Screening of entomopathogenic fungi for chitinolytic activity

A survey for fungal entomopathoges was conducted in chilli growing fields of Karnataka. Thirteen fungi were isolated through soil baiting and foliage sampling, out of which, three isolates, viz., Fusarium isolate, Verticillium lecanii and Metarhizium anisopliae were screened for their chitinolytic activity using Monreal and Reese media and broth with colloidal chitin as the sole source of carbon.further, genomic DNA was isolated from all the three fungal isolates and were screened for the presence of chitinase gene by PCR with designed primers which were conserved for a 264bp fragment of endochitinase gene. The zone of hydrolysis of the respective fungi was not visible on agar medium due to confluent growth of mycelia. However broth cultures of all the three fungi produced a clear zone of hydrolysis and could completely clear the colloidal chitin present in the broth. It was observed that complete clearance of colloidal chitin in the broth was observed in Fusarium isolate at 8th day after inoculation. In case of Metarrhizium anisopliae and Verticillium a bit of turbidity was observed in the broth tubes. Lowest clearance of colloidal chitin was observed in the case of Verticillim and Metarrhizium and complete clearance of colloidal chitin was observed in the case of Fusarium isolate. The PCR study of the purified DNA of the Fusarium isolate, Metarhizium anisopliae and Verticillium showed that presence of chitinase gene in Metarhizium anisopliae and Verticillium, but not in Fusarium isolate