Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2006
Publication Date: 4/20/2007
Citation: Seong, K., Xu, J., Kistler, H.C. 2007. Genome-wide rna expression analysis during conidial maturation and germination in the filamentous fungus, fusarium graminearum. In: Proceedings of 8th European Conference on Fungal Genetics. Vienna, Austria, April 8-11. p. 95.
Technical Abstract: The fungal plant pathogen, F. graminearum, causes Fusarium head blight disease of wheat and barley. To understand the early infection cycle of this organism, we monitored the RNA expression profiles in newly formed spores (macroconidia), in maturing spores and during the early stages of spore germination using the 18 K probe set F. graminearum Affymetrix GeneChip. Surprisingly high expression levels of thousands of genes were found in spores, structures presumed to be metabolically quiescent. Positive signals for 6,384 probe sets were detected in newly formed spores and 2,916 probe sets were detected in spores that had been aged for ten days (detection p value <0.001), indicating that spores are metabolically active. Newly formed spores differentially accumulate RNAs corresponding to proteins responsible for peroxisomal '-oxidation and key components of the glyoxylate cycle as well as gluconeogenesis. Many genes encoding catabolic enzymes involved in glucose production, such as enzymes for degrading long-chain carbohydrates, also are expressed in young spores. A total of 1,257 probe sets were up-regulated more than 2-fold during spore maturation including genes predicted to be involved in detoxification, cell wall synthesis, and autophagocytosis. Several genes encoding putative transmembrane transporters were preferentially or uniquely expressed during spore maturation, suggesting their involvement with detection of spore activation signals or in uptake of nutrients in early germination stages. Upon spore activation, a total of 2,149 probe sets were up- or down-regulated more than 2-fold during the first two hours. Spore activation was associated with high expression levels of genes involved in protein synthesis, transcription, and basic primary metabolism. Inference from gene expression profiles at different spore developmental stages may be used to develop hypotheses for the mechanisms controlling the basic processes of spore maturation, dormancy and activation.