|Kistler, H - Corby|
Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2010
Publication Date: 4/1/2011
Citation: Li, Y., Wang, C., Liu, W., Wang, G., Kang, Z., Kistler, H.C., Xu, J. 2011. The HDF1 histone deacetylase gene is important for conidiation, sexual reproduction, and pathogenesis in Fusarium graminearum. Molecular Plant-Microbe Interactions. 24:487-496. Interpretive Summary: Annually, Fusarium head blight disease reduces the value of wheat and barley crops 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 novel gene for a “master switch” controlling the ability to reproduce and the ability to make toxins in the fungus was discovered by this work. Further knowledge of the genetic basis for toxin production may be used to develop alternative approaches to loss 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: Head blight caused by Fusarium graminearum is an important disease of wheat and barley. Its genome contains chromosomal regions with higher genetic variation and enriched for genes expressed in planta, suggesting a role of chromatin modification in the regulation of infection-related genes. In a previous study, the FTL1 gene was characterized as a novel virulence factor in the head blight fungus. FTL1 is homologous to yeast SIF2, which is a component of the Set3 complex. Many members of the yeast Set3 complex, including Hos2 histone deacetylase (HDAC), are conserved in F. graminearum. In this study, we characterized the HDF1 gene that is orthologous to HOS2. HDF1 physically interacted with FTL1 in yeast two-hybrid assays. Deletion of HDF1 resulted in a significant reduction in virulence and deoxynivalenol (DON) production. The hdf1 mutant failed to spread from the inoculation site to other parts of wheat heads or corn stalks. It was defective in sexual reproduction and significantly reduced in conidiation. Expression of HDF1 was highest in conidia in comparison with germlings and hyphae. Deletion of HDF1 also resulted in a 60% reduction in HDAC activity. Microarray analysis revealed that 149 and 253 genes were down- and upregulated, respectively, over fivefold in the hdf1 mutant. Consistent with upregulation of putative catalase and peroxidase genes, the hdf1 mutant was more tolerant to H2O2 than the wild type. Deletion of the other two class II HDAC genes had no obvious effect on vegetative growth and resulted in only a minor reduction in conidiation and virulence in the hdf2 mutant. Overall, our results indicate that HDF1 is the major class II HDAC gene in F. graminearum. It may interact with FTL1 and function as a component in a well-conserved HDAC complex in the regulation of conidiation, DON production, and pathogenesis.