ARS | Publication request: Gene Expression Profiling and Functional Analysis of Spore Germination in Fusarium graminearum

Submitted to: Journal of Phytopathology
Publication Type: Abstract
Publication Acceptance Date: June 30, 2008
Publication Date: December 1, 2008
Citation: Pasquali, M., Seong, K., Dong, Y., Kistler, H.C. 2008. Gene Expression Profiling and Functional Analysis of Spore Germination in Fusarium graminearum. Journal of Phytopathology. 90:S3.27.

Technical Abstract: A full genome study on conidia and ascospores has been carried out using F. graminearum Affymetrix GeneChips to compare gene expression during germination in complete medium at 0, 2, 8, 24 hours and after 10 days of drought stress. The total number of genes detected in at least one time point was similar. The majority of genes that are annotated with known function have a common expression pattern in both conidia and ascospores. Genes involved in primary metabolism and energy production are expressed similarly in conidia and ascsospores, indicating shared fundamental biological processes during germination of these different spore types. Interestingly the greatest differences in gene expression between conidia and ascospores were found upon dessication. Desiccated ascospores contained 6,801 (p<0.001) expressed genes, a surprisingly high number (similar to the other germination stages) compared to the 2,915 genes expressed in desiccated conidia (p<0.001). Gene expression changes reflect, and to a certain degree, probably determine differences in the biological behaviour of the spore types: desiccated ascospores are more viable and pathogenic on wheat than conidia after drought stress. Moreover expression profiles of ascospore and conidial germination showed some unique patterns of genes (some perhaps likely determinative of particular developmental states for each spore type). To identify genes with functional consequence in spores, a transcription factor (FgStuA) was observed to be constitutively expressed in all stages, but in ascospores transcript levels were at least 2 fold more than in conidia. Site-specific mutagenesis showed that FgStuA has a crucial role in both conidiation and perithecium development as well as in other cellular activities.