38th Annual Meeting of the Society for Invertebrate Pathology

Beauveria bassiana Bals. Vuillemin is the most popular among the registered mycoinsecticides. One of the principal reasons for its popularity is its very wide host range of ~750 insect species. Thus it can be used for management of the myriad insect pests of a crop plant. Identification of genes expressed during pathogen-host interactions (cuticular penetration) are of interest as they help to understand the genetic basis of pathogenecity and spot genes if any expressed during infection of particular insects. A study in this direction is being carried out taking the cue from the pathogenecity related genes identified in another entomopathogenic fungus Metarhizium anisopliae by St Leger et al (2003)(NCBI). Specific primers for 20 of the M. anisopliae pathogenicity genes and degenerate primers for four genes were designed. The presence of these genes in B. bassiana is confirmed through amplification from the DNA samples and sequencing of the amplified products. To facilitate the study of genes expressed during host-pathogen interactions, induction of appressoria (infection peg)in vitro is achieved through culture of the fungus on cuticle from different insects - Helicoverpa armigera, Spodoptera litura, Chilo partellus, Mylabris pustulata and Periplanata americana. The expression profile of the selected genes is being analysed through PCR amplification from the RNA samples obtained from cultures grown on different insect cuticles (as the sole nutrient source).