Fusarium graminearum is a broad host pathogen threatening cereal crops in 
temperate regions around the world. To better understand how F. graminearum 
adapts to different hosts, we have performed a comparison of the transcriptome 
of a single strain of F. graminearum during early infection (up to 4 d 
post-inoculation) of barley, maize, and wheat using custom oligomer microarrays. 
Our results showed high similarity between F. graminearum transcriptomes in 
infected wheat and barley spike tissues. Quantitative RT-PCR was used to 
validate the gene expression profiles of 24 genes. Host-specific expression of 
genes was observed in each of the three hosts. This included expression of 
distinct sets of genes associated with transport and secondary metabolism in 
each of the three crops, as well as host-specific patterns for particular gene 
categories such as sugar transporters, integral membrane protein PTH11-like 
proteins, and chitinases. This study identified 69 F. graminearum genes as 
preferentially expressed in developing maize kernels relative to wheat and 
barley spikes. These host-specific differences showcase the genomic flexibility 
of F. graminearum to adapt to a range of hosts.