Resumo

The entomopathogenic fungus Beauveria spp. is currently used as an effective biological control agent against different insects. To evaluate Beauveria spp. as a bio-insecticide, it is important to investigate genetic variations among isolates. The present work aimed to study variations, genetic diversity and to know the genetic relationship among the population of Beauveria spp., composed of 73 isolates from different Brazilian regions, hosts and research institutes. The isolates were grown in oatmeal liquid medium to obtain mycelium which was used for DNA extraction. The characterization of microsatellite loci was performed with eight polymorphic SSRs markers and PCR reactions were performed for each locus. The product of these reactions was diluted and internal labeled with fluorescent marker-ROX, and then analyzed by capillary electrophoresis with alleles detection by fluorescence, in automatic analyzer. The size estimation of alleles in base pairs, the peak filtering and interpretation of data, defining the genotype of each individual, were performed with the GeneScan3.7 software and Genotyper2.0. The program STRUCTURE 2.3 provided the genetic organization of isolates and allocated in similar genetic groups. The program Arlequin 3.1 was used for molecular variance analysis (AMOVA) and fixation index (Fst). The structuring of variability was visualized by dendrograms constructed by genetic distance matrix, using the Similarity Coefficient Jacard and by the UPGMA grouping criteria in the PASTprogram. The eight SSR loci used allowed the detection of 42 haplotypes in the population, indicating high genetic diversity. Six main groups were identified. The AMOVA indicated that 74,69% of the total genetic variability was explained by the variation between groups, while the variance within groups accounted for only 25,31%. The Fst was 0,74, indicating that there was high genetic variability among isolates, especially among 6 formed groups. Results indicate a high capacity of SSRs markers for characterization of collections of isolates, genetic identity control and monitoring of biopesticides. The use of SSRs may become even greater national and government to record isolated and technical products or formulated products and monitor the biodiversity of Beauveria ssp. and their exploitation for the control of insect pests.