Our research is primarily directed towards understanding the biochemistry and molecular biology of entomopathogenic fungi with the aim of using them as a source of innovation for the agricultural industries. Many of our studies have employed the insect pathogenic fungus Metarhizium anisopliae as a model for understanding how fungi respond to changing environments, initiate host invasion, colonize insect tissues, and counter host immune responses. The identification and characterization of fungal toxic products, which are often specific to particular biochemical/organ systems in the insect, has provided a vast resource of genes which we are employing to enhance the pathogenicity of insecticidal fungi and viruses, and to produce insect-resistant plants. By comparing genic content and gene expression patterns in ecologically divergent strains of M. anisopliae we are also addressing the origins of intraspecific differences (gene loss/gain, modulation of gene expression) and the mechanisms by which novel pathogens emerge. In terms of Metarhizium biology (specifically) and pathogenic fungi (in general) this approach is providing great insight into: 1) the number, nature and networking of genes that regulate and execute infection processes, 2) factors contolling aggresiveness and the evolution of specificity, and 3) is identifying key factors for precision alterations of pathogen performance. In terms of broader impact genetic variation is proving a powerful tool to study host switching and the molecular basis of adaptation (one of the "Holy Grails" of evolutionary biology) of pathogens.