Oral Technical Session: Fungal-Host Transcriptomics

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Comparative analysis of Fusarium graminearum on two hosts using next generation sequencing.
H. E. SIMMONS (1), J. P. Dunham (2), G. P. Munkvold (1)
(1) Iowa State University, Ames, IA, U.S.A.; (2) University of Southern California, Los Angeles, CA, U.S.A.

Fusarium graminearum, the causative agent of Fusarium head blight, is an important fungal pathogen of wheat, barley and maize, which has recently emerged as an important pathogen on soybean. The pathogen not only reduces grain yields and quality, but also produces mycotoxins that have serious impacts on both human and animal health. The mechanism behind its emergence on soybean is not understood, but may be the result of environmental changes and/or pathogen population shifts (host-switching or a quantitative increase in virulence). In order to unravel the genetic underpinnings of this recent emergence we undertook next generation (Illumina) sequencing of seven cultures of F. graminearum collected from infected maize and soybean crops in Iowa. Three were isolated from maize in the 1990’s, three were isolated from soybean in 2007 and the last was isolated from maize in 2007. These data were aligned to the genome available from the Broad Institute using the alignment program GSNAP (Genomic Short-read Nucleotide Alignment Program), and variants were called using VCFtools. Analysis of the single polymorphism (SNP) data has revealed a significantly lower level of genetic diversity among the samples collected from maize compared to those collected from soybean (75% reduction), indicating the possibility that a host-switching event may have occurred. Further work to elucidate the function of these SNP’s is currently underway.