TaFLRS, a novel mitogen-activated protein kinase in wheat defence responses

Plants respond to biotic and abiotic stresses through the activation and coordination of various signalling pathways. The activation often requires the phosphorylation of proteins. In this study, we have identified the wheat TaFLRS MAP kinase (Fusarium and Leaf Rust Sensitive) gene that was upregulated in a wheat EST (expressed sequence tag) array analysis following a wheat-leaf rust interactive challenge. Our results demonstrate that TaFLRS is transcriptionally upregulated in incompatible interactions involving wheat and leaf rust and Fusarium graminearum, suggesting that this MAPK maybe involved in defence responses to these wheat pathogens. RT-PCR revealed that TaFLRS transcript levels are not altered by salicylic acid (SA) treatment. However, immunoprecipitation and western blotting analysis show that phosphorylation of TaFLRS at the TEY motif was enhanced by SA in the Fusarium head blight (FHB) resistant cultivar Frontana following challenge with the FHB pathogen. The role of TaFLRS MAP kinase in defence responses in wheat is discussed.