Tuesday, November 6, 2007 - 3:30 PM
147-5
Expression Analysis of Defense-Related Genes in Wheat in Response to Infection by Fusarium graminearum.
Lingrang Kong, Department of Agronomy, Purdue University, 915 W. State St., West Lafayette, IN 47907, Herbert Ohm, Purdue University-Agronomy Dept., Purdue Univ.-Agronomy Dept., 1150 Lilly Hall Rm. 1-300, West Lafayette, IN 47907-1150, and Joseph Anderson, Department of Agronomy, USDA-ARS, Purdue University, 915 W. State St., West lafayette, IN 47907-2054.
Fusarium head blight (FHB), caused by Fusarium graminearum and Fusarium culmorum, is a worldwide disease of wheat (Triticum aestivum L.). GeneCallingTM was used to identify differentially expressed genes induced or suppressed in spikes after infection by F. graminearum in FHB-resistant wheat line Ning7840. 125 individual cDNA fragments representing transcripts differentially expressed in wheat spikes were identified. Putative functions were assigned to some of the genes: 28 were assigned function in primary metabolism and photosynthesis, seven were involved in defense response, 14 in gene expression and regulation, 24 encoded proteins associated with structure and protein synthesis, 42 lacked homology to sequences in the database, and three genes were similar to cloned multidrug resistance or disease resistance proteins. Of particular interest in this study were genes associated with resistance and defense against pathogen infection. Real-time quantitative reverse-transcription PCR indicated that of 51 genes tested, 19 showed 2-fold or greater induction or suppression in the FHB resistant line Ning7840 in contrast to the water-treated control. The remaining 32 genes were not significantly induced or suppressed in Ning7840 compared to the control. Subsequently, these 19 induced or suppressed genes were examined in the wheat line KS24-1 containing FHB resistance derived from Lophopyrum elongatum and Len, a FHB-susceptible wheat cultivar. The temporal expression for some of these genes encoding resistance proteins or defense-related proteins showed FHB resistance-specific induction, suggesting that these genes play a role in protection against toxic compounds in plant-fungal interactions. On the basis of comprehensive expression profiling of various biotic or abiotic response genes revealed by real-time PCR in this study and other supporting data, we hypothesized that the plant-pathogen interactions may be highly integrated into a network of diverse biosynthetic pathways. A virus-induced gene silencing (VIGS) system is being used for identification of genes contributing to FHB resistance.