CLONING OF A CUTICLE-DEGRADING PROTEASE FROM THE ENTOMOPATHOGENIC FUNGUS, BEAUVERIA-BASSIANA

A Beauveria bassiana extracellular subtilisin-like serine endoprotease is a potential virulence factor by virtue of its activity against ins ect cuticles. A cDNA clone of the protease was isolated from mycelia o f B. bassiana grown on cuticle/chitin cultures. The amino acid sequenc e of this gene was compared to that of Metarhizium anisopliae Prl, the only pathogenicity determinant so far described from an entomopathoge nic fungus, and proteinase K, isolated from Tritirachium album, a sapr ophytic fungus. The cDNA sequence revealed that B. bassiana Prl is syn thesized as a large precursor (M(r) 37460) containing a signal peptide , a propeptide and the mature protein predicted to have an M(r) of 26 832.