliae var. acridum and Paecilomyces fumosoroseus on protease activities, conidia production, and virulence.
abstract: Isogenic strains (with and without dsRNA) of the entomogenous fungi Metarhizium anisopliae var. acridum and Paecilomyces fumosoroseus were investigated for correlation between the presence of dsRNA and the production of cuticle-degrading proteases that play an important role in host parasitism, total secreted protein, and conidia production. Similar levels of cuticle-degrading subtilisin-like (Pr1) protease were observed for isogenic strains of M. anisopliae var. acridum after growth in medium supplemented with the cuticle of the grasshopper Rhammatocerus schistocercoides. Similarly, no statistical differences were observed for protease production, detected using the chromogenic substrate azocasein. For P. fumosoroseus isogenic strains, no significant differences in protease activity were observed after growth in the presence of either Euschistus heros or Nezara viridula (Hemiptera: Pentatomidae) cuticle. Similarly, no statistical differences were observed in virulence against E. heros. A comparison of mean conidia production showed a significantly higher production in the dsRNA-free isogenic strains of M. anisopliae var. acridum. Although, for most of the fungal phenotypes analysed, no overt effects were associated with the presence of these dsRNA infections, the reduction in conidia production by the isogenic strains of M. anisopliae var. acridum with dsRNA suggested that it may not be entirely accurate to describe these infections as latent.
authors.affiliation: Departamento de Microbiologia, Universidade Estadual de Londrina, Brazil.
authors.forename: Patricia Vieira
authors.initials: PV
authors.lastname: Tiago
authors.forename: Maria Helena Pelegrinelli
authors.initials: MH
authors.lastname: Fungaro
authors.forename: Marcos Rodrigues
authors.initials: MR
authors.lastname: de Faria
authors.forename: Marcia Cristina
authors.initials: MC
authors.lastname: Furlaneto
mesh_terms: D000818:Animals; D002364:Caseins / Q000378:metabolism; D010450:Endopeptidases / Q000096:biosynthesis / Q000378:metabolism*; D005656:Fungal Proteins / Q000096:biosynthesis; D015966:Gene Expression Regulation, Fungal; D006110:Grasshoppers / Q000737:chemistry; D006430:Hemiptera / Q000737:chemistry; D006999:Hypocreales / Q000166:cytology / Q000378:metabolism / Q000472:pathogenicity / Q000821:virology*; D019476:Insect Proteins / Q000378:metabolism; D010143:Paecilomyces / Q000166:cytology / Q000378:metabolism / Q000472:pathogenicity / Q000821:virology*; D012330:RNA, Double-Stranded / Q000235:genetics / Q000502:physiology*; D013172:Spores, Fungal / Q000254:growth & development; D014774:Virulence
chemical_list: D002364:Caseins; D005656:Fungal Proteins; D019476:Insect Proteins; D012330:RNA, Double-Stranded; C026018:azocasein; C047663:cuticle proteins, insects; D010450:Endopeptidases