Abstract
Four ascomycetous strains viz., Y371-Candida valdiviana, Y207-Saccharomyces kluyveri and two strains of Williopsis californica (Y2- and Y90), which appeared as sensitive in a previous research work (Mushtaq et al., 2010 & 2013) were used in this study to screen killer, sensitive and neutral phenotypes (Killer-Sensitive-Pattern, KSP) in 556 isolates of yeasts belonging to 89 species and 31 genera. Y207- S. kluyveri and Y371- C. valdiviana appeared most suitable strains to screen KSP in yeast species from all substrates as compared to Y90-W. californica which did not showed sensitivity against slime flux yeast isolates. Whereas, sensitive strain Y2-W. californica appeared sensitive against dairy and flowers’ nectar yeast isolates only. The phenomenon of killer activity appeared as strain character, however the ecological habitat was also found to play important role in determining the killer-sensitive pattern. The sensitive ascomycetous yeast strains Y207-S. kluyveri and Y2- W. californica from flowers’ nectar habitat appeared killer as compared to sensitive against yeast isolates from dairy products; whereas, Y90-W. californica which was originally isolated from dairy products appeared killer against isolates of different yeast species from flowers’ nectar. It is inferred that the killer sensitive pattern should by carefully studied using variety of ascomycetous and basidiomycetous sensitive and killer yeast strains from various ecological habitats for bio-typing yeast strains.
