RNA profiling of fusarium head blight-resistant wheat addition lines containing the Thinopyrum elongatum chromosome 7E†

Abstract

Fusarium graminearum is the major causal agent of fusarium head blight (FHB) of wheat, a fungal disease causing significant yield losses and reduction in grain quality due to the production and deposition of mycotoxins in the seed. Relatively few sources of resistance to FHB have been identified in wheat and other cereal crops. Thinopyrum elongatum (2n = 14, EE genome), a wild relative of wheat, was identified as a new source with a high level of resistance to FHB. Greenhouse inoculation experiments have determined that the resistance is located on the long arm of its chromosome 7E. To improve our understanding of the molecular mechanisms involved in that resistance, we have used gene expression profiling by microarray to compare the susceptible wheat ‘Chinese Spring’ (CS), with two resistant addition lines containing either the 7E chromosome or a long arm telocentric of that chromosome in the CS background. The results have shown that many genes were affected similarly by F. graminearum in the resistant and susceptible lines. Seventy genes were selected for further characterization. Those genes were grouped into five major expression patterns: genes expressed at higher or lower level in both F. graminearum- and water-treated samples in resistant lines, genes that were upregulated faster or to a higher level in resistant lines and genes that were downregulated more significantly in the susceptible line. Pathogenesis-related genes, genes from the phenylpropanoid pathway or from the jasmonic acid biosynthesis and signalling pathway, a group of kinase proteins and many other genes with unknown function are considered in this report.