Ability to withstand ruminant gut passage of mutant strains of Verticillium chlamydosporium

Mutant strains of the fungus, Verticillium chlamydosporium, were generated by chemical mutant ethyl methane sulphonate and albendazole by random mutagenesis. These mutant strains (VC-ABZ and VC-EMS) were characterized for their chlamydospore forming ability, germination potential and survivability following ruminant gut passage. The wild strain of V. chlamydosporium could produce significantly increased numbers of chlamydospores (p<0.001) in millet grain culture as compared to that of the mutant strains. However, no significant differences (p>0.05) in the production of chlamydospores were observed between VC-ABZ and VC-EMS. Germination potential of wild strain was statistically superior (p<0.05) compared to other two mutant strains following the first day of plating. However, chlamydospores of all the three strains of V. chlamydosporium could germinate profusely by day 3 of plating onwards. It can be assumed from the present study that germination potential of chlamydospores of both wild and mutant strains of V. chlamydosporium was more or less similar. Both the wild strain and ABZ mutant strain had the ability to withstand anaerobic and enzymatic environment of ruminant gut and were excreted in the faeces of goats. However, EMS mutant strain could not withstand ruminant gut passage and thus could not be re-isolated from the faeces of goats.