|Kistler, H - Corby|
Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2010
Publication Date: 1/1/2011
Publication URL: http://hdl.handle.net/10113/48516
Citation: Wang, Y., Liu, W., Hou, Z., Wang, C., Zhou, X., Jonkers, W., Ding, S., Kistler, H.C., Xu, J. 2011. A novel transcriptional factor important for pathogenesis and ascosporogenesis in Fusarium graminearum. Molecular Plant-Microbe Interactions. 24(1):118-128. Interpretive Summary: Fusarium head blight is one of the most important diseases of wheat and barley world-wide. Effective control measures for the disease are not currently available. We seek to develop new principles and measures for disease management by learning more about the spread and pathogenic adaptation of the fungus causing the disease. A new gene for a "master switch" controlling pathogenicity in the fungus was discovered by this work. Further knowledge of the genetic basis for pathogenicity may be used to develop alternative approaches to disease management and control. This information will be helpful to plant improvement specialists who are working to develop plants resistant to these pathogens or for developing novel strategies for disease control.
Technical Abstract: Fusarium head blight or scab caused by Fusarium graminearum is an important disease of wheat and barley. The pathogen not only causes severe yield losses but also contaminates infested grains with mycotoxins. In a previous study we identified several pathogenicity mutants by random insertional mutagenesis. One of these mutants was disrupted in the ZIF1 gene, which encodes a b-ZIP transcription factor unique to filamentous ascomycetes. The zif1 mutant generated by gene replacement was significantly reduced in DON production and virulence on flowering wheat heads. It was defective in spreading from inoculated florets to the rachis and other spikelets, and had a disease index less than 1. Deletion of the ZIF1 ortholog MoZIF1 in the rice blast fungus also resulted in reduced virulence and invasive growth. In addition, the zif1 mutant is defective in sexual reproduction. Although it had normal male fertility, when selfed or mated as the female in outcrosess, the zif1 mutant produced small, pigmented perithecia that were sterile (lack of asci and ascospores), suggesting a female-specific role for ZIF1 during fertilization or ascus development. Similar female-specific defects in sexual reproduction were observed in the Mozif1 mutant. When mated as the female, the Mozif1 perithecia failed to develop long necks and asci or ascospores. The ZIF1 gene is well conserved in filamentous ascomycetes, particularly in the b-ZIP domain, which is essential for its function. Expression of ZIF1 in Magnaporthe oryzae complemented the defects of the Mozif1 mutant. These results indicate that this b-ZIP transcription factor is functionally conserved in these two fungal pathogens for plant infection and sexual reproduction.