Entomophaga grylli Enzyme Polymorphism as a Technique for Pathotype Identification1

Abstract

The grasshopper pathogen Entomophaga grylli was found to have two pathotypes. Pathotype 1 is characterized by a typical entomophthoralean life cycle with conidia and resting spore states. It has been identified from field populations of Camnula pellucida and Dissosteira carolina and from laboratory infection of Locusta migratoria. Occasionally it has been isolated from Melanoplus spp. Pathotype 2 is known so far only from Melanoplus spp. and lacks the conidial cycle both in the laboratory and under field conditions. Laboratory studies have shown that these pathotypes will not readily cross-infect hosts. Isozyme analysis has likewise identified two distinct groups. Isolates within each group show identical banding patterns for nine enzymes (nine presumptive structural gene loci) without any correspondence between groups. Except for four isolates, both enzyme groups and pathotypes correspond. The degree of genetic difference between these two groups based on life cycle and isozyme studies suggests that they are not members of the same species.