The subtilisins of fungal pathogens of insects, nematodes and plants: distribution and variation

The extracellular subtilisin-like protease activity of several fungal patho gens of nematodes, insects and plants was recorded after batch cultivation Nematophagous and entomophagous isolates of Verticillium, Paecilomyces, Bea uveria and Metarhizium produced Suc(Ala)(2)-Pro-Phe-pNA hydrolysing enzymes that differed in serological properties based on Western blot analysis wit h polyclonal antibodies. The antibodies used were raised against the main s ubtilisin-like proteases from one species from each of the four genera. Fro m each strain of V, chlamydosporium tested, between one and four isoforms w ith different pi values were separated by isoelectric focusing and visualiz ed by enzymoblots. The occurrence of multiple isoforms with unique N-termin al sequences in single strains might suggest the presence of subtilisin gen e families. Using as a probe a fragment of the Pr1 gene from M. anisopliae, RFLPs were observed that confirmed qualitative differences between subtili sin-like genes within and between species. In contrast to these pathogens o f invertebrates, plant-pathogenic species of Verticillium did not produce s ubtilisin-like proteases, nor were homologous genes detected, Such activity , however, and the corresponding genes, were detected in species weakly pat hogenic to plants, or saprotrophs.