Identification and Characterization of Wheat Genes Contributing in Plant Resistance to Fusarium graminearum and the Mycotoxin Deoxynivalenol

The disease Fusarium head blight and deoxynivalenol (DON), its associated mycotoxin, are major factors limiting cereal production, in particular wheat, worldwide. DON acts as a virulence factor that facilitates Fusarium graminearum colonisation of wheat head during the disease development. Using wheat genomic resources, functional genomics techniques and virus-induced gene silencing (VIGS), we found that heads with less expression of some of new genes developed more DON damage.

One example is an orphan gene identified to be taxonomically-restricted to the grass subfamily Pooidea. Expression analysis of the wheat genes and barley homologues shows a rapid up-regulation in plant tissues in response to the infection with Fusarium graminearum or DON. Using over-expressing transgenic wheat lines we present evidence that the wheat orphan gene is involved in plant resistance to Fusarium. Subcellular localization shows that the orphan protein fused to a fluorescent tag localised within punctate areas of the nucleus of wheat cells. We identify as interacting proteins a NAC-like transcription factor and TaKIN2, a wheat SnRK1 (SNF1-Related Kinase 1). This evolutionarily conserved energy sensor protein is central integrators of stress and energy signalling in plants. Interestingly silencing of SnRK1 genes in wheat or gene disruption of the homologous snf1 in yeast confer more susceptibility to the trichothecene DON and T-2 respectively. These results suggest a role of this protein kinase family in stress response induce by trichothecene. Moreover, this common role with the orphan protein in DON-induced bleaching tolerance and their physical interaction, propose that they act together in the same signaling pathway.