|PEROCHON, ALEXANDRE - University College Dublin|
|JIANGUANG, JIA - University College Dublin|
|KAHLA, AMAL - University College Dublin|
|ARUNACHALAM, C. - University College Dublin|
|Scofield, Steven - Steve|
|BOWDEN, SARAH - University College Dublin|
|WALLINGTON, EMMA - University College Dublin|
|DOOHAN, FIONA - University College Dublin|
Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2015
Publication Date: 12/1/2015
Citation: Perochon, A., Jianguang, J., Kahla, A., Arunachalam, C., Scofield, S.R., Bowden, S., Wallington, E., Doohan, F. 2015. TaFROG, a novel plant orphan gene, interacts with SnRK1 and enhances resistance to a mycotoxigenic fungus. Plant Physiology. 169(4): 2895-2906. doi: http://dx.doi.org/10.1104/pp.15.01056.
Interpretive Summary: Fusarium head blight (FHB) is perhaps the greatest disease threat for production of wheat and barley. It is caused by the fungus, Fusarium graminearum, which must produce the mycotoxin, deoxynivalenol (DON), to spread throughout the spikes of wheat and barley. This study demonstrates that a gene, designated as TaFROG, which was originally identified as being induced when wheat spikes are treated with DON, has the ability to increase FHB resistance when expressed at elevated levels in transgenic wheat. This work has significance for future efforts to develop wheat and barley with enhanced FHB resistance.
Technical Abstract: All genomes encode taxonomically restricted ‘orphan’ genes, most of which are of unknown function. We report the functional characterization of the orphan gene TaFROG as a component of the wheat resistance to the globally important Fusarium head blight (FHB) disease. TaFROG is taxonomically restricted to the grass subfamily Pooideae and gene expression studies showed that it is a component of the early wheat response to the mycotoxin deoxynivalenol (DON). DON is a virulence factor produced by the causal agent of FHB, Fusarium graminearum. The temporal induction of TaFROG by F. graminearum in wheat spikelets correlated with the activation of the classic defence gene Pr1a. But unlike Pr1a, TaFROG induction was dependent on toxin production by the fungus, as determined via comparative analysis of the effects of wild type fungus and a DON-minus mutant derivative. Using virus-induced gene silencing and overexpressing transgenic wheat lines, we present evidence that TaFROG contributes to host resistance to both DON and the fungus F. graminearum. TaFROG is an intrinsically disordered protein. At the subcellular level, it localised to the nucleus. A wheat alpha subunit of the Snf1-related kinase 1 (TaSnRK1a) was identified as a TaFROG interacting protein, based on a yeast-two hybrid study using a wheat cDNA expression library generated from DON-treated tissue. Yeast two-hybrid and bi-molecular fluorescence complementation assays confirm the interaction in yeast and in planta, respectively. Thus TaFROG is a new component of the SnRK1-mediated signaling pathway and is the first wheat orphan gene known to enhance biotic stress resistance.