ISOLATION, IDENTIFICATION AND PATHOGENICITY ASSESSMENT OF A NEW ISOLATE OF ENTOMOPATHOGENIC FUNGUS, BEAUVERIA BASSIANA IN IRAN

摘要

A new isolate (BEH) of entomopathogenic fungus, Beauveria bassiana was isolated from soil using DOC2 selective medium. This isolate was characterized by conidiophores consisting of whorls and dense clusters of short conidiophorous cells with one-celled spherical conidia. Conidial length and width were 2.27 +/- 0.22 mu m and 1.85 +/- 0.32 mu m, respectively with length/width ratio of 1.23. Colonies on SDYA medium were normally white to pale yellow and sometimes red pigmented in reverse. Because of importance of this pathogen in biocontrol programs around the world and difficulties with morphological identification, a molecular technique was developed to assist complementary identification of the fungus. Pr1, a pathogenicity-related alkaline cuticle-degrading serine protease, with defined sequence in B. bassiana was amplified using PCR technique. The presence of this gene in isolated fungus (BEH) with 744 bp sequence length, as visualized on agarose gel affirmed the data from morphological studies that the new isolate (BEH) pertained to entomopathogenic fungus, B. bassiana. Pathogenicity of new isolate against Tenebrio molitor and its recovering was the other confirmation that the isolated fungus belonged to B. bassiana, using further light microscope studies.