Characterization of a wheat transcription factor, TaWRKY45, and its effect on Fusarium head blight resistance in transgenic wheat plants

The WRKY transcription factors belong to a lame protein family characterized by the conserved WRKY domain. These factors have been identified to play biological functions in various plant developmental processes. WRKY proteins are also known to be involved in regulating plant responses to pathogen attack and stress-related hormones. In this study, we report the isolation and characterization of the gene (TaWRKY45) for the wheat WRKY45 transcription factor. Amino acid sequence alignment and phylogenetic analyses demonstrated that the TaWRKY45 protein is orthologous to rice OsWRKY45. Our analysis of its expression in wheat indicated that TaWRKY45 was constitutively expressed in various organs and throughout the lifetime of the plant. We observed that TaWRKY45 was upregulated in response to benzothiadiazole (BTH), a plant immune system strengthner, and Fusarium graminearum, which is a causal fungus for Fusarium head blight (FHB). The constitutive overexpression of the TaWRKY45 transgene conferred an enhanced resistance against F. graminearum to transenic wheat plants grown under greenhouse conditions. These results indicate that TaWRKY45 is involved M the defense systems for the biotic stressors in wheat and that it may be potentially utilized to improve the disease resistance of wheat.