Studies on strain improvement of predacious fungi: In vitro screening of mutant strains

Maximum growth of both albendazole and ethyl methane sulfonate mutants and the controls strains of Duddingtonia flagrans and Verticillium chlamydosporium was obtained in corn meal agar compared to any other media types. The next medium of their choice was potato dextrose agar. Both albendazole mutant and control D. flagrans exhibited similar and optimum growth at 26⁰C. However, the ethyl methane sulfonate mutant had lower growth profiles at 26⁰C. Consistently low growth profiles of both the mutants and the control D. flagrans were observed at 16⁰C and 40⁰C. Both albendazole and ethyl methane sulfonate mutants and control V. chlamydosporium exhibited similar growth profiles at 26⁰C. Consistently low growth profiles of both the mutants and the control V. chlamydosporium were observed at 16⁰C. Higher and optimum growth profiles of both the mutants and the control V. chlamydosporium were observed at 40⁰C. While a varied range of pH (pH 6.0–8.0) supported growth of mutants and control D. flagrans strains in terms of colony diameter, significantly increased colony diameter was observed at pH 7.0, particularly those of albendazole mutant and control D. flagrans. While least growth of all the strains was observed at pH 6.0, significantly increased growth of albendazole mutant and control D. flagrans was observed at pH 8.0. A varied range of pH (pH 6.0–8.0) supported growth of mutant strains and control V. chlamydosporium in terms of colony diameter. The albendazole mutant of D. flagrans behaved similarly as that of controls in terms of nematode-trapping ability following larval bait. However, the ethyl methane sulfonate mutant of D. flagrans doesn't show nematode trapping ability even by day 7 of larval bait. The albendazole mutant and control V. chlamydosporium appeared to be more vigorous in its egg parasitic ability compared to ethyl methane sulfonate mutant.