The ascomycete fungus Fusarium graminearum causes Gibberella stalk rot in maize and Fusarium head and seedling blight in wheat.Our global analysis of genes turned on during growth in three environments (maize, wheat, and a petri plate), showed that members of several functional categories of genes (including putative plant cell wall degrading enzymes, transcription factors and protein kinases) are similarly expressed in the two plant environments, while they are distinctly expressed in vitro.