ARS | Publication request: Identification of Metarhizium anisopliae transcripts expressed during the fungus- insect interaction

Submitted to: Society for Invertebrate Pathology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 2, 2007
Publication Date: August 12, 2007
Citation: Donzelli, B., Krasnoff, S., Gibson, D.M., Vandenberg, J.D., Churchill, A. 2007. Identification of Metarhizium anisopliae transcripts expressed during the fungus- insect interaction. Society for Invertebrate Pathology Annual Meeting. p. 87.

Technical Abstract: The identification of genes contributing to the establishment and disease progression of entomopathogenic fungi within their insect hosts has been conducted to date largely using in vitro systems mimicking specific phases of the infection. We are exploring the use of in vivo techniques to identify fungal genes expressed during pathogenicity and involved in secondary metabolism using Metarhizium anisopliae and Spodoptera exigua as our model systems. One hypothesis-driven approach is to evaluate expression in vivo by RT-PCR of genes predicted to be involved in fungal secondary metabolism. Another unbiased approach is focused on developing cDNA enriched for fungal transcripts expressed during the infection process by using either suppression subtractive hybridization (SSH) or a modification of representational difference analysis (RDA). In both cases, tester cDNA was prepared from a pool of RNAs extracted from S. exigua larvae at multiple time points after inoculation with M. anisopliae. Driver cDNA was prepared from mock-inoculated S. exigua larvae collected at identical time points as for the tester cDNA. Subtraction/enrichment efficiency was tested using semi-quantitative PCR and revealed marked differences between the two techniques. These methods will be useful for the generation of pathogenicity-related cDNA libraries containing both fungal and insect-responsive transcripts.