RESUMO
Phenotypic and genetic estimations of entomopathogenic ascomycete B.bassiana (strain Sar-31) after 6-passaging through four hosts were shown. Increasing of virulence, changes in morpho-cultural characteristics and variations in Inter Simple Sequence Repeats (ISSR) assay between initial and reisolated cultures were registered. Six passages of entomopathogenic ascomycete Beauveria bassiana (strain Sar-31) through four hosts (Galleria mellonella, Tenebrio molitor, Leptinotarsa decemlineata, Locusta migratoria) and following estimation of phenotypic and genetic differences of the initial strain and reisolated cultures were conducted. The passaging of strain through certain host led to increasing of virulence for both this host and other test-insects. Unidirectional changes of morpho-cultural characteristics: colonies pigmentation and relief strengthening, increasing of conidia production and lipolytic activity were registered in all passaged cultures. Genetic analysis with 6 ISSR markers revealed variations between initial and reisolated cultures in 3 markers. Taken together, the results of this study help us understand potential ways of fungi strains changes during epizootic process and possibilities of ISSR assay applying for investigation of pathogen transmission.
Assuntos
Beauveria/genética , Beauveria/patogenicidade , Proteínas Fúngicas/genética , Especificidade de Hospedeiro , Esporos Fúngicos/genética , Esporos Fúngicos/patogenicidade , Animais , Beauveria/enzimologia , Beauveria/crescimento & desenvolvimento , Besouros/microbiologia , Proteínas Fúngicas/metabolismo , Marcadores Genéticos , Genótipo , Lipólise , Locusta migratoria/microbiologia , Repetições de Microssatélites , Mariposas/microbiologia , Fenótipo , Pigmentação/genética , Inoculações Seriadas , Esporos Fúngicos/enzimologia , Esporos Fúngicos/crescimento & desenvolvimento , Tenebrio/microbiologia , VirulênciaRESUMO
A synchronous coinfection of the Colorado potato beetle Leptinotarsa decemlineata (Say) with the entomopathogenic bacteria Bacillus thuringiensis ssp. morrisoni Bonnifoi & de Barjak var. tenebrionis Krieg et al. and hyphomycete Metarhizium anisopliae (Metsch.) Sorokin or Beauveria bassiana (Bals.) Vuill leads to the rapid death of 95-100% of larvae. The bacteria arrest the nutrition of insects, while the fungal spores kill the weakened larvae. The synergistic effect of two pathogens is recorded at a relatively low hyphomycete titer (1-5 x 10(6) conidia/ml) and is evident in the mortality dynamics at all larval ages. These bacterial and fungal pathogens display no antagonism on artificial nutrient media. This microbial complex is highly efficient under natural conditions (80-90% larval mortality rate and no plant defoliation).
