Do entomotoxic protease inhibitors and lectins from higher fungi affect entomopathogenic nematodes?

Abstract: The control of soil insect pests in agriculture is becoming increasingly difficult due
to recent bans on several insecticides. An alternative and safer approach could be the
development of biopesticides based on entomotoxic defence proteins of higher fungi. Some of
them are currently being investigated for their potential use as biocontrol agents. Soil pests are also frequently controlled with biological control products based on entomopathogenic
nematodes. We wanted to know whether promising higher fungal proteins have negative effects on these nematodes. In laboratory bioassays, we tested the effect of six dietary protease inhibitors and 19 lectins from 15 different higher fungi of the Basidiomycota and Ascomycota on nematode survival and pathogenicity. The results indicate that most protease inhibitors and lectins have no detectable effects on the tested nematodes Heterorhabditis bacteriophora and Steinernema longicaudum. An exception in our experiments was the observed slightly negative effect of Marasmius oreades agglutinin (MOA) on the survival and pathogenicity of S. longicaudum, which was not observed in H. bacteriophora. In conclusion, it seems that the development of potential bioinsecticides based on lectins or protease inhibitors from higher fungi would be largely compatible with entomopathogenic nematodes. We will continue to investigate the entomotoxic proteins of higher fungi to provide the basis for the development of new biopesticides.