|Seong, Kye-Yong - PURDUE UNIVERSITY|
|Yao, Jiqiang - PURDUE UNIVERSITY|
|Xu, Jin-Rong - PURDUE UNIVERSITY|
Submitted to: Fungal Genetics Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2005
Publication Date: April 1, 2005
Citation: Seong, K.-Y., Yao, J., Kistler, H.C., Xu, J.-R. 2005. REMI mutagenesis and identification of infection defective mutants in wheat scab fungus Fusarium graminearum [abstract]. Fungal Genetics Newsletter. 52(Supplement):106. Technical Abstract: Fusarium graminearum is an important pathogen of small grains and maize in many areas of the world. Wheat scab (head blight), caused primarily by F. graminearum in North America, poses a major threat to wheat production. To better understand the molecular mechanisms of plant infection and virulence of F. graminearum, we used the REMI (Restriction-Enzyme Mediated Integration) approach to generate random insertional mutants. Eleven pathogenicity mutants were identified by screening 6,500 hygromycin-resistant transformants. In mutant M8, the transforming plasmid was integrated 110-bp upstream from the start codon of the cystathionine beta-lyase gene (CBL1). Gene replacement mutants deleted for CBL1 were also obtained. The cbl1 mutants were methionine autotrophic and significantly reduced in virulence, indicating that the methionine synthesis pathway is important for pathogenesis in F. graminearum. We also have identified genes disrupted by the transforming DNA in three other REMI mutants. In mutants M68, the transforming vectors were inserted in the NADH: ubiquinone oxidoreductase. The putative b-ZIP transcription factor gene ZIF1 and the transducin beta-subunit-like gene TBL1 disrupted in mutants M7 and M75, respectively, had no known homologs in filamentous fungi and were likely to be novel fungal virulence factors. Further characterization of ZIF1 and TBL1 genes are underway.