Insect cuticle-degrading enzymes from the entomogenous fungus Beauveria bassiana

Abstract

Beauveria bassiana is a promising agent for biological control of agricultural insect pests. Its broad host range includes both the Greater Wax Moth ( Galleria mellonella) and the cabbage looper ( Trichoplusia ni). Five strains of B. bassiana from the Agricultural Research Service Culture Collection were obtained and grown on defined media and a medium containing purified cuticle from either G. mellonella or T. ni. The production of cuticle-degrading enzymes (such as proteases, chitinases, and esterase) was examined. Natural strain variability in enzyme levels was significant, and there was no evidence of coordinated expression. Further, enzyme expression differed considerably as a function of cuticle source. The results suggest that it may be possible to tailor biological control agents against specific targets. Natural strain variability could be used to rationally develop improved mycoinsecticides.