Exploration of Sri Lankan soil fungi for biocontrol properties

Abstract

Sri Lankan soil is a rich source of fungi with new strains that are not well explored to date. In the present study, a total of 83 soil fungi were isolated from different locations of Sri Lanka using chitin and β-1,3-glucan selective media. Of the 83 isolates, 22 isolates showed high biocontrol activities against seven selected plant pathogenic fungi in dual culture plate assay. These 22 isolates were further analyzed for chitinase, glucanase production and for antifungal activities. Trichoderma sp. 1 showed significantly high mean chitinase (0.60±0.012 nkat/ml) and glucanase (0.42±0.031 nkat/ml) activities after 24 h and 96 h of incubation respectively compared to other isolates. Furthermore, it revealed the highest mean percentage (76.66±7.6) of inhibition against Phytophthora meadii in the well diffusion method using chitinase filtrates. Penicillium sp. 1 showed the highest mean percentage (64.75±1.6) of inhibition against Rigidoporus microporus in well diffusion method with glucanase filtrates. Three Trichoderma isolates that unveiled high enzyme activities as well as high antifungal activities were identified as Trichoderma erinaceum (Trichoderma sp. 1), Trichoderma virens (Trichoderma sp. 5) and Trichoderma asperellum (Trichoderma sp. 8) using molecular characterization.