Submitted to: Journal of Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/6/2008
Publication Date: 12/1/2008
Citation: Pasquali, M., Lysoe, E., Seong, K., Xu, J., Ma, L., Kistler, H.C. 2008. Global Gene Expression During Plant Infection and Toxin Biosynthesis in Fusarium graminearum [abstract]. Journal of Phytopathology. 90(3):S3.11-12.
Technical Abstract: To understand trichothecene accumulation and the infection cycle of the head blight pathogen F. graminearum sensu stricto, fungal gene expression profiles were monitored during plant infection using the F. graminearum Affymetrix GeneChip. Strains containing mutations in genes for three transcription factors were found to control trichothecene accumulation in planta and pathogenicity. Expression profiles were compared between wildtype and these mutants during infection of wheat. Mutants deleted for the StuA gene were greatly decreased in sporulation and produced no perithecia in culture. Unlike 'stuA mutants in F. oxysporum, F. graminearum 'stuA mutants were greatly reduced in pathogenicity. Reduced pathogenicity may be due to decreased trichothecene levels in planta, which in the mutant were <1% the levels of wildtype. Levels of transcripts corresponding to Tri5, but not other genes involved trichothecene biosynthesis, were extremely diminished in the 'stuA mutant. Thus both sporulation and trichothecene synthesis may be regulated under the control of StuA. Mutants deleted for the transcription factors Tri6 and Tri10 also were diminished for both trichothecene accumulation and pathogenicity to wheat. Largely overlapping sets of approximately 200 genes were altered in expression = two-fold in either 'tri6 or 'tri10 strains. In addition to genes responsible for trichothecene biosynthesis, genes involved in primary metabolism and transport also were significantly regulated by Tri6 and Tri10. A model for global regulation and cross pathway control of sporulation, mycotoxin biosynthesis and pathogenicity will be presented.