Expression if the insect metalloproteinase inhibitor IMPI in the fat body of Galleria mellonella exposed to infection with Beauveria bassiana

The inducible metalloproteinase inhibitor (IMPI) discovered in Galleria mellonella is currently the only specific inhibitor of metalloproteinases found in animals. Its role is to inhibit the activity of metalloproteinases secreted by pathogenic organisms as virulence factors to degrade immune-relevant polypeptides of the infected host. This is a good example of an evolutionary arms race between insect hosts and their natural pathogens. In this report, we analyze the expression of genes encoding an inducible metalloproteinase inhibitor (IMPI) in fat bodies of the greater wax moth larvae Galleria mellonella infected with an entomopathogenic fungus Beauveria bassiana . We use natural infection i.e. covering larval integument with fungal aerospores as well as injection of fungal blastospores directly into the larval hemocel. We compare the expression of IMPI with the expression of genes encoding proteins with fungicidal activity, gallerimycin and galiomycin, the expression of which reflects the stimulation of Galleria mellonella defense mechanisms. Also, the expression of the genes is analyzed in the light of survival of animals after spore injection.